Researchers are investigating whether medicines could extend the healthy lives of pet dogs, with one major clinical trial testing the drug rapamycin and a separate US company pursuing regulatory approval for a canine longevity treatment.
Scientists are studying whether some of the biological processes associated with ageing could be targeted to help dogs remain healthier for longer.
The research includes a large clinical trial testing rapamycin, a drug that affects a cellular signalling pathway involved in growth and metabolism, and separate work by a US biotechnology company developing medicines specifically intended to extend healthy lifespan in dogs.
However, no drug has yet been proven to extend the lifespan of ordinary pet dogs.
What is the Dog Aging Project testing?
One of the most significant studies is the Test of Rapamycin in Aging Dogs, known as TRIAD.
TRIAD is being conducted through the Dog Aging Project and is designed as a prospective, parallel-group, double-masked, randomised, placebo-controlled, multicentre clinical trial.
Its primary objective is to determine whether once-weekly oral rapamycin increases lifespan in medium-to-large and large companion dogs.
Researchers are also assessing measures including physical function, neurological and cognitive health and cardiovascular health.
The study authors describe lifespan as the primary endpoint, with measures of healthspan — the period of life spent in relatively good health — included as secondary outcomes.
The TRIAD study-design paper was published in GeroScience in 2025.
Why rapamycin?
Rapamycin acts on a cellular signalling system known as mTOR.
Research in laboratory animals has made mTOR an important target in ageing science, and rapamycin has extended lifespan in several experimental animal models.
That evidence prompted researchers to test whether low-dose rapamycin could produce measurable effects in companion dogs.
The key point is that TRIAD is intended to establish whether rapamycin can actually prolong dogs’ lives.
That result is not yet known.
What have previous dog trials found?
Researchers have previously conducted smaller controlled trials of rapamycin in healthy companion dogs.
A 2017 randomised study involved 24 healthy middle-aged dogs that received either placebo or a non-immunosuppressive dose of rapamycin for ten weeks.
The study reported changes in some measures of heart function that supported further investigation, but it was not designed to determine whether rapamycin extended lifespan.
A later clinical trial involved 17 client-owned dogs aged six to 10 years and weighing between 18kg and 36kg.
Dogs received either placebo or rapamycin at a dose of 0.025mg/kg three times a week for six months.
Researchers assessed the dogs at baseline, six months and 12 months.
They reported no clinically or statistically significant difference in echocardiographic measures of cardiac function between the rapamycin and placebo groups at six or 12 months.
The authors concluded that low-dose rapamycin was well tolerated in the study, while noting that the small sample size limited the conclusions that could be drawn.
A separate published case report from the research programme described severe asymptomatic hypertriglyceridaemia in one dog receiving rapamycin.
That illustrates why larger trials are needed to assess both potential benefits and risks before rapamycin could be regarded as an established longevity treatment for dogs.
Has rapamycin been proven to make dogs live longer?
No.
The earlier studies investigated safety and physiological effects but were not designed to prove an increase in lifespan.
TRIAD is specifically designed to test whether rapamycin can prolong lifespan and improve measures of healthspan in companion dogs.
Until results from that trial are available, there is no evidence from a completed large canine clinical trial showing that rapamycin makes pet dogs live longer.
A separate drug is moving through the US regulatory process
Alongside academic research, US biotechnology company Loyal is developing drugs intended to extend healthy lifespan in dogs.
Its lead candidate, LOY-002, is being developed as a once-daily pill for dogs aged 10 years or older and weighing at least 14lb, or around 6.4kg.
According to Loyal, the drug is intended to improve metabolic health by increasing insulin sensitivity and lowering insulin levels.
The company states that LOY-002 has completed two of three major technical components required for expanded conditional approval by the US Food and Drug Administration: preliminary efficacy and target-animal safety.
Manufacturing requirements remain in progress.
Loyal also states explicitly that FDA approval is not guaranteed.
What has the FDA actually accepted?
Loyal announced in January 2026 that the FDA’s Center for Veterinary Medicine had accepted the Target Animal Safetysection of its expanded conditional approval application for LOY-002.
The company says the safety package included several studies and field data from more than 400 dogs, including animals receiving LOY-002 for periods of up to one year.
Loyal reported that a study using one, three and five times the intended clinical dose found no clinically significant adverse events at those doses.
Those findings have not yet been published as a full pivotal lifespan trial, so they should be treated as company-reported regulatory data rather than independent evidence that the drug extends life.
