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Thymosin Alpha-1 · Dosing

How Thymosin Alpha-1 Is Actually Dosed

What does a real Thymosin Alpha-1 dose schedule look like?

A-Tier Immune Strong clinical

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The plain-English version

Standard protocol is 1.6 milligrams (a small subQ shot) twice a week, for 6 to 12 weeks. The branded version (Zadaxin) is approved abroad for hepatitis and chemo support. In the US, it is compounded off-label for general immune support. Always with a doctor.

Route: subcutaneous injection. Evidence tier for the dose: Strong clinical. Multiple human studies support the dosing protocol; not yet FDA-labeled for this exact indication but close.

The dose at a glance

What's typical What's the max in research
Starting dose: 1.6 mg subQ (under-the-skin shot) twice weekly. Some clinicians start at 0.8 mg for sensitive patients. Max observed in research: Some hepatitis trials used 1.6 mg twice daily for short periods. The standard 1.6 mg twice weekly is the practical maintenance ceiling - more frequent dosing has not shown added benefit.
Maintenance dose: 1.6 mg twice weekly during a 6-12 week cycle.
Frequency: Twice weekly. Most protocols use a fixed schedule (Monday and Thursday) to make it routine. Half-life: About 2 hours in plasma. Tissue effects on T-cell function are believed to last 3-5 days, which is why twice-weekly works.

Titration (how to ramp the dose)

Most users skip formal titration (slow ramp-up). Some start at 0.8 mg for the first 2 doses to test tolerance.

Cycle length and time off

On cycle: 6 to 12 weeks per cycle. Hepatitis protocols can run longer (up to 6 months) under specialist care.

Off cycle: 4 to 8 weeks off between cycles for general immune support. Continuous dosing is reserved for active hepatitis or chemo support.

Timing notes: Time of day does not matter much. Most users inject morning. Inject in stomach or thigh fat. Rotate sites.

What's commonly prescribed (per published protocols and clinical write-ups)

Branded Zadaxin (manufactured by SciClone Pharmaceuticals) is approved in 35+ countries for hepatitis and chemo support but NOT in the US. US compounding pharmacies dispense Thymosin Alpha-1 as a lyophilized (freeze-dried, shelf-stable) vial, typically 5 mg or 10 mg. Telehealth scripts usually read 'Thymosin Alpha-1 1.6 mg subQ twice weekly x 12 weeks.' Functional and integrative medicine practitioners are the most common prescribers in the US.

Source: prescribing labels, published protocols, and clinical write-ups. We have not independently tested each prescriber pattern.

Reconstitution (mixing the vial)

Lyophilized 5 mg vials reconstitute (mix back into liquid) with exactly 2 mL of bacteriostatic water (sterile water with preservative, the kind compounding pharmacies sell for reconstituting peptides). At 5 mg per 2 mL, every 0.1 mL on the syringe equals 250 mcg, so a 1.6 mg dose is 0.64 mL. If your pharmacy filled the vial with a different volume, recalculate from the mg/mL printed on your vial label - not from this page. Store reconstituted vial in the fridge, use within 30 days.

Reconstitution = mixing freeze-dried (lyophilized) powder with bacteriostatic water (sterile water with preservative) so you can draw a dose into a syringe.

Where to get it

Honest take on where to source this peptide. What fits which user, and what to watch for.

Compounded peptide vendor

Limitless Biotech

Fits: You want a Thymosin Alpha-1 cycle for immune support under prescriber direction, you want a US-based source with published COAs.

Watch: Thymosin Alpha-1 (Zadaxin) is approved in some countries but not the US. Compounded paths exist; insurance coverage does not. Pending affiliate.

(pending) Visit Limitless Biotech ->

Compounded peptide vendor

Apollo Peptide Sciences

Fits: You want a second source to cross-check COA, batch availability, or pricing for a longer Thymosin Alpha-1 cycle.

Watch: Same caveats. Pending affiliate.

(pending) Visit Apollo Peptide Sciences ->

We're evaluating vendor partnerships across this category. When we have an active affiliate relationship, we disclose it here clearly. As of now: placeholder or pending status per vendor above. Affiliate links don't change our editorial take. We only recommend what we'd actually use.

Drug interactions to watch

  • Immunosuppressive drugs (cyclosporine, tacrolimus, prednisone at high doses) - opposing mechanism; coordinate with prescriber.
  • Vaccines - may enhance vaccine response; useful timing tool but discuss with your doctor.
  • Other immunomodulators - report all current medications to the prescribing clinician.

Who should not take this (contraindications)

  • Active organ transplant on immunosuppressants (the drug works against the transplant strategy).
  • Active flares of immune-mediated disease (lupus, RA) without rheumatologist sign-off.
  • Pregnancy and breastfeeding (no safety data).
  • Known hypersensitivity to the peptide.

Common side effects

  • Mild fatigue or flu-like feeling in the first 1-2 doses.
  • Injection-site reaction (mild redness, soreness).
  • Transient low-grade fever (rare, usually first dose only).

Serious side effects (call a doctor)

  • Worsening of autoimmune disease - stop and call your rheumatologist.
  • Allergic reaction (hives, swelling) - rare but documented.
  • Persistent fever or unusual immune-related symptoms.

What to monitor while you're on it

  • CBC with differential at baseline and 6 weeks (track lymphocyte counts).
  • If using for hepatitis or chronic infection: viral load and liver enzymes per specialist protocol.
  • Symptom log - infection frequency, energy, sleep.

How to stop

Just stop at the end of the cycle. No taper needed. T-cell effects fade over weeks.

Where this dosing comes from

  • Camerini and Garaci, Thymosin Alpha-1 mechanism review (2010)
  • Multiple hepatitis B and C RCTs (Zadaxin clinical program, 1990s-2010s)
  • SciClone Pharmaceuticals prescribing information for Zadaxin (international)
  • US compounding pharmacy formularies (Tailor Made, Empower, Strive)

Where these doses come from

These doses come from human trials and prescribing protocols used by clinicians. Not FDA-approved at this exact dose, but well-supported by published data.

Always work with a real prescriber. Don't self-prescribe.

Safety reminder: None of this replaces a doctor. Peptides are gray-market in the US for most uses. Talk to a real prescriber before you change anything.

Where to go next

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Last reviewed · 2026-05-07 · Page generated by Protocol One matrix engine. None of this replaces a doctor. Peptides are gray-market in the US for most uses. Talk to a real prescriber before you change anything.