Thymosin beta-4 (full-length)
Thymosin β4, Tβ4, TB4, RGN-259
Forms: The short fragment sold as TB-500 (Ac-LKKTETQ) has its own card; vials labeled TB-500 may contain either.
Other esters and forms: TB-500 (thymosin beta-4 fragment)
The full natural 43-amino-acid tissue-repair peptide, made synthetically and used by athletes for injuries. It has had small human trials, but none in sports injuries, and it is banned in sport.
Legal status: Not approved as a medicine anywhere; sold as a 'research chemical', rules vary by country. Banned in sport at all times (WADA S2.3, thymosin-β4 and its derivatives).
What it gives
What people use it for and what the sources report. Strength is a general category from the literature: mild, clear or strong.
Purpose
Used for muscle, tendon and ligament injuries and to get back to training sooner, often with BPC-157. Human trials tested an IV form in healthy volunteers and a gel for leg ulcers, not injuries in athletes. Not approved for any use.
What people seek and what studies show
It binds actin and helps cells move into injured tissue; in animals it sped healing. A sports-medicine review finds no human orthopaedic data. In 73 patients with leg ulcers a gel was as safe as placebo and possibly sped healing; IV use in 40 healthy volunteers gave only mild or moderate side effects.
Effects
Evidence: Limited human data — some human studies, small or short
Sought effects by goal (as reported)
Possible side effects
Possible does not mean certain: whether they appear depends on dose, duration, individual response and monitoring. Below — what to watch for and how to notice it early.
4 possible side effects
level · how often it is reportedWhat the levels mean
Level: general category from the literature, not your personal risk
How often
- common
- reported often
- possible
- reported in some people
- rare
- reported occasionally
How to lower the risks
General ways to lower the chance of each side effect. No measure removes a risk completely.
Products obtained without a prescription are often fake, mislabeled or non-sterile, and there is no way to check at home. For legal supplements, third-party testing (Informed Sport, NSF) lowers, but does not remove, the risk of a positive doping test.
What is unknown cannot be lowered, only avoided; tell your doctor what you have taken.
No check-up or blood test lowers this risk; avoid with any personal or family history of cancer.
Low-level side effects
Check-ups and blood tests
Which tests and check-ups to do and when. This is a guide — agree the exact schedule with a sports physician.
Which doctors can help
Get medical help at once if
- A new lump (including in the neck), trouble swallowing or persistent hoarseness, unexplained weight loss, or blood in stool or urine — see a doctor promptly.
In an emergency, call your local emergency number.
Myth & fact
“Thymosin beta-4 gets you back from a muscle or tendon tear faster.”
Tissue repair was shown only in animal and lab studies. A sports-medicine review finds no human data for muscle, tendon or ligament injuries, and the peptide is banned in sport.
Combinations
No specific combination notes for this substance yet. The stack check still adds up side effects that several substances share.
Sources
Possible side effects by body system, combinations, how to lower the risks and which tests to do — free.
Open the stack check