Patients sometimes ask me “Will TB-500 help my injury to heal quicker?” and then I have to explain to them that it is not a clever idea to self-medicate with a horse-doping substance. So I decided to write this article to clarify what TB-500 is all about. Remember, if you need more help with an injury, you're welcome to consult one of our physios online via video call.
In this article:
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What is TB-500?
TB-500 is a lab-produced peptide. Peptides occur naturally in our bodies (and in those of other mammals) and have various functions. TB-500 mimics a section of the natural peptide thymosin beta-4 (TB4), which is involved in producing growth hormones. These growth hormones, in turn, help with things like muscle growth and tissue repair.
TB-500 was originally developed for veterinary purposes. Soon it was used to enhance the performance of race horses and was duly banned in the horse racing industry.
What does TB-500 do?
Nowadays, humans can buy TB-500 online to use on themselves.
The people who sell TB-500 for human use claim that it enhances sports performance. The thinking is that it helps athletes’ muscles and tendons to recover quicker from training and that they can therefore get more training done without risking overtraining.
The other claim, aimed at people who want to look ripped without much effort, is that it will give you bigger muscles and help you to lose fat.
But are these claims valid?
Research on TB-500 and thymosin beta-4
Medical purposes
The research on thymosin beta-4 as a drug for medical purposes for humans has not gone beyond Phase 2 clinical trials. These trials have focused on treating people with dry eye syndrome (a condition that affects the cornea) and treating people with epidermolysis bullosa, a rare disease that causes tears and sores on the skin when it bumps or rubs against something.
It should be noted that the thymosin beta-4 in these trials were applied externally to the problem areas, so it didn't affect other areas of the body. People using thymosin beta-4 and TB-500 on themselves, however, mostly take it as a nasal spray, powder, or an injection.
A drug has to make it past Phase 3 clinical trials to be considered safe for humans and for approval by the USA’s Food and Drug Administration (FDA) and similar bodies elsewhere.
There have also been studies on animals that suggest that thymosin beta-4 might be useful for repairing damage to the heart muscle, and it has been shown to have anti-inflammatory properties.
So, given the state of research on thymosin beta-4, we don’t know yet whether it’s effective and, more importantly, whether it’s safe for humans to use.
Sports performance
Neither TB-500 nor thymosin beta-4 has been researched for their effect on any aspect of sports performance, as far as I could ascertain.
However, scientists have been scratching their heads about how to detect TB-500 and thymosin beta-4 use in sportspeople. Which brings us neatly to our next topic.
Are TB-500 and thymosin beta-4 legal?
Thymosin beta-4 is registered with the FDA as a drug still undergoing clinical trials. So, it is not an approved drug in the USA (and elsewhere) and cannot be prescribed by medical doctors. TB-500, which has the same properties as thymosin beta-4, is also not approved for use.
TB-500 as well as thymosin beta-4 are banned by the World Anti-Doping Agency. Despite the lack of research, it is considered a performance-enhancing drug, likely due to what was observed in horse racing
As far back as 2015, Australia’s Department of Health, in a submission to the Therapeutic Goods Administration (the Aussie version of the FDA), pointed out how easy it was to get hold of TM-500 and thymosin beta-4.
They expressed their concern about its misuse in sport, especially by “sub-elite athletes … due to the highly competitive nature of their events, the perceived advantage provided by these substances and the less stringent doping scrutiny to which they are subject.”
In 2016, in a case that went all the way to the Court of Arbitration for Sport, in Switzerland, 32 players of the Australian Football League club Essendon were banned from the sport for two years after having used thymosin beta-4 as part of the sports supplements regime they were prescribed.
And now, almost ten years later, not much has changed. The Internet is still awash with websites and YouTube, Instagram, and TikTok videos touting TB-500 as a safe and legal way of getting bigger muscles and losing fat.
Regulatory bodies don’t seem to do much about it. A search for “TB-500” on the FDA’s website produced one result: It is a warning letter written in June 2023 to the owner of a website that sold TB-500 (injections and nasal spray) as well as SARMs and other illegal drugs.
My take on TB-500
We’re not horses. We don’t know whether it is safe to use in humans nor do we know the long-term effect it might have on your health. Like other banned substances, it might turn out to have detrimental effects on your kidneys, liver, or other organs. I would stick to proven treatments.
Injured? We can help
Need more help with an injury? You’re welcome to consult one of the team at SIP online via video call for an assessment of your injury and a tailored treatment plan.
We're all UK Chartered Physiotherapists with Master’s Degrees related to Sports & Exercise Medicine or at least 10 years' experience in the field. But at Sports Injury Physio we don't just value qualifications; all of us also have a wealth of experience working with athletes across a broad variety of sports, ranging from recreationally active people to professional athletes. You can meet the team here.
About the Author
Maryke Louw is a chartered physiotherapist with more than 20 years' experience and a Master’s Degree in Sports Injury Management. Follow her on LinkedIn and ResearchGate.