What is the difference between Thymalin and Thymosin Alpha-1?

Thymalin: Thymic peptide bioregulator; restores thymic function and T-cell production; modulates cytokine balance; shown to extend lifespan in animal models Thymosin Alpha-1: Tα1 modulates both innate and adaptive immune responses by stimulating the differentiation and maturation of T-cells, dendritic cells, and natural killer cells.

Is Thymalin FDA approved?

Thymalin is not evaluated or approved by the FDA. It is discussed for research and educational purposes only, not as medical guidance.

How is Thymalin administered in research settings?

In research settings, Thymalin is typically administered via the subcutaneous or intramuscular routes. PeptideBase does not provide dosing or administration instructions.

How is Thymosin Alpha-1 administered in research settings?

In research settings, Thymosin Alpha-1 is typically administered via the subcutaneous route. PeptideBase does not provide dosing or administration instructions.

Home›Research›Compare›Thymalin vs Thymosin Alpha-1

Peptide Comparison

Thymalin vs Thymosin Alpha-1

Name: Thymalin vs Thymosin Alpha-1 — Per-mg Price Comparison
Creator: PeptideBase
License: https://peptidebase.io/terms

Both are Immune & Thymic peptides.

Thymalin

Thymus peptide

LongevityNot EvaluatedResearch Only

Half-life: Unknown

12 providers listed

Full Thymalin profile →

Thymosin Alpha-1

Thymosin Alpha

RecoveryResearch Only

Half-life: 2 hours

215 providers listed

Full Thymosin Alpha-1 profile →

Bottom line

Thymosin Alpha-1 carries stronger published evidence (RCT, 2 key studies) than Thymalin (Review, 5); both are research compounds.

Quick Verdict

Thymalin

Half-life

Unknown

Thymosin Alpha-1

Half-life

2 hours

Which One Should You Choose?

Your goal	Better option
Stronger clinical evidence	Thymosin Alpha-1
Lower typical price per mg	Thymalin
More provider options (12 vs 215)	Thymosin Alpha-1

Research summary only — not medical advice. Consult a qualified provider before making any decisions.

Side-by-Side Comparison

Thymalin

Thymosin Alpha-1

Mechanism Family

Immune & Thymic

Half-life

Unknown

2 hours

FDA Status

not evaluated

nomination withdrawn

Admin Routes

subcutaneous, intramuscular

subcutaneous

Availability

Research Only

Providers

12 listed

215 listed

Avail. Notes

Russian thymic peptide bioregulator (Khavinson Institute). Distinct from Thymosin Alpha-1. Not FDA-approved. Not on any FDA list. Research chemical in US.

Approved as Zadaxin in China, Italy, and other countries but NOT FDA-approved. Not on FDA 503A Category 1 bulks list. Research use only in US. Immunomodulatory thymic peptide.

Research Evidence

Thymalin

Review · 5 key studies · most recent 2023

Thymosin Alpha-1

RCT · 2 key studies · most recent 2026

Research Citations

Thymalin

In vitro2023 · Int J Mol Sci

The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein…

In vitro2020 · Bull Exp Biol Med

Thymalin: Activation of Differentiation of Human Hematopoietic Stem Cells.

Review1997 · Int J Immunopharmacol

Natural and synthetic thymic peptides as therapeutics for immune dysfunction.

In vitro2022 · Int J Mol Sci

Peptides Regulating Proliferative Activity and Inflammatory Pathways in the Monocyte/Macrophage THP-1 Cell Li…

+1 more

Thymosin Alpha-1

RCT2018 · Expert Opinion on Biological Therapy

Combination of entecavir with thymosin alpha-1 in HBV-related compensated cirrhosis: a prospective multicente…

Animal2026 · J Gastroenterol Hepatol

IL-15 Plus Thymosin α1 Reduces Senescent Hepatic CD8(+) T Cells in Hepatocellular Carcinoma via PI3K/AKT Supp…

About Thymalin

Thymic peptide bioregulator; restores thymic function and T-cell production; modulates cytokine balance; shown to extend lifespan in animal models

Research Areas

immune restorationthymus function supportanti-agingimmune modulation

About Thymosin Alpha-1

Tα1 modulates both innate and adaptive immune responses by stimulating the differentiation and maturation of T-cells, dendritic cells, and natural killer cells. It upregulates MHC class I and II expression, enhancing antigen presentation. It also promotes the production of key cytokines including interferon-γ and interleukin-2, which are central to immune surveillance.

Research Areas

TH1 immune activation via Toll-like receptor upregulationhepatitis B and C treatment adjuvant — approved in 35+ countriesdendritic cell maturation and antigen-specific T-cell potentiationCOVID-19 immune support research (2020–2021 Chinese clinical data)

Safety Profile

Information below reflects published research data only — not medical advice. Consult a qualified provider before use.

Thymalin

Reported (Unverified — Pending Clinical Review)

autoimmune disease (use with caution)organ transplant (immunosuppression)

No established clinical contraindications

Thymosin Alpha-1

Absolute Contraindications

Under clinical review

Being verified by our medical team before we display contraindications for this peptide.

Price (per mg)

Thymalin

$4.56/mg

$3.06 – $5.44 range

19 vendors

View price index →Find providers →

Thymosin Alpha-1

$7.71/mg

$6.50 – $9.20 range

41 vendors

View price index →Find providers →

Find Providers

Where to source these peptides

Providers offering

Thymalin

12 listed

Browse directory →

Providers offering

Thymosin Alpha-1

215 listed

Browse directory →

PeptideBase lists providers for educational research purposes only. Always consult a qualified healthcare professional before obtaining or using any peptide.

More Immune & Thymic Comparisons

Browse all peptides →

Educational research tools — not medical advice.

Cite this page

Data last updated August 26, 2026

Free to reference and republish with attribution to PeptideBase. Choose a format:

PeptideBase. (2026). Thymalin vs Thymosin Alpha-1 — Per-mg Price Comparison. Retrieved September 11, 2026, from https://peptidebase.io/peptides/compare/thymalin/thymosin-alpha-1

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