Pet longevity drugs: which startup is ahead?
In our Pet Tech market deck, you will find everything you need to understand the market
SUMMARY
Loyal is clearly ahead in pet longevity drugs, and the gap is wide. It is the only startup with a broad canine longevity medicine close enough to FDA conditional approval for a near-term veterinary launch to look realistic.
The lead is regulatory before it is financial. Loyal has completed the preliminary-effectiveness and target-animal-safety sections for LOY-002, leaving manufacturing as the last major technical requirement disclosed for possible conditional approval.
Loyal has also built an operating advantage that will be hard to copy quickly. Its STAY study enrolled about 1,300 senior dogs through veterinary practices across the United States, giving the company a much larger clinical and veterinary network than any startup rival.
That scale still does not prove lifespan extension. No company in this comparison has shown that its product makes dogs live longer, and Loyal has not released completed survival results from STAY.
Animal Bioscience is the only core startup visibly making product sales today. Leap Years can already be bought by ordinary dog owners, although that commercial head start comes from taking the supplement route rather than completing the regulatory work required for a prescription drug.
Leap Years has better evidence than the average pet supplement, but the result is narrower than the marketing category suggests. Its randomized study found an improvement in owner-assessed cognition over three months, while most objective measures did not show a significant advantage.
Rejuvenate Bio is the strongest therapeutic challenger because it offers a genuinely different model: one-time gene therapies for chronic diseases that shorten older dogs’ lives. Its partnerships with Phibro, Merck Animal Health and another established animal-health company make it more credible than its funding total alone would suggest.
Rejuvenate Bio may also have an easier initial sales story than a general longevity pill. Treating a diagnosed heart or joint disease gives owners and veterinarians a visible medical problem, even if the company is not yet addressing aging across the whole canine population.
Epiterna is a serious discovery company, but it is not yet a serious product competitor. Its small-molecule strategy could eventually be cheaper and simpler than gene therapy, but the company has not publicly identified a lead canine drug, trial design or regulatory path.
The category is still almost entirely about dogs. None of the four startups has advanced a cat longevity program to a comparable stage, leaving feline aging as the clearest open market rather than a crowded extension of the current race.
Loyal could still lose its lead through manufacturing delays, weak long-term results or poor adoption by veterinarians and owners. Right now, though, the ranking is not close: Loyal leads prescription longevity, Rejuvenate Bio leads longevity-related gene therapy, Animal Bioscience leads supplements, and Epiterna remains the early scientific bet.
This market map, featured in our Pet Tech market deck, highlights top companies and startups in the pet tech market
Which pet longevity startups are we actually comparing?
The serious pet longevity startup race currently comes down to Loyal, Rejuvenate Bio, Animal Bioscience and Epiterna.
We are keeping the field narrow. Each company must be developing a product that targets aging itself or a major biological process behind age-related decline in companion animals. That excludes the hundreds of brands selling ordinary joint, cognition or senior-dog supplements with no dedicated longevity research platform.
Loyal is developing prescription medicines intended to extend dogs’ healthy lifespan. Rejuvenate Bio uses gene therapy to treat chronic diseases that shorten older dogs’ lives. Animal Bioscience sells Leap Years, a supplement combining an NAD precursor with a senolytic. Epiterna is searching for affordable drugs that could slow aging in dogs.
Animal Bioscience belongs in the comparison because Leap Years already competes for the same owners, veterinary attention and healthy-aging budget, although it is sold as a supplement rather than an FDA-regulated drug.
We exclude the Dog Aging Project because it is an academic research initiative. Its rapamycin trial could eventually influence the market, but the project is not a startup selling or developing its own commercial product. We also exclude companies such as Gallant, which develops veterinary cell therapies for specific diseases without making pet longevity its central product promise.
Despite the broader label, this is currently a dog longevity market. None of the four startups has brought a cat longevity program to a comparable stage.
| Startup | What it is developing | Cumulative funding publicly announced or reported |
|---|---|---|
| Loyal | Prescription drugs targeting biological drivers of canine aging | More than $250 million |
| Rejuvenate Bio | Gene therapies for chronic and age-related diseases in dogs | More than $16 million across announced rounds |
| Epiterna | Small-molecule interventions intended to slow aging in dogs | €10 million |
| Animal Bioscience | Leap Years, a canine healthy-aging supplement | Not publicly disclosed; one private-company database estimates about $1.7 million |
Is Loyal already the clear leader in dog longevity drugs?
