Can anyone take rapamycin?

Rapamycin is a powerful drug that suppresses the immune system. This effect is so strong and so well documented that it forms the basis of its use in organ transplantation: the body must not reject the new organ. But that same mechanism means that resistance to infections decreases, and in people with an active infection the drug is therefore avoided as much as possible in clinical practice.

In addition to its effect on the immune system, rapamycin can disrupt blood sugar regulation. The drug can cause temporarily elevated blood sugar levels, reduced insulin sensitivity and loss of glucose tolerance, a condition sometimes referred to as 'pseudo-diabetes'. These are well-known side effects, not rare exceptions.

Rapamycin and related compounds have been studied and approved for specific medical situations. The analogue temsirolimus has gone through phase III studies for renal cell carcinoma and is used in certain types of cancer. In heart transplant patients with a history of cancer, rapamycin as an immunosuppressant appears to show some promise, but the evidence for this is limited and based on small studies. In a specific, genetically determined form of epilepsy in which the mTOR signalling pathway is disrupted, a rapamycin-like agent may be considered as part of a personalised treatment. All of these applications take place under medical supervision, in selected patients.

Rapamycin is therefore explicitly not a drug for the general population. The combination of immunosuppression, increased infection risk and disruption of blood sugar regulation means that use outside a medical context with physician oversight carries unacceptable risks for virtually everyone. People who consider rapamycin for supposed anti-ageing effects do so at their own risk and outside the framework of existing clinical evidence.