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What should I know about TB-500 dosage?
TB-500 has no standard dose, so a prescribing clinician sets it. See the doses studied in research and what to check on a TB-500 vial.
Quick answer
No standard TB-500 dosage has been established, so a prescribing clinician sets each dose. TB-500 is not FDA-approved and has no established labeled route. FDA's 2026 review found no published human studies. Studied TB-500 doses come mostly from animals: 10 mg once in horses and 60 µg/kg per day in rats. A three-patient case series gave 10 mg weekly within a combined injection. Thymosin beta-4 trial doses apply to that parent protein. WADA prohibits TB-500 at all times.
- Published
- November 4, 2026
- Last updated
- November 4, 2026
How TB-500 doses are set
No standard TB-500 dosage has been established, so a prescribing clinician determines the dose. Review authors note that dosing, frequency, and duration1 have not yet been defined. Most published TB-500 findings come from laboratory and animal research.
TB-500 is a synthetic seven-amino-acid fragment of thymosin beta-42, the full-length protein it comes from. FDA's 2026 review found no published studies giving TB-500 to people2.
Published TB-500 doses come from research studies, mostly in animals.
What doses have studies tested?
Studies have dosed TB-500 itself in animals and in a three-patient case series3. The controlled human dose trials tested thymosin beta-4, TB-500's full-length parent protein4.
Reviewers describe TB-500 as distinct from full-length thymosin beta-45, so each molecule's doses stay separate.
| Study | Molecule | Species or population | Route | Dose and unit | Duration |
| Doping-control study | TB-500 | Horses | Subcutaneous injection2 | 10 mg6 | Single dose |
| Achilles tendon study | TB-500 | Rats | Intraperitoneal (into the abdominal cavity) | 60 µg/kg per day7 | 4 weeks |
| Nerve-injury case series | TB-500 within a combined injection of several drugs | 3 adults | Submucosal injection in the mouth | 10 mg weekly3 | 4 weeks |
| Single- and multiple-dose trial | Thymosin beta-4 (parent protein) | Healthy adults | Intravenous | 42, 140, 420, or 1,260 mg4 | Single dose, then daily for 14 days |
| Phase 1 trial | Recombinant thymosin beta-4 (parent protein) | Healthy adults in China | Intravenous | 0.05-25 µg/kg single dose8; 0.5, 2, or 5 µg/kg daily8 | Single dose, or daily for 10 days |
| Phase 3 eye-drop trial | Thymosin beta-4 (parent protein) | 18 adults with neurotrophic keratopathy | Eye drops | 0.1% solution, 5 times per day9 | About 4 weeks |
Animal doses are set per kilogram or per animal, not converted to human doses. The human TB-500 report appeared in September 2026, after FDA's review. It gave TB-500 within a combined injection. Its authors list optimal dosing3 as an open question. Products sold under the TB-500 name also include multiple salts and derivatives2.
What forms does TB-500 come in?
TB-500 is sold online as powder for reconstitution in 2, 3, 5, 10, and 15 mg vials2. Those vials are labeled for research use only. Vial size does not set the dose. TB-500 is usually injected subcutaneously or intramuscularly10, meaning under the skin or into a muscle.
TB-500 generally has limited oral bioavailability10, meaning little of a swallowed dose reaches the bloodstream. Research or experience with one route does not automatically describe another.
The details worth checking depend on a TB-500 product's form.
| Form | What to check |
| Injection vial | The exact substance (free base or acetate salt2); vial strength; identity, purity, concentration, and sterility5; aggregation and peptide-related impurities11, which FDA links to immune-reaction risk; storage; and who prepared it |
| Any oral form | Whether absorption by mouth is supported for that exact product |
| Any nasal or topical form | Whether the cited research used that route and TB-500 itself, since the eye-drop trial tested thymosin beta-49 |
A TB-500 vial holds dry powder, so a prescribed dose needs preparing first.
How are prescribed TB-500 doses prepared?
A prescribed TB-500 dose is prepared through reconstitution, mixing freeze-dried TB-500 with a specified amount of liquid. The prescribing clinician sets the target dose.
TB-500 vials are labeled in milligrams, and a prescribed dose may be written in micrograms. Vial strength and added liquid change the volume that holds that dose.
As bulk powder, TB-500 free base is stored below -4°F (-20°C)2. TB-500 acetate is reported stable below 5°F (-15°C)2, though one supplier certificate lists sealed storage at 36-46°F (2-8°C) or frozen2.
For athletes in drug-tested sport, TB-500 carries a separate rule.
The 2026 WADA Prohibited List bans thymosin beta-4 and its derivatives, including TB-50012, in and out of competition. TB-500 is listed under class S2.3, growth factors and growth factor modulators. Athletes subject to drug testing can face sanctions for TB-500 use and should check current WADA and league rules.
Getting TB-500 in 2026
Superpower will offer TB-500 formulated in FDA-registered facilities in the US, backed by third-party lab testing, and distributed from US-licensed pharmacies. Licensed clinicians will decide whether it fits each person's health care. Anyone interested can join the Superpower peptide waitlist now.
As a drug, TB-500 is not FDA-approved. The Department of Health and Human Services announced in October 2026 that it does not intend to take enforcement action13 against state-licensed pharmacies compounding TB-500 and other named peptides while the 503A Bulks List, which sets the ingredients pharmacies may use in compounding, is finalized. Conditions of this interim policy, which covers TB-500 alongside five other peptides14, include ingredients from FDA-registered facilities and a patient-specific prescription. A July 2026 FDA advisory committee had recommended putting TB-500 on the list15, and that rulemaking continues.