Thymalin is a thymic bioregulator used for immune & aging. Thymalin is a peptide extract from the thymus, the gland that trains your immune system. In plain terms: taken in short courses, it is used to refresh immune function and support healthy aging, though Western human evidence is limited.

How much water do I add to Thymalin?

You can reconstitute Thymalin with 0.5, 1, or 2 mL of bacteriostatic water. Each option produces a different concentration and syringe draw for the same dose. Use the calculator to see which is easiest to measure.

What does Thymalin cost per dose?

Cost per dose depends on vial size, price paid, and your dose. Enter your vendor's price in the Thymalin calculator to see cost per dose and monthly cost.

What is the reference dose for Thymalin?

The commonly referenced range is 5 up to 10 mg per day (start low, increase slowly), taken 10-day courses. This is reference information, not a recommendation. Talk to a licensed clinician.

What are the side effects of Thymalin?

Reported side effects of Thymalin include: Little Western human evidence.. Severity and frequency vary by person and dose.

Who should not take Thymalin?

Thymalin is generally not appropriate for: No formal Western contraindications established; Pregnancy; Immunosuppressive therapy, as a precaution. Talk to a licensed clinician before starting.

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Decoding

Thymalin_Dosage, benefits & legal status

By the Peptide Decoding Editorial Team

Published July 22, 2026 · Updated August 14, 2026

A thymus peptide taken in courses to refresh immune function and aging.

Immune & agingThymic bioregulatorResearch only

InImmune support

Common vial size10 mg

Dose5 up to 10 mg per day (start low, increase slowly)

Frequency10-day courses

RouteUnder the skin (subcutaneous)

StatusResearch only

MixYour choice, calculate it

CycledTaken in 10-day courses

Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.

What is Thymalin?

Plain language first. The technical label stays, but it never stands alone.

Overview

It is taken in short courses to refresh immune function and support healthy aging. Western human evidence is limited.

The technical version

Thymalin is a peptide extract from the thymus, the gland that trains your immune system.

What it's used for

A thymus bioregulator taken in short courses to refresh immune function and support healthy aging. It is popular in longevity circles.

How does Thymalin work?

What it does in the body, and where.

Thymalin is an extract from the thymus, the gland that trains immune cells and shrinks progressively from adolescence onward.

01
It supplies thymic peptides
The premise is that supplying what an ageing thymus no longer makes restores some immune function.
02
Long-term Russian follow-up exists but is not independently replicated
Including reported mortality data from elderly cohorts, published by the originating institute and not reproduced elsewhere.

What else is it used for?

Each use below carries its own evidence level. Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.

Refreshing immune function with age, taken in short coursesResearch only
Healthy agingResearch only

The published record

Research index

243

Records indexed for Thymalin

156 in humans, 145 of them original studies.

Browse the records

In animalsPro

In the labPro

ReviewsPro

Senior author sharePro

Counted from Europe PMC indexing, not read by a person. Human means indexed under humans, which includes reviews and work on human cells. Original studies exclude reviews and lab work on human cells.Last updated 12 September 2026.

Compound field notes

At a glance

Four things to know about Thymalin

Evidence

Research only

How much, and do you cycle it?

The range, and whether you take breaks.

5 up to 10 mg per day (start low, increase slowly), 10-day courses. Taken in 10-day coursesCommunity practice

Course dosing is how this one is normally used. Where the course length comes from is the thing to check: for most compounds in this pattern it is convention rather than a tested schedule.

Compare this against the whole library →

How long does it stay in the body?

The half-life, and where the figure comes from.

Not establishedCommunity practice

A Russian registered product, but no pharmacokinetic study has been published. The 30 minutes quoted online traces to no source.

Not yet traced to a primary source.

You can compare this against the whole library to see where it sits.

How do I dose and price it?

Enter your vial and your dose. Pick a mix. We show the draw and the cost.

The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.

Your vial size (mg)

Printed on the vial.

What you paid per vial

Used for cost per dose only.

