Thymalin is a polypeptide complex isolated from the thymus gland. It is classified as a peptide bioregulator — a short-chain amino acid preparation thought to help restore normal immune function by signaling stem cells to mature into active T lymphocytes. It has been studied primarily for immune modulation and age-related immune decline.[1][4]

How does Thymalin work?

Thymalin appears to push immature hematopoietic stem cells to complete their development into mature CD28+ T lymphocytes — key virus-fighting immune cells. In lab models it also reduced levels of inflammatory cytokines like IL-1β, IL-6, and TNF-α by 1.4 to 6 times, suggesting it can help regulate both the activation and the braking side of the immune response.[1][3]

What is Thymalin used for in research?

Research has explored Thymalin for immune restoration in elderly subjects, T-cell maturation, reduction of cytokine-storm-related inflammation, bone repair, and general geroprotection. A multi-year observational study found reduced rates of respiratory illness, heart disease, and mortality in Thymalin-treated elderly participants compared to controls.[2][5]

How is Thymalin dosed?

Published research on immunomodulation uses very small amounts per trial. The exact ranges used in studies are summarized in the dosage chart on this page. Dosing varies by model and outcome, so researchers should consult the primary literature and use the on-page calculator to determine appropriate volumes after reconstitution. This is for research use only — not medical advice.

How do you reconstitute Thymalin?

Add bacteriostatic water or sterile saline slowly down the inside wall of the vial containing the freeze-dried Thymalin powder. Do not shake — gentle swirling prevents peptide degradation. Once dissolved, store the vial refrigerated at 2–8 °C, away from light, and use within the supplier's recommended window, typically two to four weeks after mixing.

Thymalin is a research compound, not an approved therapeutic drug in most countries, and its full safety profile in humans has not been established through modern clinical trials. Long-term observational research in elderly subjects reported improved health outcomes with no serious adverse effects noted in publications,[2] but rigorous safety data are limited. Nothing here constitutes medical advice.

Тималин 5mg Vial Dosage Protocol

Reconstitution and dosing for a 5mg vial of Тималин — concentration by BAC-water volume, the units to draw on a U-100 syringe, and the cited dosing chart.

Цель	Доза	Частота	Длительность	Доказательства	Источник
Иммуномодуляция / коррекция иммунной дисфункции	0.005–0.05 mg	per trial	per trial	Preclinical	PMID 24734422

BAC water	Concentration	Volume / dose	Units (U-100)
1 mL	5 mg/mL	0–0.01 mL	0.1–1
2 mL	2.5 mg/mL	0–0.02 mL	0.2–2
3 mL	1.67 mg/mL	0–0.03 mL	0.3–3

What is Thymalin?

Thymalin is a polypeptide complex extracted from the thymus gland — a small organ sitting behind your breastbone that plays a starring role in training your immune system. Think of the thymus as a military academy for immune cells. Thymalin is essentially a concentrated signal from that academy, carrying instructions that help raw immune-cell recruits grow up into fully functional soldiers.^[1]

It belongs to a class of compounds called peptide bioregulators — short chains of amino acids that researchers believe can nudge specific tissues back toward normal function. Thymalin has been studied for decades, primarily in Russia and Eastern Europe, as a tool for restoring immune balance, especially in older adults and people with immune dysfunction.^[4]

Important note: Thymalin is a research compound only. Nothing on this page is medical advice, and Thymalin is not approved for human therapeutic use in most countries.

How Thymalin Works

Here is a simple way to picture it. Your bone marrow constantly produces hematopoietic stem cells — blank-slate cells that can become many different blood and immune cell types. To become a mature T lymphocyte (a key virus-fighting immune cell), those blank-slate cells need the right signals. Thymalin appears to be one of those signals.

In laboratory studies, Thymalin reduced the activity of early stem-cell markers (CD44 and CD117) by two to three times and boosted the marker for mature T lymphocytes (CD28) by nearly seven times. Researchers interpret this as evidence that Thymalin pushes stem cells to finish their education and become fully armed T cells.^[1]

Thymalin contains two active dipeptides — short two-amino-acid fragments called KE and EW. Lab work shows that KE stimulates cellular immunity and activates macrophages, lymphocytes, and neutrophils, while EW appears to dial down inflammatory signals linked to cytokine storms — the dangerous over-reaction of the immune system seen in severe respiratory illness.^[3] Specifically, in cell culture experiments, Thymalin and its dipeptides reduced levels of the inflammatory cytokines IL-1β, IL-6, and TNF-α by 1.4 to 6 times.^[3]

