Where to Buy Rapamycin for Cats — and What It Should Cost

Rapamycin for cats is a prescription medicine. You cannot buy it over the counter, and a site that will sell it to you with no veterinarian involved is one to leave. This guide covers how a real prescription works, what it should cost, and the one situation where you should ask your vet about a different product first.

Can you buy rapamycin for cats without a prescription?

No. Rapamycin — the same molecule your vet may call sirolimus — is prescription-only wherever it is legally supplied. The prescription is the safety step, not paperwork: it is where someone checks that your cat is a candidate, sets the dose by body weight, and plans the bloodwork. Cats with diabetes, active infection, liver disease, or a surgery coming up are not candidates, and a supplier who never asks is a supplier who would not know.

The one case where something else comes first

If your cat has been diagnosed with subclinical hypertrophic cardiomyopathy (HCM) and you are in the United States, ask your veterinarian about Felycin-CA1 before anything else. It is sirolimus — the same molecule — and in March 2025 the FDA granted it conditional approval for managing ventricular hypertrophy in cats with subclinical HCM. That is a regulatory status no compounded preparation has, and for that specific diagnosis in that specific country it is the honest first question.

Outside the US it is generally not available, which is where a veterinarian-directed protocol becomes the practical route. We wrote a full comparison of Felycin-CA1 and compounded rapamycin, including where each one wins.

How the prescription works

Two legitimate routes:

1. Your own veterinarian prescribes it. If they are comfortable doing so, they write the script and a pharmacy dispenses it. Plenty of vets have not prescribed rapamycin before and are cautious — a reasonable position, given the companion-animal evidence is still developing.
2. A veterinarian-directed service reviews the case. This is what Rapavie does: a licensed veterinarian reviews your cat’s history, confirms the strength, and the medicine is dispensed against that prescription while your own vet stays in the loop. If your cat is not a candidate, the order is declined and refunded.

What it should cost

Feline rapamycin therapy generally runs €70–€100 a month, because cats are small and the dose is set by weight. Our own strengths and both purchase modes are listed on the pricing page — one page, every number, no quote form. Treat prices far below that with no veterinary review attached as a warning rather than a bargain: the review is a real cost, and its absence is what makes the cheap option cheap.

What a legitimate supplier looks like

• A veterinary review before anything ships — no straight-to-checkout for the medicine alone.
• Dosing by your cat’s weight. The usual research dose is 0.3 mg/kg once weekly; a supplier offering one tablet for every cat is not dosing, it is shipping.
• Transparent pharmacy and prescriber, willing to share the dosing rationale with your own vet.
• The ability to say no.

You can check what strength your cat’s weight points to with our dose calculator before you speak to anyone — the vet confirms the final dose either way.

What the science says, and does not

Rapamycin extends healthy lifespan in laboratory mammals, and it is the most studied longevity molecule in veterinary medicine. In cats specifically the longevity question is under investigation, not established — there is no feline equivalent of a completed lifespan trial. Buy it for what is known: a well-studied molecule, prescribed properly and monitored. Not for a promise nobody can make yet.

For the research laid out study by study, with nothing to sell you, see the evidence library at Our Beloved Friends.

When you are ready, the cat therapy begins with a veterinary review — and if your cat is not a candidate, you pay nothing.