regulatory landscape
FDA category status, WADA prohibited list, compounding pharmacy rules, and international legal frameworks
Legal Gray Zones
TB-500 is not FDA-approved, sits on the FDA's "do not compound" list, and has been WADA-prohibited under section S2 since 2013. It remains unscheduled in most countries and is sold openly as a "research chemical" -- a legal gray zone that does not make it safe or legitimate for human use.
The 2023 FDA compounding decision pushed quality-tested supervised use off the table. LC-MS/MS detection keeps improving, with TB4 metabolites trackable for days after the last dose.
where can you actually get it?
click any jurisdiction for its current status.
Compare the Agencies
FDA, WADA, DEA, and import rules side by side.
FDA vs WADA -- two different frameworks
what each agency governs and why both matter for TB-500 users.
FDA framework
- scope: safety and efficacy for human therapeutic use
- TB-500 status: no approved NDA or BLA; category 2 compounding placement (2021)
- enforcement: no approved product = no legal prescription pathway; research use only
- relevance: affects availability and quality -- compounded TB-500 is now off the table in the US
- detection: FDA does not conduct anti-doping tests
WADA framework
- scope: fair competition in sanctioned sport
- TB-500 status: explicitly prohibited under section S2 since 2013
- enforcement: anti-doping organizations conduct LC-MS/MS urine testing; violations carry 2-4 year bans
- relevance: any competitive athlete -- professional or amateur -- risks disqualification
- detection: TB4 metabolites detectable for several days post-injection
key terms
regulatory — FDA category C biologic
classification assigned to thymosin beta-4 products that prohibits licensed compounding pharmacies from producing them for human use. effective 2021.
regulatory — IND (investigational new drug)
FDA designation required before human clinical trials may begin. TB-500 for systemic use has never held an approved IND, meaning no legally sanctioned human efficacy trials have occurred.
legal status — research chemical
informal term for substances sold as "not for human consumption" to sidestep drug regulations. TB-500 purchased outside a pharmacy falls into this legal gray area.
legal status — WADA S2 prohibition
thymosin beta-4 has been on the World Anti-Doping Agency prohibited list since 2013 under the S2 (peptide hormones, growth factors) category, banning its use by competitive athletes.