Enter vial size, bacteriostatic water volume and dose to get concentration, syringe units and doses per vial. Every dose figure on this page carries its evidence level. The compound itself is covered in the Thymosin Alpha-1 peptide guide.
A 10 mg vial of Thymosin Alpha-1 reconstituted with 2 mL of bacteriostatic water gives a concentration of 5.0 mg/mL, or 50 mcg per unit on a U-100 syringe. For a 1.6 mg dose, draw the syringe to 32.0 units (0.32 mL). At that dose the vial provides about 6.25 doses.
Defaults: 10 mg is the vial behind the lowest tracked price (/prices/thymosin-alpha-1-a1). 2 mL was set by Peptigrity for simple arithmetic (5 mg/mL); no source states a diluent volume for this compound. 1.6 mg is the approved Zadaxin label dose (hepatitis B, outside the US), shown for arithmetic only.
The 1.6 mg default is the approved Zadaxin dose for hepatitis B, given twice weekly under physician supervision outside the US. It is the only Thymosin Alpha-1 dose in our fact base attached to an approved label, and it is not a recommendation for any other use.
Draw the syringe up to
That's one 1.6 mg dose. Add 2 mL of water to your 10 mg vial first.
A 10 mg vial reconstituted with 2 mL of bacteriostatic water is 5.0 mg/mL, which is 50 mcg per unit on a U-100 syringe, so a 1.6 mg dose is 32.0 units (0.32 mL) and the vial holds about 6.25 of them. Change the water volume and the unit count changes while the peptide in the vial does not.
| Vial + water | Concentration | Per unit (U-100) | 1.6 mg dose | 3.2 mg dose | Doses per vial at 1.6 mg |
|---|---|---|---|---|---|
| 10 mg + 1 mL | 10 mg/mL | 100 mcg | 16.0 units (0.16 mL) | 32.0 units (0.32 mL) | 6.25 |
| 10 mg + 2 mL (page default) | 5.0 mg/mL | 50 mcg | 32.0 units (0.32 mL) | 64.0 units (0.64 mL) | 6.25 |
| 10 mg + 3 mL | 3.3 mg/mL | 33.3 mcg | 48.0 units (0.48 mL) | 96.0 units (0.96 mL) | 6.25 |
| 10 mg + 4 mL | 2.5 mg/mL | 25 mcg | 64.0 units (0.64 mL) | 128.0 units (1.28 mL) — exceeds a 1 mL U-100 barrel | 6.25 |
Thymosin Alpha-1 has no US approval, so in the United States there is no authoritative dose. Every figure in circulation traces to the approved Zadaxin label in the 35+ countries where the compound is approved, to protocol conventions repeated in our own science coverage, or to nothing at all. The label dose and the convention range are not the same class of evidence.
| Route | Amount | Frequency | Evidence level |
|---|---|---|---|
| Subcutaneous | 1.6 mg | Twice weekly | Approved label — Zadaxin, hepatitis B, physician-supervised, outside the US |
| Subcutaneous | 1.6 mg | Twice weekly | Human trial — chronic hepatitis B, n=240, reported viral clearance +65% vs placebo |
| Subcutaneous | 1.6–3.2 mg | Twice weekly, 8–12 week cycles | Convention — no trial in our fact base tested 3.2 mg or the cycle length |
| Intranasal spray | 200 µg | Three times daily | Convention — a different route, not calculable on this page |
| Any US-approved dose | — | — | None exists |
There is no titration schedule for Thymosin Alpha-1 in our fact base — no starting dose, step size or ramp — so this page prints none. Mechanism and trial evidence: Thymosin Alpha-1 immune activation science article.
Step 1 — Choose the water volume. No label or source in our fact base specifies one. Pick the volume that puts your intended dose mid-barrel: 2 mL in a 10 mg vial gives 5.0 mg/mL, which puts the 1.6 mg label dose at 32.0 units. At 10 mg/mL the same dose is 16.0 units, where a one-unit misread is a 6.25% error rather than 3.1%.
Step 2 — Reconstitute. Inject bacteriostatic water slowly against the inside glass wall, then swirl gently. Do not shake. The full procedure: reconstituting peptides step by step.
Step 3 — Store. How to store a reconstituted vial, and why stability depends on the compound, is covered in how to store peptides. Peptigrity does not publish an in-use period for Thymosin Alpha-1. Diluent choice is covered in the bacteriostatic water guide.
