Skip to content

Thymosin Alpha-1 vs Thymosin beta-4

Updated 13 sources

Key differences

  1. 1Both come from the thymus family of peptides but share no sequence or job: alpha-1 tunes T-cell immunity, while beta-4 (the parent of TB-500) is used for tissue repair.
  2. 2Thymosin beta-4 is WADA-prohibited under S2; alpha-1 is not named.
  3. 3Unrelated peptides that share the old thymosin name. Thymosin alpha-1 is an immune modulator; thymosin beta-4 is a repair and actin protein.

Side by side

Facts from each record, in the same words as their own pages.
Thymosin Alpha-1 and Thymosin beta-4 side by side
Thymosin Alpha-1Thymosin beta-4
Category
  • Immune, Longevity
  • Healing & recovery
Evidence
  • Some human trials
  • Some human trials
FDA status
  • Not FDA approvedRegulatory
  • In clinical trialsRegulatory
WADA
  • Not confirmed
  • Prohibited
Half-life
  • About 2 hours after an injection under the skin, with peak levels at about 2 hours and no build-up between doses (label).Regulatory
  • About 2 to 3 hours per guides; peak 1 to 2 hours after injection.Competitor guide
  • 0.5 to about 2 hours after IV recombinant thymosin beta-4 in healthy volunteers; no subQ data.Clinical study
  • Rose with dose after IV synthetic thymosin beta-4 in healthy volunteers.Clinical study
Routes
  • Subcutaneous injection
  • Intravenous (IV), Topical, Subcutaneous injection
Forms
  • Vial (powder)
  • Vial (powder), Topical
Reported doses
  • 0.8 to 3.2 mg (subcutaneous injection)
  • 40 mcg/kg (subcutaneous injection)
  • 250 to 500 mcg (subcutaneous injection)
  • 42 to 1,260 mg (intravenous (iv))
  • 0.05 to 25 mcg/kg (intravenous (iv))
  • 0.01 to 0.1% (topical)
Most cited frequency
  • Twice a week
  • One dose, then the same dose daily for 14 days
Vial sizes
  • 1.6 mg, 5 mg, 10 mg, 20 mgRegulatory
  • 5 mg, 10 mgCompetitor guide
Mixed vial keeps
  • Zadaxin mixed with its sterile water is single use: inject immediately.Regulatory
  • Fridge at 2 to 8 C, use within 7 to 10 days, avoid freeze-thaw.Competitor guide
Protocols on file
  • 19
  • 10

Doses shown are what sources report, labelled by origin. Not medical advice.

Read each in full

Sources

13 sources, each checked by date. Record updated Oct 24, 2026. Numbers are restated in our own words and labelled by where they came from.

Regulatory6

  1. WADA 2026 Prohibited ListWADA · checked Oct 24, 2026
  2. Zadaxin (thymalfasin) prescribing informationRxList, via a reference work · checked Oct 24, 2026
  3. Certain bulk drug substances that may present significant safety risksFDA · checked Oct 24, 2026
  4. Pharmacy Compounding Advisory Committee, December 4, 2024 summary minutesFDA · checked Oct 24, 2026

Competitor guide5

  1. Thymosin Alpha-1 profilepeptidesexplorer.com · checked Oct 24, 2026
  2. Thymosin Alpha-1 (TA1) guidepeptidedosingprotocols.com · checked Oct 24, 2026
  3. Thymosin Alpha-1 (10 mg vial) dosage protocolpeptidedosages.com · checked Oct 24, 2026
  4. Thymosin Alpha-1 compound pagepeptiq.io · checked Oct 24, 2026