The company also says the FDA previously accepted its Reasonable Expectation of Effectiveness, or RXE, package.
That standard is part of the US expanded conditional approval pathway and is not the same as demonstrating lifespan extension in a completed pivotal trial.
Loyal itself explains that full lifespan data will be generated through its STAY study.
What is the STAY study?
The STAY study is a placebo-controlled clinical trial investigating LOY-002 in senior dogs.
Loyal currently reports 1,317 dogs enrolled across 70 veterinary practices.
The company says the trial will collect data on lifespan, health and quality of life and will form part of the evidence required for eventual full FDA approval.
Because the trial is still under way, it does not currently establish that LOY-002 makes dogs live longer.
Is there an anti-ageing drug for dogs in the UK?
There is currently no veterinary medicine authorised in the UK specifically on the basis that it has been proven to extend lifespan in healthy dogs.
The UK Veterinary Medicines Directorate maintains the official database of authorised veterinary medicines.
Rapamycin is not established as an authorised canine anti-ageing treatment, and LOY-002 remains in development in the United States.
Why are dogs useful for ageing research?
Dogs offer researchers several advantages when studying ageing.
They have shorter lifespans than humans, meaning changes in health and survival can be studied over considerably shorter periods.
Pet dogs also live in human environments and show substantial variation in body size, genetics and age-related disease.
The TRIAD researchers say these characteristics make companion dogs a valuable model for testing interventions intended to affect healthy ageing.
Frequently asked questions
Can scientists currently slow ageing in dogs?
There is no drug currently proven through a completed large clinical trial to slow ageing and extend lifespan in pet dogs.
Researchers are testing whether this can be achieved, including through the TRIAD rapamycin trial.
What is rapamycin?
Rapamycin, also known as sirolimus, is a drug that inhibits the mTOR signalling pathway.
mTOR is involved in processes including cell growth, nutrient sensing and metabolism and has become an important target in experimental ageing research.
Does rapamycin make dogs live longer?
That has not yet been established.
Small canine trials have investigated safety and physiological effects, while the ongoing TRIAD study is designed specifically to determine whether rapamycin increases lifespan.
Is rapamycin safe for dogs?
Small controlled trials have generally reported that the low doses tested were well tolerated.
However, the numbers of dogs studied so far have been small, and an individual case of severe asymptomatic hypertriglyceridaemia has been reported during rapamycin treatment.
The larger TRIAD trial includes safety monitoring alongside its lifespan and healthspan outcomes.
Can owners give their dogs rapamycin?
Rapamycin should not be regarded as an established anti-ageing treatment for pet dogs.
The research uses carefully defined doses under veterinary and clinical-trial supervision.
There is currently no evidence supporting owners independently giving rapamycin to healthy dogs for longevity purposes.
What is LOY-002?
LOY-002 is an experimental once-daily drug being developed by US company Loyal for dogs aged at least 10 years and weighing 14lb or more.
The company says it is designed to target metabolic changes associated with ageing.
Has LOY-002 been approved?
No.
As of August 2026, Loyal says the FDA has accepted two of the three major technical components required for expanded conditional approval, while manufacturing requirements remain in progress.
The company states that approval is not guaranteed.
Has LOY-002 been shown to extend dogs’ lives?
Not yet.
The company’s large STAY study is intended to collect the lifespan and health data needed to establish whether the treatment works.
What does healthspan mean?
Lifespan is the total length of an animal’s life.
Healthspan refers to the period of life spent in good or relatively good health.
Ageing researchers are therefore interested not only in whether dogs live longer, but whether they remain healthy and functional for longer.
The studies
Test of Rapamycin in Aging Dogs (TRIAD): study design and rationale
Coleman AE et al., GeroScience, 2025.
DOI: 10.1007/s11357-024-01484-7
Read the TRIAD paper on PubMed
A masked, placebo-controlled, randomized clinical trial evaluating safety and cardiac function of low-dose rapamycin in 17 healthy client-owned dogs
Barnett BG et al., Frontiers in Veterinary Science, 2023.
DOI: 10.3389/fvets.2023.1168711
Read the full study
A randomized controlled trial of short-term rapamycin in healthy middle-aged companion dogs
Urfer SR et al., GeroScience, 2017.
Read the study on PubMed
Case report: severe asymptomatic hypertriglyceridaemia during rapamycin treatment
Evans JB et al., Frontiers in Veterinary Science, 2023.
Read the case report
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