Peptide basics

Similar names, 50 trials apart

This page compares the public evidence record of two thymic peptides. Neither is an FDA-approved medicine. Nothing here is a recommendation and no dose, schedule or route appears.

The records

Thymosin alpha-1 has 50 registered trials that we verified as administering it, with 14,247 participants between them, and its furthest phase is 4. Among compounds with no FDA-approved product it is beaten on trial count only by glutathione (72) and NAD+ (71), both of which are endogenous molecules studied for reasons unrelated to supplementation.¹³

Thymalin has none. No registered study names it as an intervention, so there is no phase, no enrolment and no result to read.²

What phase 4 without a US approval means

Phase 4 is post-marketing research, which requires a product to be marketed somewhere. Thymosin alpha-1 reaching phase 4 without appearing in Drugs@FDA indicates approval in other jurisdictions rather than in the United States.¹³

That is a meaningful distinction for a reader in the US. The compound has been reviewed by regulators, just not by that one, and the FDA column on this site records only the US position.³

Why similar names mislead

Both compounds derive from thymic tissue and both are described as immune peptides, so they appear on the same product lists and in the same articles. The naming similarity does the rest.¹²

But a shared origin story is not shared evidence. Every one of thymosin alpha-1's 50 trials tells you about thymosin alpha-1, and none of them tells you anything about thymalin.¹²

Thymalin has no registered human trial naming it as an intervention and no FDA-approved product. Its 10 indexed publications are the entire public record.

Common questions