Peptides for immune support
Thymus peptides and immune signallers, many of them from one Russian research tradition and sold in courses rather than continuously.
Much of this page traces back to one research program in St Petersburg that has been publishing on thymus extracts and short peptide bioregulators since the 1970s. Very little of that work has been repeated elsewhere, and almost none of it measures what happens to the peptide once it is in the body.
Thymosin Alpha-1 is the exception and worth treating separately. It is approved in more than 35 countries as Zadaxin, mostly for hepatitis B and as a vaccine adjuvant, and it has published pharmacokinetics and real trial data behind it. Thymopentin has a clinical history too, though its half-life is measured in seconds.
For the remaining compounds, the honest position is that nobody knows the dose, the exposure, or the duration of any effect. Immune modulation also cuts both ways, which is a reason for extra caution if you have an autoimmune condition or take immunosuppressants.
A thymus peptide that helps direct immune defenses. Well studied, and used abroad as an add-on therapy.
The body's main antioxidant, a three-amino-acid peptide. Taken for skin brightness and detox support.
Part of your own first-line immune defense. Punches holes in bacteria and helps wounds heal, on limited human data.
A thymus extract taken in short courses for immune function and aging. Western human evidence is limited.
A 2-amino-acid Khavinson peptide sold for immune balance and aging, with very little human research.
A 2-amino-acid thymus peptide from the Khavinson family, taken in courses for immunity on very little human research.
A zinc-dependent thymus peptide studied for immune balance, inflammation and pain. Human data is limited.
A 3-amino-acid Khavinson peptide sold for immune balance, with very little human research.
A cyclic lipopeptide antibiotic from soil bacteria, approved since 2003 for serious staph skin and bloodstream infections.
A bacterial peptide antibiotic found by genome mining that kills resistant Gram-negative bacteria in mice. Preclinical, with nothing for sale.
The first HIV fusion inhibitor: a 36-amino-acid twice-daily shot, approved in 2003 and withdrawn from the US in 2025.
An FDA-approved bradykinin blocker that patients inject themselves to stop hereditary angioedema attacks.
The first targeted peptide pill for psoriasis: it blocks the IL-23 receptor and was approved in the US in March 2026.
A Russian six-amino-acid rework of thymopentin, with an arginine added at each end to make it last longer.
An EU-approved liposomal immune stimulant added to chemotherapy for bone cancer in children and young adults.
The lupus peptide that passed phase 2 and missed phase 3, now awaiting a higher-dose redesign that has not started.
A frog-peptide antibiotic cream for infected diabetic foot ulcers that failed FDA review in 1999 and phase 3 in 2016.
A short fragment of a spleen protein, sold for immune support. The research is old, thin and hard to retrieve.
The five-amino-acid working part of a thymus hormone that helps immune cells mature.
A four-amino-acid antibody fragment that stimulates the cells that engulf bacteria. Selank was built from it.
Common questions
Are thymus peptides approved for anything?
Thymosin Alpha-1 is the main exception. It is approved in more than 35 countries as Zadaxin, though not in the United States. Across the 20 compounds here: 4 approved by the FDA, 3 available on prescription or through a compounding pharmacy, 1 sold as a supplement or cosmetic, 12 with no approval anywhere.
Why are so many of these Russian?
Many come from a line of research led by one group in St Petersburg, going back to the 1970s. The published work measures effects on tissue and lifespan rather than how the peptides behave in the body, and almost none of it has been repeated outside Russia.
Do any of these have a published half-life?
A few. Thymopentin clears in about 90 seconds, Thymosin Alpha-1 in about two hours and glutathione within minutes. For the rest, including the whole bioregulator group, no half-life has been established in a person or an animal.