What Are NAD+ Supplements?

NAD+ is an important molecule that helps our cells work properly. As we get older, our bodies make less of it. Scientists have been testing supplements that help increase NAD+ levels in our bodies. The main types are called nicotinamide riboside (NR), nicotinamide mononucleotide (NMN), and nicotinamide.

The Good News

Scientists have done careful studies with real people to see if these supplements work. Here's what they found:

Heart and Blood Sugar Benefits Some people who took NAD+ supplements had slightly lower blood pressure and better blood sugar control. Their arteries worked a bit better too.

Feeling Better One large review looked at 10 different studies with 489 people. The people taking NAD+ supplements reported feeling less anxious and having a better quality of life. They also had less inflammation in their bodies.

More Energy and Better Focus In one study, people who took the supplements had 27% more NAD+ in their blood. They felt less tired, could focus better, and felt less stressed in the morning.

Safety in Short-Term Studies  Studies with healthy adults, overweight people, and patients with conditions like chronic fatigue, Parkinson's disease, and prediabetes all showed that these supplements were well-tolerated for short periods of time.

The Not-So-Good News

Common Side Effects Some people had stomach problems, nausea, bloating, headaches, muscle pain, trouble sleeping, or felt tired. These usually went away on their own and weren't dangerous, but they weren't fun either.

A Serious Safety Concern Two people taking high doses of nicotinamide (3,000 mg per day) in eye disease studies developed serious liver problems. This was the most serious side effect ever reported in NAD+ supplement studies. Both people had to stop taking the supplement. Because of this, all studies using nicotinamide now don't allow people with liver problems to participate.

It's important to know that these liver problems happened with nicotinamide specifically, not with the other types (NR or NMN). But it shows that high doses can sometimes cause serious problems.

Limited Benefits Here's the disappointing part: the supplements didn't help with weight loss or long-term blood sugar problems. The benefits people saw were much smaller than what scientists expected based on animal studies.

Very Short Studies This is a huge problem. The longest study only lasted 8-12 weeks—that's less than 3 months! Scientists have no idea what happens if you take these supplements for years. Over 300 people have taken these supplements in studies, but none of them took them long enough to know about long-term effects.

Who Might Benefit?

Based on current research, NAD+ supplements might help people with:

• Chronic fatigue (constant tiredness)

• Being overweight with heart or blood sugar problems

• Healthy middle-aged and older adults who want to stay active

The Big Concerns

Scientists are worried about what might happen with long-term use:

Cancer Risk - It's Complicated This is confusing because NAD+ seems to work two different ways with cancer:

• Cancer cells need a lot of NAD+ to grow quickly

• But NAD+ also helps repair damaged DNA, which could prevent cancer from starting

The problem is that no one knows for sure what happens if someone already has cancer cells in their body and takes NAD+ supplements. Would it help the cancer grow? Scientists just don't know yet because there haven't been any long-term studies.

Cell Aging Our cells naturally get old and stop working well. NAD+ might help fix some of this damage, but it could also make certain aging processes worse. Scientists are still trying to figure this out.

Toxic Buildup Scientists worry that taking these supplements every day for years might cause harmful substances to build up in the body. However, no studies have looked at this yet because no one has studied people taking the supplements for more than 12 weeks.

Unknown Long-Term Effects The longest study only lasted 12 weeks. No one has ever studied what happens after months or years of taking these supplements. This is a major gap in our knowledge.

The Bottom Line

NAD+ supplements appear safe for short-term use (up to 3 months) and might provide small benefits for some people. Studies with doses up to 1,000-1,250 mg daily of NR and NMN showed no serious problems in the short term. However, scientists desperately need to do longer studies to know if they're safe and helpful over many years.

The benefits seen in humans are much smaller than expected, and there are worries about possible risks that haven't been studied yet. The liver problems seen with high-dose nicotinamide show that serious side effects are possible, even though they're rare.

Until we know more, it's probably best to be cautious, especially if you have liver problems or a higher risk of cancer. If you're thinking about taking NAD+ supplements, talk to your doctor first. They can help you decide if the possible benefits are worth the unknown risks for your specific situation.

Key Scientific Studies Referenced

1. Gindri IM, Ferrari G, Pinto LPS, et al. "Evaluation of Safety and Effectiveness of NAD in Different Clinical Conditions: A Systematic Review." American Journal of Physiology. Endocrinology and Metabolism. 2024.

2. Freeberg KA, Udovich CC, Martens CR, Seals DR, Craighead DH. "Dietary Supplementation With NAD+-Boosting Compounds in Humans: Current Knowledge and Future Directions." The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences. 2023.

3. Conze D, Brenner C, Kruger CL. "Safety and Metabolism of Long-Term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-Controlled Clinical Trial of Healthy Overweight Adults." Scientific Reports. 2019.

4. Fukamizu Y, Uchida Y, Shigekawa A, et al. "Safety Evaluation of β-Nicotinamide Mononucleotide Oral Administration in Healthy Adult Men and Women." Scientific Reports. 2022.

5. American Glaucoma Society and American Academy of Ophthalmology. "Position Statement on Nicotinamide Use." American Academy of Ophthalmology. 2025.

6. Braidy N, Liu Y. "NAD+ Therapy in Age-Related Degenerative Disorders: A Benefit/Risk Analysis." Experimental Gerontology. 2020.

7. Yaku K, Nakagawa T. "NAD+ Precursors in Human Health and Disease: Current Status and Future Prospects." Antioxidants & Redox Signaling. 2023.