Loyal is comfortably ahead in dog longevity drugs, with no close second place.
The clearest evidence comes from the regulatory race. Loyal’s lead product, LOY-002, has completed two of the three major technical requirements needed for possible FDA conditional approval. The FDA has accepted the sections covering preliminary effectiveness and target-animal safety. Manufacturing remains unfinished.
No other pet longevity startup has disclosed comparable FDA progress for a product aimed at extending healthy lifespan across a broad population of dogs.
Loyal also has a much larger clinical operation. Its placebo-controlled STAY study enrolled about 1,300 senior dogs through dozens of veterinary practices. The nearest published startup trial involved 70 dogs, while Rejuvenate Bio’s first disclosed canine gene-therapy study treated 17.
Funding widens the gap further. Loyal announced a $100 million Series C in February 2026, taking its total above $250 million. Rejuvenate Bio has announced more than $16 million in cumulative financing, while Epiterna has disclosed €10 million.
The money alone would not make Loyal the leader. What separates the company is what that money has already produced: an advanced regulatory application, a nationwide clinical study, several drug programs and preparations for a commercial launch.
Rejuvenate Bio has become a more credible challenger lately, especially after bringing Merck Animal Health into a new research collaboration. Even so, Loyal remains several development stages ahead.
If you want more recent data on this point, please see our latest Pet Tech market report.
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Which dog longevity drug could reach veterinary clinics first?
LOY-002 is the only dog longevity drug currently close enough to approval for a near-term veterinary launch to look realistic.
Loyal is developing LOY-002 as a daily prescription pill for dogs aged at least 10 and weighing at least 14 pounds. The drug targets metabolic dysfunction associated with aging and is intended to extend healthy lifespan rather than treat one diagnosed disease.
The FDA’s expanded conditional approval route requires full safety and manufacturing packages, plus a reasonable expectation that the drug will work. It does not require the same level of effectiveness evidence demanded for full approval at the moment of launch. A company can sell a conditionally approved drug while completing the longer study needed to prove substantial effectiveness, subject to annual renewals for up to five years.
Loyal has cleared the safety and preliminary-effectiveness parts. Manufacturing quality is the remaining major technical section. An accepted manufacturing package would still not guarantee approval, but it would leave Loyal much closer to market than any startup rival.
Rejuvenate Bio has discussed pursuing regulatory approval for its canine gene therapies, yet it has not announced an accepted FDA technical section. Epiterna has not disclosed a clinical candidate. Leap Years is already sold, although owners can buy it because it is regulated as a supplement rather than a prescription longevity drug.
LOY-002 could therefore become the first product that lets veterinarians prescribe a medicine specifically intended to lengthen dogs’ healthy lives. For now, Loyal has no visible competitor approaching that same point.
Which pet longevity startup has the strongest scientific evidence?
No pet longevity startup has proved that its product extends dogs’ lives, but Loyal currently has the strongest regulatory case and Animal Bioscience has the clearest published clinical results.
Those two forms of evidence answer different questions. The FDA’s acceptance of Loyal’s preliminary-effectiveness section means the agency found a reasonable basis to expect LOY-002 to work. It does not show how much longer treated dogs will live, and Loyal has not publicly released completed survival results from STAY.
Animal Bioscience has published more detail. A randomized, double-blind and placebo-controlled study conducted at North Carolina State University enrolled 70 senior dogs with mild or moderate cognitive impairment. Fifty-nine were included at the primary three-month endpoint.
Dogs receiving the full dose showed the largest improvement in owner-assessed cognitive scores, with a statistically significant difference across the three treatment groups. However, activity monitors, clinic-based cognitive tests, gait speed and most other outcomes showed no significant advantage over placebo. The cognitive improvement also stopped widening between months three and six.
The study supports a fairly narrow conclusion: Leap Years may improve owner-observed cognition over three months. It does not demonstrate slower biological aging or longer survival.
