NAD+ Decline and Aging: What the Science Shows, and Whether NR, NMN or Nicotinamide Help Skin
NAD+ levels fall with age in animal and human tissue. What NAD+ does, what human trials of NR and nicotinamide actually found, and what it means for your skin.
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme every cell uses to turn food into energy and to power repair enzymes such as sirtuins and PARPs. Levels decline with age in many tissues, which is why NAD+ "boosters" like nicotinamide riboside (NR) and NMN are marketed for longevity. The short answer: NR supplements reliably raise NAD+ in blood in human trials, but no trial has shown they slow aging or improve skin. The best skin evidence is for plain nicotinamide (vitamin B3), which reduced new non-melanoma skin cancers in high-risk people.
The short answer
- NAD+ falls with age in animal and some human tissues, driven by rising consumption (CD38, PARPs) and falling synthesis (Covarrubias et al., Nat Rev Mol Cell Biol, 2021).
- In a 6-week randomized crossover trial, 1,000 mg/day NR was well tolerated and raised NAD+ in blood cells of healthy middle-aged and older adults, but did not significantly change most physiological outcomes (Martens et al., Nat Commun, 2018).
- In a phase 3 trial in people with prior skin cancers, oral nicotinamide 500 mg twice daily lowered new non-melanoma skin cancers versus placebo over 12 months (Chen et al., N Engl J Med, 2015).
- Topical niacinamide (the same molecule) has evidence for skin tone, texture and barrier (Bissett et al., Dermatol Surg, 2005).
What NAD+ does in a cell
NAD+ shuttles electrons in energy metabolism, and it is also consumed as a fuel by enzymes that repair DNA (PARPs) and regulate stress responses (sirtuins). "Deregulated nutrient sensing" and "mitochondrial dysfunction," both linked to NAD+, are listed among the hallmarks of aging (López-Otín et al., Cell, 2013). When DNA damage rises, for example after UV exposure, PARPs use more NAD+, which is one reason skin researchers are interested in it.
Why levels fall with age
The review by Covarrubias and colleagues describes three drivers: more NAD+ consumption by the enzyme CD38 (which rises with inflammation), more use by PARPs as DNA damage accumulates, and less recycling through the salvage pathway. Most of the detailed data come from mice; human tissue data are smaller and less consistent.
What precursor supplements can and can't do
| Precursor | Human evidence | Skin-specific evidence |
|---|---|---|
| Nicotinamide riboside (NR) | Raises blood NAD+ in small trials | Not listed |
| NMN | Small, short trials | Not listed |
| Nicotinamide (B3) | Large phase 3 trial for skin cancer prevention | Yes, in high-risk patients |
Raising a blood marker is not the same as slowing aging. NR and NMN trials so far are short, small and focused on safety and biomarkers. Long-term safety is not established. For how NAD+ connects to sirtuins, see sirtuins: the longevity genes explained.
What this means for your skin
- If you have had skin cancer, ask your dermatologist about oral nicotinamide. That is the one evidence-backed use.
- For everyday anti-aging, topical niacinamide is a well-studied, inexpensive option; see our niacinamide anti-aging guide.
- Daily broad-spectrum sunscreen reduces the UV damage that drains NAD+ in the first place.
Frequently asked questions
Do NAD+ IV drips work?
There are no controlled trials showing NAD+ infusions slow aging or improve skin. They carry cost and infusion risks.
Is nicotinamide the same as niacin?
No. Niacin (nicotinic acid) causes flushing and affects cholesterol; nicotinamide does not cause flushing. Both are forms of vitamin B3.
Should I take NMN or NR for my skin?
There is no published evidence that either improves skin aging in humans. Talk to your doctor before starting any supplement.
Bottom line
NAD+ decline is real biology and an active research area, but supplements that raise NAD+ have not been shown to slow aging. Nicotinamide for skin cancer prevention in high-risk people and topical niacinamide for appearance are the evidence-backed takeaways.
This article is for educational purposes only and is not medical advice. Talk to your doctor or dermatologist about your situation.
Sources
- Covarrubias AJ et al. NAD+ metabolism and its roles in cellular processes during ageing. Nat Rev Mol Cell Biol. 2021. PubMed
- Martens CR et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun. 2018. PubMed
- Chen AC et al. A phase 3 randomized trial of nicotinamide for skin-cancer chemoprevention. N Engl J Med. 2015. PubMed
- Bissett DL et al. Niacinamide: a B vitamin that improves aging facial skin appearance. Dermatol Surg. 2005. PubMed
- López-Otín C et al. The hallmarks of aging. Cell. 2013. PubMed
