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All goals

Peptides studied for immune defence, antimicrobial action, and immune regulation

The compounds in this library touch three different jobs the immune system does: killing microbes directly, backing up the body's own first-line defences, and keeping the response balanced so it neither underreacts nor overreacts. A few have been tested in people, but mostly for safety or in specific disease groups; the rest rest on animal, cell-culture, or reference-source evidence. None has been shown in a controlled trial to make a healthy person's immune system stronger or to prevent everyday illness.

The biology of this goal

The immune system works in layers. The outer layer is fast, general defence: barriers like skin and the wet linings of the gut, mouth, lungs and genital tract, plus small germ-killing molecules the body makes on those surfaces. Behind that sits a slower, targeted layer built around white blood cells called T-cells and B-cells that learn to recognise specific threats. A healthy response also needs a brake: signalling that switches inflammation off once a threat is handled, so the body does not damage its own tissue. The peptides here map onto these jobs — some are natural germ-killers, some tune the T-cell system, and some act mainly as the brake.

What the research supports

9 of 11 compounds considered

Elafin

Tier 1 · Human trials

The strongest source is a tier-1 review describing elafin's roles in human mucosal immunity, while the specific antimicrobial and antiviral findings come from animal and laboratory studies.

Elafin is a protein the body makes naturally in the skin, lungs and other wet linings. It blocks destructive enzymes that immune cells release during inflammation, and it can also kill bacteria and fungi directly.

  • A review of mucosal biology reports that elafin has antimicrobial function and modulates both innate and adaptive immunity.3

  • Laboratory work found elafin and related inhibitors have defensin-like antimicrobial activity against bacteria, fungi and potentially HIV, and elafin cleared Pseudomonas aeruginosa in mice through a gene-transfer strategy.2

  • In cell and mouse studies, elafin and its precursor trappin-2 reduced herpes simplex virus-2 titres, with elafin about 7 times more potent than trappin-2 against HSV-2.1

What this doesn't establish

None of this shows that giving extra elafin strengthens immunity or prevents infection in people.

Lactoferrin

Tier 1 · Human trials

Human trials report that lactoferrin is safe and tolerable and that supplementation can improve immune biomarkers.

Lactoferrin is a natural defence protein found in milk, tears, saliva and immune cells. It fights microbes partly by locking away the iron they need to grow and partly by binding and disrupting their surfaces, and it also helps calm inflammation.

  • A randomised, double-blind, placebo-controlled trial found single and repeated intravenous doses of hLF1-11 up to 5 mg were tolerable in healthy volunteers, with a side-effect profile described as very favourable.4,5

  • Human lactoferrin is described as a natural defence protein with broad-spectrum antimicrobial activity whose N-terminal 11-amino-acid fragment is essential for antimicrobial and anti-inflammatory activity.5,4

  • In a systematic review and meta-analysis, 8 of 13 studies reported improvement in at least one biomarker of immune function following lactoferrin supplementation, and bovine lactoferrin is recognised as safe (GRAS) for several food uses in the US.6

What this doesn't establish

The human data cover safety and biomarker changes, not a proven reduction in infections or illness.

LL-37

Tier 2 · Preclinical

The strongest source is a tier-1 review of the cathelicidin family, with additional mechanistic detail from tier-2 reviews.

LL-37 is the only germ-killing cathelicidin peptide made by the human body. Because it carries a positive charge, it is pulled toward the negatively charged surfaces of bacteria, where it punches holes in them; it also helps coordinate the wider immune response.

  • A tier-1 review reports LL-37 has potent antimicrobial, antiviral, antifungal, antiparasitic and antitumour properties and serves as a key effector of innate immunity against gram-positive and gram-negative bacteria, fungi and viruses.7

  • LL-37 is the only identified human cathelicidin, profoundly affects both innate and adaptive immunity, and is being evaluated as a therapeutic in oral mucositis, cystic fibrosis and septic shock.8

  • Cathelicidins are described as major components of innate immunity, with LL-37 and its fragments playing a role in the immune response.9

What this doesn't establish

These are reviews of biology and drug candidacy — they do not establish that taking LL-37 strengthens a person's immune system.

Imunofan

Tier 2 · Preclinical

Human trials report that imunofan corrects immune abnormalities, but the studies are in specific disease populations rather than healthy people.

Imunofan is a synthetic peptide based on a fragment of thymopoietin, a natural thymus hormone that guides immune T-cells. It is described as an immunomodulator that nudges out-of-balance immune measures back toward normal rather than simply revving the system up.

  • A review reports imunofan can restore cell immunity, the neutrophil bactericidal system and antiviral antibody production, and that in complex therapy for chronic infections it enhances antiviral and antibacterial immunity and shortens symptoms.10

  • In a randomised study of 69 type 2 diabetes patients with diabetic foot syndrome, adding imunofan significantly normalised cellular and humoral immunity compared with basic therapy alone.11

  • In 89 patients with chronic suppurative otitis media after surgery, imunofan combined with myelopid restored T-helper, B-lymphocyte and phagocyte counts more effectively than antibacterial therapy alone.12

What this doesn't establish

It has not been tested for strengthening immunity in generally healthy individuals, and the trials are small and mostly Russian-language.

Thymulin

Tier 3 · Reported use

Evidence is mixed: a tier-1 review of thymic peptides and a tier-2 observational study support the biology, while the more specific immune claims come from tier-3 practitioner commentary.

Thymulin is a small hormone made by the thymus gland that helps immune T-cells mature and keeps the immune response balanced. It only works when bound to zinc, so its levels drop when the body is short of zinc or badly malnourished.

  • A tier-1 review reports thymic peptides stimulate T-cell differentiation and maturation, regulate NK and dendritic cells, and are used in neoplastic disease, viral infections, autoimmune disease and immunodeficiency.14

  • Practitioner commentary describes thymulin promoting T-cell differentiation, increasing NK cytotoxicity, balancing cytokines and enhancing antiviral immune responses.15

What this doesn't establish

There is no controlled human trial of thymulin itself for strengthening immunity, and several of the clinical claims are unverified practitioner statements.

Vilon

Tier 3 · Reported use

Animal and laboratory studies suggest immune effects, supported by tier-3 community and practitioner descriptions; there are no Western randomised controlled trials.

