Evidence strength for the context described on this page.
PEPTIDE ATLAS / IMMUNE & GUT / THYMOSIN ALPHA-1
Not FDA-approvedEarly human
Thymosin alpha-1
ALSO KNOWN ASThymalfasin · Zadaxin
An immune-modulating peptide used in some countries but not FDA-approved in the United States.
01CATEGORYImmune & gut
02REGULATORY STATUSNot FDA-approved
03COMMON ROUTESubcutaneous in international medical use and most studies
04DOSE BASISInternational label + human studies
HOW TO USE THIS PAGE
Read the profile in the order that protects the decision.
- 01Verify what it is
Confirm the exact molecule, route, regulatory lane and actual human evidence.
- 02Read limits before dose
Unsupported claims, contraindications and uncertainty come before any protocol.
- 03Build the monitoring plan
Define the target, baseline checks, reassessment point and stop rules with a qualified clinician.
This peptide does not have an FDA-approved product or dose for the claims described here. Research dosing and vendor protocols are not consumer prescribing guidance.
RESEARCH PASSPORT
The five facts to know first.
REVIEWED
JULY 2026
Status is product-, formulation- and indication-specific.
Trial, label or reported-practice basis is always named.
Official labels, regulators, trials and indexed literature where available.
Peptide hormones, growth factors and related substances may be prohibited.
Check Global DRO ↗OVERVIEW
What Thymosin alpha-1 is.
A 28-amino-acid thymic peptide studied in infections, immune dysfunction and as an adjunct in selected diseases. International approvals do not automatically establish a U.S. indication or product standard.
HOW IT IS THOUGHT TO WORK
Modulates innate and adaptive immune signaling rather than simply 'boosting' immunity.
EFFECTS & EVIDENCE
What the evidence supports—and what it does not.
- Condition-specific research in selected infections and immune states
- No established general immune-resilience benefit for healthy adults
- Prevention of routine illness
- Cancer treatment by itself
- Universal post-viral recovery
- A wellness dosing cycle
Evidence grade: Early human. For an approved drug, “high” refers only to its labeled indication—not every off-label or wellness claim.
DOSAGE CONTEXT
Best available dosing range.
International label + human studiesBest-established international thymalfasin regimen: 1.6 mg subcutaneously twice weekly, spaced 3–4 days apart; patients under 40 kg have been dosed at 40 mcg/kg twice weekly. Historical hepatitis regimens commonly continued 6–12 months. This is international-label and trial context—not an FDA-approved U.S. or universal immune-wellness protocol.
BEST AVAILABLE GENERIC RANGE
Men and women.
The basis is named above. Reported-use ranges describe what clinics or communities publish; they are not proof of safety, efficacy, legality or product quality.
- Schedule in that source context
- Twice weekly; historical hepatitis regimens commonly continued 6–12 months. Acute illness and oncology studies have used different schedules under specialist care.
- How to interpret it
- This is the most documented thymalfasin regimen, but it is not an FDA-approved U.S. wellness dose. Diagnosis, transplant/autoimmune status, cancer therapy and product source materially change the risk.
ACTUAL HUMAN DOSES REPORTED IN THE RECORD
Research regimens may use different routes, diagnoses, formulations and monitoring. They cannot automatically be converted into a general protocol.
- International Zadaxin/thymalfasin regimen: 1.6 mg subcutaneously twice weekly for 6–12 months.
- Body weight under 40 kg: 40 mcg/kg subcutaneously twice weekly in international label materials.
- Some acute-disease studies used higher or more frequent regimens, which should not be generalized to wellness use.
- Route
- Subcutaneous in international medical use and most studies
- Duration
- Condition-specific; historically 6–12 months for chronic hepatitis
- Men & women
- No routine sex-based dose. The same 1.6 mg twice-weekly regimen is described for adult men and women; pregnancy and immune conditions need specialist review.
Clinician verification required. Always double-check the exact molecule or salt, concentration, route, volume, schedule, indication, patient-specific contraindications, interactions and applicable law with the prescribing clinician and dispensing pharmacy. A disclaimer does not make an unapproved product FDA-approved, and a reported-use range is not a prescription.
MONITORING
What should be tracked.
- Diagnosis-specific clinical outcomes
- Autoimmune activity and concurrent immunotherapy
- Injection reactions and laboratory markers only when clinically relevant
SAFETY
Risks, red flags and reasons to avoid it.
- Immunogenicity and impurities in compounded products
- Unknown interaction with autoimmune disease, transplant care or cancer immunotherapy
- Injection reactions
- Inadequate U.S. product-quality information
- Self-treatment of infection or cancer
- Transplant or autoimmune disease without specialist oversight
- Replacing vaccination or antiviral care
- Pregnancy without medical review
Stop and seek careGet urgent medical help for trouble breathing, facial or throat swelling, chest pain, fainting, severe persistent abdominal pain, neurologic changes, severe hypoglycemia, uncontrolled vomiting or a prolonged painful erection.
CLINICIAN VISIT CHECKLIST
Six questions worth bringing with you.
Molecule or analog, salt, concentration, route, manufacturer or compounder, lot and beyond-use date.
Name the diagnosis or target, how it will be measured and the realistic time to reassess.
Ask how it compares with FDA-approved, lower-risk or better-studied alternatives.
Label, human trial, specialty guideline or clinic convention—and whether that route and formulation match.
Baseline checks, follow-up measures, interactions, pregnancy considerations and symptoms that mean stop.
Pharmacy license, prescription, identity/potency testing, sterility controls and who handles a product complaint.
Do not improvise reconstitution or convert “units” without the exact concentration. Mixing, storage and beyond-use instructions are product-specific; confirm them with the dispensing pharmacy.
PRIMARY SOURCES
Read the record yourself.
We prioritize official prescribing information, FDA regulatory material, registered trials and indexed biomedical literature. A source supports the specific statement beside it—not every claim made about the molecule.
PRODUCTS & TREATMENT ACCESS
There is no product we can responsibly recommend.
Approved in some countries for selected uses; no FDA-approved U.S. thymosin-alpha-1 drug.
Immune modulation is not the same as a universal immune boost. Benefit can depend on diagnosis, timing and the rest of the treatment plan.
Evidence before affiliate revenue.
We do not rank or sell unapproved research peptides. Use the Atlas to discuss safer, evidence-backed alternatives with a qualified clinician.
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