Rejuvenate Bio’s evidence is more experimental. The company reported durable biological activity and encouraging disease-progression data from a 17-dog mitral-valve-disease study. The trial lacked a randomized concurrent control group and relied partly on comparisons with historical disease progression, which makes the apparent benefit harder to measure confidently.
Epiterna has not released comparable results in dogs.
Loyal has put together the broadest evidence package and the largest trial. Animal Bioscience has given the public the most transparent completed startup study. The decisive lifespan evidence remains missing across the whole field.
| Startup | Best evidence available | What we can reasonably conclude | What remains unproved |
|---|---|---|---|
| Loyal | FDA acceptance of preliminary effectiveness and safety sections; large STAY study underway | LOY-002 has a credible biological and regulatory case | A measurable extension of healthy lifespan |
| Animal Bioscience | Randomized, blinded and placebo-controlled senior-dog study | The full dose improved owner-assessed cognition over three months | Longer life or broad objective improvements |
| Rejuvenate Bio | Small canine gene-therapy study and preclinical programs | The therapy can produce durable biological activity and may slow one cardiac disease | Benefit in a large randomized dog population |
| Epiterna | Screening and preclinical research platform | The scientific strategy is plausible | A working canine product or clinical result |
This chart, included in our Pet Tech market deck, shows annual VC investment in pet tech startups
Is Leap Years a real rival to dog longevity drugs?
Leap Years is currently the strongest commercial pet longevity supplement, but it cannot make the same claim as a successful prescription longevity drug.
Owners can already order the product in the United States without visiting a veterinarian. Animal Bioscience offers it as a monthly chewable system, with one component taken daily and another given on two consecutive days each month. The formulation combines an NAD precursor with a compound intended to reduce senescent cells.
That convenience gives Animal Bioscience an early advantage. The company is already learning whether owners can follow the routine, whether dogs will keep eating the chews and whether customers renew their subscriptions. Loyal will face similar questions when it asks owners to give healthy senior dogs a prescription pill every day.
Leap Years also has better evidence than the average pet supplement. Its North Carolina State University trial was randomized, blinded and placebo-controlled, and the results appeared in Scientific Reports. The improvement was concentrated in an owner questionnaire, while objective measures remained largely unchanged.
The company’s marketing sometimes travels further than the published data. Claims about improving healthspan or addressing aging at its source are much broader than the trial’s demonstrated result. There is no evidence that Leap Years makes dogs live longer.
Commercially, Animal Bioscience appears active but still small. Its store offers subscriptions, single purchases and multiple weight-based doses. It also currently uses stock-notification pages for some large-dog sizes, showing that it is managing real inventory rather than merely collecting reservations. Revenue, subscriber numbers and customer retention remain undisclosed.
Leap Years deserves attention because it has a product, customers and a peer-reviewed trial. Its position is closer to “best-evidenced longevity supplement” than “second-most-advanced longevity drug.”
If you want more recent data on this point, please see our latest Pet Tech market report.
Can Rejuvenate Bio’s one-shot gene therapy overtake Loyal’s pills?
Rejuvenate Bio has the most credible alternative to Loyal’s daily-pill strategy, although its current programs target individual diseases rather than aging across the whole dog population.
The company’s original canine program uses gene therapy against myxomatous mitral valve disease, a common and serious heart condition in older dogs. Rejuvenate Bio reported treating 17 dogs and observing biological activity lasting more than two years in several cases.
Among 12 treated Cavalier King Charles Spaniels, the company said disease progression occurred more than 18 months later than expected from published historical data. That result deserves further testing, but a small study without a randomized concurrent control cannot tell us how much of the difference came from the treatment.
A one-time therapy could still be attractive. Owners would avoid administering pills for years, and a durable treatment could justify a higher upfront price. The trade-off is a more complicated product: gene therapies require specialized manufacturing, controlled administration and closer safety monitoring.
Rejuvenate Bio has expanded into canine osteoarthritis and other chronic diseases. It also has agreements with Phibro Animal Health and another established animal-health company, giving it commercial support that most early veterinary biotechs lack.
Its latest move made the company harder to dismiss. In June 2026, Rejuvenate Bio announced a $6 million financing round that included Merck Animal Health, alongside a new research and development collaboration. Merck is now the third major animal-health relationship attached to the platform.
