Thymosin Alpha-1 dosage and evidence

What is Thymosin Alpha-1?

How does Thymosin Alpha-1 work?

It helps T cells mature and work. It acts on dendritic cells, the immune cells that raise the alarm, and on immune signals called cytokines. That supports both the body's fast defences and its targeted ones.

What have studies in people found about Thymosin Alpha-1?

Thymosin alpha-1 has been given to thousands of people in controlled trials. Most had chronic hepatitis B or sepsis, a life-threatening reaction to infection. Most trials ran in China and Italy. The pattern is the same throughout. Small and mid-sized trials report a benefit. The one large trial that used a dummy drug found none.

• A review pooled 10 trials in 1,349 people with hepatitis B. They ran in Bangladesh, China, Italy, Korea, Singapore and Taiwan between 1991 and 2018. Fewer people died on the drug (3 trials, 907 people) and fewer had a serious side effect (5 trials, 1,056 people). But the reviewers rated how sure they could be as very low for deaths and low for side effects. It made little or no difference to quality of life or to liver tissue. Industry paid for four of the ten trials. Sixteen more studies could not be judged because they reported too little, and no author answered requests for data.
• The best sepsis trial: 1,106 adults at 22 Chinese hospitals got the drug or a dummy drug. After 28 days, 23.4% had died on the drug and 24.1% on the dummy. That is no clear difference.
• An earlier sepsis trial: 361 patients at six Chinese teaching hospitals. The patients did not know their group, but their doctors did. After 28 days, 26.0% had died on the drug and 35.0% in the other group. That gap was right on the edge of what chance could explain. An immune marker on white blood cells improved more on the drug at day 3 and day 7.
• COVID-19: a review pooled 8 studies. Deaths ran about 40% lower on the drug. But the studies disagreed with each other far more than chance explains. The need for a breathing machine and the time in hospital were no different.
• An older review pooled four trials in 199 people with hepatitis B. It compared thymosin alpha-1 with interferon alpha, another immune drug, on clearing the virus, liver blood tests and full response.
• An early hepatitis B trial in 98 patients: at 18 months the virus was fully cleared in 40.6% after a 26-week course and 26.5% after a 52-week course, against 9.4% of people left untreated.

What this does not tell you: None of these trials tests thymosin alpha-1 as an immune boost for a healthy person, which is what it is mostly sold for. Every trial took people who were already ill, with hepatitis B, sepsis or COVID-19. The hepatitis research is old. Most of it came before today's standard antiviral drugs. The Cochrane reviewers, an independent review group, rated every result except serious side effects as very low certainty. The COVID-19 studies disagree with each other far more than chance explains, so their pooled number is shaky. Where the research comes from matters too: much of it comes from a few countries where the drug is sold. And the single best trial on record, 1,106 patients given the drug or a dummy drug, found 28-day deaths of 23.4% against 24.1%.

What do people who took Thymosin Alpha-1 report?

This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.

• Discussion is small and comes almost entirely from people with an existing immune problem rather than from healthy users, which is worth holding in mind before reading anything into it.
• Doses described run from around 500 mcg to about 1.67 mg as a shot under the skin, on schedules ranging from every other day in a short run of a few injections to twice weekly.
• What people track is bloodwork rather than how they feel. Rising white cell and lymphocyte counts within roughly two weeks are the most repeated observation, and a matching report is that those numbers drift back within about two weeks of stopping, which posters take to mean continuous use rather than a course.
• Side effect reports are sparse, limited to a headache after a first injection and a couple of disturbed nights, with the person reporting them unsure of the cause. In a group this small, made up of people who chose to post, that is an absence of complaints, not proof of safety.
• At least one person describes finishing a trial of it and being unable to say whether it did anything.
• Sourcing is a live concern. People describe few suppliers at a sensible price, research chemical vendors as the usual route, and doubts about authenticity when the material comes from overseas.

Sources: Threads on ExcelMale, found by site-restricted search and read directly, September 2026. Nothing above is attributed to any specific post and no post is reproduced.

The state of the research

The evidence, in charts

The studies we cite

• Study in people1998
  Efficacy of thymosin alpha1 in patients with chronic hepatitis B: a randomized, controlled trial

  Thymosin alpha-1 helped clear long-standing hepatitis B in some patients, in a small and old trial. 98 people got a 26 week course, a 52 week course, or nothing at all. At 18 months, 40.6% of the short course group and 26.5% of the long course group had cleared the virus fully. 9.4% of the untreated group did. Oddly, the longer course did worse than the shorter one. The comparison group got nothing rather than a dummy shot, so expectation is not ruled out.

