04. What harm the studies found
NAD+ side effects were worse with an IV drip
Short pill studies found no major harm. IV drips caused more pain and add a separate risk when pharmacy staff prepare the liquid.
What the short NAD+ safety studies showed
Pill studies found no major harm over weeks or months. They tested NMN or NR, two ingredients based on a vitamin.
Your body turns those pill ingredients into NAD+. People had more trouble with IV NAD+.
Faster drips caused chest or belly pain, a fast heart rate, and nausea. One pharmacy shot failed a safety test and was recalled by the FDA.
That mixing risk doesn't apply to a pill in the same way. These short studies can't promise long-term safety for you.
They followed only certain people and only for a limited time. NAD+ is sold without approval as a medicine.
There isn't an approved drug label listing every known risk. That leaves you with less official safety guidance.
How people felt after NMN or NR pills
NMN and NR come from a common vitamin. Your body turns each pill ingredient into NAD+.
A short NMN test involved healthy men. Each man took 100, 250, or 500 mg once.
Heart rate and blood pressure showed no clear bad change. Oxygen, sleep, and lab tests also stayed much the same [7].
An NR trial used 100-1000 mg/day for eight weeks. Side effects weren't worse than with a placebo, or sugar pill.
No one had flushing, which means sudden warmth and red skin [4]. Bad cholesterol didn't rise.
The study also checked a body process using folate and other B vitamins. It found no harmful change.
Another NR trial used 1000 mg/day for six weeks [6]. No grave side effects appeared.
An NMN trial found no safety issue at 300-900 mg/day over 60 days [3]. Over the weeks or months studied, neither pill caused major trouble.
We don't have the same answer for years of use. If you're very ill, these trials can't settle safety for you.
What NAD+ sales claims can't prove
In the United States, sellers put NAD+ products in the supplement aisle. The government hasn't approved them as medicines.
There is no approved NAD+ medicine or amount for any disease. A sales claim can't replace the government's drug review.
NMN has one more issue. The FDA says drug testing on NMN began before sellers called it a supplement.
FDA rules can bar supplement sales when drug testing came first. Sellers and the FDA still disagree about whether that rule controls NMN.
The dispute doesn't mean NMN is banned or illegal. Its outcome may change sales rules, but not finished trial results.
What risks still need watching
First, more NAD+ in your blood hasn't proved better health. A 2025 review found weak proof and few tests on samples taken from people [14].
Second, lab tests raise a cancer question. Healthy cells and cancer cells both use NAD+.
Lab tests raise one worry: extra NAD+ might help a cancer already in your body, but no trial has found this harm in people who took NAD+ products during care. Tell your doctor that this worry comes from lab work, not harm found in people.
While mending DNA, your cells spend NAD+. In a badly hurt cell, repair can drain NAD+ until the cell loses power and dies [11].
No one knows whether taking NAD+ changes that process in you. The lab finding isn't proof of help or harm.
Third, a product may hold the wrong amount or unwanted material. Some sellers post a report from a lab they don't own.
A useful report matches the batch number on your bottle and shows what the lab found. Without that match, you can't confirm the contents.
Not every seller pays for an outside check. IV use adds mixing risks, and these facts can't predict your response.
What harm did pill studies find?
Short trials found no serious harm from the pills. NR up to 1000 mg/day for 6-8 weeks [4][6] and NMN at 250-900 mg/day [3] did no worse than a placebo, or sugar pill.
IV NAD+ was harder to bear and has far fewer good studies [8]. These findings can't guarantee safety for you.