Your dose (mg)

Commonly referenced range: 5 up to 10 mg per day (start low, increase slowly)Community practice

Choose your mix

0.5 mL water25units · 20 mg/mL

Half a 100-unit syringe

1 mL water50units · 10 mg/mL

One full 100-unit syringe

Easiest

2 mL water100units · 5 mg/mL

Two full 100-unit syringes

your own mL

units · —

Enter your own volume

Measuring the water1 mL = one full 100-unit syringe.

Your draw

100 / 100 units

Full calculator with reorder date →Read a syringe →

What it costs

Thymalin starts at $19.00 across 16 vendors, typically $3.00 – $7.50 per mg.

20 listings, last read Sep 5, 2026. Shipping and card fees are not included.

See all 20 listings →

How do you store it?

Before mixing, and after.

Dry powder in the freezer or fridge. Once mixed, fridge, and use within about a month.

Unmixed lyophilized Thymalin keeps for a long time cold. Once you add water the clock starts: most reconstituted vials hold up for roughly 28 to 30 days at fridge temperature. Keep it out of light, and do not freeze it after mixing.

What are the side effects and cautions?

Known cautions and warnings for this compound.

Who should avoid it

Check these before anything else.

No formal Western contraindications established
Pregnancy
Immunosuppressive therapy, as a precaution

Stop and get help

These are emergencies. Seek care.

Signs of an allergic reaction
Worsening of an autoimmune condition

Common effects

Expected, and usually mild.

Reported as well tolerated in Russian studies
No modern Western controlled trials exist

Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.

Is Thymalin approved?

And where the numbers on this page come from.

No. Thymalin is not approved for any use, anywhere. It is sold labelled for laboratory research only, and there is no legal route to buy it for human use.

Approval status
Research only
Route
Under the skin (subcutaneous)
Checked
July 2026

What has happened recently

We have not yet written a full regulatory note for this compound. The status above is current as of the date shown.

You can compare this against the whole library, or read how to check a seller.

DoseFrom research and community reports. No regulator has reviewed this dose.
Vial sizeFrom what vendors typically list; not a recommendation.
Sources
Khavinson et al., Peptide Regulation of Gene Expression: A Systematic Review (Molecules 26:7053)
Reviewed22 July 2026

What else is like Thymalin?

Others in Immune support, side by side.

If you're weighing Thymalin, it's worth reading Vilon, Glutathione, and Thymosin Alpha-1 in the same class.

YOU ARE HERE

THYMA

Thymalin

A thymus peptide taken in courses to refresh immune function and aging.

Research only

Dose: 5 up to 10 mg per day (start low, increase slowly)
How often: 10-day courses

VILON

Vilon

A tiny bioregulator taken in courses for immunity and aging, with thin evidence.

Research only

Dose: Varies (course-based)
How often: Courses

GSH

Glutathione

Your body's master antioxidant, taken for glowing skin and detox support.

OTC / supplement

Dose: 250 up to 1000 mg per day (start low, increase slowly)
How often: Daily (oral)

TA-1

Thymosin Alpha-1

A well-studied shot that tunes up the immune system.

Clinical use

Dose: 1.6 mg per dose
How often: 2x per week

See other immune support

Guides for this compound

How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.

Sources

Khavinson et al., Peptide Regulation of Gene Expression: A Systematic Review (Molecules 26:7053)(2021)
This review states directly that the dipeptide KE, Lys-Glu, is part of the drug Thymalin, which makes what it reports about KE relevant here. Of all 400 possible dipeptides modelled against double-stranded DNA, KE showed the best binding to the TCGA sequence, which the authors located in the promoter of the APG5L gene, and KE went on to regulate that gene's expression in cell culture. The agreement between the model and the experiment is the strongest single piece of mechanistic evidence in this literature. Note what it is not: a computational docking result plus a cell culture result, in a review written by Khavinson and colleagues at the institute where these compounds originated, with no clinical outcome attached.

Last reviewed 22 July 2026

Beyond these, 243 records are indexed. Browse the records