TB-500
Also called Thymosin Beta-4, TB500, thymosin b4 acetate
A synthetic version of a fragment of thymosin beta-4, a protein your body already makes.
The published research here is animal and laboratory work. The ranges below come from community-reported dosing and results — what people have settled on in practice, and what they report happening.
- Recovery & injury
The quick answer
A synthetic version of a fragment of thymosin beta-4, a protein your body already makes. Its job is managing actin - the scaffolding cells use to move. In a repair site, that means getting cells to where the damage is.
What it is not
No human trial has tested it for the use people run it for - the human work was topical and ophthalmic. What there is instead is a large, consistent body of user experience, and twelve weeks of it rather than four.
Why people use it
Soft tissue, tendon and ligament recovery. Almost always run with BPC-157 rather than alone, and the reason is mechanical: if BPC-157 is building the supply road into damaged tissue, TB-500 is moving the crew in. Different jobs on the same site.
What people report using
These are ranges other people have reported running. They are here so you can see what has actually been done — they are not medical advice and not a recommendation for you.
- How often
- Twice a week
- Route
- subcutaneous
- Evidence for this
- Community practice
Most describe nothing much in week one, easier movement somewhere in weeks two to four, and the real change — the thing that was still there after months — landing between weeks four and eight.
What to expect, and when
Week 1-3: the loading stretch, and most people report nothing in it. Week 4-8: the first change, usually described as an old injury feeling different rather than fixed. Week 8-12: where the reports people write actually land. Twelve weeks is the run.
Side effects, and what people do about them
Injection-site reactions are the most reported. Little else consistent.
Go deeper
Open these only if you want them.
How it actually works
Synthetic fragment of thymosin beta-4; actin regulation and cell migration.
More on the evidence
Synthetic fragment of thymosin beta-4. Animal work; human trials were topical/ophthalmic.
What people report, in full
TB-500 is one of the most discussed compounds in the injury communities, and the discussion is overwhelmingly about protocol rather than about safety - in a published analysis of 12,755 posts across peptide forums, dosing and protocol talk made up 28.4% of posts and safety 2.6%.
Two conventions come up more than anything else. The first is duration: people describe twelve weeks as the run, not four, and the single most common reason somebody says it did nothing is that they bought four vials and stopped. A loading period at the start followed by a lower maintenance stretch is the widely-shared shape. The second is location, and here the community has a clear and useful answer to a question everyone asks: it does not need to be injected near the injury. It works systemically, it travels, and people who contorted themselves to inject a shoulder are told they did not have to.
The pairing with BPC-157 is close to universal - the two are discussed as a unit often enough to have earned their own nickname - and the reasoning given is that they work through different routes, one systemic and one more local, so they add rather than duplicate. The reports themselves centre on chronic and stubborn injuries rather than fresh ones: shoulders, tendons, old knees. People describe it as the thing that finally moved something that had been stuck for a year, and they describe it slowly.
Sources and review
https://pubmed.ncbi.nlm.nih.gov/10469335/
https://www.nature.com/articles/nature03000
Last reviewed 2026-09-08.
People also look at
Still not sure?
Ask it the way you would ask a person. Follow-up questions are the point — it remembers what you already said.
Ask about TB-500