  98 patients: complete virological response at 18 months in 40.6% after a 26-week course and 26.5% after 52 weeks versus 9.4% of untreated controls.

  PMID 9581695 Hepatology
• Study in people2025
  The efficacy and safety of thymosin alpha 1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial

  The biggest test thymosin alpha-1 has ever been put through, and it failed. 1,106 adults who were seriously ill with sepsis got either the peptide or a dummy injection, across 22 hospitals in China. A month later, 23.4% of the treated group had died of any cause, against 24.1% on the dummy. That gap is smaller than one person in a hundred. A trial this large would have found a real benefit if there was one to find.

  1,106 adults with sepsis at 22 Chinese centres: 28-day mortality 23.4% with thymosin alpha-1 vs 24.1% with placebo (HR 0.99), so no clear mortality benefit.

  PMID 39814420 BMJ
• Study in people2013
  The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial

  An earlier, smaller sepsis trial leaned towards a benefit that a bigger trial later failed to confirm. 361 patients at six Chinese hospitals were split by chance into a thymosin alpha-1 group and a comparison group. The patients did not know which they were in. Their doctors did. After 28 days, 26.0% of the treated patients had died of any cause against 35.0% of the others. That gap was not big enough to separate from chance. The larger TESTS trial later found no difference.

  361 patients at six Chinese centres: 28-day all-cause mortality 26.0% versus 35.0%, relative risk 0.74 (95% CI 0.54 to 1.02), P=0.062 unstratified. Single-blind. The larger double-blind TESTS trial later found no difference.

  PMID 23327199 Critical Care
• Review of studies2016
  Immune Modulation with Thymosin Alpha 1 Treatment

  A review of how it works, through alarm signals in immune cells called dendritic cells. It sums up lab, animal and human studies in infection, cancer and the weaker immune system of old age.

  Reviews the pleiotropic mechanism (Toll-like receptor signaling in myeloid and plasmacytoid dendritic cells) and summarizes preclinical and clinical studies in infection, cancer and age-related immune suppression.

  PMID 27450734 Vitamins and Hormones
• Review of studies2008
  Comparison of the efficacy of thymosin alpha-1 and interferon alpha in the treatment of chronic hepatitis B: a meta-analysis

  A review that pooled four studies in 199 people with long-term hepatitis B. It compared thymosin alpha-1 with interferon alpha, another immune drug, on clearing the virus and on liver tests.

  Meta-analysis of four RCTs (199 patients) comparing thymosin alpha-1 with interferon alpha on virological, biochemical and complete response in chronic hepatitis B.

  PMID 18078676 Antiviral Research
• Review of studies2026
  Thymosin-ɑ1 for people with chronic hepatitis B

  The hepatitis B evidence leans positive and the reviewers trust almost none of it. Ten trials covering 1,349 people were pooled. Fewer people died on thymosin alpha-1 and fewer had a serious side effect. The reviewers rated both answers very low or low certainty, meaning better studies could easily overturn them. Quality of life and liver tissue barely moved. Four trials were paid for by industry. Sixteen more could not be judged because their reporting was too incomplete, and no new trials are under way.

  10 randomized trials, 1,349 participants: all-cause mortality risk ratio 0.53 (95% CI 0.29 to 0.96, very low certainty) and serious adverse events 0.72 (95% CI 0.53 to 0.99, low certainty), with little to no effect on quality of life or histology. Four trials industry-funded, sixteen further studies unassessable for incomplete reporting, no ongoing trials identified.

  PMID 42713852 Cochrane Database of Systematic Reviews
• Review of studies2023
  The efficacy of thymosin alpha-1 therapy in moderate to critical COVID-19 patients: a systematic review, meta-analysis, and meta-regression

  Pooling eight COVID studies points to fewer deaths on thymosin alpha-1, and the studies disagree with each other so badly that the pooled number cannot be trusted. Deaths ran roughly 40% lower on the drug. Time in hospital and the need for a ventilator were no different. Most of the spread between studies is not explained by chance. None of this comes from a single large trial, and the authors say proper controlled trials are still needed.

  8 studies pooled: mortality risk ratio 0.59 (95% CI 0.37 to 0.93) with I2 of 84%, and no difference in mechanical ventilation or hospital length of stay. The authors state randomized trials are still required.

  PMID 37845598 Inflammopharmacology