PeptideStackers
Grey-marketPeptideaka Thymosin Beta-4 fragment · TB4

TB-500

A synthetic version of part of the thymosin beta-4 protein, sold as BPC-157's recovery sidekick. Popular in horse racing before it was popular in gyms — which tells you where the evidence comes from.

ProofDAnimal-only, with biological plausibility.
Promise3/5
Risk3/5
Risk/Reward 63%

What people claim

Improves recovery, flexibility and healing; reduces inflammation; often 'stacked' with BPC-157 for injuries.

Human evidence

No robust human trials for the recovery claims. Full-length thymosin beta-4 has been studied clinically for a few specific conditions, but the grey-market 'TB-500' fragment people inject is not the same thing and isn't backed by human data.

Animal evidence

Animal and cell studies suggest thymosin beta-4 plays a role in cell migration and tissue repair. Much of the 'TB-500' hype borrows credibility from that protein research without matching products or doses.

Risk flags

  • Mostly animal data
  • Unregulated / grey-market supply
  • Purity & quality unknowable
  • Long-term effects unknown
  • Theoretical growth/cancer debate
  • Banned in tested sport (WADA)
  • Injection & sterility risk
  • Legal grey area (US/UK)

Regulatory status

US: Not FDA-approved. Prohibited in animal racing and banned by WADA in sport. Sold only as a 'research chemical.'

UK: No UK marketing authorisation; not a licensed medicine. WADA-banned. Grey-market only.

What people report

Typical reported ranges — reporting, not a recommendation

Vendor sheets and forums often report weekly totals in the low single-digit milligram range, sometimes split across the week and tapered after a 'loading' period.

Entirely anecdotal — there are no human trials for the injectable 'TB-500' fragment, so there is no evidence-based dose. Reports vary wildly and describe a grey-market product of unverifiable content. Reporting, not advice.

Everyone's an expert

Who says what

Gym Bros Say

"BPC's healing partner. You run them together for injuries — one for the local fix, one for the whole-body thing."

Clinics Say

Recovery-focused clinics bundle it with BPC-157 as a 'healing stack,' usually with more confidence than citations.

Reddit Says

Seen as BPC-157's less-essential cousin. Debate about whether it adds anything, and whether the 'stack' is just doubling your unknowns.

Science Actually Says

Grade D. The underlying protein is real science; the injectable fragment sold as 'TB-500' isn't backed by human evidence, and animal repair results don't reliably translate to people.

PeptideStackers Says

It rides BPC-157's coat-tails. 'Stacking' the two doesn't multiply the evidence — it multiplies the unknowns. Interesting protein, unproven product.

Honesty section

What we still don't know

  • ?Whether the injectable fragment does anything the full protein research implies.
  • ?Long-term human safety — no data.
  • ?Whether combining it with other peptides changes the risk picture at all.

Real questions people ask

FAQ

What does TB-500 do?
It's marketed as a recovery aid based on thymosin beta-4's role in tissue repair in animal and cell studies. Whether the injected fragment helps humans recover is unproven.
Is TB-500 the same as BPC-157?
No. They're different molecules that get 'stacked' together in recovery folklore. Both share the same problem: strong animal interest, weak-to-absent human evidence.
Does TB-500 show up on a drug test?
It's banned by WADA, so for tested athletes it's a real anti-doping risk. Don't treat 'peptide' as a loophole.

Before you do anything

Questions to ask a qualified professional

  • 01Is there any human evidence for the 'TB-500' fragment specifically, not thymosin beta-4 in general?
  • 02What am I actually adding by combining two unproven compounds?
  • 03If I'm a tested athlete, do I understand this is a WADA ban?

Related

Sources

Last reviewed: 2026-07-07