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 it should not be started without your own veterinarian involved. 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 your own veterinarian 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 — rule these out with your vet before starting.

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 compounded protocol, used under your own veterinarian’s guidance, 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 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. You order from a supplier such as Rapavie, guided by your own vet. Share the protocol with your own veterinarian and confirm it suits your cat before starting — and keep them in the loop for monitoring.

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, or a seller that tells you no vet is needed, as a warning rather than a bargain.

What a legitimate supplier looks like

• A plain statement that it is a prescription medicine, to be used only under the guidance of your own veterinarian.
• 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.
• Transparency about the medicine and its dosing rationale, so you can share both with your own vet.
• Clarity about who should not take it, so you can rule that out with your own vet.

You can check what strength your cat’s weight points to with our dose calculator before you speak to anyone — then confirm the final dose with your own veterinarian.

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, see the cat therapy. Strengths follow body weight — check the strength with your own veterinarian before starting.