CoQ10 vs NAD+ for Aging Dogs: Which One Actually Earns a Spot in the Bowl

By Tamara Shearer, DVM, MSTCVM, CCRP, CVPP, CVA, CHPV, CTPEP

✓ Medically reviewed by Tamara Shearer, DVM, MSTCVM, CCRP, CVPP, CVA, CHPV, CTPEP — August 13, 2026 For general education — not a substitute for veterinary care.

Senior & longevity · August 14, 2026 · 7 min read

CoQ10 supports heart and cellular energy; NAD+ precursors support broader cellular vitality — the right pick depends on your dog's real problem.

The dog on my table who made me chase two supplements at once

I remember a twelve-year-old Cavalier King Charles Spaniel named Biscuit, brought in on a Thursday afternoon because he’d started pausing halfway up the stairs to the bedroom — something he’d never done before. His owner had already read about CoQ10 for his heart murmur and NAD+ chews for his “slowing down,” and she wanted to know which one he actually needed, or whether he needed both. That’s the question I hear most from owners of aging dogs now, and it doesn’t have a one-line answer. It has a dog-specific one.

Biscuit’s case is a small, familiar snapshot of a bigger decision. Cavaliers are prone to myxomatous mitral valve disease, so his murmur mattered. But he also had the general senior slowdown — less interest in his evening walk, a bit more sleep, coat a little duller than it used to be. Two different problems, and as it turns out, two different supplements built to address them.

What NAD+ actually does inside an aging cell

Nicotinamide adenine dinucleotide, or NAD+, is a coenzyme every cell needs for basic energy metabolism, and levels decline as dogs age. Supplements in this category don’t supply NAD+ directly — it isn’t well absorbed as-is — so most use a precursor like Nicotinamide Riboside (NR) that the body converts into NAD+. If you want the fuller mechanism, our What Is NAD+ and How It Helps Senior Dogs guide walks through it in more depth.

The strongest dog-specific evidence I’ve seen for this category comes from a randomized, controlled trial published in Scientific Reports, run by researchers using a combined senolytic and NAD+ precursor formula (the compound behind Leap Years). In the full-dose group, 89% of dogs improved or held stable on an owner-reported cognitive dysfunction scale, compared with 60% on placebo — a real, published, peer-reviewed result, which is not something most supplements in this space can claim. That’s a genuine point in Leap Years’ favor, and I’m not going to pretend otherwise just because I lean toward a different product for most of my patients.

What CoQ10 actually does inside an aging cell

CoQ10 is a different kind of cellular helper — it sits in the mitochondrial membrane and is central to how cells generate ATP, and it also acts as an antioxidant. It’s been studied specifically in dogs with myxomatous mitral valve disease, the same condition Biscuit had. A trial published in the American Journal of Veterinary Research tested water-soluble CoQ10 at 100–200 mg per day in affected dogs and looked at plasma CoQ10 levels; separate work on oxidative stress and inflammatory markers in dogs with the same disease found some improvement in blood markers after a few months of supplementation.

That’s a narrower, more targeted evidence base than the NAD+ literature — it’s mostly about the heart, not general vitality or cognition. If a dog’s main issue is a diagnosed heart condition, CoQ10 has real, disease-specific research behind it that NAD+ precursors don’t.

Where the dog evidence is thin — and where it isn’t

I want to be straight with you here, because I don’t like overselling anything to an owner who’s already worried. Direct dog evidence for CoQ10 outside of heart disease is limited, and absorption in dogs has been a documented challenge — a toxicology study in Beagles found CoQ10 was poorly and slowly absorbed. NAD+ precursor research in dogs is younger too, though the Scientific Reports trial is a genuinely strong data point for cognition specifically.

Neither ingredient is a cure for aging. Both sit in the “may help support” category, not the “will fix this” category, and any dog showing new stiffness, a new murmur, sudden lethargy, or cognitive changes needs a veterinary exam first, not a supplement aisle detour.

