率直なFAQ。

Indoor cats commonly live 13 to 17 years, and reaching the early twenties is no longer unusual. Outdoor access shortens life expectancy substantially, largely through trauma, infectious disease and predation rather than accelerated biological aging.

Yes, for one specific diagnosis. Felycin-CA1 (sirolimus delayed-release tablets) received conditional FDA approval in March 2025 for managing ventricular hypertrophy in cats with subclinical HCM. It is available in the US. Conditional approval means a reasonable expectation of effectiveness, not the substantial evidence full approval requires.

Yes. They are two names for the same molecule. Rapamycin is the original name, given after Rapa Nui where the compound was found in 1972; sirolimus is its international non-proprietary (generic) name, which is what appears on prescriptions and regulatory approvals.

Either — you will reach the same drug. Research papers usually say rapamycin; prescriptions, pharmacy labels and approvals usually say sirolimus. A seller who treats them as two different drugs is a reason for caution.

Yes. Felycin-CA1 is a sirolimus delayed-release tablet, and sirolimus and rapamycin are two names for the same molecule. The differences are formulation, regulatory status and availability, not the active drug.

It means the manufacturer demonstrated a reasonable expectation of effectiveness rather than the substantial evidence required for full approval, and may market the drug while collecting the remaining data. It must be renewed annually for up to five years.

Common early signs include a new or growing lump, a sore that will not heal, unexplained weight loss, appetite loss, new low energy, unusual bleeding, and lameness that does not resolve. Any of these in an older dog is worth a veterinary check-up.

It is the leading cause of death in adult dogs, and roughly half of dogs over ten will face it. Early detection greatly improves the options, which is why acting quickly on warning signs matters.

A carcinoma is a cancer that starts in epithelial tissue — the cells lining skin, glands and internal organs. It differs from sarcomas (connective tissue) and lymphoma (immune cells), and that distinction shapes how it behaves and is treated.

Lifespan extension is proven in mice, where rapamycin extended median lifespan even when started in late middle age. In dogs, the definitive lifespan question is still being tested by the NIH-funded TRIAD trial within the Dog Aging Project. Earlier smaller canine studies reported improvements in cardiac function, which is why many veterinarians consider the healthspan case stronger than the lifespan case today.

The three conditions that dominate feline mortality after middle age are chronic kidney disease, cancer, and heart disease — most commonly hypertrophic cardiomyopathy (HCM). Each is strongly age-associated, which is why interventions that target aging biology itself are of growing interest.

Rapamycin targets mTOR, the same aging pathway studied in mice and dogs. In cats, the most advanced clinical work concerns hypertrophic cardiomyopathy, where a delayed-release formulation has been studied for its effect on disease progression. Whether it extends overall feline lifespan has not been established. It is a prescription medicine used under veterinary direction.

No. The evidence points to slowing the progression of wall thickening, not reversing existing disease. A delayed-release formulation studied in cats with subclinical HCM was associated with reduced progression compared with placebo. Anyone describing it as a reversal is going beyond the data.

Not established. mTOR signalling is involved in the fibrosis that drives CKD progression, and studies in cats are underway at veterinary institutions, but no rapamycin protocol has been shown to alter the course of feline CKD. Anyone claiming otherwise is ahead of the evidence.

Not established. mTOR inhibition is a recognised anticancer mechanism in human oncology and is being studied in canine cancers, including within trials in osteosarcoma. Preliminary work is interesting, but no study has shown that rapamycin prevents cancer in dogs, and it should not be presented as doing so.

mTOR is a protein complex that acts as a nutrient sensor. When food and growth signals are plentiful it tells cells to grow and build; when they are scarce it steps back and lets cells repair and recycle. It is named after rapamycin — the "mechanistic target of rapamycin".

Autophagy is the cell’s recycling system: damaged proteins and worn-out components are broken down and their parts reused. It is suppressed when mTOR is active and switches on when mTOR quiets down. Its role in cellular housekeeping was recognised with the 2016 Nobel Prize in Physiology or Medicine.

In mice, yes — rapamycin extended median lifespan in rigorous multi-site studies, even when treatment began in late middle age, making it the most reproducible pharmacological lifespan extender known. Whether this translates to cats and dogs is the question being tested now; it has not been demonstrated in either species.

Because mTOR is essential. Cells need it to grow, repair tissue, mount immune responses and maintain muscle. Longevity protocols aim at partial, intermittent inhibition — nudging the pathway rather than shutting it down, which is why dose and schedule matter so much.

Not yet. It extends healthy lifespan in laboratory mammals and is being studied in companion dogs through the NIH-funded TRIAD trial, which has not reported its primary results. Its effect on canine lifespan is under investigation, not established.

It is not "better" so much as different. Rapamycin has far deeper study of the aging process and is a prescription medicine with veterinary oversight; supplements are cheaper, need no prescription and carry low risk. For simple, affordable support a quality supplement is reasonable; for a considered, monitored protocol, rapamycin has the deeper evidence.