Vilon is one of the simplest possible peptides — just two amino acids (lysine and glutamic acid) — developed in the Soviet-era Khavinson bioregulator program. Its developers propose that, because it is so small, it can enter the cell nucleus and switch certain immune-related genes on or off.

  • Practitioner sources describe Vilon as an immune-targeted bioregulator that enters cells and nuclei, binds DNA promoter regions and modulates immune-cell gene expression, with rodent studies reporting improved CD4/CD8 ratios and innate immune markers.16

  • A database profile describes Vilon as a Lys-Glu dipeptide showing modest, receptor-independent immune signalling in THP-1 macrophages, with an overall evidence rating of 2/5 (preclinical/early).17

  • A peptide-therapeutics review lists immune modulation among the beneficial applications reported for peptide bioregulators.18

What this doesn't establish

The DNA-binding and gene-reactivation story is unconfirmed in humans, and almost all of the evidence comes from a single research group.

Alpha-MSH

Tier 2 · Preclinical

Antimicrobial activity is supported by tier-2 laboratory reviews, while a tier-1 animal study shows α-MSH can also suppress certain immune responses.

Alpha-MSH is a small natural hormone best known for driving skin tanning and calming inflammation. Researchers have also found it can kill some bacteria and fungi directly, sharing features with the body's germ-killing peptides.

  • A review reports α-MSH shares characteristics with antimicrobial peptides and has direct antimicrobial activity against fungal and bacterial pathogens, with its C-terminal residues showing activity parallel to the whole peptide.19

  • In a tier-1 mouse study, α-MSH acting on the MC5R receptor promoted myelopoiesis and immunosuppression that accelerated tumour growth, and an MC5R antagonist boosted antitumor immunity and anti-PD-1 immunotherapy.20

  • Preclinical findings suggest α-MSH downstream signalling may promote immune escape and cancer resistance to therapy.21

What this doesn't establish

The antimicrobial data are lab-level, and the same signalling can promote immunosuppression and tumour immune escape, so 'strengthening immunity' is not a straightforward claim for this peptide.

Selank

Tier 2 · Preclinical

A tier-1 clinical study noted antiviral effects as a secondary observation, while the immune-regulation findings come from tier-2 animal and review sources.

Selank is a lab-made seven-amino-acid peptide built from tuftsin, a natural immune-signalling fragment of human antibody. It is mainly studied as a calming and memory-supporting agent, but it also carries immune-modulating activity.

  • A review reports tuftsin, from which Selank is derived, is an immunomodulator that regulates the immune response against infections, and that tuftsin derivatives show antimicrobial activity.22

  • A clinical study of Selank in anxiety disorders reported that it has significant antiviral effects.23

  • In mice, Selank and its fragment Gly-Pro altered expression of genes mediating different immune responses in the spleen, described as maintaining immune-system balance.24

What this doesn't establish

The immune effects are secondary to Selank's main use as an anxiolytic, and there is no dedicated human trial testing it for immune strengthening.

KPV

Tier 3 · Reported use

Animal and laboratory studies suggest KPV has antimicrobial and anti-inflammatory activity.

KPV is a three-amino-acid fragment (Lys-Pro-Val) taken from the tail end of alpha-MSH. Most sources describe it as calming inflammation, and it has also shown the ability to kill bacteria and fungi directly.

  • KPV, the C-terminal tripeptide of α-MSH, showed antimicrobial activity against Staphylococcus aureus and Candida albicans across a broad range of concentrations including the physiological picomolar range, possibly by increasing cellular cAMP.25

  • KPV can bind MC-1R and modulate antigen-presenting cells, and researchers suggested KPV and KPV-pulsed dendritic cells may be useful in inflammatory, autoimmune and allergic diseases.26

  • KPV is taken into immune and intestinal epithelial cells via the PepT1 transporter, and oral KPV reduced inflammation in two mouse models of colitis.27

What this doesn't establish

There are no human trials; the antimicrobial and anti-inflammatory effects were shown in cell cultures and mouse models.

How they work together

These compounds split into two broad camps that can complement each other. Elafin, lactoferrin and LL-37 are frontline antimicrobial defences that kill or block microbes by different mechanisms — LL-37 punctures membranes, lactoferrin starves microbes of iron, and elafin shields tissue by inhibiting neutrophil enzymes — so pairing them broadens coverage rather than duplicating it. Alpha-MSH also adds antimicrobial and anti-inflammatory action through a separate melanocortin route, complementing all three. On the regulatory side, imunofan, thymulin and vilon all push the T-cell system back toward balance; because they converge on the same output, combining them is largely redundant — imunofan and thymulin in particular reach the same thymic endpoint, and imunofan and vilon overlap heavily. Thymulin and vilon are described as reasonably complementary if the aim is restoring aged or depleted immunity. KPV is essentially the anti-inflammatory tail of alpha-MSH, so stacking the two for inflammation is redundant; alpha-MSH simply adds pigmentation and appetite effects that KPV was designed to avoid. Selank sits mostly apart, with immune-balancing activity that can complement thymulin or vilon. Several pairs — for example alpha-MSH with selank or vilon, and selank with LL-37 or KPV — have no documented interaction in our data, which is an absence of evidence rather than a clearance.

  • Imunofan + Thymulin

    Worth caution — see why below

    Both are thymus-derived peptide hormones that normalize T-cell maturation, CD4/CD8 balance and NK cytotoxicity while dampening pro-inflammatory cytokines. Because they converge on the same thymic immune-tuning output, running them together is largely redundant rather than additive — pick one thymic immunomodulator rather than stacking two.

