The honest headline is that TB-500's side-effect profile in humans is not characterized, because there are no controlled human clinical trials of it. The research that exists is on thymosin beta-4 in animal models, aimed at tissue-repair mechanisms rather than a human adverse-event profile.[1][2]
Reviewed for accuracy · Last reviewed July 7, 2026Community reports describe mostly local or vague effects, such as injection-site irritation and occasional temporary fatigue or a head-rush, but these are anecdotal. Because TB-500 is a research chemical rather than an approved medicine, product purity and accurate content are real-world concerns, and its long-term safety in humans is simply unstudied. It is also prohibited in drug-tested sport.
With no human safety data, unknowns dominate. Rotating injection sites and watching for signs of infection or an allergic reaction are the practical basics; product-quality concerns are best addressed by not using unverified material.
This page is an independent educational reference and is not medical advice, and does not indicate any approval status for any use. Talk to a doctor before starting any compound.