What the Research Shows

Most of the published research on Thymalin comes from the St. Petersburg Institute of Bioregulation and Gerontology. Here is a plain-language summary of the key findings:

Stem cell differentiation: A 2020 cell-culture study found that Thymalin strongly promoted the maturation of human hematopoietic stem cells into CD28+ T lymphocytes — the same immune cells that become depleted in severe COVID-19.^[1]
Long-term aging study: A six-to-eight-year clinical observation involving 266 elderly participants found that Thymalin-treated patients experienced roughly a 2-fold drop in acute respiratory illness, reduced rates of heart disease and hypertension, and a 2.0–2.1-fold lower mortality rate compared to controls. When Thymalin was combined with the pineal peptide Epithalamin annually for six years, researchers recorded a 4.1-fold decrease in mortality versus control.^[2]
COVID-19 inflammation model: A 2023 molecular and in-vitro study mapped out how Thymalin's KE and EW dipeptides interact with DNA sequences linked to cytokine-storm genes, and confirmed in cell culture that these peptides meaningfully reduced key inflammatory proteins.^[3]
Bone repair: A 2024 animal study in rats found that injecting thymalin around a mandible (jawbone) defect accelerated cleanup of dead tissue, improved immune-cell activity at the repair site, and enhanced bone regeneration when combined with a hydroxyapatite graft material.^[5]
Tumor and thymus interactions: Research has also explored Thymalin's role in activation therapy alongside antitumor models, examining effects on both tumor tissue and thymus function in animal subjects.^[6]

What Thymalin Is Being Studied For

Immune restoration and immunomodulation in aging populations^[2]
T lymphocyte differentiation and antiviral immune support^[1]
Inflammatory cytokine regulation, including cytokine-storm models^[3]
Tissue repair and reparative osteogenesis^[5]
Geroprotection — slowing age-related functional decline^[4]
Oncology-adjacent immune research^[6]

How Thymalin Is Dosed in Research

Dosing in published research varies depending on the model and the outcome being studied. The dosage chart on this page summarizes the ranges used in immunomodulation and immune dysfunction correction research. You can also use the calculator on this page to work out volumes based on your reconstitution concentration. Always refer to the primary literature and a qualified researcher before applying any dosing protocol.

Mixing and Storing Thymalin

Thymalin in research settings is typically supplied as a lyophilized (freeze-dried) powder in a sealed vial. To reconstitute it, researchers add bacteriostatic water or sterile saline slowly down the side of the vial — never shake it, as this can break down the peptide chains. Gently swirl until the powder fully dissolves. Once reconstituted, store the vial in a refrigerator (2–8 °C / 36–46 °F), keep it away from light, and use it within the timeframe recommended by the supplier — typically two to four weeks. Unmixed powder, kept sealed and away from moisture and heat, can remain stable for considerably longer. Always label vials with the date of reconstitution.

Sources

Thymalin: Activation of Differentiation of Human Hematopoietic Stem Cells. — Bulletin of experimental biology and medicine, 2020. PMID 33237528.
[Geroprotective effect of thymalin and epithalamin]. — Advances in gerontology = Uspekhi gerontologii, 2002. PMID 12577695.
The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein Synthesis Involved in the Pathogenesis of COVID-19. — International journal of molecular sciences, 2023. PMID 37686182.
Peptides and Ageing. — Neuro endocrinology letters, 2002. PMID 12374906.
Reparative osteogenesis in mandible in cases of filling a bone defect with hydroxyapatite-containing osteotropic material and injecting the surrounding soft tissues with thymalin: experimental and morphological study. — Wiadomosci lekarskie (Warsaw, Poland : 1960), 2024. PMID 38431810.
Effect of Thymalin on the Tumor and Thymus under Conditions of Activation Therapy In Vivo. — Bulletin of experimental biology and medicine, 2018. PMID 29797130.

Storage & handling

Lyophilized (freeze-dried) peptide is typically kept refrigerated and protected from light; once reconstituted with bacteriostatic water it is generally refrigerated at 2–8 °C and used within a few weeks. Follow aseptic technique to avoid contamination, per CDC injection-safety guidance.

Injection technique

Subcutaneous injections are usually given into the fat of the abdomen or thigh: clean the site with an alcohol swab, pinch the skin, insert at the recommended angle, and rotate sites to protect the tissue. See MedlinePlus for a step-by-step subcutaneous-injection guide.

General aseptic-technique and injection references for educational use — they are not specific to any research compound.