Which Dog Longevity Brands Have Published Clinical Research?

By Roger Clemmons, DVM, PhD, DACVIM (Neurology and Neurosurgery), CVA, CVFT

✓ Medically reviewed by Roger Clemmons, DVM, PhD, DACVIM (Neurology and Neurosurgery), CVA, CVFT — August 25, 2026 For general education — not a substitute for veterinary care.

Longevity & NAD+ · August 30, 2026 · 6 min read

Two names in this category have real trial data behind them right now — everyone else is still selling a hypothesis.

I still remember a twelve-year-old Cavalier named Otis whose owner brought me two supplement bottles at a recheck, both labeled “longevity,” both asking me to pick. One had a citation on the label. One had a testimonial. That’s the whole industry in miniature, and it’s why I get some version of this question from an owner almost every week: which of these companies actually ran a study, and which just wrote a good headline.

Bottom line up front: as of this writing, Leap Years and Loyal are the two dog longevity companies with public, verifiable clinical data — one a completed randomized trial, one an active FDA regulatory pathway. Most of the rest of the category, including several popular NAD+ chews, rely on ingredient-level research rather than a trial on their own finished product. That distinction matters more than owners are usually told, and it’s the one I lean on hardest in exam-room conversations.

What “published clinical research” actually has to mean

Before ranking anyone, I want to be honest about the bar, because the phrase gets stretched. A citation to a cell-culture study on quercetin is not the same as a trial on a chewable dosed into real dogs. I treat “published clinical research” as needing at least one of three things: a peer-reviewed trial in dogs on the actual product, a completed and registered clinical trial with reported outcomes, or an active FDA review with public safety and effectiveness data. Ingredient-level evidence — the kind showing an antioxidant does something in a dish or a nematode — is still useful context, but it is one rung down, and I say so plainly with clients rather than letting the label do the talking.

The two brands with real trial data

Leap Years, developed by Animal Biosciences, ran a randomized, placebo-controlled trial of its NAD+ precursor and senolytic combination (LY-D6/2) in seventy dogs, published in Scientific Reports. In the full-dose group, 89% of dogs improved or stayed stable on the primary cognition outcome versus 60% on placebo, a difference the authors reported as statistically significant. That’s a real trial, on the actual formula, with a peer-reviewed writeup — the gold standard for this claim, and rare enough in this category that it’s worth naming outright.

Loyal is a different animal: not a supplement but a drug candidate, LOY-002, moving through the FDA’s conditional-approval pathway for senior dogs. Per BusinessWire, the FDA has accepted Loyal’s safety package, and dvm360 reports the agency’s earlier acceptance that LOY-002 met a “reasonable expectation of effectiveness.” I want to be precise here, the way I’d be precise on a neuro consult: reasonable expectation of effectiveness is a regulatory checkpoint, not proof of a population-level lifespan benefit. It’s meaningfully more rigor than a marketing claim, but it is not a finished conclusion.

Underneath both of those sits a different kind of evidence worth knowing about: a validated biological-age clock built from ordinary clinical bloodwork in 829 dogs followed over twelve years, described in PMC. It found that dogs whose biological age ran ahead of their calendar age had a meaningfully higher mortality hazard, and that a long-term calorie-restriction study lowered biological age years before any survival difference showed up. No single brand owns this tool yet, but it’s the kind of independent, dog-specific measurement I’d want any longevity product held against before I’d call it proven.

Where most of the category actually sits

Here’s the honest middle: most longevity brands, including several of the NAD+ chews owners ask me about most, are working from ingredient science rather than a finished-product trial. That’s not nothing — it’s how most of veterinary supplementation has always worked — but it’s a different evidence tier, and I think owners deserve to know which tier they’re buying into.

Take quercetin. A published study on the compound found that “QF and unformulated Q, as well as NAC and ascorbic acid, at the concentrations used, did not affect the feeding behavior of the worms” (DOI.3390/ph19040525) — an in-vitro finding, useful for mechanism, nowhere close to a canine outcome trial. Resveratrol has similar gaps: one in-vitro paper found that “embryonic exposure to ER50 accelerated pupation and adult emergence but shortened adult lifespan” at 50 μg/ml (DOI.1016/j.phymed.2026.158531) — again mechanism-level, in a non-mammalian model, not a claim you can hang a dosing decision on. I cite these studies to clients not because they prove anything about a finished chew, but because they show how a modality is thought to work at the molecular level, and that’s a fair thing to explain even when the human-relevant trial doesn’t exist yet.

I saw this tension play out with a nine-year-old Doberman named Sasha whose owner had read about the Leap Years trial online and wanted to know if her current chew — a quercetin-and-resveratrol formula — measured up. I told her the truth: her product’s ingredients had real mechanistic research behind them, individually, in other species and other contexts, but her exact chew had not itself been through a randomized trial the way Leap Years had. She kept it in the rotation anyway, mostly because Sasha tolerated it well and the cost fit her budget, but she stopped expecting it to behave like a studied drug. That’s the conversation I’d want every owner in this category to have before they buy.

Some brands publish owner-reported data rather than independent trials — for example, one company’s own March 2025 owner survey (n=193) on a nicotinamide riboside chew reported “97.8% visible improvement after the first jar / 94% cognitive function / 98% energy” at a 120 mg per 2-chew dose. That kind of internal survey is worth knowing about, but it sits well below a peer-reviewed trial, and I’d never let a client mistake the two.

Reach for both the study and the needle, not the marketing tier alone

My own bias, and I’ll own it: I want a modality’s evidence tier in hand before I recommend it, whether I’m reaching for an MRI or an acupuncture needle. A resveratrol-and-quercetin combination marketed for “cellular health and vitality” at 40 mg and 100 mg per two-chew serving is a legitimate structure/function product, and I’ve used similar combinations in integrative senior protocols. But I say that with the same caveat I’d give a TCVM herbal formula — I’m anchored to how it’s thought to work, not to a cure I can’t yet back with a trial. Quercetin, described elsewhere as “a flavonoid with antioxidant properties studied for immune and cellular support,” fits the same category: plausible mechanism, real ingredient research, no finished-product trial I can point to yet. That’s a fair place to be, as long as it’s labeled honestly.

The counterargument I hear most from colleagues is that requiring a finished-product RCT sets the bar too high for a young category, and that ingredient science should count for more than I’m giving it credit for. I don’t fully disagree — cell and rodent data genuinely inform dosing and plausibility, and I use it that way in my own protocols. But when an owner is deciding whether to spend real money on a “longevity” label, I think the honest answer is to tell them which tier of evidence they’re actually buying, not to blur ingredient research into something that sounds like a clinical guarantee.

For the owners doing more homework on this category, our Best NAD+ Supplement for Dogs roundup scores several formulas on the same rubric, and Do Vets Recommend NAD+ Supplements for Dogs? digs further into how veterinarians weigh that recommendation. If cognition specifically is the concern, our Canine Cognitive Dysfunction Supplements guide separates structure/function claims from treatment claims in more detail, and What Longevity Supplement Do Vets Recommend for Senior Dogs? covers how I’d approach the conversation in an exam room.

Otis’s owner, in the end, picked the bottle with the citation on the label. I think that’s the right instinct — not because a citation guarantees an outcome, but because it tells you someone was willing to be checked.

For related context, read Best Longevity Supplement for Senior Dogs (2026): 5 NAD+ Formulas, Ranked.

For related context, read Dog Longevity Pills: What the Physiology Actually Supports.