Thymosin Alpha-1 Dosing: 1.5mg 5on/2off Protocol

Thymosin alpha-1 is a 28-amino acid immune-modulating peptide originally isolated from thymic tissue. Its synthetic form (thymalfasin) is approved in over 30 countries and has been studied in more than 11,000 human subjects.

Not FDA-approved in the US. Approved in 30+ countries for hepatitis B and immune support. This is not medical advice.

Quick Reference: Standard Protocol

Standard protocol: 1.5 mg subcutaneous in the morning, 5 days on / 2 days off, for 8-week cycles. For the full thymosin alpha-1 profile, see our thymosin alpha-1 peptide page.

Cycling Details

The standard cycle is 8 weeks on, 8 weeks off. The 5on/2off daily schedule provides periodic receptor rest while maintaining consistent immune modulation throughout the week.

Acute immune support: Some run 1.5 mg daily (no rest days) for 1-2 weeks during active illness, then transition to the standard 5on/2off schedule. Seasonal/preventive: 8-week courses during cold/flu season or 1-2 weeks before international travel.

Enhanced Protocol (Clinical)

Note: The standard protocol above follows the cheat sheet. The clinical protocol below reflects hepatitis B trial dosing.

Clinical trials used twice-weekly dosing for extended periods. The community 5on/2off daily protocol provides higher weekly exposure but with cycling to prevent long-term receptor adaptation.

Routes of Administration

Subcutaneous (standard and only route): Upper arm, abdomen, or thigh — rotate between sites. Use 29-31 gauge, 1/2 inch insulin syringe. Rapid absorption with peak serum levels within 2 hours.

Reconstitution Quick Reference

10 mg vial + 2 mL BAC water = 5 mg/mL. Your 1.5 mg dose is 30 units on an insulin syringe.

Swirl gently — do not shake. Refrigerate at 2-8°C and use within 28 days.

Where These Numbers Come From

Thymosin alpha-1 has one of the strongest clinical evidence bases of any peptide in the research community.

Immune Modulation: A comprehensive review confirmed thymosin alpha-1's pleiotropic effects on T-cells, NK cells, dendritic cells, and macrophages — restoring immune function across diverse clinical settings (Tuthill et al., 2016).

Hepatitis B Trials: Thymalfasin was extensively studied at 1.6 mg twice weekly for 6-12 months, showing improved virological response and enhanced vaccine responsiveness in immunocompromised patients.

Sepsis Data: A large Phase III trial (TESTS) evaluated thymosin alpha-1 at 1.6 mg in sepsis patients, providing significant data on immune modulation in critical illness (Li et al., 2025). An earlier meta-analysis showed trends toward reduced mortality from multiple organ failure (Li et al., 2015).

Safety Review: A narrative review covering 11,000+ subjects across 30+ trials confirmed an excellent safety profile with no dose-limiting toxicities (Dinetz et al., 2024).

Stacking Protocols

Thymosin Alpha-1 + LL-37 (Immune Defense Stack)

Thymosin Alpha-1 + Thymulin

Complementary thymic peptides — TA-1 acts downstream on function, thymulin acts upstream on development.

Thymosin Alpha-1 + BPC-157

Side Effects & Safety

• Injection site reactions — mild erythema, minor discomfort (most common, transient)
• No dose-limiting toxicities identified across 30+ clinical trials
• No significant organ toxicity reported in 11,000+ subjects
• No immune overstimulation — modulates rather than simply stimulates immunity
• Safe in immunocompromised — extensively used in HIV, hepatitis, and cancer patients
• Caution in autoimmune conditions — immune modulation warrants monitoring
• Caution with organ transplant — immune enhancement could theoretically affect tolerance

Frequently Asked Questions

What is the standard thymosin alpha-1 dose?

1.5 mg subcutaneous daily in the morning, 5 days on / 2 days off, for 8-week cycles. Draw 30 units from a 10 mg vial reconstituted with 2 mL BAC water.

How long should a thymosin alpha-1 cycle last?

8 weeks on, 8 weeks off is the standard cycle. Clinical trials ran 6-12 months for hepatitis. Some use 1-2 week acute courses during illness.

Can thymosin alpha-1 be stacked with LL-37?

Yes — this is the premier immune defense stack. TA-1 handles adaptive immune modulation while LL-37 provides direct antimicrobial activity and innate immune support. Completely different mechanisms.

Is thymosin alpha-1 FDA-approved?

Not in the US. Thymalfasin is approved in 30+ countries for hepatitis B and immune support, with clinical data across 11,000+ trial subjects.

Does thymosin alpha-1 have side effects?

Exceptional safety profile. Mild injection site discomfort is the most common. No dose-limiting toxicities, organ damage, or immune overstimulation across large clinical trials.

How do I reconstitute thymosin alpha-1?

Add 2 mL BAC water to a 10 mg vial (5 mg/mL). 1.5 mg = 30 units on an insulin syringe. Swirl gently, refrigerate, use within 28 days.

Related Guides

• Thymosin Alpha-1 Benefits — 7 immune effects ranked by evidence quality
• Thymosin Alpha-1 Results Timeline — Week-by-week expectations
• Thymosin Alpha-1 Bloodwork Guide — 6 labs to track immune response
• LL-37 Dosing Guide — Antimicrobial peptide for immune stacking
• Thymulin Dosing Guide — Another thymic peptide for immune support
• BPC-157 Dosing Guide — Healing peptide with immune-supportive properties
• Calculate Your Thymosin Alpha-1 Cycle Cost — Estimate vials needed and total cost

References

For educational and research purposes only. This is not medical advice. Thymosin alpha-1 is approved in 30+ countries but not FDA-approved in the US.