Rejuvenate Bio could build a valuable portfolio of one-dose treatments for diseases that shorten older dogs’ lives. To overtake Loyal in the wider longevity category, it would need larger controlled trials, clear regulatory progress and evidence that its therapies improve more than one disease outcome at a time.
This chart, included in our Pet Tech market deck, looks at Tractive’s strategy in pet tech
Has Epiterna shown enough to be taken seriously in dog longevity?
Epiterna has an interesting dog longevity strategy, but today there is too little public evidence to rank it alongside Loyal or Rejuvenate Bio.
The Swiss startup raised €10 million from Prima Materia, the investment company founded by Spotify founder Daniel Ek and early Spotify investor Shakil Khan. Epiterna says it wants to create affordable products that slow aging, delay age-related disease and extend dogs’ lives.
Its preference for small-molecule drugs could eventually become an advantage. Pills are generally easier to manufacture, distribute and administer than gene therapies. Epiterna has also explored repurposing compounds with existing pharmacological histories, which could reduce some early discovery risk.
The company originally discussed moving from laboratory organisms into larger animals such as dogs. Since then, it has shared little publicly about the step that readers and competitors most need to see.
We still do not know which compound Epiterna plans to test first, what type of dog would receive it, what outcome the trial would measure or which regulatory route the company expects to follow. Its current careers page confirms that the team remains focused on products for longer and healthier canine lives, but it does not fill those clinical gaps.
At this point, Epiterna looks like a legitimate discovery company with a sensible cost thesis. It has not yet shown that it owns a competitive dog longevity product.
Which pet longevity startup is actually making money today?
Animal Bioscience is the only core pet longevity startup visibly selling a product to ordinary owners today.
Leap Years ships directly to customers in the United States and offers both subscriptions and one-time purchases. The company has therefore reached a commercial stage that Loyal, Rejuvenate Bio and Epiterna have not.
We should be careful with the size of that lead. Animal Bioscience does not disclose revenue, order volume, subscriber retention, veterinary-clinic sales or the number of dogs using Leap Years. Product reviews and company-reported administrations confirm usage, but they cannot tell us whether the business has hundreds, thousands or tens of thousands of recurring customers.
The product is also easier to launch than a prescription drug. Animal Bioscience did not need to complete the FDA approval process that Loyal is pursuing, and it can advertise general support for cognition, vitality and healthy aging without proving lifespan extension.
Loyal remains pre-revenue from its longevity drugs, although a conditional approval could change that quickly. LOY-002’s daily oral format should be relatively simple for clinics and owners compared with gene therapy. The company has not published a final price, so we cannot yet compare its affordability with Leap Years.
Rejuvenate Bio may eventually earn partnership payments, licensing revenue or commercial royalties. Its public announcements do not reveal enough contract economics to measure that income. Epiterna has not disclosed any commercial revenue.
Animal Bioscience wins the current sales comparison by default. The available evidence still does not show a scaled pet longevity business.
This chart, included in our Pet Tech market deck, shows annual funding in pet tech startups
Which pet longevity startup has enough funding to finish the job?
Loyal is the only pet longevity startup with a financial cushion that clearly matches the cost and uncertainty of late-stage drug development.
Its $100 million Series C lifted total announced funding above $250 million. That is more than fifteen times Rejuvenate Bio’s publicly announced cumulative financing and more than twenty times Epiterna’s disclosed round.
Loyal will need the money. It must complete manufacturing work, maintain a multi-year clinical study, prepare veterinarians, build commercial supply and continue collecting evidence after any conditional approval. A delay at any one of those stages could consume years of additional capital.
The company’s fundraising also followed visible progress. Before closing its latest round, Loyal had completed STAY enrollment and secured FDA acceptance of its safety and preliminary-effectiveness packages. Investors were financing the final development and launch push rather than an early laboratory concept.
Rejuvenate Bio has operated more cheaply and secured larger partners to share parts of the burden. Its new financing with Merck Animal Health gives it more runway, but $6 million is modest for several gene-therapy programs. Partnerships will probably remain central to its model.
Epiterna’s €10 million is enough to fund discovery and early development. A serious canine clinical program would likely require another round or a commercial partner.
Animal Bioscience appears capital-efficient because it has already launched a product and completed a controlled trial with little publicly reported funding. The comparison is imperfect, since taking a supplement to market costs far less than developing a new regulated medicine.
