An experimental drug developed using artificial intelligence has attracted international attention after early research suggested it could reduce biological age by as much as six years. But rentosertib was designed to treat a serious lung disease, not to reverse ageing, and the findings behind those headlines require careful interpretation. Aesthetic physician Dr Susan Burger examines the clinical evidence, the growing interest in longevity medicine and why this investigational drug should remain firmly outside the biohacking marketplace.
In September 2026, a headline went around the world: a new drug had made patients “biologically younger” by up to six years. The drug is called Rentosertib, and it is already turning up in longevity and biohacking conversations alongside peptides like BPC-157 and epitalon. Here is what it actually is, what the studies really showed, and what you should do if someone offers it to you.
First, it is not a peptide
Rentosertib is often lumped in with peptides, but it is a different kind of medicine altogether. It is a small-molecule drug: a pill, made by chemical synthesis, not a chain of amino acids that has to be injected.
It is being developed by Insilico Medicine, a biotechnology company that uses artificial intelligence to discover drugs, and it is famous mainly for that reason.
AI was used both to choose the drug’s target in the body and to design the molecule itself. It is the first drug developed this way to reach a late-stage clinical trial.
How it works
Rentosertib blocks an enzyme called TNIK.
TNIK sits at a junction of several signalling pathways that drive scarring (fibrosis) and inflammation. By switching it down, the drug aims to slow, stop or even partly reverse the build-up of scar tissue.
In laboratory studies, it also calmed down “senescent” cells, the worn-out cells that accumulate with age and release inflammatory signals. That laboratory finding is where the anti-ageing interest began.
Who it is being developed for
Rentosertib is being tested for one disease: idiopathic pulmonary fibrosis (IPF).
IPF is a serious lung condition, mostly affecting people over 60, in which the lungs gradually scar and stiffen. Survival after diagnosis is often only a few years. The two existing IPF medicines can slow the decline but cannot stop it, so a drug that does more would be a genuine advance.
In a 12-week trial of 71 patients in China, published in Nature Medicine in 2025, people on the highest dose saw their lung capacity rise by about 100 ml on average, while those on placebo lost about 20 ml. That is encouraging, but it was a small, short study, and its main purpose was to test safety rather than prove benefit.
A full-scale trial of 320 patients, treated for a year, began in China in July 2026. That trial will tell us whether the early signal is real.
The “younger by six years” story
The anti-ageing headlines came from a follow-up analysis of blood samples from 42 of the same lung patients. Researchers ran the blood proteins through six “ageing clocks”, computer models that estimate biological age. All six suggested lower biological age in patients on the drug.
That is interesting science, but it is a long way from proof that rentosertib slows ageing. The patients were sick, the study was short, and not every comparison was statistically meaningful. A clock reading is a prediction, not a health outcome: nobody lived longer or felt younger in this study.
Even the researchers note that they cannot tell whether the clocks were measuring slower ageing or simply less lung disease. Most of the authors also work for the company that owns the drug. Nobody has tested rentosertib in healthy people for anti-ageing purposes.
Who it is not for
At this stage, it is not for anyone outside a clinical trial. In particular, it is not for healthy people hoping to turn back the clock.
In the lung trial, side effects were common in every group, including placebo, but more patients on rentosertib stopped because of side effects, mainly liver problems and diarrhoea. Liver injury is not something to risk for an unproven benefit. Effects in pregnancy, in people with existing liver disease, and alongside other medicines have not been established.
When can the public expect it?
Not soon.
The current trial runs for a year per patient and has only just started, so results are unlikely before 2028. Approval, if it comes, would be for IPF and would probably come first in China. Approval in the United States, Europe or South Africa would follow later and may require further studies. There is no approved anti-ageing use on the horizon at all.
The warning that matters most
Rentosertib is not registered anywhere in the world.
Insilico supplies it only to approved clinical trials, and it cannot be legally made by a compounding pharmacy. Anything sold online as rentosertib, whether labelled as capsules, powder or a “research chemical”, is therefore not the real product from a legitimate source. It may contain nothing, the wrong substance, or something harmful.
In South Africa, the law is straightforward. Under the Medicines Act, an unregistered medicine may not be sold. The only lawful route to one is a Section 21 application to SAHPRA, made by a doctor for a named patient, and that route exists for serious illness, not for longevity experiments.
The bottom line
Rentosertib is a genuinely important drug, for two reasons: it may become a new treatment for a devastating lung disease, and it shows that AI can help invent new medicines.
But it is a lung-fibrosis drug in trials, not a longevity pill.
The honest summary today is “promising for IPF, unproven for ageing, unavailable to the public”. If you are curious, follow the Phase 3 results. If you are offered it, walk away.
Sources: Ren F et al. Nat Biotechnol 2024 (doi:10.1038/s41587-024-02143-0); Xu Z et al. Nat Med 2025 (doi:10.1038/s41591-025-03743-2), ClinicalTrials.gov NCT05938920; Tang Q et al. Aging Dis 2025 (doi:10.14336/AD.2024.1492); Zhavoronkov A et al. Nat Biotechnol 2026 (doi:10.1038/s41587-026-03286-y); Insilico Medicine Phase III announcement, 7 July 2026; Medicines and Related Substances Act 101 of 1965, ss 14 and 21.
About the author
MBBCh (Wits), Aesthetic Physician, AAAM Board Certified (American Academy of Aesthetic Medicine), AAMSSA member
Dr Susan Burger is a General Practitioner with over 20 years of experience. She specialises in aesthetic medicine and runs a busy practice in Kempton Park, with a core focus on skin health and optimisation.
She is passionate about education and improving the way in which Aesthetic Medicine is practised. As a faculty member of the AAAM (American Academy of Aesthetic Medicine) and local trainer for thread and filler companies in South Africa, she is active in the education of new doctors entering the field of Aesthetic Medicine.
She is a trainer for Mint PDO threads and Fillmed (Filorga) South Africa.
She also regularly presents lectures and performs live treatment demonstrations during the annual Aesthetics Congress in South Africa (AMCSA).