All seven vendors we compared in September list thymosin alpha-1 (TA1), and PSPeptides and Peptide Plugs document it best: PSPeptides posts an August 2026 North American Diagnostics certificate with a batch number plus endotoxin, sterility and heavy metals reports, and Peptide Plugs shows a Freedom Diagnostics accession code you can check at the lab. Ascension Peptides names labs per batch. No vendor has independent Finnrick data for TA1.
Notice: Research peptides are sold for in-vitro laboratory research only. They are not FDA-approved, not for human or animal consumption, and this page is not medical advice.
Our criterion: a TA1-specific COA with a named lab and lot number beats a generic "third-party tested" claim. We don't test products; we check what each vendor publishes.
Regulatory status of thymosin alpha-1
- FDA: research-labeled TA1 isn't an approved drug. FDA's Category 2 compounding page (content current as of April 22, 2026) lists "thymosin alpha-1 (Ta1)" among nominations "withdrawn by the nominators," with FDA's note that it "may pose significant risk for immunogenicity for certain routes of administration."
- July 2026 advisory meeting: TA1 wasn't among the seven peptides FDA's Pharmacy Compounding Advisory Committee reviewed. See our regulatory news tracker.
- Outside the US: a 2020 review in the World Journal of Virology describes thymalfasin, the synthetic form, as approved in more than 35 countries. Research-labeled TA1 from these vendors isn't any of those approved products.
- WADA: the 2026 Prohibited List doesn't name thymosin alpha-1. It names "thymosin-β4 and its derivatives e.g. TB-500" under S2.3, a different peptide (2026 list text). Athletes should confirm status with their anti-doping organization.
- DEA: not on DEA's controlled substances list dated August 27, 2026.
More: are peptides legal? and FDA peptide regulation in 2026.
Thymosin alpha-1 by vendor
Single-vial prices shown on September 26, 2026, including any displayed sale price. $/mg is price divided by labeled mg. Vendors appear in our editors' order, which isn't sorted by score.
| Vendor | Stocks it | Vial size(s) | Price | $/mg | TA1 COA / lab | Review |
|---|
| American Peptides | Yes | 10 mg | $125 (list) | $12.50 | Lot TA110-0803; lab not shown | Review |
| NextGenPeps | Yes | 10 mg | $67 | $6.70 | BioRegen, Jan 15, 2026, 99.62%; no lot shown | Review |
| PSPeptides | Yes | 10 mg | $54.99 | $5.50 | North American Diagnostics, batch PSP-08202026TA1, Aug 28, 2026 | Review |
| Ascension Peptides | Yes | 10 mg | $71.00 | $7.10 | Kovera Labs, batch 33-05260628, May 26, 2026 | Review |
| Peptide Plugs | Yes | 10 mg | $60 | $6.00 | Freedom Diagnostics, accession code on page | Review |
| Swiss Chems | Listed, stock not confirmed | 5 mg | $63.99 | $12.80 | HPLC report thumbnail; date and lab not shown | Review |
| Alpha Pro Peptides | Yes (stock not shown) | 5, 10 mg | $29.99 / $39.99 | $6.00 / $4.00 | 5 mg lots only (Aug 2026); lab not confirmed | Review |
Notes on the table:
- American Peptides: the product page lists 10 mg at $125, with an automatic discount showing $93.75 when we checked. Its COA page shows lot TA110-0803 and a superseded lot, with no lab or purity shown.
- NextGenPeps: the product page showed $67, down from $84. Its only COA library entry is a BioRegen report from January 2026.
- PSPeptides: the product page links endotoxin, sterility, heavy metals and fentanyl reports. The August certificate reports 99.97% purity and 9.76 mg measured, by HPLC with mass spectrometry.
- Ascension Peptides: the product page lists Kovera Labs (May 2026) and MZ Biolabs (February 2026) batches, with no purity shown on the page (checked September 26, 2026). Regular price is $99.99.
- Peptide Plugs: the product page shows accession code Pept2607220354, 99.2% purity and 10.18 mg measured; the lot field reads "Red," not a lot code. Its COA page dates the latest test July 25, 2026. The $36 advertised price is for 10 or more vials.
- Swiss Chems: sells 5 mg vials. The product page showed an out-of-stock notice and an HPLC report thumbnail without a visible date or lab.
- Alpha Pro Peptides: its testing page lists two 5 mg certificates (August 20, 2026: 99.47%, 5.79 mg; lot AP-4692117, August 7, 2026: 99.72%, 5.25 mg) and none for the 10 mg vial. We couldn't open the PDFs to confirm the lab.
- Licensed Peptides (added to our list September 28, 2026; not in the table): we couldn't confirm whether it stocks thymosin alpha-1, because its full catalog and prices require a free account (research access, checked September 28, 2026). Review
What is thymosin alpha-1?
Thymosin alpha-1 is "a peptide naturally occurring in the thymus," made of 28 amino acids, according to the 2020 review cited above. It has been studied in immunology research. Despite the similar name, it's a different peptide from thymosin beta-4, which TB-500 relates to (best TB-500 vendors).
How to check a thymosin alpha-1 COA
- Match the lot and the size. Alpha Pro's certificates cover its 5 mg vial only.
- Check that the lot field is a lot. Peptide Plugs' page shows "Red" there, so match the accession code instead.
- Check identity by mass spectrometry, which distinguishes TA1 from thymosin beta-4 products.
- Compare measured content to the label before concentration math.
See how to read a peptide COA, the COA checklist and the reconstitution calculator.
Independent test data
None of the seven vendors we compared had independent Finnrick results for thymosin alpha-1 on September 26, 2026. Licensed Peptides, which we added on September 28, 2026, has no Finnrick profile. Finnrick lists ten tests for Swiss Chems, covering BPC-157, ipamorelin and CJC-1295 only, and the other six vendors we compared have no Finnrick tests. Every certificate above was commissioned by the vendor, which chooses the sample it sends. More on community testing: what is Finnrick?
Vendor links
In our editors' order. Each review covers the vendor's policies, red flags and full testing record.
Looking for a discount? See Thymosin Alpha-1 coupon codes for prices after each partner code.
Bottom line
For thymosin alpha-1, PSPeptides has the most complete recent certificate and the lowest price per mg among vendors with a 10 mg certificate, though its blog publishes human dosing guides, which we count against it. Peptide Plugs offers a lab-checkable accession code. Ascension names labs without showing purity on the page, and NextGenPeps' only report is from January 2026. Alpha Pro's 10 mg vial has no certificate, and American Peptides and Swiss Chems don't show the lab. For the full comparison, see best peptide vendors in the USA and third-party tested peptides.
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