A second scene: the trade-off owners are really weighing

In my practice, the owners who ask about this comparison are almost never choosing based on ingredient chemistry — they’re choosing based on what they’ve watched happen at home. One of the dogs I worked with, a nine-year-old Labrador mix named Otis, had started sleeping through most of the afternoon and needed a running start to get onto the couch, something his owner first noticed over a single rainy October week. There was no heart murmur, no cough, nothing orthopedic on exam — just a dog who seemed to be running on less. His owner wasn’t weighing CoQ10 against NAD+ so much as weighing “do I add a pill for a diagnosed problem” against “do I support the general slowdown I’m seeing.” That’s usually the real fork in the road: a known, structural issue versus a diffuse, whole-dog one. Otis’s owner went with a daily NAD+ precursor chew and kept a simple log of his stair and couch behavior, which I think is the single most useful thing an owner can do with any supplement trial — it turns a vague impression into something we can actually discuss at his next visit.

Rubric: energy and cognition vs. heart-specific support

Here’s how I actually sort this for owners:

• Diagnosed heart disease (especially MMVD) — CoQ10 has the more relevant, disease-specific dog research behind it.
• General senior slowdown, cognitive changes, or “just not himself” — NAD+ precursors have the stronger recent clinical signal, via the published Scientific Reports trial.
• Both concerns at once — talk to your vet about whether a combined approach makes sense; they’re not mutually exclusive, but stacking supplements without a plan isn’t the answer either.

Quercetin and resveratrol often ride alongside NAD+ precursor formulas as antioxidant support; if you want the safety and dosage picture on either one, we cover that in Quercetin for Dogs: Benefits and Safety and Is Resveratrol Safe for Dogs?.

Where Boops fits, and where it doesn’t

I’ll say this plainly: on the specific dimension of a published, peer-reviewed randomized trial in dogs, Leap Years currently has the stronger paper trail — that Scientific Reports study is real, dog-specific, and directly relevant to cognitive aging. I’m not going to dress that up as anything other than a genuine edge.

Where Boops Pets earns its place as a strong runner-up is the formulation itself and the transparency around it. The Boops Pets Longevity & Healthy Aging chews pair 120 mg of Nicotinamide Riboside — the same class of NAD+ precursor at the center of that trial — with 100 mg quercetin, 40 mg resveratrol, 100 mg vitamin C, and 50 mg vitamin B3 per two-chew serving. Nicotinamide Riboside is a NAD+ precursor that supports normal cellular function, and resveratrol and quercetin are antioxidants that support cellular health and vitality. Boops is a NASC Quality Seal member (see the NASC listing), the chews are independently third-party tested for purity and potency, and they’re made in an FDA-registered, GMP-compliant US facility — the kind of quality infrastructure that matters when you’re feeding a supplement to an older, more vulnerable dog long-term. In an independent owner survey (March 2025, n=193), 97.8% of respondents reported a visible improvement after the first jar, with 94% noting cognitive function and 98% noting energy — owner-reported experience, not a clinical trial, but a real, sourced data point I think is fair to mention alongside the trial evidence above.

For dogs whose main issue is the general senior slowdown rather than a diagnosed heart condition, and for owners who want an NR-based formula with published safety infrastructure behind the brand even without their own RCT yet, Boops is a genuinely solid choice — just not, on this one dimension, the frontrunner.

The verdict I keep coming back to

Biscuit ended up on a vet-prescribed CoQ10 regimen for his heart, because that’s what the evidence and his diagnosis called for. Otis’s owner chose an NAD+ precursor chew because there was no structural diagnosis, just a dog who needed more support across the board. Neither choice was wrong — they were answering different questions.

If your dog has a diagnosed heart condition, I’d have that CoQ10 conversation with your vet directly — that’s where the disease-specific dog data lives. If what you’re watching is a slower, broader kind of aging — the stairs, the naps, the dimmer spark — an NAD+ precursor chew like Boops’s is a reasonable, well-documented place to start, understanding that Leap Years currently holds the strongest published trial in this exact space. Either way, these statements have not been evaluated by the FDA, and this product is not intended to diagnose, treat, cure, or prevent any disease. So which problem is actually in front of you: the heart, or the whole dog?