NMN & NAD+Explainer
The molecule your cells use to repair DNA starts to drop around 25. NMN brings it back up.
Your cells repair their DNA with a molecule called NAD+, and your supply starts to drop around 25. In human trials, taking NMN brought it back up.
Brands have paid for promotional consideration in these articles.
Your DNA breaks tens of thousands of times a day.
That’s normal, and your cells are built for it. They have repair enzymes that find the breaks and fix them, all day, every day.
Those enzymes run on a molecule called NAD+. And your supply of it begins to drop around 25.
What NAD+ does
NAD+ is in every cell you have, and it does 2 big jobs there.
It carries the energy your cells run on. NAD+ is how your mitochondria generate ATP, the fuel a cell burns to do its work.
It powers repair. The enzymes that fix DNA breaks run on NAD+. So do the sirtuins, the enzymes science links to longer life.
When NAD+ drops, sirtuins shut down.
The same molecule fuels your neurons and their repair pathways. It drives energy metabolism across your heart and blood vessels, and it powers autophagy, the system your cells use to clear debris and rebuild from within.
It also supports the cells that build collagen and elastin in your skin.
How fast it falls
NAD+ remaining, by age
Show these figures as a table
| Age | NAD+ |
|---|---|
| Around 25 | Begins to drop |
| Mid-30s | 25% gone |
| 50 | 50% gone |
The decline starts earlier than most people expect.
NAD+ begins to drop around 25.
25% is gone by your mid-30s.
50% is gone by 50.
Meanwhile the DNA breaks keep coming, and your cells have less NAD+ to fix them with.
Without enough NAD+, the damage compounds into aging.
How your body makes more
Your body makes a molecule called NMN for one purpose: to rebuild NAD+.
NMN converts to NAD+ in a single step and goes straight to work.
That’s the idea behind an NMN supplement. Take NMN, and your body converts it into NAD+.
That fresh NAD+ fuels the enzymes that repair your DNA, the sirtuins that keep your cells young, and the mitochondria that power them.
What the human trials found
NMN has been tested in people, in controlled trials.
Taking NMN has been shown to more than double NAD+ levels, restoring NAD+ to the level it was at age 25. (This is true on average but not for everyone.)
That finding comes from 2 human trials, one published in npj Aging in 2022 (Igarashi et al.) and one in GeroScience in 2023 (Yi et al.).
A separate trial found higher doses produced the greatest gains in aerobic capacity (Liao et al., 2021). Doses up to 2,000 mg per day have been studied in controlled trials.
3 things to check before you buy NMN
The research only helps you if the capsule matches it. Check 3 things.
The dose. More than half of the NMN supplements sold today deliver 500 mg or less per serving.
The trials went as high as 2,000 mg a day, and in one of them the higher doses did the most.
The form. Only the beta form of NMN builds NAD+, and a label that just says NMN doesn’t tell you which form is inside.
The proof. No rule requires a supplement company to show you a 3rd-party lab test of its product.
So look for a brand that sends its finished capsules to an outside lab, and publishes the report.
There’s a reason to ask. In 2021, a test of 22 NMN supplements found that 14 contained less than 1% of the NMN on the label (Niagen Bioscience, 2021).
The leading brands measured this year look very different. In September 2026, an independent 3rd-party lab measured NMN-99 and 5 top competitors, and all 5 competitors delivered between 90% and 104% of their labels.
That testing was commissioned and paid for by the maker of one of the six products tested.
Read the lab reports for all 6 NMN products
How NMN-99 measures up
NMN-99 measured highest in that lab comparison, so here’s how it does on the same 3 checks.
The dose. Each serving is 1,000 mg, a full clinical-range dose.
In a controlled trial, NMN at this level raised blood NAD+ 3.7 times above placebo (Bhasin et al., 2023).
The form. NMN-99 uses only Uthever, the world’s first patented NMN backed by its own randomized, double-blind, placebo-controlled human trial.
Uthever holds 7 patents and is verified at 99+% purity in the beta form.
The proof. Every batch is tested by an independent 3rd-party lab, and the results are published.
The current batch measured 1,139.6 mg of NMN per serving, against 1,000 mg on the label.
In the September 2026 comparison, that was more NMN than any of the other 5 brands tested.
More than double the NMN of 4 out of the 5 top competitors tested.
The exception was Black Forest NMN 1000 mg, which delivered 905.0 mg per serving.
NMN-99 suits you if you want the full 1,000 mg in one serving, and a lab report you can read before you buy.
Sources
- Igarashi et al., npj Aging, 2022
- Yi et al., GeroScience, 2023
- Liao et al., Journal of the International Society of Sports Nutrition, 2021
- Niagen Bioscience, 2021
- Bhasin et al., 2023
- Read the lab reports for all 6 NMN products
Brands have paid for promotional consideration in these articles.