    Not fully established

    While both peptides share three approved tags (innate_immune, anti_inflammatory, T_cell_regulation) and produce overlapping functional outcomes (T-cell maturation, CD4/CD8 balance, NK enhancement, cytokine modulation), the mechanism descriptions reveal distinct molecular pathways that do not justify 'same_mechanism' classification. Imunofan targets thymopoietin receptors via adenylate/guanylate cyclase and PKC-dependent P-glycoprotein modulation, with antioxidant effects through ceruloplasmin-transferrin and glutathione systems. Thymulin operates through NF-κB and p38 MAPK inhibition with zinc-dependent metallopeptide activation and α7-nicotinic receptor potentiation. These are fundamentally different signaling cascades (cAMP/PKA vs. NF-κB/MAPK) with different receptor systems and cofactor requirements. Shared functional endpoints do not establish mechanistic equivalence. The claim that they are 'largely redundant' cannot be supported from the provided mechanisms—convergent outputs from divergent pathways typically allow complementary rather than redundant effects.
  • Imunofan + Vilon

    Worth caution — see why below

    Vilon is a Khavinson bioregulator that improves CD4/CD8 ratio, stimulates thymic/immune cell differentiation and suppresses TNF/IL-6, reaching the same immune-normalizing endpoint as imunofan but via a proposed gene/chromatin route rather than thymopoietin receptors. Overlapping goals mean modest additive value at best and heavy redundancy in immune correction.

    Not fully established

    Both peptides' mechanisms clearly establish the three shared dimensions. Imunofan targets thymopoietin receptors and normalizes CD4/CD8 ratios, enhances immune cell differentiation, and modulates TNF/IL-6 downward. Vilon improves CD4/CD8 ratio, stimulates thymic/immune cell differentiation, and suppresses IL-1β/IL-6/TNF-α. Both are tagged innate_immune, anti_inflammatory, and T_cell_regulation. The proposed relationship correctly identifies that despite different upstream mechanisms (receptor-mediated vs. proposed gene/chromatin), both converge on similar downstream immune-normalizing endpoints (CD4/CD8 correction, thymic stimulation, cytokine suppression). The 'same_downstream' classification is justified by the mechanism descriptions showing parallel functional outcomes in immune correction, even though the pathways diverge upstream.
  • Thymulin + Selank

    Worth caution — see why below

    Selank is built from tuftsin, an immune-signaling antibody fragment, and shares T-cell/cytokine-balancing and anti-inflammatory activity with thymulin. They modulate immunity through different mechanisms (thymic-hormone maturation vs. tuftsin-like Th1/Th2 balancing), so they can complement each other in immune normalization.

    Not fully established

    Both peptides' mechanisms clearly establish the claimed shared dimensions. Selank explicitly targets T_cell_regulation (approved tag) and anti_inflammatory (approved tag) via Th1-Th2 balancing and cytokine signaling. Thymulin explicitly targets T_cell_regulation (approved tag) and anti_inflammatory (approved tag) via T-lymphocyte maturation, CD4/CD8 modulation, and cytokine network suppression. The proposed relationship correctly identifies that they operate through distinct mechanistic pathways (thymic hormone maturation vs. tuftsin-derived immune signaling) while both converging on immune normalization endpoints. This mechanistic distinction without target overlap supports the complementary relationship claim.
  • Lactoferrin + Alpha-MSH

    Worth caution — see why below

    Lactoferrin defends against microbes largely by sequestering iron and binding microbial surfaces, and calms inflammation via immune modulation — a completely different route from alpha-MSH's melanocortin/NF-κB-based antimicrobial and anti-inflammatory action. The two converge on innate immune defense through non-overlapping mechanisms, which is the hallmark of a complementary combination.

    Not fully established

    Both peptides' mechanisms clearly establish the two shared dimensions claimed. Alpha-MSH achieves anti-inflammatory effects via NF-κB suppression and antimicrobial effects through melanocortin receptor signaling (approved tags: anti_inflammatory, antimicrobial). Lactoferrin achieves anti-inflammatory effects via immune modulation and antimicrobial effects via iron sequestration and microbial surface binding (approved tags: anti_inflammatory, antimicrobial). The mechanisms are indeed non-overlapping: Alpha-MSH operates through melanocortin receptors and NF-κB pathways, while Lactoferrin operates through iron binding, direct microbial surface interactions, and PI3K/Akt signaling. This represents convergence on shared functional outcomes (innate immune defense) through mechanistically distinct pathways, which justifies the 'complementary' relationship type.
  • Alpha-MSH + Elafin

    Worth caution — see why below

    Elafin protects tissue by inhibiting neutrophil serine proteases and dampening NF-κB, whereas alpha-MSH suppresses inflammation through melanocortin/cAMP signaling and NF-κB. Both also carry antimicrobial activity. These are different upstream mechanisms landing on the same goal of resolving inflammation and protecting mucosal/tissue surfaces, making them a complementary pairing.

    Not fully established

    Both peptides' mechanisms clearly establish the three claimed shared dimensions: (1) Anti-inflammatory: Alpha-MSH suppresses NF-κB via IκBα preservation and uses cAMP/PKA signaling; Elafin modulates NF-κB pathway directly. (2) Antimicrobial: Both explicitly list antimicrobial activity in their effects. (3) NF-κB modulation: Both have this as an approved tag and documented mechanism. The explanation correctly identifies that they achieve these outcomes through distinct upstream mechanisms (melanocortin/cAMP signaling vs. protease inhibition and direct pathway modulation), which is the hallmark of complementarity. The characterization as 'complementary' is justified—they target the same inflammatory/tissue-protective endpoints via different molecular pathways, supporting the proposed relationship type.
  • Alpha-MSH + LL-37

    Worth caution — see why below

    Both peptides fight microbes and modulate inflammation, but by different routes: alpha-MSH works through melanocortin receptors and NF-κB suppression, while LL-37 is a cationic cathelicidin that directly disrupts microbial membranes and signals through TLR/FPR2 pathways. Their distinct mechanisms converge on innate defense and tissue protection, so they are conceptually complementary rather than redundant.

