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.
Research-context information only. Thymosin alpha-1 is a research peptide. Protocols, doses, and reactions reported below come from published research and self-reported community sources. This article reports what has been documented, not what should be done. Consult a licensed physician for personal medical decisions.
Not FDA-approved in the US. Approved in 30+ countries for hepatitis B and immune support. This is not medical advice.
Thymosin Alpha-1 Dosing Table
Match your vial size below — reconstitution and dose math update automatically.
| Dose | Syringe units | mL volume | Schedule |
|---|---|---|---|
| 1.5 mg | 30 units | 0.3 mL | Daily SubQ (5-on/2-off)Standard |
| 1.6 mg | 32 units | 0.32 mL | 2x/week SubQClinical-trial dose |
| 3 mg | 60 units | 0.6 mL | Weekly SubQAdvanced |
Math assumes U-100 insulin syringes (1 mL = 100 units). Verify your syringe matches before injecting. Round half-units to the nearest visible mark.
| Dose | Syringe units | mL volume | Schedule |
|---|---|---|---|
| 1.5 mg | 60 units | 0.6 mL | Daily SubQ (5-on/2-off)Standard |
| 1.6 mg | 64 units | 0.64 mL | 2x/week SubQ |
Math assumes U-100 insulin syringes (1 mL = 100 units). Verify your syringe matches before injecting. Round half-units to the nearest visible mark.
Quick Reference: Standard Protocol
| Parameter | Standard Protocol |
|---|---|
| Dose | 1.5 mg (30 units on insulin syringe) |
| Route | Subcutaneous injection |
| Timing | AM |
| Frequency | 5 days on, 2 days off |
| Cycle | 8 weeks on, 8 weeks off |
| Vial size | 10 mg |
| Reconstitution | 2 mL bacteriostatic water → 5 mg/mL |
| Draw amount | 30 units on insulin syringe |
| Storage | Refrigerate, use within 28 days |
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 reflects the common community protocol. The clinical protocol below reflects hepatitis B trial dosing.
| Parameter | Clinical Protocol |
|---|---|
| Dose | 1.6 mg twice weekly |
| Duration | 6-12 months |
| Indication | Chronic hepatitis B, immune adjuvant |
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): Trial protocols and community resources describe subcutaneous injection in the upper arm, abdomen, or thigh, with site rotation documented. Reported syringe specifications: 29-31 gauge, 1/2 inch insulin syringes. Pharmacokinetic data show rapid absorption with peak serum levels within 2 hours.
Reconstitution Quick Reference
| Vial Size | BAC Water | Concentration | 1.5 mg Dose |
|---|---|---|---|
| 10 mg | 2 mL | 5 mg/mL | 30 units |
10 mg vial + 2 mL BAC water = 5 mg/mL. A 1.5 mg dose corresponds to 30 units on an insulin syringe at this concentration.
Protocols describe swirling gently rather than shaking, then refrigerating at 2-8°C and using within 28 days.