The evidence is not comparable. Rapamycin has decades of study and active companion-animal trials; most longevity supplements rest on early data or extrapolation from other species. That does not make supplements useless — omega-3s, for instance, have solid support — but their evidence for slowing aging is far thinner.

No. Rapamycin is not a proven cancer treatment in dogs. The largest trial — 324 dogs with osteosarcoma — found no improvement in disease-free interval or survival when sirolimus was added to standard care. A dog with cancer should be seen by a veterinary oncologist.

Because it blocks mTOR, a growth pathway that matters in cancer, and mTOR inhibitors are used in some human cancers. The biological rationale is real and rapamycin does reach its target in canine tumours — but rationale is not the same as a proven survival benefit, and the pivotal dog trial was negative.

Healthy aging, not cancer treatment. The NIH-funded TRIAD trial in the Dog Aging Project is testing whether low, once-weekly rapamycin supports healthy lifespan in healthy older dogs. Those results have not been published yet, so it is described as under investigation.

There is no evidence that it prevents tumours. Rapamycin is studied for healthy aging in dogs, and when tested directly against an aggressive canine cancer it did not improve survival. It should not be used as a cancer preventive.

No. There is no trial showing rapamycin treats carcinomas in dogs, and the pivotal canine cancer trial (osteosarcoma) showed no survival benefit. Rapamycin is studied for canine aging, not as a carcinoma treatment.

At the low, intermittent doses used in longevity protocols, rapamycin has been well tolerated in published canine trials. The most commonly reported side effect is mild, transient gastrointestinal upset in a small minority of dogs. Dogs with diabetes, active infections, significant liver disease or planned surgery are generally not candidates. Rapamycin is a prescription medicine and should only be given under veterinary supervision.

At longevity doses the most commonly reported effect is mild, transient gastrointestinal upset in the first weeks. Mouth ulcers, delayed wound healing and changes in blood lipids or glucose are recognised effects of mTOR inhibition and are among the reasons periodic bloodwork is part of the protocol.

Animals with diabetes or impaired glucose regulation, active or recurrent infections, significant liver or kidney disease, and those scheduled for surgery — mTOR inhibition can slow wound healing. Pregnant or nursing animals are excluded. A full medication review comes before the first dose.

Yes. It is metabolised by the CYP3A4 enzyme system, so drugs that inhibit or induce that pathway — including some antifungals, antibiotics and antiseizure medications — can raise or lower rapamycin levels significantly. Every medication and supplement your pet takes should be disclosed during the review.

At longevity doses the most commonly reported side effect is mild, transient stomach upset in the first few weeks, which often settles when the dose is given with food. Serious effects are uncommon at these doses, but the medicine is not appropriate for every animal.

At the high daily doses used in transplant medicine it does. At the low, intermittent doses studied for longevity, several studies report the opposite — an improved immune response. The effect depends entirely on dose, which is why a veterinarian sets it.

Animals with diabetes or impaired glucose regulation, active infection, significant liver disease (or, in dogs, significant kidney disease), a planned surgery, or that are pregnant or nursing. The veterinary review screens for all of these before anything is dispensed.

No. Because the effect flips with dose, and because several conditions rule it out, rapamycin should only be used at a veterinarian-set dose after a review of your animal’s health. Self-dosing removes the safeguard that makes it safe.

Rapamune is a human brand of sirolimus, so the molecule is the same, but the product is not made for animals. Human tablet strengths are far too large for a cat or a small dog, and splitting them at home is unsafe. Dosing must be set by a veterinarian.

No. Felycin-CA1 is conditionally approved to manage ventricular hypertrophy in cats with subclinical HCM, which is narrower than treating or curing heart disease. No sirolimus product is approved to cure HCM or to extend life in cats.

Longevity protocols use far lower doses than transplant medicine, given intermittently rather than daily — commonly three times per week, with the strength scaled to body weight. A veterinarian sets the exact dose after reviewing the dog’s weight, age, bloodwork and medication list.

Most protocols target healthy middle-aged and senior dogs — roughly from age 6 in medium breeds, earlier in large and giant breeds that age faster. The rationale is to intervene before age-related disease is established rather than after.

Most veterinary guidelines classify cats as mature from around 7 years and senior from around 11. Twice-yearly examinations with bloodwork and blood pressure are typically recommended from the senior stage, because cats conceal illness until it is advanced.

Echocardiography is the definitive test — it measures left ventricular wall thickness directly. A heart murmur, a gallop rhythm or an elevated NT-proBNP blood test raises suspicion, but none of them confirm HCM on their own, and many affected cats have no murmur at all.

Maine Coons, Ragdolls, British Shorthairs, Sphynx and Persians carry higher breed-associated risk, and two genetic mutations are recognised in Maine Coons and Ragdolls. But HCM is common in domestic shorthairs too, which is why screening is based on age and signs rather than pedigree alone.