    Not fully established

    Both peptides' mechanisms clearly establish the two shared dimensions. (1) Antimicrobial: Alpha-MSH has 'Antimicrobial' listed as a direct effect; LL-37 has 'Broad-spectrum antimicrobial' as a primary effect. (2) Anti-inflammatory: Alpha-MSH explicitly shows 'Anti-inflammatory / immunomodulatory' and 'NF-κB suppression'; LL-37 shows 'Immunomodulation (both anti- and pro-inflammatory)' and 'NF-κB signaling'. The explanation correctly identifies distinct mechanistic routes (melanocortin/NF-κB suppression vs. cationic membrane disruption/TLR-FPR2 signaling) that converge on overlapping functional outcomes. This is a valid characterization of complementarity—different pathways achieving related defensive and immunomodulatory effects without redundancy.
  • Alpha-MSH + KPV

    Worth caution — see why below

    KPV is literally the C-terminal three-amino-acid tail (Lys-Pro-Val) of alpha-MSH and carries over the parent hormone's anti-inflammatory action — stabilising IκBα and suppressing NF-κB. In fact KPV was developed as the anti-inflammatory 'business end' of alpha-MSH without the pigmentation and appetite effects. Stacking the two for inflammation is largely redundant because they push the same NF-κB brake; alpha-MSH just adds melanocortin-receptor effects (tanning, appetite) that KPV was designed to avoid. Choose based on whether you want those extra effects, rather than combining for additive anti-inflammatory benefit.

    Not fully established

    The mechanism descriptions clearly establish that both KPV and alpha-MSH share anti-inflammatory and NF-κB modulation pathways. KPV's mechanisms explicitly include NF-κB suppression via IκBα stabilisation and IKK complex inhibition. Alpha-MSH's mechanisms include NF-κB suppression and IκBα preservation. Both peptides are tagged with anti_inflammatory and NF_kB_modulation. The explanation that KPV is the C-terminal tripeptide fragment of alpha-MSH is consistent with the provided material (alpha-MSH is described as a 13-amino-acid peptide; KPV is Lys-Pro-Val). The claim that they share the same NF-κB-suppressive mechanism is directly supported by both peptides' documented pathways. The distinction that alpha-MSH engages multiple melanocortin receptors (MC1R, MC3R, MC4R, MC5R) while KPV's receptor engagement is contested/limited does not contradict the shared_mechanism relationship on the specified dimensions—it merely indicates KPV achieves similar anti-inflammatory effects through a narrower or different receptor profile. The proposed relationship focuses on the overlapping anti-inflammatory and NF-κB dimensions, which are clearly present in both mechanisms.
  • Vilon + LL-37

    Worth caution — see why below

    LL-37 is a human cathelicidin providing frontline antimicrobial and innate-immune signaling; Vilon supports adaptive/T-cell immunity via gene reactivation. They cover different arms of immunity, so they are complementary rather than redundant, though LL-37's context-dependent pro-inflammatory effects warrant monitoring.

    Not fully established

    The mechanisms clearly establish complementary roles in immunity. Vilon targets adaptive immunity (T-cell regulation, CD4/CD8 ratio improvement, thymus stimulation, age-silenced gene reactivation in lymphocytes) via receptor-independent chromatin remodeling and gene expression modulation. LL-37 targets innate immunity (antimicrobial activity, TLR/FPR2 signaling, neutrophil chemotaxis, NET promotion) via multiple cell-surface receptors. Both peptides modulate anti-inflammatory pathways (Vilon: IL-1β/IL-6/TNF-α suppression; LL-37: NF-κB and TLR signaling with documented anti-inflammatory effects), but through distinct mechanisms and immune arms. The shared tags (innate_immune, anti_inflammatory) are justified by their respective mechanisms, and the explanation accurately captures their non-redundant, complementary positioning—Vilon reactivates adaptive immunity while LL-37 provides frontline innate defense. The caveat about LL-37's context-dependent pro-inflammatory effects is supported by the mechanism description noting 'both anti- and pro-inflammatory' immunomodulation.
  • LL-37 + KPV

    Worth caution — see why below

    Both have reported antimicrobial and immune-modulating activity but by different means: LL-37 is a cathelicidin that directly disrupts microbial membranes and neutralises endotoxin, while KPV calms the downstream inflammatory response via NF-κB. Together they cover microbial killing plus inflammation control, though LL-37 can be pro-inflammatory and cytotoxic at higher concentrations, so this is a nuanced pairing.

    Not fully established

    Both peptides' mechanisms clearly establish the claimed shared dimensions. KPV demonstrates anti-inflammatory effects via NF-κB suppression (IκBα stabilisation, IKK inhibition, p65RelA nuclear import blocking) and antimicrobial activity (S. aureus, C. albicans in vitro). LL-37 demonstrates innate immune activation through multiple TLR and FPR2 pathways, antimicrobial activity (broad-spectrum bacteria, fungi, viruses), and NF-κB signaling, while also showing anti-inflammatory capacity (endotoxin neutralization). The proposed relationship correctly identifies mechanistic complementarity: KPV acts primarily on downstream inflammatory resolution (NF-κB modulation), while LL-37 combines direct antimicrobial disruption with immune cell recruitment and endotoxin neutralization. The caveat about LL-37's pro-inflammatory and cytotoxic effects at higher concentrations is explicitly supported by the mechanism description ('pro- and anti-inflammatory', 'cytotoxicity to human cells at higher concentrations'). The explanation accurately reflects the distinct pathways and their potential synergy without overstating the relationship.
  • Thymulin + Vilon

    May be complementary

    Both are thymus-linked immune bioregulators that push the immune system toward balance rather than pure stimulation. Vilon is reported to stimulate thymus tissue growth and improve CD4/CD8 ratios, while thymulin drives T-lymphocyte maturation and normalizes CD4/CD8 balance from the endocrine side. They approach the same immune-normalizing endpoint by different routes, which makes them reasonably complementary for restoring aged/depleted immunity.

    Not fully established

    The mechanisms clearly establish both peptides as immune modulators with overlapping functional outcomes. Both target thymic function (Vilon stimulates thymus tissue growth and differentiation; thymulin promotes T-lymphocyte maturation in thymic tissue), both modulate CD4/CD8 ratios (explicitly stated for both), both suppress excessive proinflammatory cytokines (IL-1β, IL-6, TNF-α suppression documented for both), and both engage NF-kB modulation (Vilon via gene expression modulation, thymulin via NF-kB inhibition). The four shared dimensions are directly supported by the provided mechanisms. The 'complementary' relationship type is justified: Vilon acts via receptor-independent chromatin remodeling and gene reactivation, while thymulin acts via cell-surface receptor binding and endocrine signaling—distinct mechanistic routes converging on immune normalization (T-cell balance, cytokine suppression, thymic function). This represents genuine complementarity rather than redundancy.
  • Lactoferrin + Elafin

    May be complementary

    Lactoferrin defends by sequestering iron away from microbes and calming inflammation, while elafin blocks neutrophil serine proteases. They are two arms of innate mucosal immunity working through different mechanisms toward the same goal of infection control and reduced inflammatory tissue damage.

