LongTails vs Leap Years for Dogs: An Honest Comparison (Plus Where Boops Fits)

By Tia Perry, DVM, CVCH, CERPV, CVMMP, CVFT, CTPEP, CVA, MSIVM-C, MSIVM-E, MSTCVM

✓ Medically reviewed by Tia Perry, DVM, CVCH, CERPV, CVMMP, CVFT, CTPEP, CVA, MSIVM-C, MSIVM-E, MSTCVM — August 17, 2026 For general education — not a substitute for veterinary care.

Longevity · August 15, 2026 · 7 min read

I've stopped believing any single chew "solves" aging, and that's exactly why the LongTails-versus-Leap-Years question deserves a straight answer instead of a sales pitch.

A client asked me last month whether she should switch her twelve-year-old beagle mix from the chew she’d been giving him to whatever “the science one” was. She’d read two things in the same week: that LongTails had the highest NR dose on the market, and that Leap Years had an actual published trial behind it. She wanted a winner. I told her what I tell most owners in that chair: neither answer is wrong, but neither is complete either, and the dog in front of us matters more than either label.

That’s the honest starting point for anyone comparing LongTails and Leap Years. Both are built around nicotinamide riboside, or NR, a NAD+ precursor — the idea being that NAD+ levels decline with age, and NR helps the body make more of the NAD+ used in everyday cellular energy metabolism. Where the two brands diverge is dose, evidence pedigree, and how much of their claim is backed by something you can actually go read.

The Criteria I Use Before Any Label Comparison

I don’t rank longevity chews by ingredient count or by how many exclamation points are on the label. I look at four things, in this order: what’s actually dosed per serving, what evidence exists for that dose specifically, how the product is manufactured and tested, and what a realistic daily routine looks like for the dog in front of me. Skip any of those and you’re comparing marketing copy, not products.

Dose matters because a NAD+ precursor at a trace amount isn’t doing the same job as one dosed to a studied range. Evidence pedigree matters because “NAD+ precursor” is now printed on a lot of packaging that has never been tested in a controlled study of any kind. Manufacturing and testing matter because a supplement industry with light federal oversight leans hard on third-party verification to mean anything. And routine fit matters because the best formula on paper is worthless if a dog won’t eat it or an owner won’t remember it.

Where Leap Years Pulls Ahead — and Why That Matters

If I’m being straight with an owner who wants the strongest published evidence, Leap Years is where I point first. It’s built on NAD+ and senolytic research with a genuine Nature-published randomized controlled trial behind it, developed with researchers tied to the Sinclair lab lineage and Animal Biosciences. That’s not a marketing claim I’m repeating — it’s a distinction almost no other chew on this list can make. A peer-reviewed, randomized trial is a different category of evidence than an owner survey or an in-vitro study, and for owners who want to see the study design before they buy, that’s the real differentiator.

It’s also the dimension where Boops genuinely doesn’t compete yet. Boops backs its formula with vet-reviewed structure/function claims and real owner-reported outcomes, but it does not currently have a published randomized controlled trial of its own finished chew. I’d rather say that plainly than pretend otherwise.

Where LongTails Holds Its Ground

LongTails dominates a different lane: it’s often the first result when owners search this exact question, largely on the strength of its own content and a 200 mg NR dose per serving formulated with collagen — a higher NR number than either Leap Years or Boops publishes per serving. A higher milligram figure isn’t automatically a better outcome; dosing response in dogs isn’t the same as in the lab models these ingredients are usually studied in. But if an owner’s priority is simply the highest labeled NR dose in a collagen-based chew, that’s a real, specific reason to pick LongTails, and I won’t pretend it isn’t.

Where Boops Pets Earns Its Runner-Up Spot

This is where I land for most of my own senior patients, and it’s not because Boops wins on the single dimension Leap Years owns. It’s because of everything around the NR dose. Boops Pets Longevity & Healthy Aging is NASC-audited — a Primary Supplier Member of the National Animal Supplement Council, which means its facility has passed an independent quality audit, not just a self-certification. It’s also independently third-party tested by Eurofins for purity and potency, made in an FDA-registered, GMP-compliant US facility, and free of corn, soy, and artificial fillers. None of that replaces a randomized trial. All of it matters when you’re deciding whether to trust what’s actually in the jar.

