Thymalfasin

n/c: not counted here; see the cited review.

Several small randomised trials, mostly from the 1990s, gave mixed results. A Taiwanese trial of 98 patients reported higher combined viral clearance at 18 months with a 26-week course than with no treatment. A US phase 3 double-blind placebo-controlled trial of 97 patients did not show a statistically significant difference. A meta-analysis of four small trials against interferon alpha found responses accumulated after treatment ended. FDA's 2024 review judged the evidence insufficient, noting outdated comparators and assays; none of the trials tested current standard antivirals as comparators.

• [1] Higher complete virological response at 18 months than untreated controls in 98 patients with chronic hepatitis B
• [2] Complete response 14% versus 4% with placebo in 97 patients, not statistically significant; authors state results do not confirm earlier reports
• [3] Across four small randomised trials (199 patients), responses were not better than interferon alpha at end of treatment but higher six months after treatment

Registered-study counts: ClinicalTrials.gov intervention search “thymosin alpha 1 hepatitis B”, fetched 2026-10-10. Registered studies include trials of other uses; the gap between registered and reported is itself a finding.

n/c: not counted here; see the cited review.

A randomised, double-blind, placebo-controlled trial in 552 patients who had not responded to earlier interferon-based therapy found no difference in sustained viral response when thymosin alpha-1 was added to peginterferon and ribavirin (12.7% versus 10.5%); a higher rate appeared only in a subgroup completing all 48 weeks. A small earlier placebo-controlled pilot reported no viral clearance. These trials used older interferon regimens, not current direct-acting antivirals.

• [4] No difference in sustained viral response versus placebo in the intention-to-treat population of 552 patients

Registered-study counts: ClinicalTrials.gov intervention search “thymosin alpha 1 hepatitis C”, fetched 2026-10-10. Registered studies include trials of other uses; the gap between registered and reported is itself a finding.

n/c: not counted here; see the cited review.

The largest trial, TESTS (1,106 adults with sepsis in 22 Chinese centres, double-blind, placebo-controlled), found no difference in 28-day mortality (23.4% versus 24.1%). An earlier single-blind randomised trial (ETASS, 361 patients) reported lower 28-day mortality with a marginal p-value. The randomised evidence is therefore conflicting, and the larger, better-blinded trial was negative. All trials were conducted in China.

• [5] No difference in 28-day all-cause mortality versus placebo in 1,089 analysed adults with sepsis
• [6] 28-day mortality 26.0% versus 35.0% in 361 patients with severe sepsis, marginal statistical significance

Registered-study counts: ClinicalTrials.gov intervention search “thymosin alpha 1 sepsis”, fetched 2026-10-10. Registered studies include trials of other uses; the gap between registered and reported is itself a finding.

n/c: not counted here; see the cited review.

A randomised trial in 488 patients with metastatic melanoma compared dacarbazine plus interferon alpha with arms adding thymosin alpha-1. More tumour responses were seen in two thymosin arms, but the differences in overall and progression-free survival did not reach statistical significance. FDA's 2024 review of liver and lung cancer studies found small randomised trials, single-arm and retrospective studies, and concluded the evidence was insufficient. These regimens are not current standard care.

• [7] More tumour responses with thymosin alpha-1 arms in 488 patients with metastatic melanoma; survival differences not statistically significant

Registered-study counts: ClinicalTrials.gov intervention search “thymosin alpha 1 cancer”, fetched 2026-10-10. Registered studies include trials of other uses; the gap between registered and reported is itself a finding.

n/c: not counted here; see the cited review.

Evidence comes mainly from retrospective cohort studies early in the pandemic. A meta-analysis pooling eight studies reported lower mortality with marked heterogeneity and no difference in need for mechanical ventilation or length of stay; its authors called for randomised trials. FDA's 2024 review noted that three of four meta-analyses found no mortality reduction and judged the information insufficient.

• [8] Pooled data from eight mostly non-randomised studies associated treatment with lower mortality (high heterogeneity), with no difference in ventilation need or hospital stay

Registered-study counts: ClinicalTrials.gov intervention search “thymosin alpha 1 COVID-19”, fetched 2026-10-10. Registered studies include trials of other uses; the gap between registered and reported is itself a finding.

No human trial of any design has been published for this use.

FDA's 2024 review for the Pharmacy Compounding Advisory Committee found no clinical studies of thymosin alpha-1 in ME/CFS and no data supporting effectiveness. No animal model study for this claim was identified in this review.

Registered-study counts: ClinicalTrials.gov intervention search “thymosin alpha 1 chronic fatigue”, fetched 2026-10-10. Registered studies include trials of other uses; the gap between registered and reported is itself a finding.