Home / Compounds / TB-500

TB-500

Synthetic peptide fragment · Related to thymosin beta-4, often conflated with it

UK status

Unlicensed medicine

Availability

Research use only

Evidence base

Animal studies, no human trials

Controlled drug

No, but WADA prohibited

TB-500 is usually described as thymosin beta-4. It is not quite. It is a short fragment of that protein, and the distinction matters when you go looking for the research behind the claims.

01What it is

Thymosin beta-4 is a naturally occurring protein of 43 amino acids involved in cell movement and tissue repair. TB-500 is a synthetic fragment of it, a much shorter sequence containing the region thought to carry the actin-binding activity.

Marketing material tends to use the two names interchangeably. Research on the full protein is then presented as though it applies to the fragment being sold. Sometimes it may. It is not automatic, and it is worth checking which one any given study actually used.

02How it came about

Thymosin beta-4 is a real protein with a genuine research literature, involved in cell movement and tissue repair. Some clinical work has been done on thymosin beta-4 preparations for specific indications such as corneal and skin wound healing.

TB-500 emerged as a shorter synthetic fragment containing the region thought to carry the actin-binding activity. It entered the grey market through veterinary and equine use before becoming common in human fitness circles.

03UK legal and licensing status

Athletes: prohibited by WADA at all times. Thymosin beta-4 and its fragments fall within the prohibited classes, and as with BPC-157 strict liability applies.

04How it works

The proposed mechanism involves binding actin, a protein central to how cells move, and thereby influencing cell migration into damaged tissue and the formation of new blood vessels. This is derived from laboratory and animal work on thymosin beta-4.

05What it is not

Claims that attach themselves to this compound and do not hold up.

• Not thymosin beta-4. A fragment of it. Research on the full protein is routinely presented as though it applies to the fragment being sold, which it may or may not.
• Not clinically tested as sold. No human trial evidence exists for TB-500 in the form vendors ship.
• Not a licensed medicine anywhere.

06What the evidence shows

Animal and laboratory studies report effects on wound healing and tissue repair. Human clinical trial evidence for TB-500 as sold does not exist in any meaningful form. Some clinical work has been done on thymosin beta-4 preparations for specific indications, which is a different compound in a different context from a vial bought online.

07Reported harms

No regulated safety profile exists. The risks that can be stated with confidence are those of unregulated supply: unverified identity and purity, non-sterile handling, and no route to redress.

08Interactions and cautions

Unknown, for the same reason as BPC-157. No development programme means no interaction data.

09Stopping

Undocumented.

10Monitoring

Nothing. No markers, no checks, no reporting route.

11Questions worth asking

Take these to a doctor or pharmacist. A good clinician will not mind being asked, and the answers are specific to you in a way nothing on this page can be.

1. Is the research I have read about the full protein or the fragment being sold?
2. Is there a licensed option for what I am actually trying to treat?
3. If I am tested in sport, do I understand this is prohibited at all times?

12Common questions

13Sources

Links go to the authoritative source. Where a document sits behind a paywall or moves around, the full citation is given so you can find it yourself.

1. Unlicensed medicines guidanceMHRA
2. Prohibited ListWADA
3. Thymosin beta-4 and tissue repair, review literaturePubMed