That is a cardiologist’s decision. Historically, subclinical HCM had no treatment shown to change its course, so many cats were simply monitored. The interest in mTOR inhibition comes precisely from that gap — the question being studied is whether intervening early alters progression.

Increased drinking and urination usually come first, followed by weight loss, a duller coat, reduced appetite and lethargy. These appear late — often when around two-thirds of kidney function is already lost — which is why bloodwork on a cat that still looks well matters so much.

No. Nephrons that are lost do not regenerate, so chronic kidney disease is managed rather than cured. The realistic goal is slowing further loss and keeping the cat comfortable, which good management does achieve — many cats live years after diagnosis.

SDMA is a blood marker that rises earlier in kidney disease than creatinine — often when roughly 40% of function is lost rather than 75%. It gives a wider window to intervene with diet and blood pressure control, and it is now routine in senior feline panels.

A lump that grows or changes, unexplained weight loss, persistent lameness, difficulty eating or swallowing, non-healing sores, abnormal bleeding, sudden collapse or pale gums, and lasting changes in appetite or energy. Any of these deserves an examination rather than a wait-and-see approach.

Golden Retrievers, Boxers, Bernese Mountain Dogs, Flat-Coated Retrievers, Rottweilers and Scottish Terriers carry well-documented elevated risk, and large and giant breeds face higher osteosarcoma risk. Breed shapes screening intensity, not certainty — mixed-breed dogs develop cancer too.

It can, and the effect differs by cancer type and breed. Early gonadectomy reduces mammary tumour risk but has been associated with increased risk of some other cancers in certain large breeds. This is a genuinely individual decision to make with your veterinarian rather than a universal rule.

Far less than in transplant medicine, and intermittently rather than daily. Dogs commonly take a weight-scaled dose three times a week; cats are typically dosed once weekly with a delayed-release formulation at strengths calibrated to body weight. The exact dose is a veterinary decision based on weight, age, bloodwork and concurrent medications.

Generally yes. Because mTOR inhibition can slow wound healing, protocols typically pause dosing before and after planned surgery. Timing should be agreed with the veterinarian performing the procedure and the veterinarian managing the protocol.

Yes, and we prefer it. We share the dosing rationale and monitoring schedule with your veterinarian so everyone is working from the same information. Rapavie’s review works alongside your vet, not instead of them.

Often yes, but it is a question for the veterinarian who sets the rapamycin dose, since some supplements interact with monitoring or the animal’s conditions. Raise it during the review rather than combining things unsupervised.

Research protocols in cats use about 0.3 mg/kg once weekly, which is also the dose of the conditionally approved feline product. The exact strength is confirmed by the prescribing veterinarian after reviewing your cat.

No. Published protocols use about 0.3 mg/kg once weekly in cats and about 0.15 mg/kg once weekly in dogs, and the dose is then set by the individual animal’s weight. Weekly dosing, not daily, is what companion-animal research uses.

If your cat has subclinical HCM and you are in the United States, ask your veterinarian about Felycin-CA1 first — it is conditionally approved for exactly that. Outside the US it is generally unavailable, and for cats without an HCM diagnosis it is outside its label, which is where a vet-directed protocol applies.

No. It is a feline product and its conditional approval covers cats with subclinical HCM. Dogs are dosed differently — around 0.15 mg/kg once weekly in published protocols — and rapamycin in dogs is being studied through the NIH-funded TRIAD trial, which has not reported its primary results.

Your first step should be a veterinary oncologist, who can stage the cancer and use treatments with proven benefit. Rapamycin is a longevity research compound, not a cancer therapy, and using it in place of oncology care is not supported by the evidence.

See a veterinarian first. A lump or a changing mass needs professional assessment and staging — no supplement or longevity compound substitutes for that, and delay can narrow the treatment options.

By a veterinary oncologist, usually with surgery as the mainstay, and sometimes radiation or chemotherapy depending on the type and stage. These are the treatments with real evidence behind them.

Not as a cancer treatment. The right first step is a veterinary oncologist. Rapamycin’s studied role is healthy aging in healthy dogs, under veterinary direction — a different goal from treating an existing tumour.

No. Rapamycin is a prescription-only medicine, and a legitimate supplier will not dispense it without a licensed veterinarian reviewing your dog first. A site that sells it with no vet involved is one to avoid.

Usually in the region of €100–€130 a month, because the dose is set by body weight and larger dogs need a higher strength. The veterinary review is included in that price. Every strength is listed on our pricing page.

Because it is a prescription medicine and the price includes a licensed veterinarian’s review, weight-based dosing and monitoring guidance. A supplement is an off-the-shelf product with none of that. You are paying for oversight, not just the molecule.

No. Rapamycin, also called sirolimus, is a prescription-only medicine. A legitimate supplier will not dispense it without a licensed veterinarian reviewing your cat first, and a site that sells it with no vet involved is one to avoid.

Usually €70–€100 a month, because the dose is set by body weight and cats are small. The veterinary review is included in that price at Rapavie. Every strength is listed on our pricing page.