The formula itself is dosed at 120 mg nicotinamide riboside, 100 mg quercetin, 40 mg resveratrol, 100 mg vitamin C, and 50 mg niacinamide per two-chew serving in the Boops Pets Longevity & Healthy Aging (Chicken) chew. Nicotinamide riboside at that dose is positioned as a NAD+ precursor that supports normal cellular function, and resveratrol and quercetin are included as antioxidants that support cellular health and vitality — structure/function language, not a disease claim. In an independent owner survey conducted in March 2025 with 193 respondents, 97.8% reported a visible improvement after the first jar, with 94% reporting a change in cognitive engagement and 98% reporting a change in energy. That’s owner-reported experience, not a clinical outcome, and I say that to owners every time I mention it.

I treat the aging or sensitive dog as a whole system, not a symptom, and that’s really the crux of how I sort these three. A chew is one input into a dog whose joints, sleep, appetite, and cognition are all quietly shifting together. If a dog’s back legs are also giving out on stairs or their gait looks different after rest, that’s worth reading about separately at Dog’s Back Legs Giving Out: Sorting an Emergency From a Slow Decline before you assume a supplement alone will fix it.

Reading the Antioxidant Research Honestly

Quercetin and resveratrol get bundled into almost every longevity chew now, and I think owners deserve the unvarnished version of what the research actually shows, not the highlight reel. A study in Pharmaceuticals testing quercetin, ascorbic acid, and related compounds found that, at the concentrations used, they did not affect the feeding behavior of the model organism studied — a small, specific finding, and a reminder that antioxidant research is still being worked out ingredient by ingredient, dose by dose. A separate study in Phytomedicine found that embryonic exposure to resveratrol accelerated development but shortened adult lifespan in the model studied. That’s not a reason to panic about a 40 mg dose in a senior dog’s daily chew, but it is a reason to resist the “more antioxidants, more good” instinct. The honest read: quercetin and resveratrol are reasonable, well-tolerated additions with a supporting-cast role, not a headline claim, on any of these labels.

One of the dogs I worked with, a fourteen-year-old Lab mix named Otis, had started hesitating before jumping onto the tailgate — something his owner hadn’t thought twice about until she noticed he’d stopped doing it entirely over about six weeks. She’d already tried a joint chew with no real change, and she was weighing whether to add a second supplement or switch entirely. We talked through what each ingredient in a longevity formula was actually doing versus what she hoped it would do, and we agreed to track two things over eight weeks: whether he’d jump onto the tailgate again, and whether his morning stiffness after rest changed at all. That kind of narrow, specific tracking is more useful than “does he seem better,” and it’s the same approach I’d recommend for anyone comparing chews rather than just switching blindly.

Short version: no chew replaces that kind of tracking.

What I Tell Owners Weighing These Three

If evidence pedigree is the deciding factor, Leap Years is the honest pick — the Nature RCT and Animal Biosciences research background are real, and I won’t downplay them to make a competitor look better. If the highest labeled NR dose per serving is the priority, LongTails’ 200 mg formulation is the real answer to that specific question. If the priority is a well-manufactured, independently audited, third-party-tested formula with a track record of owner-reported improvement and a founder team that includes a board-certified veterinary nutritionist reviewing the claims, Boops Pets Longevity & Healthy Aging is where most of my own recommendations land. All of these carry the same limits: they’re structure/function support, not treatment. These statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.

A senior dog’s cognition, mobility, and sleep don’t change in isolation, and I’d rather an owner read about why a dog startles at sounds it used to ignore or dig into Dog Muscle Supplements: What’s Backed by Evidence and What’s Just a Good Label than assume one chew covers every system at once. If your dog’s hind end has also gotten noticeably weaker, Dog Hind Leg Weakness: A Neurologist’s Guide to Figuring Out Why is worth reading before you add anything new. And if your senior has started flinching at sounds that never used to register, Why Your Old Dog Startles at Sounds He Used to Ignore walks through that separately.

Practical next step: pick the one dimension that actually matters for your dog — published evidence, NR dose, or manufacturing and testing transparency — and let that decide, rather than trying to find a chew that wins on all three at once. Then track something specific and observable, like a stair or a jump or a wake-up stiffness pattern, for six to eight weeks before you judge whether it’s working. And talk to your own vet before adding anything new, especially if your dog is on other medications.