    Not fully established

    Both peptides' mechanisms clearly establish the three claimed shared dimensions. (1) Innate_immune: Elafin targets neutrophil elastase and proteinase 3 (neutrophil serine proteases) and modulates NF-κB and IRF3/IFN-β antiviral signalling; Lactoferrin modulates inflammatory, humoral and cellular immune responses and has antiviral activity. (2) Antimicrobial: Elafin has documented antimicrobial activity against bacteria and fungi; Lactoferrin has broad-spectrum antimicrobial activity (antibacterial, antifungal). (3) Anti_inflammatory: Elafin is explicitly tagged anti_inflammatory with NF-κB pathway modulation; Lactoferrin is explicitly tagged anti_inflammatory with modulation of inflammatory immune responses. The explanation accurately describes their distinct mechanisms (iron sequestration vs. protease inhibition) converging on mucosal defense, which is consistent with the 'complementary' relationship type and the mechanisms provided. The proposed relationship is well-justified by the material.
  • Lactoferrin + LL-37

    May be complementary

    Both are frontline innate-immune defence peptides but attack microbes by different routes: LL-37 is a cationic peptide that punches holes in bacterial membranes, while lactoferrin starves microbes of iron and also binds their surfaces. Because the mechanisms differ, they can broaden antimicrobial coverage and both help calm inflammation — a classic complementary innate-immunity pairing seen naturally in neutrophils and mucosal fluids.

    Not fully established

    The mechanisms clearly establish both peptides as innate-immune antimicrobial agents with distinct modes of action. Lactoferrin targets iron binding and microbial cell-surface binding via cationic sequences, while LL-37 acts as a cationic peptide with membrane-disrupting capacity (implied by FPR2/TLR signaling and broad-spectrum antimicrobial effects). Both demonstrate anti-inflammatory activity (lactoferrin via PI3K/Akt/mTOR and immune modulation; LL-37 via NF-κB and TLR signaling). The proposed relationship correctly identifies mechanistically distinct but complementary antimicrobial pathways—iron starvation vs. membrane disruption—and both are documented to modulate inflammatory responses. The claim that they represent a natural pairing in neutrophils and mucosal fluids is consistent with their described roles in innate immunity. The three shared dimensions (antimicrobial, innate_immune, anti_inflammatory) are all supported by the provided mechanisms.
  • Elafin + LL-37

    May be complementary

    Both are human host-defense molecules but hit different targets: LL-37 is a cathelicidin that directly punctures microbial membranes, while elafin blocks the destructive enzymes (elastase, proteinase 3) that neutrophils release. Together they cover both direct killing and protection of the tissue from friendly-fire enzyme damage, converging on mucosal defense and repair.

    Not fully established

    The proposed relationship is well-justified by the mechanism material. Both peptides share the four claimed dimensions: (1) innate_immune—both are explicitly tagged and described as host-defense molecules with immune modulation roles; (2) antimicrobial—both have broad-spectrum antimicrobial activity documented; (3) anti_inflammatory—both are tagged and show anti-inflammatory effects; (4) tissue_repair—both are tagged with tissue repair/mucosal protection roles. The 'complementary' relationship type is strongly supported: the mechanisms show distinct but synergistic modes of action—LL-37 targets membrane receptors (FPR2, TLRs) and directly kills microbes, while elafin inhibits neutrophil serine proteases (elastase, proteinase 3) to prevent tissue damage. The explanation accurately reflects that they converge on mucosal defense through different mechanisms: direct antimicrobial activity versus protection from collateral enzyme damage. This is a textbook complementary relationship where both peptides address the same biological problem (mucosal defense) via non-overlapping mechanisms.
  • Elafin + KPV

    May be complementary

    Both dampen inflammation at mucosal surfaces largely by restraining NF-κB signaling, but by different means: KPV (an α-MSH fragment) suppresses inflammatory cytokines and stabilizes IκBα, while elafin blocks tissue-destroying proteases. In a gut/mucosal setting they address inflammation and barrier protection from complementary angles.

    Not fully established

    The mechanisms clearly establish complementary roles in mucosal inflammation control. Both peptides share three documented dimensions: (1) innate_immune function—elafin via protease inhibition and antimicrobial activity, KPV via immunomodulation and cytokine suppression; (2) anti_inflammatory effects—elafin through NF-κB modulation and tissue protection, KPV through TNF-α/IL-1β/IL-6 suppression; (3) NF-κB_modulation—elafin via NF-κB pathway modulation (src-17, src-23), KPV via IκBα stabilization and IKK complex inhibition. The explanation accurately characterizes their distinct mechanisms: KPV acts through cytokine suppression and IκBα stabilization, while elafin acts through protease inhibition and tissue protection. Both target mucosal barrier integrity and inflammation resolution in overlapping contexts (gut/mucosal surfaces), making them genuinely complementary rather than redundant. The proposed relationship type and shared dimensions are directly supported by the provided mechanism material.
  • Imunofan + Lactoferrin

    No known conflict in the research

    Lactoferrin adds broad-spectrum antimicrobial and iron-homeostasis activity plus immune/antioxidant modulation. Its mechanisms differ from imunofan's thymic pathway, so combining innate antimicrobial defense with imunofan's enhanced phagocytic and NK activity is a reasonable complementary immune-support pairing.

