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Immune-modulating peptide approved in dozens of countries.
Last reviewed Oct 7, 2026 · How we rate evidence · Report an error
A 28-amino-acid peptide produced naturally by the thymus. As Zadaxin (thymalfasin) it is approved in about 35 countries for hepatitis B/C and as a vaccine adjuvant, and has been studied in sepsis and cancer support.
Enhances T-cell maturation and dendritic cell function, modulating innate and adaptive immunity.
Evidence
4/5
Multiple RCTs in hepatitis and sepsis; mixed results in sepsis (large trial neutral).
Half-life
About 2 hours
Known as
Tα1, Thymalfasin, Zadaxin
Compare Thymosin Alpha-1 with: LL-37TB-500KPVVIPor any other →
Strong human trialsLarge or multiple RCTs exist. It is not yet approved, approved outside the US, or approved only for a narrow use.
Multiple RCTs in hepatitis and sepsis; mixed results in sepsis (large trial neutral). How we rate evidence
Raises T-cell function in clinical trials.
Approved indication in several countries.
Improved response in older or immunocompromised people.
“Anecdotal” means reported by users, not shown in controlled trials. Sources
Not recommendations. These are commonly cited ranges, shown so you can see what real-world use looks like.
| Plan | Dose | Frequency | Duration | Route |
|---|---|---|---|---|
| Clinical (Zadaxin) | 1.6 mg | 2× per week | 6–12 months in studies | Subcutaneous |
| Short course (community) Used around illness or stress. | 1.6 mg | 2× per week | 4–6 weeks | Subcutaneous |
Set up for Thymosin Alpha-1. Switch vial size any time. Educational math only, not dosing advice.
At a common mix of 10 mg of Thymosin Alpha-1 in 2 mL of water (5 mg/mL), these commonly reported doses come to the following on a U-100 insulin syringe (100 units = 1 mL). They are examples of the arithmetic, not recommendations.
| Reported plan | Dose | Draw to | Volume |
|---|---|---|---|
| Clinical (Zadaxin) | 1.6 mg | 32 units | 0.32 mL |
Concentration (mg/mL) = vial mg ÷ mL of water; units = dose (mg) ÷ concentration × 100. A different vial size or amount of water changes every number above.
Amino Club sells Thymosin Alpha-1 as a research chemical. Its listings are research-use-only and not for human use; we show them for price tracking and their published lab reports.
Research-use-only listing — not for human use.
40% off through our link (code MYPEPSINFO applies automatically), until Dec 31, 2026.
| Size | Price | Per mg | Stock | Latest COA |
|---|---|---|---|---|
| 10 mg | $23.99 | $2.40 | In stock | 99.92% pure, lot THA0001 ILS Labs, tested Jul 30, 2026 |
List price, checked daily since Oct 7.
| Oct 7, 2026 | $39.99 | |
| Oct 8, 2026 | $39.99 | |
| Oct 9, 2026 | $39.99 | |
| Oct 10, 2026 | $39.99 | |
| Oct 11, 2026 | $39.99 | |
| Oct 12, 2026 | $39.99 | |
| Oct 13, 2026 | $39.99 | |
| Oct 14, 2026 | $39.99 | |
| Oct 15, 2026 | $39.99 | |
| Oct 16, 2026 | $39.99 | |
| Oct 17, 2026 | $39.99 | |
| Oct 18, 2026 | $39.99 | |
| Oct 19, 2026 | $39.99 | |
| Oct 20, 2026 | $39.99 | |
| Oct 21, 2026 | $39.99 | |
| Oct 22, 2026 | $39.99 | |
| Oct 23, 2026 | $39.99 | |
| Oct 24, 2026 | $39.99 | |
| Oct 25, 2026 | $39.99 | |
| Oct 26, 2026 | $39.99 | |
| Oct 27, 2026 | $39.99 | |
| Oct 28, 2026 | $39.99 | |
| Oct 29, 2026 | $39.99 | |
| Oct 30, 2026 | $39.99 | |
| Oct 31, 2026 | $39.99 | |
| Nov 1, 2026 | $39.99 |
HPLC purity from each published lab report; lowest 99.92%.
| Jul 30, 2026 | 99.92% | lot THA0001 |
Amino Club list prices as of Nov 1, 2026; sale prices include the 40% applied through our link. Multi-buy: 2+ units 5% off, 3+ units 7.5% off, 10+ units 40% off. Prices change; confirm on the listing.
An email when it’s back in stock, its price drops, a sale starts, or its FDA or WADA status changes.
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All Thymosin Alpha-1 lab reports, lot by lot →
Diluent: Sterile water or bacteriostatic water.
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Powder
Freezer / fridge
Keep sealed vial in the freezer (−20 °C) for long-term storage; fridge (2–8 °C) is fine for a few weeks. Keep dry and out of light.
After mixing
~14 days
Refrigerate at 2–8 °C. Never freeze after mixing. Keep upright, capped, and out of light.
Travel
Keep cool
Short trips at room temperature are generally fine for powder; keep mixed vials cold.
Orphan designations have been granted, but no US approval. Approved as Zadaxin in China, Italy, Singapore and others.
Regulations change often — verify with the FDA, EMA, MHRA, Health Canada, TGA and WADA before acting.
No — different peptide with different functions (Tα1 immune; Tβ4 repair).
It depends on the mix. At a common mix of 10 mg of Thymosin Alpha-1 in 2 mL of water (5 mg/mL), 1.6 mg is 32 units (0.32 mL) on a U-100 insulin syringe. The formula is dose in mg ÷ concentration in mg/mL × 100. Change the vial size or water in the calculator and the units update. This is math, not a dose recommendation.
Sterile water or bacteriostatic water. A common mix is 10 mg + 2 mL, which gives 5 mg/mL. Less water makes a stronger mix and fewer units per dose; more water makes a weaker mix and more units. Pick the amount that lands your dose on an easy-to-read line.
Refrigerate at 2–8 °C. Never freeze after mixing. Keep upright, capped, and out of light. Plan on about 14 days once it is mixed, and discard it sooner if it turns cloudy or has particles. The calculator shows how long a vial lasts at your dose and flags a vial that outlasts its shelf life.
Evidence rating (4/5): Multiple RCTs in hepatitis and sepsis; mixed results in sepsis (large trial neutral).
Legal status: Orphan designations have been granted, but no US approval. Approved as Zadaxin in China, Italy, Singapore and others.
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