While longevity science made incremental progress in 2025, we are still waiting for the first drugs to be approved for ageing. Nonetheless, early adopters are hoping to reap some of the benefits of these new discoveries today, many by visiting the growing number of ‘longevity clinics’ springing up around the world.

The longevity medicine sector continued to expand in 2025: a market sizing exercise estimated the ‘Longevity clinics and preventative health’ sector at $23.4 billion in 2025 and growing rapidly. Meanwhile, a survey of 82 clinics by Longevity.Technology revealed a substantial diversity of offerings, from clinics that only prescribe weight loss drugs, to others offering far more experimental stem cell and peptide therapies.

However, with no medication or supplement proven to slow ageing, the upside of such treatments is uncertain, while an incident at a biohacking festival highlighted the risks: two people were rushed to hospital after peptide injections at RAADfest in Las Vegas in July. In the aftermath, The LI’s Directors Andrew Steele and Kamen Shoylev told Lifespan.io:

It’s hard to generalize when there’s such a diversity of levels of evidence for different therapies—a longevity scientist self-experimenting with rapamycin is very different from a non-expert seeking out stem cells from an unlicensed practitioner. Overall, we should be very cautious if we want longevity medicine to be perceived as a legitimate medical specialty. If people start to think that ‘longevity’ means unproven supplements or peptides, it’s just another communications challenge for a field that’s already facing numerous ethical questions, such as whether treatments will only be accessible to billionaires.

The incident at RAADfest formed part of a broader discussion about standards in longevity medicine. In October 2025, an editorial in the journal Aging called for regulatory clarity, noting that many clinics operate in ‘a grey zone where ambitious interventions can be marketed without adequate safety, accountability, or transparency’. Meanwhile, the third Roundtable of Longevity Clinics convened in December 2025 at the Buck Institute, bringing together clinic operators and researchers to work toward defining standards for diagnostics and interventions.

There is clearly more work to be done on standardising treatments and protocols, and hopefully 2026 will see more such discussions.

Do weight-loss drugs slow ageing?

As mentioned above, many longevity clinics prescribe weight-loss drugs—and a huge theme in this year’s discourse in both science and medicine around them has been the idea that these ‘GLP-1’ drugs may slow the ageing process itself.

The idea might sound far-fetched, but there are several ways it could happen. Firstly, such a slow-down  might be caused by weight loss itself, as we know that inflammatory molecules produced by fat can accelerate ageing. Secondly, we are beginning to understand that these drugs have broader effects, some of which kick in before the weight loss is observed—perhaps these ‘side-effects’ could be beneficial for longevity?

One study suggested broad slowing of age-related changes in mice using a GLP-1 drug called exenatide, but lifespan wasn’t investigated and the study was very small. A preprint in patients with HIV showed that semaglutide (sold as Wegovy and Ozempic) reduced ‘biological age’ as measured by an epigenetic clock—but the study had extensive caveats, including its small size, and more fundamental issues with using epigenetic clocks as measures of ageing.

The more significant results have been in humans and, while not examining ageing per se, demonstrated GLP-1 drugs’ diverse protective effects. The year started with an extensive review of the benefits and side-effects of the drugs, while results presented in May showed impressive and rapid benefits for heart disease risk before weight loss had started.

More pessimistic news for the hypothesis was the failure of semaglutide to slow Alzheimer’s in a major trial. It could be that giving the treatment earlier would meet with more success, but nonetheless this failure against dementia hurts the thesis that GLP-1s protect against all aspects of ageing.

Weight-loss drugs will nonetheless be preventative medicines taken by substantial fractions of the population—something that could lay the groundwork for longevity medicines, which could end up being taken by almost everyone. In December, the WHO called for wider global access to weight-loss drugs—and it’s easy to imagine such calls being repeated for the longevity drugs of the future.