Thymosin Alpha-1
Tα1 · Zadaxin · Thymalfasin
An immune-modulating thymic peptide approved in dozens of countries for hepatitis and as an immune adjunct.
Class
Synthetic thymic peptide / immunomodulator
Half-life
~2 hours
Evidence
Randomized human trials
Randomized human trials
Supported by randomized controlled trials in humans. Several compounds at this level are FDA-approved for specific indications.
Overview
Thymosin alpha-1 is a peptide originally isolated from the thymus, the organ that trains T-cells. Unlike most compounds in this library it has substantial human clinical evidence and is approved in dozens of countries (as Zadaxin/thymalfasin) for chronic hepatitis B and C and as an immune adjunct in certain infections and cancers.
Its role is immune modulation rather than stimulation — it helps mature and rebalance T-cells, enhances the function of dendritic cells, and can dampen excessive inflammation while improving the response to genuine threats. This dual action is why it has been studied both in infection (to boost defence) and in sepsis (to rebalance a dysregulated immune response).
It was studied during COVID-19 for immune support in severe cases with mixed but generally encouraging signals. It is not FDA approved in the US but is obtainable through compounding pharmacies, and it has one of the better safety records here.
How it works
- Promotes maturation and differentiation of T-cells, restoring immune balance.
- Enhances dendritic cell and natural killer cell function.
- Modulates cytokine production, capable of both boosting defence and dampening excess inflammation.
- Increases response to vaccines and antiviral therapy in studied populations.
What the research shows
Researched effects
- Improved response to hepatitis B and C treatment in randomized trials
- Immune restoration in immunocompromised and sepsis patients
- Adjunct benefit in some cancer immunotherapy settings
- Studied for immune support in severe COVID-19 with encouraging signals
Limitations & what it won't do
- US regulatory status is compounded, not FDA-approved.
- Benefit is best established in specific clinical populations, not general 'immune boosting'.
- Optimal dosing for wellness use is extrapolated from clinical protocols.
Dosing protocols
These ranges reflect published trials and community protocols. They are reference information, not a prescription. Doses are per injection unless noted.
Immune support protocol (compounded)
1.6 mg1.6 mg is the standard clinical unit dose. Acute protocols may dose more frequently. Follow a prescriber's guidance.
Reconstitution & measuring your dose
Handling
- Typical vial sizes
- 1.6 · 5 · 10 mg
- Suggested BAC water
- 2 mL
- Storage
- Lyophilised powder refrigerated at 2–8 °C, protected from light.
- After reconstitution
- Reconstituted: approximately 30 days refrigerated.
Why 2 mL? A 5 mg vial in 2 mL yields 2.5 mg/mL — a 1.6 mg dose lands on ~64 units of a U-100 syringe. Single-dose 1.6 mg vials are reconstituted in the supplied diluent.
Dose calculator
Draw to
64units
= 0.64 mL · 25 mcg per unit
Concentration
2500 mcg/mL
Doses per vial
3
Side effects
Common
- Injection-site reactions
- Generally very well tolerated in trials
- Occasional transient fatigue
Serious / rare
- Rare hypersensitivity
- Theoretical risk of aggravating autoimmune activity
Contraindications & interactions
Do not use if you have
- Organ transplant recipient
Immune stimulation directly opposes the immunosuppression that keeps a transplanted organ from being rejected. Contraindicated.
- Pregnant, breastfeeding, or trying to conceive
No pregnancy safety data.
Use caution if you have
- Autoimmune condition
Enhancing immune function can flare autoimmune disease. Discuss with a specialist.
Medication interactions
- avoidImmunosuppressants / biologics — Directly counteracts immunosuppressive therapy — a serious problem for transplant or biologic patients.
- cautionCorticosteroids — Opposing immune effects; the interaction is unpredictable.
What to monitor
- Autoimmune symptoms if applicable
- Response to the underlying condition being treated
Commonly combined with
References
- Thymosin α1 combined with immune checkpoint inhibitors — immune remodeling (review)2026
- Liu Y et al. — Thymosin alpha 1 in severe COVID-19Clinical Infectious Diseases 2020
Research & educational information only — not medical advice.
You must be 18 or older to use this site. The peptides described are presented as research chemicals intended for research purposes only. Most are not approved by the FDA for human use. Dosing ranges reflect what has appeared in the scientific literature or community protocols and are not prescriptions. Nothing here replaces evaluation by a licensed physician who knows your full medical history.
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