    Not fully established

    Both peptides' mechanisms clearly support the claimed complementary relationship with the three shared dimensions. Imunofan targets thymopoietin receptors to enhance T-cell development, NK cytotoxicity, phagocytic activity, and adaptive immunity (approved tags: innate_immune, anti_inflammatory, T_cell_regulation). Lactoferrin provides direct antimicrobial activity via iron binding and microbial cell-surface interactions, plus innate immune modulation (approved tags: innate_immune, anti_inflammatory, antimicrobial). Both demonstrate anti-inflammatory effects (TNF/IL-6 modulation for Imunofan; inflammatory response modulation for Lactoferrin) and antioxidant activity (glutathione/catalase pathways vs. ROS scavenging). The mechanisms are indeed distinct—Imunofan works through thymic hormone signaling and adaptive immunity enhancement, while Lactoferrin operates via direct antimicrobial binding and innate defense—making them mechanistically complementary rather than redundant. The explanation accurately reflects that combining Imunofan's enhanced phagocytic/NK activity with Lactoferrin's broad-spectrum antimicrobial and iron-homeostasis functions represents a reasonable pairing of adaptive and innate immune support.
  • Imunofan + Elafin

    No known conflict in the research

    Imunofan is a thymopoietin-based immunomodulator that boosts phagocytic/antimicrobial defenses and supports tissue repair, complementing elafin's antiprotease and antimicrobial actions. Different mechanisms supporting immune balance and mucosal repair.

    Not fully established

    Both peptides share the three claimed dimensions in their approved tags and mechanisms. Elafin targets neutrophil serine proteases and provides antimicrobial/tissue protection via protease inhibition and NF-κB modulation. Imunofan enhances phagocytic/bactericidal activity and tissue repair via thymopoietin receptor signaling and antioxidant pathways. Their mechanisms are distinct (protease inhibition vs. immune cell activation) yet both contribute to innate immunity, anti-inflammatory effects, and tissue repair. The 'complementary' relationship is justified: they operate through different pathways (Elafin: direct protease inhibition; Imunofan: immune cell enhancement and redox balance) to achieve overlapping functional outcomes in immune defense and tissue homeostasis.
  • Imunofan + Selank

    No known conflict in the research

    Selank (a tuftsin analog) has immunomodulatory and Th1/Th2-balancing, anti-inflammatory effects alongside its main anxiolytic/nootropic role. Its immune actions run parallel to imunofan's without sharing the same receptor, so the two could complement each other where mild immune modulation plus CNS support is the goal.

    Not fully established

    Both peptides' mechanisms clearly support anti-inflammatory and T_cell_regulation dimensions. Imunofan targets thymopoietin receptors and modulates Th1/Th2 balance with explicit TNF/IL-6 reduction and CD4/CD8 normalization. Selank targets GABAergic and serotonergic systems but its mechanisms include Th1-Th2 and interferon signaling pathways, plus immunomodulatory effects. The proposed relationship correctly identifies that they operate through distinct receptor systems (thymopoietin vs. GABA/5-HT/enkephalin) while both producing anti-inflammatory and T-cell regulatory outcomes. This non-overlapping receptor profile with parallel functional endpoints is a valid basis for calling them complementary rather than redundant. The explanation accurately reflects the mechanism material provided.
  • Imunofan + LL-37

    No known conflict in the research

    Imunofan bidirectionally normalizes immune function, boosts phagocytosis/NK activity and antioxidant defenses, and supports tissue repair, while LL-37 adds direct antimicrobial and TLR-based innate actions. Different mechanisms converging on immune balance and repair.

    Not fully established

    Both peptides' mechanisms clearly support the three claimed shared dimensions. (1) Innate_immune: LL-37 targets FPR2, TLRs, and promotes NETs/chemotaxis; Imunofan enhances phagocytic/bactericidal activity and NK cytotoxicity. (2) Anti_inflammatory: LL-37 shows immunomodulation with both pro- and anti-inflammatory effects; Imunofan explicitly modulates anti-inflammatory cytokines (reduced TNF, IL-6). (3) Tissue_repair: LL-37 promotes angiogenesis, wound healing, and keratinocyte migration; Imunofan stimulates fibroblast and keratinocyte proliferation. The explanation accurately characterizes their complementary nature—LL-37 provides direct antimicrobial/TLR signaling while Imunofan provides bidirectional immune normalization and antioxidant support—with both converging on innate immunity, inflammation control, and tissue repair. The mechanisms justify this relationship type and all three shared dimensions.
  • Imunofan + KPV

    No known conflict in the research

    KPV is a potent NF-κB-suppressing anti-inflammatory (lowering TNF-α, IL-1β, IL-6) with mucosal/antimicrobial activity, working through a different mechanism than imunofan's thymic immunocorrection. Both push toward calmer inflammation and better mucosal defense, making them a plausible complementary anti-inflammatory pairing.

    Not fully established

    Both peptides' mechanisms clearly establish the two shared dimensions. (1) Innate_immune: Imunofan enhances phagocytic/bactericidal activity of neutrophils and macrophages, and NK cell cytotoxicity; KPV shows antimicrobial activity and mucosal barrier repair. (2) Anti_inflammatory: Imunofan modulates anti-inflammatory cytokines (reduced TNF, IL-6); KPV suppresses TNF-α, IL-1β, IL-6 via NF-κB inhibition. The explanation correctly identifies mechanistic distinction (thymic immunocorrection vs. NF-κB suppression) and complementarity is justified: they target inflammation through different pathways (Imunofan via thymopoietin/cAMP-PKA/Th1-Th2 balance; KPV via NF-κB/MAPK) while both reducing pro-inflammatory cytokines and supporting innate immunity. The proposed pairing is well-grounded in the provided mechanisms.
  • Thymulin + Lactoferrin

    No known conflict in the research

    Thymulin fine-tunes T-cell maturation and dampens excess pro-inflammatory cytokines, while lactoferrin acts on the innate/antimicrobial front. Their immune roles are distinct but converge on balanced immune function, making them a plausible complementary immune-support pairing.

    Not fully established

    Both peptides' mechanisms clearly establish the claimed shared dimensions. Lactoferrin is explicitly tagged with innate_immune and anti_inflammatory, with documented effects including 'Anti-inflammatory and immunomodulatory activity' and 'Modulation of inflammatory, humoral and cellular immune responses.' Thymulin is similarly tagged innate_immune and anti_inflammatory, with effects including 'Suppresses excessive proinflammatory cytokine production' and 'Reported anti-inflammatory...effects.' The proposed relationship type 'complementary' is justified: lactoferrin operates through broad-spectrum antimicrobial activity and innate immune pathways (PI3K/Akt, ROS-mediated apoptosis), while thymulin operates through adaptive immune fine-tuning (T-cell maturation, CD4/CD8 balance, NF-kB/p38 MAPK inhibition). Their distinct mechanistic pathways converging on immune homeostasis and anti-inflammatory outcomes clearly supports a complementary relationship. The explanation accurately reflects the mechanism material provided.
  • Thymulin + Alpha-MSH

    No known conflict in the research

    Alpha-MSH suppresses NF-kB (preserving IkBα) and calms inflammatory cytokines through melanocortin receptors, a different upstream mechanism than thymulin's zinc-dependent immune regulation, but both converge on reduced inflammatory cytokine output.

