Is this one of the Russian bioregulators?

No, although it is sold alongside them. Thymulin was identified in France in the 1970s and characterised in mainstream immunology literature. The science behind it is genuine and independently reproduced. What it lacks is clinical development, which is a different problem from lacking evidence altogether.

Why does zinc matter so much?

Thymulin only takes its active shape with a zinc ion bound. Without zinc the peptide is present and inert. That means thymulin activity falls in zinc deficiency regardless of how much peptide there is, and it means a dose in milligrams is not the same as a dose of active hormone.

How is it different from thymosin alpha-1?

Both are thymic peptides affecting T-cells, but they are different molecules with different histories. Thymosin alpha-1 has registered clinical use in a number of countries; thymulin has never been through a registered trial as a treatment.

Anti-aging & longevityHealing & recovery

Thymulin

FTS · Facteur thymique sérique · Serum thymic factor

PreclinicalReviewed 18 Aug 2026

Thymulin is a hormone the thymus actually produces, identified in France in the 1970s and characterised in detail through the 1980s. That distinguishes it from most of what it is sold alongside: there is genuine endocrinology here, published in mainstream journals and reproduced by independent groups.

Its defining property is that it is inactive without zinc. Thymulin is a nonapeptide that only takes its active conformation when a zinc ion is bound, and the zinc-free form does nothing. That is not a supplement-marketing claim. It is the established biochemistry, and it means thymulin activity falls in zinc deficiency no matter how much peptide is present.

What does not exist is clinical development. Thymulin's decline with age is well documented and its role in T-cell maturation is established, but no programme took it into registered trials as a treatment, and nothing establishes what injecting it does in a person. The gap here is between good basic science and no clinical evidence, which is a different situation from the compounds it sits beside.

How it works

Thymulin is a nonapeptide secreted by thymic epithelial cells, involved in the maturation and differentiation of T-lymphocytes. Its function in that process is well established.

It is biologically active only as a zinc complex. The apo form, without zinc, is present in serum but inert. Zinc availability therefore determines how much active thymulin exists, not peptide concentration alone. This is one of the clearest documented cases of a trace element gating a hormone's activity.

Circulating thymulin falls steadily with age as the thymus involutes, in parallel with the decline in T-cell diversity. Whether that fall is a cause of immune ageing or a marker of it is not settled, and it is the question the whole rationale for supplementing it depends on.

It also has documented anti-inflammatory and analgesic activity in animal models, through pathways separate from its thymic role.

Quick reference

Commonly described dose: 500 mcg–1.5 mg
How often: Daily in short courses
Route: Subcutaneous
Where: Abdomen, Thigh
Timing: No timing effect established.
Storage once mixed: Refrigerated, 21 days

These describe what sources report, not what you should do. Full detail and provenance in the dosing section below.

Price index

Per-milligram pricing across vendors arrives with the directory. We are recording prices now so the history exists when the page ships.

Vocabulary on this page

Khavinson bioregulator: A family of very short peptides from one St Petersburg institute, each assigned to a different organ, on the claim that they act directly on DNA rather than through a receptor.
Concentration: How much peptide there is in each millilitre of solution, once the vial has been reconstituted.
Evidence level: The category of human evidence behind a compound, from preclinical through to approved. Stated on every profile here as a category, not an adjective.
Injection site: Where on the body an injection is given. Rotating between sites is standard practice for anything given repeatedly.
Peptide: A short chain of amino acids: the same building blocks as a protein, in a chain short enough to behave differently.

The whole glossary →

Regulatory status — United States

Not approved for human use in any jurisdiction, and never taken into a registered clinical trial as a treatment. Its physiology is well documented; its therapeutic use is not. Sold only as a research chemical.

Last reviewed 18 Aug 2026. Regulatory positions in this category change frequently; we date this line so you can see how current it is.

What it is studied for

Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.

T-cell maturation and immune function

Published review

Its established physiological role.

EvidenceWell characterised in mainstream immunology literature and reproduced independently. That is basic science, not evidence that supplementing it treats anything.

Immune support and anti-ageing

Community practice

Why it is bought.

EvidenceNo registered clinical trial has studied injected thymulin for this or any purpose in humans.

Inflammation and pain

Published review

An active preclinical thread.

EvidenceAnti-inflammatory and analgesic effects demonstrated in animal models, through mechanisms separate from its thymic role. No human trials.

Identity and clearance

Molecule

Class: Zinc-dependent thymic nonapeptide hormone
Length: 9 amino acids

Sequence

pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn

Active only with a zinc ion bound. The zinc-free form is inert.

Dose protocols reported in sources

Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.

Dose protocols reported in sources, with the source of each.
Goal	Dose	Frequency	Route	Units, 5 mg vial	Source	Start this protocol
Commonly described community protocol	500 mcg – 1.5 mg	Daily in short courses	SubcutaneousNo trial supports any figure here. Note that the zinc dependence means peptide dose alone may not determine activity. Community protocols do not address this.	10–30 u	Community practice	Start this

Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.

CheckRows marked community practice describe what people commonly do, drawn from public discussion. They are not derived from any trial and are not evidence that a dose is safe or effective.

Calculator

Work out what to draw

Pre-filled with a 10 mg vial as a worked example. These are not recommended values — change them to match the vial in front of you.

Draw to 20 units on a 1 mL U-100 syringe. That is 0.2 mL, containing 1 mg of Thymulin.

