Thymosin Alpha-1

Main evidence: Human clinical trials. Updated 2026-10-28.

What research and users report, not a recommendation or medical advice. Many of these products are not approved for human use. Ask your doctor. Packs report what sources say, each with its evidence label. A claim labelled community, educator, manufacturer or animal has not been validated in humans.

Summary

This pack organizes cited evidence, protocol context, safety cautions, and Australian legal status for the compound.

What the sources say

A 690-person randomized cirrhosis study compared thymosin alpha-1 plus entecavir with entecavir alone; major clinical, virologic, serologic and biochemical outcomes were similar, so the study did not establish an added combination benefit. (Human clinical trials; Wu et al., "Combination therapy of entecavir with thymosin alpha-1 in HBV-related compensated cirrhosis: a multicenter randomized trial" (publication record gives year 2018; exact day not stated; accessed 2026-10-28), 2026-10-28)
Thymosin alpha-1 (thymalfasin) is an immunomodulatory peptide with indication-specific human evidence; a large phase 3 sepsis trial did not reduce 28-day mortality. (Human clinical trials; Prescott et al., "The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial", 2025-01-15)
In the larger TESTS phase 3 trial, 1,089 analysed adults with sepsis had 28-day mortality of 23.4% with thymosin alpha-1 and 24.1% with placebo (hazard ratio 0.97; 95% CI 0.76–1.24; P=.82); the authors found no clear mortality benefit. (Human clinical trials; Prescott et al., "The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial", 2025-01-15)
In the 361-patient ETASS severe-sepsis trial, the primary 28-day mortality comparison was 26.0% with thymosin alpha-1 versus 35.0% with placebo (P=.062), not statistically significant; in-hospital mortality was 28.7% versus 39.4% (P=.032). (Human clinical trials; Wu et al., "The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial", 2013-01-17)
A small pilot combined thymosin alpha-1 with an adjuvanted influenza vaccine in hemodialysis patients and found improved vaccine immunogenicity measures; it did not establish protection against clinical influenza illness. (Small human studies; Carraro et al., "Thymosin-alpha 1 (Zadaxin) enhances the immunogenicity of an adjuvanted pandemic H1N1v influenza vaccine (Focetria) in hemodialyzed patients: a pilot study", 2012-02-01)
A Reddit user with self-described post-COVID CFS reported improved function while taking thymosin alpha-1; the post does not verify diagnosis, product, dose, comparator or other causes, and is anecdote only. (Community reports; Reddit, "I am now 75-80% of normal" (undated post; accessed 2026-10-28), 2026-10-28)
The FDA evidence review describes thymosin alpha-1 as a 28-amino-acid immunomodulatory peptide and discusses proposed TLR and immune-cell effects; these mechanisms do not establish clinical benefit for every proposed use. (Educator material (not peer reviewed); FDA, "Thymosin Alpha-1 (Ta1) Related Bulk Drug Substances" (Pharmacy Compounding Advisory Committee briefing), 2024-12-04)
The sepsis evidence is mixed: an earlier trial had a non-significant primary 28-day mortality result, while the larger phase 3 TESTS trial found no significant mortality or secondary-outcome benefit. (Human clinical trials; Prescott et al., "The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial", 2025-01-15)
The FDA evidence review lists injection-site irritation, redness and discomfort among commonly reported effects and describes safety uncertainties, including limited evidence in immunosuppressed transplant recipients and potential immune-related concerns. (Educator material (not peer reviewed); FDA, "Thymosin Alpha-1 (Ta1) Related Bulk Drug Substances" (Pharmacy Compounding Advisory Committee briefing), 2024-12-04)
No thymosin alpha-1/thymalfasin/Zadaxin ARTG entry was identified in the public register search checked on 2026-10-28; this is a search finding and not a substitute for product-specific legal advice or a TGA determination. (Educator material (not peer reviewed); TGA, "Searching the Australian Register of Therapeutic Goods (ARTG)" (public search checked 2026-10-28; page last updated 2021-06-22), 2026-10-28)
The TGA states that therapeutic peptide products generally require ARTG inclusion before supply unless a specific approval, authority or exemption applies; restricted pathways for unapproved goods are not general marketing approval. (Educator material (not peer reviewed); TGA, "How we regulate therapeutic peptide products" (undated page; accessed 2026-10-28), 2026-10-28)
In a 2020 enforcement notice about specific advertised products, the TGA stated that thymosin alpha-1 products in that context were not included in the ARTG and that it had not registered products for COVID-19 prevention; this notice should not be overread as a ruling on every formulation or access pathway. (Educator material (not peer reviewed); TGA, "SGC Products fined $63,000 for alleged unlawful advertising on 'Dr. Ageless' website in relation to COVID-19", 2020-07-31)

Sources

Dosing, stacking and protocol details are not published here.