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Immune
Immune-modulating peptide approved in dozens of countries.
Immune
A three-amino-acid anti-inflammatory fragment of α-MSH.
Thymosin Alpha-1 is not FDA-approved and rated 4/5 for evidence; KPV is not FDA-approved and rated 2/5. Thymosin Alpha-1 has more human evidence behind it. KPV is banned in sport by WADA; Thymosin Alpha-1 is not. Both are used for immune goals.
| Compare | Thymosin Alpha-1 Immune-modulating peptide approved in dozens of countries. | KPV A three-amino-acid anti-inflammatory fragment of α-MSH. |
|---|---|---|
| Category | Immune | Immune |
| Evidence | 4/5Multiple RCTs in hepatitis and sepsis; mixed results in sepsis (large trial neutral). | 2/5Cell and mouse colitis studies (e.g. Dalmasso 2008, Gastroenterology). No published human trials. |
| FDA status | Not FDA-approved (approved in ~35 other countries) | Not FDA-approved |
| WADA (sport) | Not on the Prohibited List | Banned |
| Also known as | Tα1, Thymalfasin, Zadaxin | Lys-Pro-Val, α-MSH (11–13) |
| How it works | Enhances T-cell maturation and dendritic cell function, modulating innate and adaptive immunity. | Gets into gut-lining and immune cells through the PepT1 transporter and dampens the NF-κB and MAP-kinase inflammation pathways. Unlike full α-MSH, its anti-inflammatory effect in gut cells does not appear to run through melanocortin receptors, so it is not a tanning peptide. |
| Half-life | About 2 hours | Not characterized in humans |
| Commonly reported doses |
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| Route | Subcutaneous | Subcutaneous |
| Good once mixed | ~14 days in the fridge | ~28 days in the fridge |
| Top side effects |
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| Lowest research-listing price per mg | $2.40 (10 mg vial, 40% off) | $2.40 (10 mg vial, 40% off) |
| Latest lab purity | 99.92% (lot THA0001) | 99.36% (lot KPV0002) |
Want a third? Add another peptide. Doses are commonly reported ranges, not recommendations.
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Connect MyPeps to ChatGPT or Claude and ask follow-ups about Thymosin Alpha-1 and KPV. It answers from these same pages, with links back here.
Thymosin Alpha-1 is not FDA-approved and rated 4/5 for evidence; KPV is not FDA-approved and rated 2/5. Thymosin Alpha-1 has more human evidence behind it. KPV is banned in sport by WADA; Thymosin Alpha-1 is not. Both are used for immune goals.
Thymosin Alpha-1: Not FDA-approved (approved in ~35 other countries). KPV: Not FDA-approved. Regulations change, so confirm with the FDA.
Thymosin Alpha-1 is rated 4 out of 5: Multiple RCTs in hepatitis and sepsis; mixed results in sepsis (large trial neutral). KPV is rated 2 out of 5: Cell and mouse colitis studies (e.g. Dalmasso 2008, Gastroenterology). No published human trials. The scale is explained on our methodology page.
Thymosin Alpha-1 is not named on the WADA list, though the general rule on non-approved substances (S0) can still apply. KPV is banned by WADA, by name or as part of a named class.