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Peptide reference

TB-500

TB-500

In vitro

TB-500 is a grey-market name, not one molecule. A vial may hold full-length synthetic thymosin beta-4 (43 amino acids) or short fragments of it. Thymosin beta-4 is a protein that binds actin, which helps cells move during tissue repair. In animals it speeds wound healing, calms inflammation and helps grow new blood vessels. Almost all of that research used the full-length protein. No human trial of any version has tested tendon repair.

FDA status
No FDA approval. On July 23, 2026, PCAC recommended inclusion of TB-500 on the 503A Bulk Drug Substances List. FDA final action is pending.
WADA status
Prohibited in sport
Route
subcutaneous injection

WADA Prohibited List 2026. No long-term human safety data. The immunomodulatory and angiogenic mechanisms are well-established in animals; human extrapolation remains speculative.

Frequently asked

  • What is TB-500?

    TB-500 is a grey-market name, not one molecule. A vial may hold full-length synthetic thymosin beta-4, a 43-amino-acid peptide, or a short fragment of it. Almost all published research used the full-length peptide. Thymosin beta-4 binds actin inside cells and helps regulate the cytoskeleton. In animal wound models it's linked to cell migration, blood vessel growth, and inflammation resolution. Human mechanistic data for tendon repair doesn't exist.

  • Does TB-500 actually heal tendons?

    No human tendon trial of TB-500 has been registered or published. The tendon-specific evidence is a 2020 lab study growing cells on a scaffold, not an injection into a human tendon. The animal data showing tissue-repair signal doesn't have a human tendon result attached to it yet.

  • Is TB-500 approved by the FDA?

    No. TB-500 has no FDA-approved drug application. On July 23, 2026, the FDA's Pharmacy Compounding Advisory Committee (PCAC) recommended inclusion of TB-500 on the 503A Bulk Drug Substances List, the list that covers pharmacy compounding. That's an advisory vote, not an approval, and FDA final action is pending. Outside that process, TB-500 is sold as a research chemical.

  • Is TB-500 banned for athletes?

    Yes. TB-500 falls under WADA's S2 category covering growth factors and substances that affect muscle, tendon, and vascular regeneration, and it's prohibited at all times. Athletes subject to WADA testing should treat it as banned in and out of competition, regardless of how the FDA's compounding review turns out.

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Research on TB-500

TB-500 and Tendon Repair: The Actin Science Is Real. The Human Data Isn't.

WADA

Thymosin beta-4's actin-grabbing mechanism is well mapped in the lab. Whether an injected synthetic version actually speeds tendon repair in a human body is a question the published research has never actually asked.

tb-500

What is PCAC? The FDA committee that reviews peptides for compounding

PCAC is the FDA advisory committee that reviews which raw ingredients compounding pharmacies may use. Here is what it does and what its votes mean.

bpc-157
kpv
tb-500
mots-c
ghk-cu
dihexa
ll-37
peg-mgf
melanotan-ii
semax
epithalon

TB-500 Doesn't Suppress Inflammation. The Evidence Says It Redirects It.

WADA

TB-500 gets sold as an anti-inflammatory peptide. The animal studies behind that claim used a different molecule than the one in most vials, and nobody has tested whether timing during the wound's inflammatory window changes the outcome.

tb-500

TB-500's Real Paper Trail Is About Hearts, Not Tendons

TB-500's reputation rests on tendon anecdote, but the peer-reviewed record on thymosin beta-4 is overwhelmingly cardiac: actin sequestration, epicardial progenitor signaling, coronary angiogenesis. No human cardiac trial exists, and grey-market TB-500 may not match the molecule studied.

tb-500

PCAC Recommended Both BPC-157 and TB-500. That's Not a Stacking Protocol.

WADA

PCAC voted to recommend BPC-157 and TB-500 for the FDA's 503A compounding list, each on its own 8-6 vote. Here's what the human trial record for each peptide shows, and where the case for stacking them turns from evidence into theory.

bpc-157
tb-500

The Injury-Recovery Peptide Stack: What the Evidence Actually Supports, Compound by Compound

BPC-157, TB-500, and GHK-Cu are sold as one interchangeable injury-recovery stack, but their human evidence ranges from a real Phase 2 trial to a molecular identity gap to a null placebo-controlled result. Each is graded on its own record, not the group's pitch.

bpc-157
tb-500
ghk-cu

The Wolverine Stack: what BPC-157 and TB-500 together could do

WADA

The Wolverine Stack pairs BPC-157 and TB-500 into one repair protocol — on paper a genuinely good idea: two peptides doing two different repair jobs. Here's what the pairing is meant to do for you, why the biology is exciting, and the one thing nobody has ever tested — the two of them run together.

bpc-157
tb-500

The peptide the FDA already voted against

Everyone heard "peptides are coming back." Almost nobody heard that the FDA already sat down with some of the most-stacked ones and voted no. Here's which, when, and what a July 2026 yes would actually buy you.

bpc-157
cjc-1295
ipamorelin
tb-500

Peptide access by US state: why the regulatory patchwork right now is real

The federal compounding framework applies the same way in every state. The state pharmacy boards do not. The result is a real state-by-state patchwork that decides whether a telehealth prescription for a compounded peptide is actually fillable where you live.

bpc-157
tb-500
ghk-cu
ipamorelin
cjc-1295

503B outsourcing pharmacies and compounded peptides: the regulatory gap that still matters

Section 503B outsourcing facilities are the higher-volume, FDA-inspected cousin of the corner compounding pharmacy. The 503B Bulks List is its own regulatory pipeline — and it changes what an actual peptide supply chain looks like when one opens.

bpc-157
tb-500
kpv
mots-c
aod-9604

The PCAC review happened July 23–24, 2026. Here is what that means for peptide access.

Two days at FDA's White Oak campus decided which of seven peptides US compounding pharmacies may eventually dispense by prescription. The recommendation is not an approval, the docket is not all the peptides, and the framing the forums used going in was mostly wrong.

bpc-157
kpv
tb-500
mots-c
dsip
semax
epithalon
ghk-cu

Collagen-synthesis peptides: what a better repair signal could do for you

WADA

Collagen is the scaffolding under your skin, tendons, and joints — and three peptides now in front of the FDA each lean on how your body builds it. Here is what that could mean for repair and ageing, why the biology is genuinely exciting, and how far the human proof actually goes.

bpc-157
ghk-cu
tb-500

New blood vessels: the repair signal behind BPC-157, TB-500 and GHK-Cu

WADA

Repair runs on fresh plumbing — new blood vessels growing into damaged tissue. It's the mechanism three of the most-talked-about recovery peptides — BPC-157, TB-500 and GHK-Cu — are built on. Here's what that could mean for how you heal, and the one question the same biology always raises.

bpc-157
tb-500

BPC-157 vs TB-500 for injury: which one is built for your tear

WADA

BPC-157 and TB-500 aren't two flavours of one recovery peptide — they're unrelated proteins aimed at different kinds of damage. Here is what each could actually do for you, which one fits which injury, and how far the human proof goes for both.