Thymosin Alpha-1
A thymus peptide that tunes the immune system. Used clinically in many countries.
Also listed as Ta1, Thymalfasin, Zadaxin, Thymosin Alpha 1.
Peptide Compare tracked 39 vendors selling Thymosin Alpha-1 on 10 Oct 2026. The cheapest in-stock 5 mg vial is $7.20 per mg at Good Science after its 20% coupon, 24% under the $9.50 median. Prices are scraped from vendor sites; trust scores come from Finnrick blind tests.
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Best value right now · 5 mg
GS
Good Science
IN STOCKUNTESTED
Per mg24% under the $9.50 median
Vial price5 mg · verified Oct 10
Avg per mg · 5 mg
$15.52−24.7%
Ranged $12.77 – $20.60 across 39 vendorsCompare 10 vendors · 5 mg
Across all sizes, verified in-stock listings run $37.00 to $300.00 from 26 vendors.
VendorStock
Showing 8 of 10 vendors · 2 more from $8.40/mg
Thymosin Alpha-1 prices verified Oct 10, 2026
$7.20/mgGood Science · $36.00
Buy best priceSee how Thymosin Alpha-1 moved against the rest of the catalogue in the Peptide Price Index: median price per mg now versus 30 and 90 days ago, every tracked peptide, with a CSV.
Thymosin Alpha-1 price by vial size
| Vial size | Lowest per mg | Vial price | Vendor |
|---|---|---|---|
| 3 mg | none verified in stock | 1 vendor carries it | |
| 5 mg | $7.20 | $36.00 | Good Science10 vendors carry it |
| 10 mg | $4.00 | $39.99 | Amino Club34 vendors carry it |
Verified 10 Oct 2026. Lowest figures are in-stock listings checked within the last week, with any coupon applied; a size with none says so.
Price movement · 30 days
+2.8%median per mg, all sizes
Cheapest ever recorded: $3.75/mg on Aug 31. Today is 6.6% above that low.See our top-ranked Thymosin Alpha-1 vendors
Ranked by Finnrick trust score, independent lab testing, and price.
Compare Thymosin Alpha-1 head-to-head
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Quick Summary
A synthetic 28-amino-acid peptide based on a thymus hormone, given the international nonproprietary name thymalfasin and marketed outside the United States as Zadaxin. It has been studied in hepatitis and as an adjunct in cancer and sepsis. Available from 39 vendors, priced from $37.00 to $300.00.
Research: The 4,400-patient figure that used to appear here could not be located in any source outside the manufacturer's own material and has been removed. A precise round number repeated across vendor pages with no citation attached is the signature of an unsourced manufacturer claim. The 35-country approval count is not the figure the manufacturer filed: SciClone's Form 10-K for 2016, filed with the SEC on 9 March 2017, states that Zadaxin is approved in over 30 countries, primarily in China and in the Pacific Rim, Latin America, Eastern Europe and the Middle East.
Side effects: No adverse event table was verified for this page
Approved internationallyMarketed as Zadaxin outside the United States. Not FDA approved. FDA's Orphan Drug Product designation database records four designations held by SciClone Pharmaceuticals under the generic name thymalfasin: chronic active hepatitis B (3 May 1991), DiGeorge anomaly with immune defects (8 January 1998), hepatocellular carcinoma (6 March 2000) and stage IIb through stage IV malignant melanoma (13 March 2006). All four are recorded as Designated and Not FDA Approved for Orphan Indication, so the hepatitis B, liver cancer and DiGeorge designations that vendor pages cite are on the FDA record and none of them is an approval.
- 37 of 39 vendors currently have it in stock
- Highest-rated vendor: NUPEPS Peptides (9.0 Finnrick score)
- Most common vial size: 10mg
- Category: Immune / Inflammation — Immune modulators and anti-inflammatory peptides
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