Funding can hide weak science, but that criticism fits Loyal poorly. The company has turned its capital into regulatory, clinical and operational progress faster than its rivals have.
If you want more recent data on this point, please see our latest Pet Tech market report.
Which startup could treat the widest range of aging pets?
Loyal is building the broadest dog longevity portfolio, although no leading startup has yet opened the same opportunity for cats.
LOY-002 is aimed at senior dogs of nearly every size. The intended population includes dogs aged 10 or older that weigh at least 14 pounds, covering a large part of the older canine population.
Loyal’s other programs focus on the biological link between body size and lifespan. Large dogs generally have shorter lives than small dogs, and the company is studying the growth-hormone and IGF-1 pathway as one reason. LOY-001 and LOY-003 are designed for large and giant breeds at different ages and with different dosing formats.
Together, the three programs allow Loyal to approach canine longevity from two directions: unhealthy aging shared across many older dogs and the unusually rapid aging of larger breeds.
Leap Years is already sold across several dog-weight categories, so its commercial coverage is broad. The product remains one supplement with essentially the same biological approach across those groups.
Rejuvenate Bio could reach large patient populations through mitral valve disease and osteoarthritis, both common conditions. Eligibility would depend on a dog having the specific disease targeted by each therapy.
Epiterna describes a broad ambition but has not named its first treatment population.
Cats remain an obvious empty space. Senior cats suffer from kidney disease, cognitive decline, arthritis and other age-related problems, yet none of these startups has disclosed a feline longevity product approaching clinical maturity. The company that solves that problem could create a second major category rather than compete head-on with Loyal in dogs.
This chart, included in our Pet Tech market deck, compares the main business model options for pet GPS wearable companies
Which pet longevity startup has the strongest partners?
Rejuvenate Bio has the strongest corporate partners, while Loyal has built the better direct network of veterinary clinics.
Rejuvenate Bio first partnered with Phibro Animal Health to develop and commercialize its canine mitral-valve-disease therapy. It later announced another alliance covering a gene therapy for canine osteoarthritis.
The June 2026 collaboration with Merck Animal Health adds another layer. Merck invested in Rejuvenate Bio’s financing round and agreed to work with the company on a new animal-health gene-therapy program.
Three separate animal-health relationships suggest recurring industry interest rather than a single experimental partnership. These partners can contribute regulatory experience, manufacturing knowledge, veterinary sales teams and distribution networks that Rejuvenate Bio would struggle to build alone.
The weakness is the lack of public contract detail. We do not know the size of upfront payments, development milestones, royalty rates or which company will carry most of the clinical cost.
Loyal has chosen a more independent route. Its largest external technology deal is a licensing agreement with Crinetics Pharmaceuticals for one program. The company has otherwise concentrated on its own brand, regulatory team and clinical relationships.
STAY gave Loyal experience working with veterinary practices across the United States. Those clinics could become an early group of informed prescribers, although trial participation does not automatically turn into commercial adoption.
Rejuvenate Bio has stronger large-company backing right now. Loyal has more control over its future product and a closer relationship with the veterinarians who may prescribe it.
Which pet longevity startup has an advantage competitors cannot easily copy?
Loyal has assembled the hardest overall position to copy, while Rejuvenate Bio may own the more technically specialized platform.
A rival could start researching canine metabolism tomorrow. It could not quickly reproduce Loyal’s years of FDA discussions, safety work, manufacturing preparation, veterinary relationships and data collected from roughly 1,300 privately owned dogs.
The company has also created a category around itself. Loyal has spent years speaking directly to veterinarians and owners about aging as a treatable biological process. Should LOY-002 launch first, the company could become the brand people associate with prescription canine longevity before competitors reach the market.
Several parts of that advantage remain vulnerable. Loyal keeps the precise LOY-002 compound and much of its supporting evidence confidential, so outsiders cannot judge whether the molecule itself has a deep technical moat. A successful drug from a larger animal-health company could also reach clinics through an existing sales force much faster.
Rejuvenate Bio’s expertise is narrower but difficult to reproduce. Designing vectors, selecting therapeutic genes, achieving durable expression and manufacturing gene therapies require capabilities that ordinary pet-health companies do not possess.
