Thymosin Alpha-1
TA-1 — 28-amino-acid immunomodulator (Zadaxin)
A 28-amino-acid synthetic version of natural thymosin alpha-1, originally isolated from thymic tissue. Drives T-cell maturation, NK cell activation, and dendritic cell modulation. FDA-approved as Zadaxin in 30+ countries (not US) for chronic Hepatitis B/C. Off-label use centers on post-viral recovery, autoimmune modulation, and immunosenescence.
Quick reference
How Thymosin Alpha-1 works
Thymosin Alpha-1 was originally isolated from the thymus gland in 1972 and is now produced synthetically as a 28-amino-acid peptide. It modulates immune function via three primary mechanisms: T-cell maturation (specifically Th1 polarization), NK cell activation, and dendritic cell modulation (improving antigen presentation).
Unlike broad-spectrum immunosuppressants or stimulants, TA-1 is a balanced modulator — it amplifies appropriate immune responses without driving systemic inflammation. This is why it's clinically valuable in viral infections (where T-cell exhaustion is the bottleneck) and tolerable in autoimmune contexts (where most immune-active compounds are contraindicated).
The most-cited clinical use is chronic Hepatitis B/C — TA-1 + interferon combination shows improved sustained virologic response vs interferon alone. Off-label uses include long COVID / post-viral fatigue, immunosenescence (age-related immune decline), and adjuvant cancer immunotherapy.
In the DoseCraft framework, Thymosin Alpha-1 targets Inflammation (immune balance) and indirectly ATP Shortage (post-viral mitochondrial recovery via reduced systemic inflammatory load).
Reconstitution math
- Remove the flip-off cap from the 1.6 mg or 5 mg vial.
- Draw 1 mL of bacteriostatic water into a sterile syringe (for 5 mg vial).
- Inject slowly down the vial wall.
- Swirl gently. Do not shake.
- Refrigerate. Stable approximately 30 days at 2–8°C.
Dose math
5 mg vial + 1 mL bac water → 5 mg per mL (5,000 mcg/mL).
On a 100-unit insulin syringe (1 IU = 0.01 mL):
- • 30 IU = 1.5 mg (1,500 mcg)
- • 50 IU = 2.5 mg (2,500 mcg)
- • Standard dose: 30-50 IU per injection
Safety + side-effect profile
One of the most well-tolerated peptides in clinical practice. Side effects are uncommon and mild.
Not documented at standard doses: hepatotoxicity, hormonal disruption, significant cardiovascular effects. Contraindications: active immunosuppressive therapy (TA-1 antagonizes the intent), organ transplant patients on rejection prophylaxis, pregnancy (insufficient data), lactation.
Interaction notes: stacks well with most peptides. Avoid combining with biologic immunosuppressants (TNF blockers, JAK inhibitors) — direct mechanistic conflict. Generally synergistic with antiviral therapy. Caution in autoimmune diseases — TA-1's Th1 polarization can theoretically worsen Th1-driven conditions (some autoimmune contexts), though clinical evidence is mixed.
- • Mild injection-site soreness (rare)
- • Occasional transient flu-like feeling in first 3-5 days (immune activation)
- • Rare allergic reactions
Frequently asked
What is Thymosin Alpha-1?
Thymosin Alpha-1 (TA-1) is a 28-amino-acid synthetic version of a peptide originally isolated from the thymus gland. Drives T-cell maturation, NK cell activation, and dendritic cell modulation. FDA-approved as Zadaxin in 30+ countries (not US) for chronic Hepatitis B/C.
What is the typical TA-1 dose?
Canonical foundational protocol: 1 mg (1,000 mcg) subcutaneous DAILY, long-term (no cycling required — TA-1 is daily-forever in the Top 4 longevity stack). For acute viral or bacterial infection adjunct: 1.6 mg daily × 7–14 days then drop to 1 mg maintenance. Older community descriptions of "1.5–2.5 mg every other day" are drift from the consolidated canonical baseline of 1 mg/day.
How do I reconstitute TA-1?
5 mg vial + 1 mL bacteriostatic water → 5 mg/mL. On a 100-unit insulin syringe, 30 IU = 1.5 mg, 50 IU = 2.5 mg. Refrigerate after reconstitution; stable approximately 30 days.
Is TA-1 effective for long COVID?
Off-label use is documented in practitioner reports for long COVID / post-viral syndromes. Mechanism is plausible (TA-1 addresses T-cell exhaustion, which is documented in long COVID immunology). Formal trials are emerging but not yet conclusive. Most practitioner protocols run 1.6 mg daily for 7–14 days (acute phase) then drop to 1 mg daily maintenance, assessing response on systemic energy and cognitive symptoms over 4–6 weeks.
Can TA-1 trigger autoimmune flares?
Theoretical risk in Th1-driven autoimmune diseases (rheumatoid arthritis, MS, Hashimoto's). Clinical evidence is mixed — some patients improve, others see neutral or mild worsening. Practitioner consensus is to start low (0.5-1 mg) and monitor inflammatory markers + symptoms. Th2-driven conditions (allergies, eczema) are generally well-tolerated.
Is TA-1 safe long-term?
30+ years of cumulative safety data from Zadaxin indications worldwide. No documented hepatotoxicity, hormonal disruption, or cardiovascular concerns. The canonical foundational protocol is 1 mg DAILY, long-term (TA-1 sits in the Top 4 Forever stack as a daily-forever immune competence layer). Cycled use (4–8 weeks on / 4–8 weeks off) is the older community pattern; the consolidated baseline favors continuous low-dose daily use.
Should I cycle TA-1?
The canonical baseline is daily long-term — no cycling required. TA-1 is positioned as a daily-forever immune-competence layer in the Top 4 longevity stack. For acute viral or post-viral contexts, ramp to 1.6 mg daily × 7–14 days then drop to 1 mg/day maintenance. Older community 4–8 weeks on / 4–8 weeks off cycling reflected a different protocol-design lens and is not the consolidated canonical recommendation.
Related compounds
Often researched, stacked, or compared with Thymosin Alpha-1.
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