thymic immunomodulatory peptide

Thymosin alpha-1

aka thymalfasin · Tα1 · Ta1

Evidence grade
Grade B: Moderate human evidence
for immune support / infection defence
User score too few reports (9) needs ≥ 10 reports
US FDA Not approved checked 2026-11-13
WADA 2026 Not named no clearance either · checked 2026-11-13
EU EMA's 2003 record described Italian authorization as an influenza-vaccine immune enhancer and an EU orphan designation for liver cancer; current authorization was not verified and designation is not marketing approval. · checked 2026-11-13

Goals: Immune Compare with another peptide →

User reports

approximate — combined from two independent Reddit reads

Men 45–60

0 men aged 45–60

No reports in this group yet.

All men

1 man

small sample · n = 1

Outcome positive 1 of 1

Benefits energy 1 of 1 · recovery 1 of 1

Side effects none reported

Stopped 0 of 1 Used with other compounds 1 of 1

Everyone

9 people

small sample · n = 9

Outcome positive 5 of 9 · negative 3 of 9 · no effect 1 of 9

Benefits energy 3 of 9 · endurance 2 of 9 · focus / cognition 1 of 9 · immune 1 of 9 · other 1 of 9 · recovery 1 of 9

Side effects other 3 of 9 · fatigue 2 of 9 · insomnia 1 of 9

Why stopped side effects 3 of 9

Stopped 3 of 9 Used with other compounds 1 of 9

User reports are anecdata, not evidence: self-selected, unverified, often combined with other compounds.

In their words

  • “Taking this peptide has improved my fatigue immensely. I have returned to at least 80% of my normal.”

  • “Ultimately, Thymosin Alpha 1 was the only thing that got me back in the gym after ~2.5 yrs.”

  • “It did not help me.”

  • “Both Thymalin and TA-1 gave me flu like symptoms day one. I was pretty dysfunctional. I can't afford to be out of commission”

Read summaries and method notes

Read 1. No man aged 45–60; one man (on TRT, age not stated) said TA1 was the only thing that got him back in the gym after about 2.5 years. Of eight users, five positive (big improvements in fatigue and exertion tolerance over weeks to months; one back to ~80% after 96 days), two negative (severe crash, swollen nodes, poor sleep, feeling ill — both stopped), one no effect. Long-COVID/ME-CFS fluctuation is a major confounder.

Read 2. One self-reporter (the same person as for Thymalin): TA-1 also caused debilitating flu-like symptoms on day one and an immediate stop. The four seed threads could not be opened. n=1 is too limited.

Note 1. No target-age men. Mostly Long COVID, CFS or CIRS populations with variable natural history and concurrent treatments.

Note 2. Only one accessible cross-referenced thread; the four seed threads were not available.

Each read counted people independently. Overlap between the two reads is estimated from shared threads and removed; counts are approximate. How we count.

Summary

28-aa thymic peptide. Routine immune, longevity or recovery benefit in healthy aging adults is not established. Decades of clinical use. Enhances T-cell and NK cell activity. Balances immune response rather than simply stimulating it.

Proposed mechanism

Immune-cell and cytokine mechanisms are biological hypotheses, not proof of infection prevention or clinical benefit in healthy people.

  • Increases CD4+ and CD8+ T-cell numbers and activity
  • Enhances NK cell activity
  • Proposed/preclinical anti-tumor effects include proliferation inhibition and apoptosis; these do not establish clinical cancer treatment.
  • Reduces IL-1β, TNF-α
  • The claimed zinc requirement for clinical T-cell/NK activation was not substantiated.
  • Modulates cytokine production for balanced inflammation

Safety

  • Injection-site discomfort and occasional rash or itching
  • Hypersensitivity contraindication
  • Caution with deliberate immunosuppression, autoimmune disease and immune-modulating drugs
  • Limited pregnancy, lactation and pediatric data
  • Compounded peptide immunogenicity and impurity concerns

From labels, regulators and trials. No signal in small studies ≠ safe.

Evidence B immune support / infection defence

B stands, softly. Narrow national approvals abroad for chronic hepatitis B are the same kind of use (immune modulation) and are backed by published RCTs; the file adds a positive 120-person open-label RCT in hepatitis-B liver failure. Against it: the 1,106-patient sepsis RCT showed no mortality benefit, the positive trial's own competing-risk analysis was not significant (found in the spot-check), and nothing shows a benefit in healthy older adults.

Human trials · 2

  1. NCT028672672025multicentre double-blind placebo-controlled RCT 1,106 people

    Adults with sepsis

    No clear 28-day mortality benefit; corrected hazard ratio 0.97 (95% CI 0.76–1.24); 1,089 analyzed. Source

  2. NCT030828852022open-label RCT 120 people

    Adults with hepatitis B-associated acute-on-chronic liver failure

    90-day transplant-free survival was 75.0% versus 53.4% with standard therapy alone; replication is needed. Source

Bar length = trial size on a log scale.

Dose ranges

Reported ranges from labels and studies, with context. Not a recommendation.

  • approved label, Indonesia, chronic hepatitis B
    1.6 mg subcutaneously twice weekly for 6 months Source on a non-primary host — not linked
  • clinical trial, adult sepsis
    1.6 mg subcutaneously every 12 hours for up to 7 days Source
  • clinical trial, hepatitis B-related acute-on-chronic liver failure
    1.6 mg subcutaneously daily for 7 days, then twice weekly for 11 weeks Source on a non-primary host — not linked

Editorial ratings EDITORIAL

Editors’ judgement, 0–5. Opinion, not data; separate from grade and user score.

  • Safety 4.5 out of 5
  • Sleep 3.5 out of 5
  • Recovery 4 out of 5
  • Cognitive 3 out of 5

Sources

  1. pmc.ncbi.nlm.nih.gov/articles/PMC11780596/
  2. pubmed.ncbi.nlm.nih.gov/35616850/
  3. fda.gov/media/185642/download
  4. wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
  5. ema.europa.eu/en/documents/orphan-designation/eu302110-public-summary-positive-opinion-orp
  6. pubmed.ncbi.nlm.nih.gov/39814420/
  7. pmc.ncbi.nlm.nih.gov/articles/PMC11886152/
  8. pmc.ncbi.nlm.nih.gov/articles/PMC9754924/
  9. clinicaltrials.gov/study/NCT03082885
  10. fda.gov/media/183820/download
  11. fda.gov/media/183819/download#page=1
  12. fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-pres
  13. fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-pres
  14. fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-c

Reddit threads read · 6

5 further sources on commercial or non-primary hosts not listed.

Research checked 2026-11-13.