Thymalin

Thymic signals for an ageing immune system, approved in Russia since 1982.

Evidence: BHuman trials what's this?
Grade B. Russian clinical data and approval; longevity claims contested; little Western replication.
Also known as: Thymus peptide bioregulator
Class: Polypeptide complex extracted from calf thymus; Khavinson immune bioregulator

The 30-second version

WhatA mixture of short peptides from young calves’ thymus glands, not a single molecule.

Why people use itRebuilding immune competence with age or after illness; longevity courses with Epitalon.

The honest catchThe headline "halved mortality" claims are methodologically contested.

What it is

The thymus, behind the breastbone, is where T-cells are trained. It starts shrinking at puberty and by your 60s and 70s has largely turned to fat. That decline (immunosenescence) helps explain why older people get more infections and cancers. Vladimir Khavinson, the researcher behind Epitalon, developed Thymalin in the 1970s to resupply the signals an aged thymus stops making. It’s different from Thymosin α-1, which is one defined peptide.

How it works

Short peptides such as KE and EW are thought to bind DNA and its packaging proteins.

Immune genes controlling T-cell development are regulated.

T-cells rebuilt. CD4 and CD8 counts rise and the CD4:CD8 ratio normalises.

Balance. NK activity up, IL-2 restored, cytokines rebalanced, blood-cell production supported.

Recalibrated, not just stimulated. In COVID the interest was in preventing cytokine storm.

What the research shows

In people: decades of Russian studies, mostly in elderly people, report that short courses improved T-cell counts, the CD4:CD8 ratio and immune competence, and reduced infections². Long-term follow-ups claimed up to a two-fold mortality reduction with periodic thymus-plus-pineal courses. That’s the headline, and also the weakest part¹. In severe COVID-19 in older patients, adding Thymalin sped clinical improvement, lymphocyte recovery and the normalisation of inflammation markers³. In animals: it preserved thymic structure, slowed spontaneous tumours and extended lifespan^1,2.

Genuine immune-restoration data. The longevity claims go further than the evidence.

Evidence at a glance

Use	Grade	Best evidence	Main gap	Read
Immune restoration	BHuman trials	T-cells restored, fewer infections²	Russian, older methods	Genuine signal
Severe COVID-19	BHuman trials	Faster recovery and immune regulation³	Small, single setting	Notable
Longevity, mortality	DCommunity use	Claimed mortality reduction¹	Contested methods	Caution
Mechanism	ELab & animal	Thymus preserved; T-cell activity up	Preclinical	Consistent

Dosing: what has been reported

Not a recommendation. These figures describe what was studied or what circulates in practice, kept separate so you can see how solid each one is. Speak with a qualified clinician before acting on any of it.

Setting	Figure	Route	Grade
Approved (Russia)	10–20 mg daily for 5–10 days, repeated periodically	Intramuscular	B
Community	5–20 mg/day in 5–10-day courses, 2–3 times a year, often with Epitalon	IM or SC	D

Preparing & storing

Reconstitute the lyophilised powder for injection, keep it cold and dark, and don’t shake it. Because it’s an animal-derived biological extract, the supplier’s purity and consistency matter more than for a synthetic peptide.

Reported side effects

Injection-site soreness
Allergic reaction: it’s a foreign, calf-derived protein
Occasional transient flu-like feeling as immunity is stimulated

Track a CBC with lymphocytes (and CD4/CD8 if available) before and after a course, and keep note of how often you get infections.

Who should avoid it

Organ transplant recipients on immunosuppression
Active lymphoma, leukaemia or autoimmune disease without specialist guidance
Bovine-product allergy; pregnancy and breastfeeding

Regulatory status checked Oct 2026

Body	Status	Detail
FDA (US)	Not approved	Research use only.
EMA (EU)	Not approved	—
Russia	Approved	Since 1982 for immune disorders and immunodeficiency.
WADA	Not listed	Low doping relevance.

The NexGen read

Long history, imperfect proof

Thymalin has decades of clinical use behind its immune-restoration effects, and a recent COVID study adds weight. Treat the dramatic lifespan claims sceptically, and choose a supplier who can document the extract’s quality.

References

Khavinson VKh, Morozov VG. Peptides of pineal gland and thymus prolong human life. Neuro Endocrinol Lett. 2003;24(3–4):233–240. PMID 14523363
Khavinson VKh, et al. Thymalin for immunocorrection and molecular aspects of its biological activity. PMC8365293
Khavinson V, Shapovalov K, Linkova N, et al. Thymalin regulates immune status in severe COVID-19 older patients. Adv Gerontol. 2021.