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FDA Category 2 · restricted from compounding

This compound is on the FDA’s interim Section 503A Category 2 bulks list and cannot be legally compounded by US pharmacies. An HHS announcement in February 2026 signaled intent to restore several peptides to Category 1, but no Federal Register action has been published. Check the FDA PCAC schedule for updates.

Read the full regulatory context
PreclinicalImmuneIMDaily for 5–10 daysPartial data

Thymalin

Complex of thymic peptides developed in Russia for immune restoration and geriatric use.

§ 01   Overview

Overview

Complex of thymic peptides developed in Russia for immune restoration and geriatric use.

Russian clinical literature. Limited Western replication.

§ 02   Mechanism

Mechanism of action

Thymalin is a mixture of short peptides extracted from thymic tissue; it is proposed to restore T-cell maturation and immune balance in aging individuals.

  • 01Immune restoration in elderly populations (Russian data)
  • 02Adjunct use in chronic infection and recovery

§ 03   Dosing

Dosing protocol

Standard Protocol

Dose Range
5 – 10 mg per course
Route
IM
Frequency
Daily for 5–10 days
Cycle
1–2 courses per year

§ 04   Evidence

Evidence & research

Preclinical

Russian clinical literature. Limited Western replication.

FDA Status

Not FDA-approved.

§ 06   News

In the news

2 articles from the last 12 months · updates hourly

§ 07   Sourcing

Sourcing & supply

Regulatory status

Restricted from compounding

Placed on the FDA's 503A Category 2 list and cannot be lawfully compounded in the US. No brand pharmacy alternative exists. US buyers encounter only research-use-only (RUO) channels, which the FDA's Intended Use Doctrine treats as unapproved drug sales.

International · 2

International

Cosmic Nootropic

The most credible Russian / Khavinson source for US buyers. Sources authentic bioregulators through 'Peptides Company' (ex-NPCRIZ).

Visit
International

Rupharma

12+ year Russian pharmacy reseller. Reviews.io 4.84/5 (81+). Has a genuine US warehouse for common peptides.

Visit

Listings are informational, not endorsement. Verify credentials and flags against FDA and PCAB databases before purchasing. Full directory & how to verify →

§ 09   Safety

Safety & side effects

Side effects

  • 01Injection site reactions

Contraindications

None specified.

§ 10   Questions

Thymalin FAQ

What is Thymalin?
Complex of thymic peptides developed in Russia for immune restoration and geriatric use. Thymalin is a mixture of short peptides extracted from thymic tissue; it is proposed to restore T-cell maturation and immune balance in aging individuals.
What is Thymalin used for?
Reported uses include immune restoration in elderly populations (russian data) and adjunct use in chronic infection and recovery. Evidence strength is rated Preclinical — see the evidence section for detail.
How is Thymalin dosed?
Commonly referenced dosing is 5 – 10 mg per course, typically daily for 5–10 days, administered IM. This is educational reference only; consult a licensed clinician before use.
What are the side effects of Thymalin?
Commonly reported side effects include injection site reactions. This list is not exhaustive.
Is Thymalin legal?
Placed on the FDA's 503A Category 2 list and cannot be lawfully compounded in the US. No brand pharmacy alternative exists. US buyers encounter only research-use-only (RUO) channels, which the FDA's Intended Use Doctrine treats as unapproved drug sales. FDA status: Not FDA-approved..

This site is for educational and research purposes only. It does not constitute medical advice. Always consult a qualified healthcare provider before using any peptide or supplement.