Anti-aging
Thymosin Alpha-1
A naturally occurring immune-regulating peptide, approved as a prescription drug (Zadaxin) in dozens of countries for chronic hepatitis B/C and as an immune adjuvant, one of the few peptides here with real regulatory approval somewhere in the world.
Approved abroad (Rx) Anti-aging Longevity Peptide bioregulators
- Full name
- Thymosin α1 (Tα1)
- Also known as
- TA-1, Tα1, Zadaxin (brand name)
- Regulatory status
- Approved prescription drug (as Zadaxin) in roughly 35 countries for chronic hepatitis B/C, certain cancers as adjunct therapy, and immune support, though not FDA-approved in the United States. Widely used off-label/self-administered for general immune modulation.
Origin
First isolated from the thymus gland in 1972, a naturally occurring 28-amino-acid peptide fragment involved in T-cell maturation and immune regulation.
Mechanism
Modulates the immune system in both directions: it can boost an underactive response (helpful in chronic infection) while dampening an overactive one (of interest in some autoimmune contexts), largely through effects on dendritic cell maturation, T-cell differentiation and cytokine signalling, including toll-like receptor pathways.
Research summary
Evidence
Genuinely well studied relative to most peptides in this wiki, including real RCTs: shown to improve outcomes in chronic hepatitis B and C (part of why it holds drug approval in multiple countries), studied as an adjuvant in several cancer types and for improving vaccine response in immunocompromised populations, and investigated for cystic fibrosis and various chronic/recurrent infections, including some COVID-19-era research for severe cases. One of the more legitimately evidence-backed compounds discussed in self-experimentation circles, even though it isn't FDA-approved domestically.
Evidence tier: Approved abroad (Rx) — see the methodology note for how this is assessed.
Citations
- Safety and efficacy of Thymosin α1 in the treatment of hepatitis B virus-related acute-on-chronic liver failure: a randomized controlled trial — Chen et al. 2022
- Combination of entecavir with thymosin alpha-1 in HBV-related compensated cirrhosis: a prospective multicenter randomized open-label study — Wu et al. 2018
- A multicenter, randomized, observation-controlled clinical trial to evaluate the efficacy and safety of thymalfasin adjuvant therapy in patients with HBV-related HCC after curative resection - first announcement of the protocol — Qiu et al. 2015
- Thymosin alpha 1 - Reimagine its broader applications in the immuno-oncology era — Mao 2023
Reported benefits
- Reduced frequency/severity of recurrent infections reported by long-term users
- Used by some with autoimmune conditions seeking immune 'rebalancing' rather than pure suppression or pure stimulation
- General immune support during illness or high-stress/high-training periods
Dosing protocols reported in the literature & community
These are protocols reported by compounding pharmacies, published trials, or self-experimentation communities — not a prescription. Start low, especially for anything new.
| Route | Reported protocol |
|---|---|
| Subcutaneous injection — standard protocol | The approved Zadaxin dosing (in countries where it's licensed) is 1.6 mg subcutaneously, twice weekly. Self-experimenters largely mirror this. |
| Acute illness / short-term immune support | Some users increase frequency to 2-3x per week during an active infection or high-risk exposure period, then return to twice-weekly maintenance. |
Side effects
- Generally well tolerated in the clinical literature backing its drug approval abroad
- Mild injection-site reactions reported
- As an immune modulator, caution is warranted for people on immunosuppressant therapy or with autoimmune conditions — effects on an already-dysregulated immune system are harder to predict
Safety notes
Community & reddit notes (anecdotal — not clinical evidence)
Popular among people who get frequent colds/infections, and within the EDS/HSD and chronic-illness communities as a general immune-support peptide. Regarded as one of the 'more legitimate' peptides because of its overseas drug approval, a common talking point when comparing evidence quality across peptides.
Related peptides
Mixing compatibility
Pulled from a community-charted mixing-compatibility reference (anecdotal, clinic-use, and community-reported signals) — not a safety guarantee. Verify independently before combining anything.
Used together in wellness-clinic protocols
- BPC-157
- CJC-1295 / Mod-GRF (1-29)
- CJC-1295 with DAC
- Epithalon
- Ipamorelin
- LL-37
- MGF
- Pinealon
- Selank
- Semax
- TB-500 / Thymosin Beta-4
- Thymalin