---
title: "Thymalin vs Thymogen: Study Dosage, Side Effects, FDA Status"
description: "Thymalin vs Thymogen guide: benefits from studies, study-dose caveats, side effects, FDA status, legal status, and Russian clinical terminology."
canonical_url: "https://khavinsonatlas.com/peptides/thymalin.html"
last_updated: "2026-05-05"
---

# Thymalin vs Thymogen

Thymalin, also spelled Timalin, is a thymus-derived peptide complex from Russian/USSR clinical literature. Thymogen, also spelled Timogen, is the synthetic EW dipeptide Glu-Trp. Thymalin is not a single EW sequence, Thymogen is not thymosin alpha-1, and Thymalin is not thymulin.

## Evidence map

Thymalin has older Russian-language human literature and later mechanism-focused work. PubMed-indexed entries include immunologic reactivity in non-specific lung diseases and a 2020 paper on hematopoietic stem-cell differentiation markers. These are not substitutes for modern independent clinical trials for a specific marketed product.

## Benefits and study-only dosage

- 1989 Russian lung-disease abstract: reports only a 5 ml preparation volume and 4-6 injections per course, added to standard treatment; route and concentration are not stated in the accessible abstract.
- 2020 hematopoietic stem-cell paper: accessible abstract and publisher preview describe human umbilical-cord-blood HSC marker changes but do not state dose or exposure concentration.
- 2014 Khavinson table: identifies Thymogen as EW and lists it as an immunomodulator; Thymogen EW is not identical to Thymalin complex.

## Side effects

Some Khavinson-authored historical sources describe Thymalin as well tolerated, but that is not modern systematic adverse-event evidence. Safety depends on product, route, manufacturer, country, and patient context.

## FDA and legal status

This site does not identify an FDA-approved Thymalin drug in the United States as of the May 5, 2026 review. FDA's 2024 US Chem Labs warning letter treated marketed "Thymalin" products with disease and structure/function claims as unapproved new drugs and misbranded drugs for those products.

## Key sources

- PubMed Thymalin HSC paper: https://pubmed.ncbi.nlm.nih.gov/33237528/
- Springer preview: https://link.springer.com/article/10.1007/s10517-020-05016-z
- PubMed lung-disease abstract: https://pubmed.ncbi.nlm.nih.gov/2741122/
- FDA warning letter: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/us-chem-labs-669074-02072024

## Sitemap

See the full [markdown sitemap](/sitemap.md) for all pages.