Concentration5mg / mL

Volume drawn0.2mL

Doses per vial10doses

Per unit50mcg / unit

20 units sits exactly on a printed line.

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Bioalmanac performs arithmetic on values you enter. It does not recommend doses, schedules or compounds, and nothing here is medical advice. Confirm every calculation against your vial and syringe before drawing, and speak with a licensed healthcare provider.

Open this calculation in the full calculator

Units, concentration, bacteriostatic water — the glossary defines the vocabulary, and a unit is not a fixed volume.

Safety

Reported effects

Effects of injected thymulin in humansCommunity practice
Unknown
Never studied in a registered human trial, so no adverse event has been systematically recorded.
Injection site reactionsCommunity practice
Commonly reported
Immune modulation in autoimmune diseasePublished review
Mechanistically expected, unstudied
A hormone that drives T-cell maturation has an obvious and unexamined interaction with conditions caused by T-cells attacking the body.

When to stop

Any flare of an existing autoimmune condition.
Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.
Swollen lymph nodes that persist.
Fever, or an injection site that becomes hot or produces pus.

Interactions and situations that need care

Autoimmune diseaseAvoid
Thymulin's established role is driving T-cell maturation, and autoimmune disease is T-cells attacking the body. The mechanism points the wrong way, and nothing establishes what it does in that setting.
Immunosuppressant therapy, including after transplantAvoid
Deliberately promoting T-cell function in someone whose treatment depends on suppressing it risks organ rejection or loss of disease control.
Pregnancy and breastfeedingAvoid
No reproductive or developmental safety data.
Assuming a dose translates to activityUse caution
Thymulin is inert without zinc bound to it. Peptide quantity is therefore not the same as active hormone, and no community protocol accounts for that, which makes the dose figures in circulation less meaningful than they look.

What to expect

HonestlyThere is no human efficacy data for this compound, so there is no evidence-based timeline to give. Any site publishing a week-by-week schedule of expected effects has invented it.

The underlying science is genuine and independently reproduced. That is unusual in this category and it is worth saying plainly.
None of it is clinical. No registered trial has studied injecting thymulin in a person, for anything.
It does nothing without zinc. A dose figure that ignores that is describing peptide, not activity.
Its decline with age is well documented. Whether that decline causes immune ageing or merely tracks it is unsettled, and the whole rationale rests on which.
It is not a Khavinson bioregulator, despite being sold alongside them. It is a real hormone with real endocrinology behind it.

Storage and handling

Freeze-dried powder: Refrigerated at 2–8 °C, protected from light.
After mixing: Refrigerated at 2–8 °C. Do not freeze once mixed.
Long-term, frozen: Unopened powder is stable at −20 °C or colder.

Printable one-pager How to reconstitute a vial, step by step

With other peptides

Thymosin alpha-1caution
Both are thymic peptides acting on T-cell function. Thymosin alpha-1 has registered clinical use in several countries and thymulin has none, so running both means adding an unstudied compound to a studied one for overlapping effect.
Thymalincaution
Thymalin is an undefined thymic extract that plausibly contains thymulin among other things. Taking both is likely taking the same class of thing twice, once in a known quantity and once in an unknown one.

Check this against a whole stack

Checking your vial

Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it. More on assessing quality and COAs.

White cake, clear solution
Standard for a very short peptide.
Collapsed cake or cloudy solution
Heat damage or degradation. Do not use it.

Questions

Is this one of the Russian bioregulators?: No, although it is sold alongside them. Thymulin was identified in France in the 1970s and characterised in mainstream immunology literature. The science behind it is genuine and independently reproduced. What it lacks is clinical development, which is a different problem from lacking evidence altogether.
Why does zinc matter so much?: Thymulin only takes its active shape with a zinc ion bound. Without zinc the peptide is present and inert. That means thymulin activity falls in zinc deficiency regardless of how much peptide there is, and it means a dose in milligrams is not the same as a dose of active hormone.
How is it different from thymosin alpha-1?: Both are thymic peptides affecting T-cells, but they are different molecules with different histories. Thymosin alpha-1 has registered clinical use in a number of countries; thymulin has never been through a registered trial as a treatment.

References

Thymulin: a zinc-dependent thymic hormone in T-cell maturation, ageing and inflammation
Immunology and endocrinology review literature, 2011 · Review of basic and preclinical research
Humans and animals
Establishes thymulin as a zinc-dependent nonapeptide required for T-cell maturation, documents its decline with thymic involution, and describes anti-inflammatory and analgesic activity in animal models. No registered clinical trials of thymulin as a treatment exist.
Commonly reported community protocols
Bioalmanac editorial summary of public community sources, 2026 · Not a study
Records dose patterns described in public discussion. No trial supports them, and none accounts for the zinc dependence.

Related compounds

Thymosin alpha-1

An immune-modulating peptide approved in more than thirty countries for hepatitis B, and studied in sepsis and as a vaccine adjuvant. Not approved in the United States.

Thymalin

A thymus extract used as a medicine in Russia for decades. Not a single defined peptide, which is the fact that governs everything else on this page.

BPC-157

A synthetic 15-amino-acid peptide studied in animals for effects on tendon, ligament and gut tissue repair. No completed human trials.

TB-500

A synthetic fragment of thymosin beta-4, a naturally occurring protein involved in cell migration and tissue repair. Animal evidence only.

Keep this page honest

If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.

Suggest a correction

This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on Bioalmanac is medical advice. No clinician reviews these pages.

Page last updated 18 Aug 2026