Rapamycin (sirolimus) for healthy aging
Sold as Rapamune
The most credible candidate for a genuine anti-aging drug in dogs, currently being tested in a real randomized trial that has not yet reported results. There is no honest basis today for giving it to a healthy dog outside that trial.
Why this grade
The definitive trial is running but has not reported. TRIAD is a properly randomized, placebo-controlled, multicentre trial with lifespan and healthspan endpoints, but as of mid-2026 it has enrolled roughly 180 of a target 580 dogs and only a few have completed the full three-year period. Published TRIAD output so far is baseline cohort description, not outcome data. Tier U means untested, not disproven. This is the most scientifically serious longevity effort in dogs, and it deserves patience rather than extrapolation.
What the trials show
TRIAD, the Test of Rapamycin in Aging Dogs, is run through the Dog Aging Project and described by its investigators as the first rigorous test of a pharmacologic intervention against biological aging with lifespan and healthspan endpoints performed outside the laboratory in any species. Eligible normally aging dogs at least seven years old receive oral rapamycin or placebo for one year, followed by a two-year observation period. As of 2026, enrollment stands at over 180 dogs against a target of 580, with a handful having completed the full three years. The trial survived a funding crisis via a $7 million grant. The published TRIAD work to date covers cognitive assessment methodology and baseline cohort characteristics rather than any efficacy result. One example: 35 dogs examined for inclusion, with a median age of 9.2 years and median weight of 27.7 kg. Anyone citing rapamycin as proven in dogs is citing mouse data or hope.
Harms and cautions
Not characterized for long-term use in healthy dogs, which is precisely what the trial exists to determine. Rapamycin is an immunosuppressant at transplant doses; the geroscience hypothesis relies on intermittent low doses behaving differently, and that assumption is being tested, not established. Plausible concerns include impaired wound healing, metabolic effects, and infection susceptibility. A healthy dog given this off-label is absorbing unquantified risk for an unquantified benefit.
Practical detail
- Route
- Oral, intermittent dosing in the trial protocol
- Typical course
- TRIAD protocol: 1 year of dosing, 2 years of observation
- Monitoring
- Within the trial, extensive. Outside it, no established monitoring protocol exists.
- Cost
- varies
Regulatory status
- United States
- Not approved for any use in dogs. Human formulations are sometimes prescribed off-label, which is legal but places the evidentiary burden entirely on the prescribing veterinarian.
- Note
- Off-label prescribing outside a trial means accepting an unknown risk-benefit ratio in exchange for an unproven benefit.
Questions worth asking your vet
- Is my dog eligible for TRIAD, and is there an enrolling site near me?
- If you would prescribe this off-label, what monitoring plan and stopping rules would you use, given no protocol has been validated?
- What would we be giving up by waiting for the trial to report?
The evidence, one study at a time
Dog Aging Project. Test of Rapamycin in Aging Dogs (TRIAD). Multicentre randomized placebo-controlled trial, ongoing.
ongoing trial 2026
The trial that will actually answer this question. Until it reports, the honest answer about rapamycin in dogs is that nobody knows.
- Design
- Randomized, placebo-controlled, multicentre
- Dogs analyzed
- 180
- Blinding
- double-blind
- Control
- Placebo
- Duration
- 1 year of treatment plus 2 years of observation
- Population
- Healthy, middle-aged, medium-to-large companion dogs aged 7+, target enrollment 580
- Primary outcome
- Lifespan and healthspan
- Result
- Enrollment ongoing; no efficacy results published as of mid-2026.
- Funding
- National Institute on Aging and philanthropic support, including a $7 million rescue grant
Canine cognition assessments in the Test of Rapamycin in Aging Dogs (TRIAD). 2024.
observational 2024
Methodological groundwork, explicitly not an efficacy result. Included so the distinction is visible rather than blurred.
- Design
- Baseline cohort characterization
- Dogs analyzed
- 35
- Blinding
- not-applicable
- Population
- Dogs screened for TRIAD inclusion; median age 9.2 years, median weight 27.7 kg
- Result
- Median CADES score 1.0, median Sustained Gaze score 9.0 at baseline.
$7M grant rescues dog study investigating rapamycin for canine aging. American Veterinary Medical Association, 2025.
regulatory 2025
Context on why results are slower than the surrounding enthusiasm suggests.
- Design
- News report on trial funding
- Blinding
- not-applicable
- Result
- Funding secured to continue TRIAD after a shortfall threatened it.