Thymosin Alpha-1 (Thymosin Alpha-1 (Thymalfasin))
A thymic peptide approved in over 35 countries for immune modulation. Enhances T-cell function, dendritic cell maturation, and anti-viral/anti-tumor immunity without overstimulation.
How it works
Activates toll-like receptors (TLR2, TLR9) on dendritic cells, promotes T-cell maturation and differentiation, enhances NK cell cytotoxicity, and modulates cytokine profiles.
Key facts
- Molecular weight: 3108.3 Da
- Half-life: ~2-3 hours
- Bioavailability: ~85% subcutaneous
- Storage: Lyophilized: 2-8°C. Reconstituted: 2-8°C for up to 14 days.
Dosing overview
- Typical dose: 1.6-3.2 mg
- Frequency: 2-3x per week
- Duration: 4-12 weeks or longer
- Route: Subcutaneous injection
Protocol notes
- A common protocol is 1.6 mg twice weekly, stepping to 3.2 mg or 3x weekly during active immune challenges.
- For chronic immune support, many run lower, less frequent dosing (e.g. 1.6 mg twice weekly) over longer periods.
- Often paired with other immune peptides (LL-37, KPV) during acute illness windows.
Reported benefits
- Enhanced T-cell immunity
- Anti-viral activity
- Dendritic cell activation
- Cancer immunosurveillance
- Vaccine adjuvant effects
Possible side effects
- Injection site discomfort
- Mild fatigue
- Low-grade fever (rare)
- Muscle aches
Research
- Thymalfasin in hepatitis B treatment (2019): Improved sustained virologic response rates by 25% when combined with standard antiviral therapy.
- Thymosin alpha-1 immune modulation in COVID-19 (2021): Reduced mortality and improved T-cell counts in severe COVID-19 patients as adjunctive therapy.
Community reviews of Thymosin Alpha-1
- nerdy_nomad340 rated it 4/5 - Helped me stay steady through a rough winter stretch: I tried Thymosin Alpha-1 over about 12 weeks when I was getting run down here in India, teaching yoga in a dusty season and also doing early morning walks that kept leaving me a bit wiped. For me, it seemed to help me bounce back faster after those little viral bugs that keep going around. I still had one annoying week where I felt off, so not a fairy tale, but overall I was getting through the season more steadily.
- megan302 rated it 3/5 - held steady, but i expected more: i ran thymosin alpha-1 for about 12 weeks this winter while i was trying to stay upright through the usual west coast cough-and-cold parade and keep training without getting sidelined. for me, it seemed to help me feel a little less run down, and i did not seem to get knocked flat by every minor bug floating around. that said, the change was pretty subtle. i did not feel some dramatic immune upgrade, just a mild sense of being more resilient (or maybe i was having a decent stretch anyway). i’d give it 3 out of 5. mild benefit, nothing flashy, and i’d still want to think hard before running it
- vet945 rated it 4/5 - steadier winters, less drama than i expected: i ran thymosin alpha-1 for about 10 weeks because i’m in a gym all day in singapore, breathing everybody’s lovely little coughs and sniffles, and at my age i’m not keen on getting flattened by every bug going around. for me it seemed to make those rough patches less frequent, but the best bit was how steady i felt overall. i still preferred cjc-1295 with ipamorelin for recovery, though, that one felt more useful for my training.
- amber724 rated it 3/5 - Helped a bit, but my sleep got oddly light: I ran Thymosin Alpha-1 for about 6 weeks in winter, because working in a lab in the Netherlands means everybody brings their germs like it is a hobby. It seemed to help me catch fewer little bugs, but my sleep got a bit lighter and I woke up more often.
- travis231 rated it 2/5 - Skeptical at first, stayed skeptical after 10 weeks: I went in skeptical because I wanted something to help me stay steady during recovery and long shifts in the Philippines, but basically it did not move much for me. Maybe a small sense of being less run down, but nothing clear enough to change my mind. The few flu-like feelings were annoying, so 2/5.
- longevity_grinder rated it 5/5 - Fewer sick days in the middle of meet prep: For me, the biggest thing was I quit getting knocked out by every little bug that floated through the gym and ICU. Over about 4 months on thymosin alpha-1, I just stayed steadier through meet prep and winter in the South. Couldve been coincidence, but it felt real to me.
Compare Thymosin Alpha-1
Research and educational reference only. Not medical advice.