Nicotinamide Riboside and Urolithin A are each a small molecule rather than a peptide.
| Comparison | Nicotinamide Riboside (NR) NR · Niagen | Urolithin A Mitopure · UA |
|---|---|---|
| How it works | How it works NR enters the same salvage pathway as NMN, one step earlier. | How it works Urolithin A is not in the fruit. Your gut makes it, if you have the right bacteria. |
| What it is | The NAD+ precursor that kept its paperwork in order. | The mitophagy supplement with two real trials, both of which missed. |
| Status | Supplement | Supplement |
| Typical dose | 300–1000 mg per day | 500–1000 mg per day |
| How often | Daily | Daily |
| Stays active | Short, with the NAD+ effect outlasting it | Around 20 hours as the conjugated form |
| Dose comes from | Clinical trial protocol | Clinical trial protocol |
| Cycled? | Continuous in the trials Clinical trial protocol | Continuous in the trials Clinical trial protocol |
| What it does | ||
| Drug class | NAD+ precursor, vitamin B3 form (not a peptide) | Gut metabolite (oral, not a peptide) |
| Used for | An oral NAD+ precursor with the cleanest US regulatory position of the group, and the same open question about whether raising NAD+ does anything you would notice. | An oral supplement taken for muscle and mitochondrial aging, with the most human data of any longevity compound sold this way. |
| Receptors hit | — | — |
| Numbers | ||
| Full dose line | 300 up to 1,000 mg per day | 500 up to 1,000 mg per day |
| Why that cycle | Trials dose daily for weeks to months without a break, and blood NAD+ returns toward baseline after stopping. No study supports cycling. | Both randomized trials dosed daily for four months with no break. Nothing has tested whether the mitophagy effect persists after stopping, or whether cycling changes anything. |
| Weight / effect | Not measured in a trial | Not measured in a trial |
| Chain length | Not disclosed | Not disclosed |
| Common vial | — | — |
| Before you start | ||
| Route | By mouth (oral) | By mouth (oral) |
| Do not use if | Pregnancy and breastfeeding, on absent data Active cancer, for the same unsettled reason as the rest of this family Children, who have not been studied | Pregnancy and breastfeeding, on absent data rather than known harm Any active cancer, since mitophagy effects on tumor cells are not characterized Children, who were not studied |
What people actually report
Nicotinamide Riboside (NR)
- The safety file is genuinely good for a supplement, and that is a separate question from whether it works.
- Almost all of the published trial evidence is on one company's ingredient, funded by that company.
- Trials reliably raise blood NAD+. Functional outcomes are much less consistent.
Stop and get help if
- Persistent nausea or stomach pain
- Any new or unexplained symptom that starts after beginning it
Urolithin A
- Both randomized trials missed the endpoint they were designed around, which is not how the 12 percent strength figure is usually presented.
- Both were funded by Amazentis, the company that sells it, with company employees as authors.
- Roughly 60 to 70 percent of people cannot make meaningful amounts of it from food, because the gut bacteria required are not universal.
Stop and get help if
- Persistent stomach pain or diarrhea
- Any new or unexplained symptom that starts after beginning it
Side effects are what users and trials report most often, not a complete list. Anything sudden, spreading, or breathing-related is an emergency regardless of which compound caused it.
People also compare
This comparison does not cover cost, long-term safety, or how you personally will respond. Effect figures come from separate trials in different populations and are not always directly comparable to each other. Nothing here is medical advice or a recommendation to use any of these. Talk to a clinician about your own situation.