TB-500 Questions: What the studies can answer

What the fragment is and what it may do

What is TB-500?

A man-made piece of thymosin beta-4 is sold as TB-500. It uses amino acids 17 through 23 of that protein ^[5]. Amino acids are linked parts of protein. The numbers mark where the short protein section came from. They don't show an effect in your body. Sellers offer TB-500 for animals and dish work. It isn't approved to treat people.

What do TB and TB-500 mean?

The letters refer to thymosin beta-4, the whole thymosin beta-4 protein. TB-500 is a sales name for its short piece. That isn't the fragment's formal science name ^[5].

What have researchers studied TB-500 for?

Tests examined wounds, eyes, hearts, brains, scars, and new vessels ^[5][3]. Most animals received the whole protein. Eye studies also used that protein. Researchers haven't proved that the fragment helps people.

How does TB-500 work in cells?

TB-500 contains the section that touches actin. Actin is a cell protein that sets shape and movement. Whole thymosin beta-4 holds one actin protein, a 1:1 match ^[1][5]. The short piece lacks the rest of that protein.

The missing parts may change what the short piece can do.

What animal and human heart tests found

What happened to the heart in TB-500 research?

Researchers tied off a heart artery in mice. The mice received whole thymosin beta-4. More young heart cells lived, and hearts pumped better ^[2]. TB-500 hasn't produced that result in people.

Does TB-500 protect the heart after a heart attack?

Rodent hearts had less harm after whole thymosin beta-4 ^[8][9]. Pig hearts did not have less injury ^[4]. None of these animals received TB-500.

Did heart studies help people?

A thymosin beta-4 heart-attack study ended without a posted result. Phase 1 gave healthy people up to 1260 mg of whole thymosin beta-4 ^[6]. That test watched safety, not heart repair. No sound study in people has shown heart help from the fragment.

For any heart claim you read, note whether mice, pigs, or people took part.

What changed in wounds, muscles, and strokes

Does TB-500 help wounds heal?

Whole thymosin beta-4 helped animal wounds grow skin. The wounds closed more and made more collagen and vessels ^[3]. Collagen is the strong protein in skin. Later animal work also found more blood flow and repair ^[14][15].

How long did wound changes take?

Rat skin grew about 42% faster after 4 days. The gain reached 61% after 7 days ^[3]. The rats got whole thymosin beta-4. Their times don't give a TB-500 healing time for people.

Can TB-500 help tendons and ligaments?

Animal injury tests used whole thymosin beta-4. A 2026 review covered TB-500 and whole thymosin beta-4 ^[16]. It looked at muscle, tendon, and ligament injuries. A ligament is the tough tissue joining bones. No sound study in people has shown a benefit.

Does TB-500 help muscle tears or exercise recovery?

A 2026 review reported repair signs from animal work ^[16]. It found little human safety proof. In one long mouse test, more muscle fibers grew. Strength didn't improve ^[4].

Does TB-500 protect the brain?

Stroke rats improved at 2 and 12 milligrams per kilogram of the animal's weight. Thymosin beta-4 failed at 18 milligrams for each kilogram ^[13]. Researchers tied each amount to rat weight. No person took part.

Does TB-500 reduce swelling?

Whole thymosin beta-4 lowered swelling in animal and dish work ^[5]. A 2024 study found that the body began switching off heat and swelling ^[12]. The short piece hasn't shown that benefit in people.

Does TB-500 grow new blood vessels?

Thymosin beta-4 moved vessel cells and helped them form vessels ^[7]. That could feed healing tissue. It could also feed a tumor ^[5].

A rat wound can't tell you what will happen to your knee.

What human safety tests leave unanswered

What are the side effects of TB-500?

No human test gives a proven list. Phase 1 put up to 1260 mg of whole thymosin beta-4 into a vein ^[6]. No serious harm was linked to the amount. Tumor growth remains a worry ^[5]. A research vial may have the wrong substance or amount.

Does TB-500 cause cancer?

Several cancers contain much thymosin beta-4. The whole protein moves cells and helps vessels grow. Those actions might help a tumor spread ^[5]. No study has shown TB-500 causing cancer in people.

Is long-term TB-500 use safe?

No long human test has answered that. One mouse test lasted 6 months. More muscle fibers grew, but strength didn't improve ^[4]. The tumor worry makes long use hard to judge ^[5].

Have people taken part in TB-500 trials?

People have received whole thymosin beta-4. That work includes Phase 1 ^[6] and eye drops. A heart-attack test ended, but its result isn't posted. No human study has fairly compared TB-500 with other care. Human safety for TB-500 is still unknown.

Your doctor can help weigh what missing long-term proof means.

How the fragment differs and what access requires

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

TB-500 is cut from thymosin beta-4. BPC-157 comes from another protein in the stomach. A 2026 review covered both for muscle, tendon, and ligament repair ^[16]. Ligaments are tough bands joining bones. Human safety proof was thin.

Do sports groups ban TB-500?

Yes. The World Anti-Doping Agency bans TB-500 and whole thymosin beta-4 ^[16]. The ban applies during sports events and between them. Tests have found TB-500 in samples from horses and people.

Is TB-500 FDA approved?

No. The FDA hasn't approved TB-500 to treat people. FDA once put it in Category 2; the agency now lists the nomination as withdrawn ^[17]. That safety list holds drug parts with major concerns.

Is TB-500 legal?

TB-500 has no FDA-approved use in people. FDA places the withdrawn TB-500 nomination outside its active 503A review list, with safety concerns still recorded ^[17]. Sports groups also ban TB-500 ^[16]. Laws can differ by place and purpose. These are broad facts, not legal advice.

Can a pharmacy make custom TB-500?

A clinician can consider TB-500 prescription care, while the pharmacy must establish that it can lawfully make the requested medicine ^[18]. A batch means several supplies made ahead. That route has its own legal duties and does not turn an unapproved drug into an approved one. Any lawful custom drug still needs a doctor's review and valid prescription.

What is the FDA status of TB-500?

The thymosin beta-4 piece called TB-500 used to be in Category 2 ^[17]. The nomination now appears in the FDA's withdrawn table, alongside safety concerns ^[17]. An FDA committee discussed two TB-500 forms ^[19]. One is plain. The other has acetate, a salt added to that form. The committee discussion did not determine anyone's prescription access ^[18][19].

The short piece comes from thymosin beta-4. Its nomination is no longer in Category 2, which does not establish permission to compound ^[17][18].

Check the current FDA listing with your doctor or pharmacy.