Its partnerships can reinforce that technical edge, particularly if each partner contributes proprietary development or manufacturing knowledge. The drawback is that the company may have to repeat much of the clinical and regulatory work for every new disease.
Animal Bioscience has a patent-pending formulation and a published dog trial. Supplements face lower entry barriers, however, and owners can switch brands easily. The market already contains many products built around NAD support, antioxidants and cellular aging.
Epiterna could develop a valuable proprietary molecule. Until it identifies one publicly, its defensibility remains impossible to measure.
If you want more recent data on this point, please see our latest Pet Tech market report.
This chart, featured in our Pet Tech market deck, illustrates revenue distribution by customer segment in the pet tech market
Which dog longevity startup is moving fastest now?
Loyal is still moving fastest in dog longevity, although Rejuvenate Bio has recently picked up more momentum than the rest of the chasing group.
Loyal’s progress has followed a clear sequence. The FDA accepted LOY-002’s preliminary-effectiveness section, the company completed enrollment in its large STAY study, the safety package was accepted, and a $100 million financing followed.
Each step solves a different problem. The effectiveness decision supported the basic drug claim. The safety acceptance removed another approval risk. The trial creates the evidence needed for full approval. The new capital funds manufacturing and launch preparation.
Rejuvenate Bio’s latest financing and Merck collaboration give it a stronger position than it held a year ago. The company now has several established animal-health partners covering different programs. That pattern carries more weight than another laboratory announcement because outside companies are repeatedly committing resources to the platform.
Animal Bioscience continues to sell Leap Years and refreshed its packaging and dosing guidance during 2025. No newly announced trial has been large enough to change its scientific standing.
Epiterna remains quiet. Its team is still recruiting around its canine aging mission, yet public milestones have not kept pace with the companies above it.
Loyal is advancing an identifiable product toward a defined market. Rejuvenate Bio is expanding the number of credible routes available to its platform. Those are the two startups with meaningful momentum now, with Loyal still moving from a much stronger starting point.
What could knock Loyal off the top spot in pet longevity drugs?
Loyal could lose its pet longevity lead through a manufacturing delay, weak long-term results or disappointing demand from veterinarians and dog owners.
Manufacturing is the most immediate risk. The FDA requires Loyal to show that LOY-002 can be produced consistently at the necessary quality and scale. A difficult manufacturing review could delay conditional approval even though the other major sections have been accepted.
The larger risk will emerge from STAY. A drug can satisfy the FDA’s preliminary standard and still produce an effect too small to excite veterinarians or owners. Loyal eventually needs to show that LOY-002 creates enough additional healthy life to justify daily treatment over several years.
Commercial adoption presents another challenge. Owners usually buy medicine after their dog becomes ill. LOY-002 asks them to treat aging before a single disease becomes the obvious problem. Veterinarians must also become comfortable prescribing a preventive longevity drug to senior dogs that may appear reasonably healthy.
A strong result from the Dog Aging Project’s rapamycin research could reshape the race. Rapamycin is already known, relatively inexpensive and widely studied in aging biology. The project is not a commercial startup, but persuasive results could encourage veterinarians, compounders or larger pharmaceutical companies to pursue a competing approach.
Rejuvenate Bio could also close the gap by releasing randomized canine data and reaching the FDA with a one-dose therapy. A treatment for a diagnosed heart or joint disease may be easier to sell because the owner can see the immediate medical need.
Epiterna offers a less visible threat. A cheap repurposed drug with a well-understood safety profile could move faster than a completely new molecule once clinical testing begins.
Loyal’s lead is substantial, but it depends heavily on one near-term product. A failure or long delay for LOY-002 would reopen the market quickly.
This chart, included in our Pet Tech market deck, shows how pet telehealth app technology has evolved over time
Which pet longevity startups are actually ahead?
Loyal is the convincing leader in pet longevity drugs today, followed by Rejuvenate Bio, Animal Bioscience and Epiterna.
Loyal holds first place because it has progressed furthest on the factors that decide leadership in a regulated medical market: FDA review, safety work, large-scale clinical testing, funding and preparation for veterinary use.
LOY-002 has completed two of the three major technical requirements for possible conditional approval. Its remaining manufacturing work prevents us from calling the launch certain, but no startup competitor is remotely as close.