    Not fully established

    Both peptides' mechanisms clearly establish anti-inflammatory and NF-kB modulation effects through distinct upstream pathways: Thymulin inhibits NF-kB and p38 MAPK while modulating cytokine networks (TNF-alpha, IL-1beta, IL-6) via zinc-dependent metallopeptide activation and T-cell regulation; Alpha-MSH suppresses NF-kB through IκBα preservation via melanocortin receptor signaling and cAMP/PKA pathway. The mechanisms describe different receptor systems and activation routes (zinc-dependent vs. melanocortin/cAMP-dependent) converging on the same downstream outcomes (NF-kB inhibition and reduced inflammatory cytokine production). This is a textbook complementary relationship—parallel anti-inflammatory effects achieved through mechanistically distinct pathways.
  • Thymulin + Elafin

    No known conflict in the research

    Thymulin normalizes T-cell balance and tamps down excess pro-inflammatory cytokines via NF-κB inhibition, while elafin controls neutrophil protease-driven tissue damage. They modulate adaptive and innate immunity from different angles toward a calmer, better-regulated immune response.

    Not fully established

    Both peptides' mechanisms clearly support the proposed complementary relationship across all three claimed shared dimensions. (1) Innate_immune: Elafin directly inhibits neutrophil serine proteases (elastase, proteinase 3) and shows antimicrobial activity; Thymulin enhances NK cell cytotoxicity and modulates innate responses. (2) Anti_inflammatory: Elafin is explicitly tagged anti_inflammatory with NF-κB pathway modulation; Thymulin suppresses excessive proinflammatory cytokine production (TNF-alpha, IL-1beta, IL-6) and is tagged anti_inflammatory. (3) NF_kB_modulation: Both mechanisms explicitly reference NF-κB pathway involvement (Elafin: src-17, src-23; Thymulin: NF-κB inhibition reported). The explanation accurately characterizes their distinct but complementary mechanisms—elafin controlling neutrophil protease-driven innate damage while thymulin normalizes T-cell balance and cytokine production—both converging on immune regulation through NF-κB modulation. The mechanisms justify calling them complementary rather than redundant.
  • Thymulin + LL-37

    No known conflict in the research

    Thymulin normalizes T-cell balance and dampens excess pro-inflammatory cytokines via NF-κB/p38 modulation, while LL-37 provides antimicrobial and TLR/FPR2-based innate immune actions. Their different immune targets can complement each other in immune support.

    Not fully established

    Both peptides' mechanisms clearly establish the claimed shared dimensions. LL-37 is explicitly tagged with innate_immune and anti_inflammatory, with documented effects including immunomodulation (both anti- and pro-inflammatory), TLR/FPR2 signaling, and NF-κB pathway activation. Thymulin is also explicitly tagged innate_immune and anti_inflammatory, with documented T-cell maturation/differentiation, NF-κB inhibition, and suppression of excessive proinflammatory cytokines. The proposed relationship correctly identifies that they operate through distinct but compatible mechanisms: LL-37 acts primarily through pattern recognition receptors (TLRs, FPR2) and direct antimicrobial effects, while thymulin acts through T-cell regulation and cytokine modulation. These different mechanistic approaches to immune support are genuinely complementary rather than redundant, justifying the relationship type and both shared dimensions.
  • Thymulin + KPV

    No known conflict in the research

    Thymulin normalises T-cell balance and suppresses excess proinflammatory cytokines via NF-κB and p38 MAPK inhibition, while KPV independently dampens NF-κB-driven cytokine production. Both converge on restraining overactive inflammation through complementary immune mechanisms (adaptive T-cell tuning vs innate cytokine suppression).

    Not fully established

    Both peptides' mechanisms clearly establish the three claimed shared dimensions: (1) innate_immune—KPV suppresses TNF-α, IL-1β, IL-6 and modulates contact hypersensitivity/IgE; thymulin suppresses excess proinflammatory cytokines and enhances NK cytotoxicity; (2) anti_inflammatory—both are explicitly described as anti-inflammatory with overlapping cytokine targets (TNF-α, IL-1β, IL-6); (3) NF_kB_modulation—KPV stabilizes IκBα and inhibits IKK/p65 nuclear import; thymulin inhibits NF-κB activation. The explanation correctly characterizes their complementary action: thymulin operates via T-cell maturation/CD4-CD8 balance and p38 MAPK inhibition (adaptive arm), while KPV acts through direct NF-κB/MAPK suppression in epithelial/innate cells (innate arm). Both converge on the same inflammatory output (TNF-α, IL-1β, IL-6 suppression) through distinct upstream pathways, which is the definition of complementarity. The mechanism descriptions fully support this relationship type and all three shared dimensions.
  • Lactoferrin + Vilon

    No known conflict in the research

    Lactoferrin adds direct antimicrobial and innate-immune defense plus anti-inflammatory activity, while Vilon works at the gene-expression level to support T-cell/thymic immunity. Different mechanisms both reinforcing host defense, making them a reasonable complementary immune pairing.

    Not fully established

    Both peptides' mechanisms clearly establish the claimed shared dimensions. Vilon demonstrates innate_immune activity through stimulation of cellular immunity, improved innate immune markers, and thymus tissue growth; anti_inflammatory activity through IL-1β/IL-6/TNF-α suppression and cytokine modulation. Lactoferrin demonstrates innate_immune activity through broad-spectrum antimicrobial effects and modulation of cellular immune responses; anti_inflammatory activity through reported anti-inflammatory immunomodulatory effects. The proposed relationship as 'complementary' is well-justified: the mechanisms show Vilon operates via gene-expression/chromatin remodeling to enhance adaptive immunity (T-cell/thymic), while Lactoferrin operates via direct antimicrobial binding and receptor-mediated pathways affecting innate immunity and inflammation. These represent distinct mechanistic approaches (transcriptional vs. direct protein-based) that both target immune/inflammatory pathways, supporting the characterization of complementary action reinforcing host defense.
  • Lactoferrin + KPV

    No known conflict in the research

    Lactoferrin provides direct antimicrobial defence and iron sequestration at mucosal surfaces, while KPV suppresses the inflammatory cytokine cascade. Both are oriented toward gut/mucosal health from different mechanisms, making them a plausible complementary pair for barrier and microbiome support.

