Chapter threeEvidence & next steps

What do the sources actually show?

When an article or treatment offer mentions a study, check whether it tested TB-500 or the whole thymosin beta-4 protein.

The names matter because these are different substances. Use the questions below to discuss the offer with a doctor.

An empty reading table beside a wide window looks out onto leafy branches.

Is TB-500 the same as thymosin beta-4?

No. Thymosin beta-4 is a protein found in the body; TB-500 is a lab-made copy of a small piece of it.

'Full-length' thymosin beta-4 means the whole protein, rather than a small piece.

Results for the whole thymosin beta-4 protein cannot be treated as results for TB-500.

Studies in people using the whole thymosin beta-4 protein mainly tested eye drops and skin gels.

Did the full protein clearly help?

Studies of the whole thymosin beta-4 protein had mixed results in the review checked in September 2026.

An early dry-eye study of 72 people tested eye drops made with the whole thymosin beta-4 protein.

The drops did not clearly beat drops without the study medicine at easing eye discomfort or reducing damage to the eye's surface.

Some other test results were better with the medicine drops, but these were not the study's main tests of whether the drops worked.

Two small studies tested skin gel made with the whole thymosin beta-4 protein.

Sores healed about as often with dummy gel as with the medicine gel.

A dummy gel contains no study medicine; researchers use it to see whether the medicine makes a difference.

In the leg-sore study, sores had closed after 12 weeks in 12 of 55 people using thymosin beta-4 gel.

They closed in 4 of 17 people using dummy gel.

In the pressure-sore study, sores closed in 8 of 53 people using thymosin beta-4 gel and 3 of 18 using dummy gel.

These small studies do not prove that the skin gel works or does not work.

Those studies do not show that injected TB-500 helps an injury.

What is the immune concern?

An immune reaction means the body's defences treat a substance as an invader.

The FDA warns of possible immune reactions to injected TB-500 in the review checked in September 2026.

Clumps and unwanted material may raise that risk; the FDA found no studies in people that checked this risk for TB-500.

What if I compete in sport?

The World Anti-Doping Agency publishes a banned list for sport and is known by the initials WADA.

Under the WADA list in force in September 2026, TB-500 is barred during competition and outside it.

The NCAA, the US college sports body, also names TB-500 in its list for the 2026–27 year.

Questions to take into a visit

Tick the questions you want to raise, then print this list.

This checklist does not identify a legal supplier of TB-500.

HHS proposes to withhold enforcement for prescribed TB-500 made for one patient by state-licensed pharmacies or licensed physicians meeting its conditions. 503B outsourcing facilities fall outside its October 30, 2026 draft.

Product tests cannot replace studies in people or make TB-500 an approved medicine.

How can I check a doctor's licence?

  1. Get the name and state.

    Get the doctor's full name and write down the state where you will be located during the visit.

  2. Go to the state board.

    Open that state's board website from the medical board directory in the chapter notes.

  3. Match the public record.

    Match the doctor's name to the record, confirm the licence is current, and look for penalties or pending formal charges listed by the board.

A disciplinary action is a penalty for breaking the board's rules, such as a restriction on a doctor's licence.

The board may also list formal charges that have not yet been decided; these are not the same as a penalty.

A record without penalties does not tell you how skilled the doctor is.

Chapter notes

Need to revisit the basics?

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