A vial lasts as many weeks as the label mass divided by the weekly amount — water volume changes nothing about it. At the label dose of 1.6 mg twice weekly, that is 3.2 mg a week, so a 10 mg vial is about 3.13 weeks and a 20 mg vial about 6.25.
| Vial size | Weeks at 1.6 mg twice weekly | Doses per vial at 1.6 mg | Weeks at 3.2 mg twice weekly | Doses per vial at 3.2 mg |
|---|---|---|---|---|
| 5 mg | 1.56 | 3.13 | 0.78 | 1.56 |
| 10 mg | 3.13 | 6.25 | 1.56 | 3.13 |
| 12 mg | 3.75 | 7.5 | 1.88 | 3.75 |
| 20 mg | 6.25 | 12.5 | 3.13 | 6.25 |
Across 234 independent lab tests from 19 labs, Thymosin Alpha-1 holds a Purity Index of 99.53, ranking 32nd of 64 indexed compounds (as of 1 September 2026); the compound page shows 226 tests on file averaging 99.51% HPLC purity (last updated May 2026). The 99.51% is the unweighted average, the 99.53 the recency-weighted index. That establishes vendors are broadly selling the correct molecule; it says nothing about efficacy, dosing or the amount in your vial. Records: Thymosin Alpha-1 lab test records and the Purity Index.
As of 10 August 2026, the median tracked price was $6.80 per mg and the lowest tracked $2.50 per mg, on a 10 mg vial at $25.00, across 59 shops in stock. At the median, a 1.6 mg dose is about $10.88 of compound and a week at twice weekly about $21.76; at the lowest tracked price the same dose is about $4.00. These figures exclude shipping, taxes and customs charges; coupon codes and bulk discount tiers; multi-vial kits; and email-only or account-required pricing. They are the lowest tracked price, not the lowest payable price. Current offers: Thymosin Alpha-1 price per milligram.
| Question | Status |
|---|---|
| FDA-approved in the United States? | No, not currently in the United States (compound page, May 2026) |
| Approved elsewhere? | Approved in 35+ countries as Zadaxin for hepatitis B, hepatitis C and related immune indications (compound page). Our science article adds that it is not approved by the EMA for general use. |
| 503A bulks list | Withdrawn from Category 2 of the 503A bulks list in September 2024 |
| PCAC | Thymosin Alpha-1 was not on the agenda of the 23–24 July 2026 PCAC meeting (verified 11 Sep 2026). |
| WADA | Our compound page states that Thymosin Alpha-1 is not specifically prohibited by WADA, while our own science article lists it under WADA Prohibited List section S4, hormone and metabolic modulators. The two statements contradict each other and we have not resolved which is current. |
In the United States it is sold as a research-use compound. Category: immune and longevity peptides. Loading a reconstituted vial into a pen: loading Thymosin Alpha-1 into a refillable pen. The same arithmetic for other compounds: how to calculate peptide doses.
It depends on the concentration. At the page default of 5.0 mg/mL (10 mg vial + 2 mL), 1.6 mg is 32.0 units on a U-100 syringe. At 10 mg/mL it is 16.0 units, and at 2.5 mg/mL it is 64.0 units. A units figure quoted without a concentration cannot be used.
No source states a diluent volume for this compound, so the choice is yours. Peptigrity set 2 mL for simple arithmetic: it gives 5.0 mg/mL and puts 1.6 mg at 32.0 units, where a one-unit misread is about 3%. 1 mL gives 10 mg/mL and 16.0 units, where the same misread is over 6%.
The only dose with an approved label behind it is 1.6 mg subcutaneously twice weekly, for hepatitis B, under physician supervision in the countries where thymalfasin is approved. Our science coverage also describes a 1.6–3.2 mg twice-weekly convention in 8–12 week cycles. There is no FDA-approved Thymosin Alpha-1 dose in the United States, and Peptigrity does not recommend one.
No — not currently in the United States, though it is approved in 35+ countries as Zadaxin for hepatitis B, hepatitis C and related immune indications. It was withdrawn from Category 2 of the FDA's 503A bulks list in September 2024, and it was not on the agenda of the 23–24 July 2026 PCAC meeting (verified 11 Sep 2026).
At 1.6 mg twice weekly — 3.2 mg a week — a 5 mg vial lasts about 1.56 weeks, a 10 mg vial about 3.13, a 12 mg vial about 3.75 and a 20 mg vial about 6.25. Water volume changes none of this; it changes only how far you push the plunger.
No. The indexed tests establish that vendors are broadly selling the correct molecule at roughly the stated purity. A certificate confirms identity and purity; it does not confirm the net peptide content or the amount in your particular vial. See why 10 mg isn't 10 mg.