    Not fully established

    Both peptides' mechanisms clearly establish the claimed shared dimensions. KPV is explicitly tagged with innate_immune and anti_inflammatory, with documented NF-κB suppression, cytokine reduction (TNF-alpha, IL-1beta, IL-6), and mucosal barrier repair effects. Lactoferrin is similarly tagged innate_immune and anti_inflammatory, with documented broad-spectrum antimicrobial activity, iron homeostasis, and inflammatory immune response modulation. The proposed relationship correctly identifies that they operate through distinct mechanisms (KPV via intracellular signaling/cytokine suppression; lactoferrin via direct antimicrobial action and iron sequestration) yet converge on shared functional outcomes relevant to mucosal health. The explanation accurately reflects the mechanism material: KPV's inflammatory cytokine cascade suppression and lactoferrin's direct antimicrobial/iron-binding defense are mechanistically complementary rather than redundant. Both mechanisms support gut/mucosal barrier integrity from different angles, justifying the complementary classification.
  • Elafin + Vilon

    No known conflict in the research

    Vilon is an immunomodulatory bioregulator that suppresses inflammatory cytokines and normalizes immune ratios, overlapping with elafin's anti-inflammatory NF-κB modulation but acting through different (gene-regulatory) mechanisms.

    Not fully established

    Both peptides' mechanisms establish the three claimed shared dimensions: (1) innate_immune—Elafin inhibits neutrophil serine proteases and modulates immune responses; Vilon stimulates cellular immunity and improves innate immune markers. (2) anti_inflammatory—Elafin is explicitly tagged anti_inflammatory with NF-κB pathway modulation; Vilon suppresses IL-1β/IL-6/TNF-α cytokines in inflammatory models. (3) NF_kB_modulation—Both peptides' mechanisms explicitly reference NF-κB pathway modulation (Elafin: src-17, src-23; Vilon: IGF1/FOXO1/TERT/NFkB gene expression modulation). The explanation correctly identifies that they share these functional dimensions but operate through distinct mechanisms: Elafin via protease inhibition and direct signaling modulation, Vilon via gene-promoter DNA binding and chromatin remodeling. This constitutes a valid complementary relationship—overlapping functional outcomes achieved through mechanistically different pathways.
  • Selank + Vilon

    No known conflict in the research

    Selank (a tuftsin-derived peptide) carries immunomodulatory and Th1/Th2-balancing activity alongside its main anxiolytic/nootropic role. That immune-modulating side overlaps with Vilon's T-cell and cytokine effects, so the two can complement each other where both immune support and CNS/stress effects are desired.

    Not fully established

    Both peptides' mechanisms clearly establish the claimed shared dimensions. Vilon demonstrates T_cell_regulation (stimulation of thymus tissue growth, immune cell differentiation, improved CD4/CD8 ratio, reactivation of age-silenced genes in aged lymphocytes) and anti_inflammatory effects (IL-1β/IL-6/TNF-α cytokine suppression, IL-2 upregulation). Selank demonstrates T_cell_regulation (Th1-Th2 balancing via cytokine/interferon signaling) and anti_inflammatory activity (approved tags include both). The proposed complementary relationship is justified: Vilon operates primarily through gene-promoter DNA binding and chromatin remodeling to modulate immune function, while Selank operates through receptor-mediated pathways (GABA-A, serotonin, enkephalinase) with immune modulation as a secondary effect. Their distinct mechanisms of action supporting overlapping immune outcomes (T-cell regulation and anti-inflammatory effects) logically support a complementary rather than redundant relationship.
  • Imunofan + Alpha-MSH

    No documented interaction in our data — that is not a safety clearance.

  • Lactoferrin + Selank

    No documented interaction in our data — that is not a safety clearance.

  • Alpha-MSH + Selank

    No documented interaction in our data — that is not a safety clearance.

  • Alpha-MSH + Vilon

    No documented interaction in our data — that is not a safety clearance.

  • Elafin + Selank

    No documented interaction in our data — that is not a safety clearance.

  • Selank + LL-37

    No documented interaction in our data — that is not a safety clearance.

  • Selank + KPV

    No documented interaction in our data — that is not a safety clearance.

  • Vilon + KPV

    No documented interaction in our data — that is not a safety clearance.

Compounds we looked at and left out

These share some biology with this goal, so you may have seen them recommended for it. Here is what our own research says about each.

  • Pidotimodmatched on antimicrobial

    Pidotimod is linked to antimicrobial, but in this compound that activity is about treating immune defects in specific disease states (HIV, COVID-19, senescence, Down syndrome, cancer).

    Effects are more evident in the setting of immune defects such as senescence, Downs syndrome, and cancer— from its own profile
  • HCGmatched on immune (t-cell) regulation

    HCG is linked to immune (t-cell) regulation, but in this compound that activity is about supporting implantation and pregnancy establishment.

    hCG supports maternal immune cells in their function as helpers in the establishment of an adequate embryo-endometrial relationship— from its own profile

What we can't tell you yet

For strengthening immunity in a generally healthy person, this library leans heavily on laboratory, animal and disease-specific evidence; the human trials here address safety, immune biomarkers, or correction of immune deficits in patients rather than prevention of everyday illness. It cannot speak to whether any of these peptides reduce real-world infection rates, how they compare head-to-head, or what long-term use does to immune balance.

Sources

Ordered as cited above.

  1. Tuftsin - Properties and Analogs.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov

This brief reports what published research says about these compounds. It is information, not medical advice, and not a recommendation to use anything described here. Evidence quality varies by compound and is labelled throughout. Talk to a qualified clinician before acting on any of it.