RUO · Research Use Only⚠ Cancer Concern✓ Free to read

TB-500

Also called Thymosin Beta-4 fragment

A 'healing' shot with a catch built into the label: what you buy is a short fragment, but the studies people cite are about a longer protein.

Updated 19 May 2026Read 3 minBacked by 60 studies

The quick version

What it is: A lab-made fragment loosely based on a healing protein (thymosin beta-4)
Is it FDA-approved?: No. Sold 'for research only'
How strong is the proof?: Very weak in people. Mostly animal data
How you take it: A shot under the skin
Typical result: Hard to say. No real human trials of this exact molecule
Biggest catch: Its mechanism overlaps with how tumors grow. A real cancer concern

Any word with a dotted underline is a science word — tap it for a plain-English meaning.

In plain words.

TB-500 is a short, lab-made . It is loosely based on the active part of a natural protein called thymosin beta-4, which helps tissue heal.

There is an important label trap here. The healing studies and the doping bans you read about are usually about the full protein (44 amino acids). What gets sold to people is TB-500, a shorter 17 fragment. They are not the same molecule, and the full-protein research does not transfer cleanly.

It is not . It is sold "for research only." People use it off-label for recovery.

What people use it for.

People use it to try to heal soft-tissue injuries faster, like muscle tears and tendon problems.

It is often stacked with BPC-157, another recovery .

It started out in the horse-racing world, where it was used and then banned.

Does it actually work?

Honestly, we do not know. There are essentially no randomized human trials of the TB-500 fragment.

There are around 120 animal studies and a handful of small early trials of the full-length protein (a different molecule). So the buzz is built on animal data and on a related molecule, not on real human proof of this product.

One telling sign: it is banned by WADA and by several horse-racing groups. That means regulators think the performance effect is real enough to police. That is not the same as a clean safety record.

what you’ve probably heard.

The claims floating around online, and how true they actually are.

“BPC-157 plus TB-500 is the Wolverine stack that heals anything.”

overblown

Both look interesting in animals, but neither has convincing human proof. Worse, stacking them doubles the blood-vessel-growth load, which is the exact mechanism that makes the cancer concern real. We avoid that pairing in anyone with a cancer history.

“There are tons of studies backing TB-500.”

half true

There are around 120 animal studies, but mostly of the full 44-piece protein, a different molecule. What gets sold is a shorter 17-piece fragment, and there are essentially no human trials of that. The research does not transfer cleanly.

“It is just thymosin beta-4, a protein your body already makes.”

not quite

What you inject is a short lab-made fragment loosely based on that protein, not the protein itself. The healing studies and doping bans people cite are usually about the full version, which is not the thing in the vial.

“It is safe, athletes use it all the time.”

It is banned by WADA and several horse-racing groups, which means regulators think the effect is real enough to police. There is no good human safety data, so the serious risks are simply unknown.

How you take it.

People take it as a shot under the skin, often 2-5 mg a week, for a short course.

It comes as a freeze-dried () powder you mix with ().

If you it with BPC-157, do not buy a pre-mixed "BPC+TB" vial. Buy two separate vials and mix each yourself. Pre-mixed blends are a common way to get underdosed, and you cannot adjust or stop one part on its own.

What to watch out for.

The serious stuff

The main worry is the mechanism. TB-500 promotes new blood-vessel growth () and cell movement. Tumors use the same tools to grow and spread.

Avoid it if you have a personal or family history of cancer.
Stacking it with BPC-157 doubles that blood-vessel-growth load. We avoid that in anyone with a cancer history.
It is banned by WADA. Do not use it in any tested sport.

We do not have good human safety data, so serious side effects are simply unknown. Talk to a real doctor. We are not your doctor.

Where people get it.

From safest to riskiest.

Brand. None. There is no TB-500.
. Contested. As of early 2026 most compounders stopped selling it. Where still sold, about $200-$400 a month, and those pharmacies are legally exposed.
Research-only (). The main supply. Sold "for research only," about $80-$200 a month. Some vendors ship the full protein at fragment prices, so a mass spec identity check matters.
. Overseas raw, about $15-$35 a month. Identity uncertain.

Whatever the source, it is banned for tested athletes.

Our honest take.

This is a cautious "maybe," and only in a narrow case. For a stubborn soft-tissue injury, in someone with no cancer history, a short, time-boxed course aimed at one clear question (did this tendon heal or not) is among the more defensible experiments.

It is not a chronic, everyday recovery tool. The blood-vessel-growth mechanism is real, and so is the cancer concern.

If you have any cancer history, skip it. If you do try it, run it on its own rather than stacked with BPC-157, and put it down once you have your answer.

The studies behind this.

We read the research so you don't have to. Here's where the facts on this page come from.

Learn about these too.

Anti-inflammatory · less hype

We're not your doctor, and this isn't medical advice. It's a plain-English summary of what the research says, so you can have a smarter conversation with someone who is.

Keep up with this stuff

Want the rest of the peptide world, in plain English?

New breakdowns, safety updates, and what's actually worth your money. Free. Unsubscribe in one click.