What do you need to know about TB-500?

What is TB-500?

TB-500 is a short protein fragment made in a lab. Proteins are chains of tiny building blocks. The TB-500 fragment takes seven links from thymosin beta-4, a natural full protein made after injury ^[1]. You can't get the sold fragment as an approved medicine.

What does TB stand for in TB-500 and what is TB-500?

The letters TB mean thymosin beta, a family of natural proteins ^[1]. TB-500 is a lab-made seven-part fragment copied from thymosin beta-4. It grips actin, a protein involved in cell movement. When you see 500, remember the number is a sales name; it isn't a dose or medical grade.

What is TB-500 used for in research?

Scientists study whether the fragment helps cells move. Full thymosin beta-4 helped new blood vessels grow and wounds heal in animals ^[5]. Most work used rats with wounds or strokes ^[3][4]. You won't find a clinic test of the small fragment in people.

Did TB-500 protect the brain in animal tests?

In rat stroke tests, full thymosin beta-4 helped at 2 or 12 milligrams for each kilogram the rat weighed ^[4][7]. Rats given 18 milligrams per kilogram got no gain ^[4]. A 2024 review also found that middle amounts worked better than high ones ^[12]. Those rats can't predict your brain result.

What dose of thymosin beta-4 was used in stroke studies?

Researchers gave rats belly shots of 2, 12, and 18 milligrams for each kilogram the rat weighed. The thymosin beta-4 shots began 24 hours after a stroke ^[4]. Scores improved at 2 and 12 milligrams for each kilogram, while 18 milligrams for each kilogram had no effect. You can't turn a later computer guess into your personal dose.

Does TB-500 heal torn muscles or help workout recovery?

A 2026 sports medicine review said athletes use TB-500 for muscle pulls even though it isn't approved ^[11]. Full thymosin beta-4 helped cells move in animals. If you pull a muscle, no human trial shows that the small fragment heals it.

Does TB-500 cause cancer or promote tumor growth?

Cancer doctors worry because thymosin beta-4 makes cells move while new blood vessels form. That change might feed a tumor you already have ^[5]. A 2026 medical review raised the same possible risk ^[11]. Studies haven't shown that the fragment causes cancer, but they can't give you an all-clear.

Is TB-500 banned by WADA and in competitive sports?

Yes. Sports drug rules from the World Anti-Doping Agency ban TB-500 at all times ^[11]. The ban covers both events and training. Labs can test your blood and urine for signs of use. If you compete, a positive test can bar you.

Is TB-500 FDA approved?

No. The FDA has never approved TB-500 for medical use in people ^[17]. Federal records call TB-500 a thymosin beta-4 fragment. Its old Category 2 request raised serious safety concerns and was later withdrawn. Withdrawal doesn't give you an approved drug.

Are there any human clinical trials on TB-500?

Zero finished trials have tested the TB-500 fragment in people. Doctors tested full thymosin beta-4 in an early Phase 1 safety trial with 40 healthy adults ^[6]. In 2026, medical reviews still gave you no human proof that TB-500 is safe or works ^[11].

How does TB-500 work?

The small fragment grips actin in an exact 1:1 match ^[1]. Actin supports a cell and lets it travel. The grip keeps loose actin ready while cells head toward damage ^[5]. That dish result is limited evidence, not proof for your injury.

How long does it take for TB-500 to work for injury healing?

Any timeline you see online comes from animals, not patients. In rat wound tests, skin reached 42% closure after four days and 61% after seven days with full thymosin beta-4 ^[3]. Your doctor doesn't have a proven timeline for the fragment in a human joint.

Can TB-500 help with tendon injuries and ligament repair?

Interest in tendons comes from animal work showing that thymosin beta-4 helps cells move and limits scar tissue ^[5]. In 2026, a sports medicine review said athletes try the fragment despite zero proof in patients ^[11]. If your ligament is torn, doctors haven't shown that it mends the tear.

Does TB-500 affect the heart?

In mice with heart attacks, thymosin beta-4 helped heart muscle cells survive early harm ^[2]. In 2021, a pig study found that more repair cells lived in damaged heart tissue ^[13]. If your heart is hurt, those animals can't promise that the shots will help.

Does TB-500 spur new blood vessels and is that dangerous?

In animals, thymosin beta-4 helps new blood vessels grow toward healing tissue ^[5]. That can help your wound close. Cancer doctors worry the same growth might feed a hidden tumor. Human tests can't tell you how large that risk is.

Does TB-500 reduce inflammation?

In animals, full thymosin beta-4 calmed swelling and limited scar tissue in damaged organs ^[5]. In one mouse study, the liver had less scar tissue after that protein ^[15]. For your swollen joint, studies in people don't prove that the fragment helps.

What are the side effects of TB-500?

Doctors haven't published trusted TB-500 side effects data for the small fragment ^[5]. One hospital trial sent up to 1260 milligrams of full thymosin beta-4 through a vein. That early Phase 1 safety test found no major harm ^[6]. You can't apply its result to the fragment.

What is the difference between TB-500 and BPC-157?

You're looking at two separate lab chemicals. TB-500 copies the part of thymosin beta-4 tied to cell movement ^[1]. The other one is an unrelated protein fragment first found in digestive fluid in the stomach. In 2026, medical reviews listed both as unapproved ^[11].

Does TB-500 help wound healing?

In animals, full thymosin beta-4 helped skin cuts and eye wounds close ^[3]. Rat wounds reached 42% closure by day four and 61% by day seven. You need to know the thymosin beta-4 study didn't use the small fragment. It doesn't prove that your wound will heal.

Is TB-500 safe for long-term use?

Nobody can give you that answer. There aren't long-term human safety studies on the TB-500 fragment ^[5]. Doctors worry about odd cell growth and new blood vessels over time ^[11]. You'd face an unknown risk with daily use.

Why is TB-500 used in racehorses?

Some horse trainers used black-market TB-500 hoping sore tendons and muscles would heal faster ^[11]. Racing officials treated that use as doping. If you saw it called horse medicine, that was wrong. The drug wasn't approved for those horses.

Is TB-500 legal?

Where you are and why you'd use it both matter. In the U.S., the FDA hasn't approved TB-500 as medicine ^[17]. Federal records dated April 22, 2026, show that the applicant withdrew the TB-500 pharmacy request; the safety concerns weren't cleared ^[16]. Your pharmacist gets no legal basis from that request. Sports rules ban TB-500 worldwide ^[11].

Can you get TB-500 from a compounding pharmacy?

No. Your licensed pharmacy can't routinely make TB-500 ^[17]. The old request entered Category 2 over safety risks and was later withdrawn ^[16]. Withdrawal didn't approve the raw powder. A pharmacist who follows federal law can't treat that request as permission ^[16].

What is the FDA 503A status of TB-500?

Section 503A is the federal law for pharmacies making your custom medicine. The FDA put the thymosin beta-4 fragment, called TB-500, in Category 2 on September 29, 2023, after safety concerns ^[17]. The applicant withdrew its request before a review group met in 2026 ^[18]. FDA staff advised against listing it, and you still have no final vote allowing it.