Thymic peptides, antimicrobial peptides, and immunomodulators for buyers managing chronic infection, recurrent illness, or compromised immune response.
The most-studied immune peptide on the market. 99.5% purity, lab-tested. View product →
by Lumen Labs · ★ 4.9 (847 reviews)
A 28-amino-acid thymic peptide approved in 30+ countries (as Zadaxin) for hepatitis B and C. Modulates T-cell maturation and innate-immune responses. The most evidence-backed immune peptide available. Frequent stack partner with BPC-157 for combined immune + recovery support.
Human cathelicidin — the only cathelicidin in human biology. Broad-spectrum antimicrobial against bacteria, viruses, and fungi. Used by buyers managing chronic Lyme, biofilm-driven infections, or recurrent sinus issues. Bidirectional inflammation effects — start low. Cross-shops with skin.
C-terminal tripeptide of alpha-MSH with NF-kB anti-inflammatory effects. Most useful for buyers whose immune dysfunction shows up as chronic inflammation rather than infection-susceptibility. Sweet-spot product for recovery and immune crossover.
Higher-concentration Thymosin Alpha-1 vial for longer protocols — typical immune-support cycle runs 1.6 mg twice weekly for 12 weeks. Better cost-per-mg than the 5mg vial for established users.
Smaller trial vial of LL-37 for first-time buyers establishing tolerability. Recommended starting dose is 100 mcg/day for 5 days before any escalation — LL-37 has bidirectional inflammatory effects that depend on dose and context.
The immune category requires more precise diagnosis than most peptide categories because "immune function" can fail in two opposite directions: underactivity (recurrent infections, slow recovery from illness) and overactivity (autoimmunity, chronic inflammation). The three peptides in this category target both ends of that spectrum, and choosing correctly means understanding which direction your immune dysregulation runs.
Thymosin Alpha-1 is a 28-amino-acid peptide naturally produced by the thymus gland. It modulates T-cell maturation, increases TH1 cytokine response, and improves natural-killer cell activity. Approved in 30+ countries (as Zadaxin) for chronic hepatitis B and C and as an adjuvant to certain cancer therapies. The mechanism is restorative rather than stimulatory — it supports underactive immune function without driving overactivity. Typical protocol: 1.6 mg subcutaneous twice weekly for 8–12 weeks. Cross-shops with recovery for athletes recovering from heavy training loads.
LL-37 is the human cathelicidin — the only cathelicidin in human biology and one of the body's primary innate-immune antimicrobials. Broad-spectrum activity against bacteria, viruses, and fungi, with particular effectiveness against biofilms. Used by buyers managing chronic Lyme, recurrent sinus infections, and biofilm-driven gut dysbiosis. Important caveat: LL-37 has bidirectional inflammatory effects depending on dose and tissue context. Start at 100 mcg/day for the first five days and titrate carefully.
KPV targets the other side of immune dysregulation — chronic inflammation. As the C-terminal tripeptide of alpha-MSH, it modulates NF-kB signaling and reduces pro-inflammatory cytokine production. Useful for buyers whose immune issue is autoimmune-flavored (IBD, eczema flares, generalized inflammation) rather than infection-susceptibility-flavored.
Thymosin Alpha-1 has the cleanest profile — mild injection-site reactions, occasional mild fatigue during the first week. LL-37 carries real risks: its bidirectional inflammatory profile can worsen rather than help if dosed incorrectly or in the wrong context. KPV is very well tolerated. None of these peptides are FDA-approved for over-the-counter immune support; products are sold for research or wellness use. Always consult a licensed healthcare provider, especially with autoimmune conditions, active cancer, or immunosuppressant medications.
| Your immune issue | Start with | Why |
|---|---|---|
| Recurrent infections / slow recovery | Thymosin Alpha-1 | Broad restorative modulation |
| Chronic Lyme / biofilm infection | LL-37 | Antimicrobial + biofilm activity |
| Autoimmune / chronic inflammation | KPV | NF-kB anti-inflammatory |
| Athlete immune drag | Thymosin Alpha-1 | Cross-shops with recovery |
| Recurrent skin infections | LL-37 | Cross-shops with skin |
Want the full deep-dive? Read our complete guide to peptides for immune function with dosing schedules and protocol design.
Published evidence suggests Thymosin Alpha-1 is a modulator rather than a pure stimulator — it normalizes T-cell function rather than driving it upward indefinitely. It's been used safely in autoimmune-adjacent contexts, but consult your physician if you have an active autoimmune diagnosis.
It can. LL-37 has bidirectional inflammatory effects: pro-inflammatory at some doses and contexts, anti-inflammatory at others. If you have rosacea, certain autoimmune conditions, or active gut inflammation, work with a knowledgeable practitioner before starting. Start low — 100 mcg/day.
Speak to your prescriber before combining. Thymosin Alpha-1 is theoretically immune-supportive (potentially counterproductive to immunosuppression goals) while KPV is anti-inflammatory (potentially additive). Never adjust prescribed immunosuppressant dosing based on a peptide protocol.
Thymosin Alpha-1: typical cycle is 8–12 weeks followed by a break. LL-37: usually short courses (4–6 weeks) for infection-driven issues. KPV: can be run continuously for chronic inflammation but most buyers cycle 8 weeks on / 4 weeks off.