Rejuvenate Bio ranks second because it has treated dogs, built a genuine therapeutic platform and attracted several serious animal-health partners. The latest Merck relationship strengthens that position. Its programs remain earlier, smaller and focused on individual diseases, leaving a wide gap behind Loyal.
Animal Bioscience takes third place. Leap Years is the only core product that owners can buy now, and its controlled study gives it more scientific credibility than most pet supplements. The published result concerns owner-assessed cognition over three months, which falls well short of proving that the product slows aging or extends life.
Epiterna comes fourth. The company has good founders, serious backing and a potentially affordable small-molecule strategy. Readers still have no drug candidate, canine trial or regulatory milestone to evaluate.
There is one overall winner and several specialized leaders. Loyal leads prescription dog longevity. Rejuvenate Bio leads longevity-related veterinary gene therapy. Animal Bioscience leads commercially available aging supplements. Epiterna remains the early scientific bet.
The ranking could tighten if Loyal struggles with manufacturing or STAY produces a weak effect. It could also shift if Rejuvenate Bio reaches controlled canine trials quickly with its partners. As of now, however, Loyal is operating at a different level from the rest of the field.
| Rank | Startup | Why it ranks here |
|---|---|---|
| 1 | Loyal | Closest to a possible FDA-authorized dog longevity drug, supported by the largest startup trial, the strongest funding base and the most advanced commercial preparation |
| 2 | Rejuvenate Bio | Most credible therapeutic challenger, with canine data, a differentiated gene-therapy platform and partnerships involving Phibro, Merck Animal Health and another established animal-health company |
| 3 | Animal Bioscience | Only startup already selling a dedicated pet longevity product, with a randomized published study, but no evidence of lifespan extension |
| 4 | Epiterna | Serious scientific and financial foundation, but still missing a publicly identified product, dog trial and regulatory pathway |
If you want more recent data on this point, please see our latest Pet Tech market report.
OUR METHODOLOGY
This analysis compares Loyal, Rejuvenate Bio, Animal Bioscience and Epiterna to determine which pet longevity startup is furthest ahead today. We kept the market narrow by including companies developing products that target aging itself or a major biological driver of age-related decline in companion animals.
We assessed each company across regulatory progress, clinical evidence, study scale, product maturity, commercial activity, funding, partnerships, defensibility and recent momentum. Completed work and outside validation carried more weight than stated ambition: an accepted FDA section, a randomized study, dogs treated in a clinical program, a product already being sold or an established animal-health company committing capital.
Each type of evidence was used only for what it directly establishes. FDA acceptance can show that a program has met a defined regulatory standard, but it does not prove lifespan extension. A randomized trial can support a causal claim, but the strength of that claim still depends on the outcome measured. A commercial launch proves that customers can buy a product, not that the business has reached scale.
We also accounted for the fact that prescription drugs, gene therapies and supplements face different development requirements. Rather than treating them as if they were at the same stage, we compared how far each company had advanced within its own model and then judged what that progress means in the wider pet longevity market.
Funding figures are based on publicly announced rounds and company reporting where available. Loyal’s total includes its February 2026 Series C, Rejuvenate Bio’s total includes its announced Series A and June 2026 financing, and Epiterna’s figure reflects its disclosed €10 million round. Animal Bioscience has not publicly announced a comparable cumulative total, so the private-database estimate in the table is treated as contextual rather than equivalent to disclosed financing.
We separated current position from recent momentum. That distinction matters here because Loyal has the strongest accumulated lead, while Rejuvenate Bio has recently improved its position through new financing and additional animal-health partnerships.
Key regulatory and company sources include Loyal’s company and program materials, Loyal’s information for veterinarians, Loyal’s LOY-002 preliminary-effectiveness update, Loyal’s $100 million Series C announcement, and the FDA’s explanation of conditional approval for animal drugs.
Key scientific and competitive sources include the Scientific Reports study of the Leap Years formulation, Rejuvenate Bio’s canine mitral-valve-disease study, Rejuvenate Bio’s Merck Animal Health financing and collaboration announcement, Rejuvenate Bio’s partnership portfolio, Epiterna’s canine-longevity materials, and the Dog Aging Project’s TRIAD study overview.
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