TB-500 (thymosin beta-4 fragment)
TB500, Thymosin β4, Tβ4, TB4, LKKTETQ
Forms: Sold either as the short fragment (Ac-LKKTETQ) or as full-length synthetic thymosin beta-4 under the same name.
A synthetic copy or fragment of thymosin beta-4, a natural tissue-repair protein. Sold as a 'healing' peptide; the fragment itself has never been tested in humans.
Legal status: Not approved for human use anywhere; sold as a 'research chemical'. Banned in sport at all times (WADA S2.3, growth factors).
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 recovery, often together with BPC-157. Animal studies show faster tissue repair; full-length thymosin beta-4 had small human trials (eye, skin wounds) with mixed results.
What people seek and what studies show
People hope for faster healing of strains and tears and less stiffness. Thymosin beta-4 binds actin and helps cells move into injured tissue; in animals it sped skin and eye healing, reduced scarring and, in mice, improved heart function after a heart attack. A small placebo-controlled trial of a gel for leg ulcers found it safe, with only a possible speed-up of healing. Sports injuries are unstudied in people.
Effects
Evidence: Animal data only — effects in people are unproven
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, look for third-party testing (Informed Sport, NSF).
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 your doctor.
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
“TB-500 is just a natural healing protein, so it is safe.”
Your own thymosin works inside cells in tightly controlled amounts; an injected synthetic fragment of unknown purity has no human safety data.
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