NAD+ Supplement Benefits: Studies, Side Effects and Cost Guide

If you are asking whether an NAD+ supplement is worth trying, the short answer is that the human studies so far are small and early. They show that certain NAD+ building blocks raise NAD-related markers in the blood, and the people in those trials generally tolerated them over weeks. None of the trials below looked at memory or lifespan, so they cannot tell you whether a supplement will change how you feel or how you age. We suggest a short talk with your pharmacist or prescriber, and a written list of everything you take, before you spend money on any product.

What is NAD+, and why is it in the news?

NAD+ is a molecule your cells use to make energy and to run many repair and signaling jobs. A 2023 review in PubMed (Endocrine Reviews) notes that NAD+ levels decrease throughout life, and that this age-related decline has been proposed as a contributor to many age-related diseases. That link is why supplement makers market these products to older adults. Most products do not contain NAD+ itself. They contain building blocks such as NMN or NR that the body converts into NAD+, as Fortune’s 2026 NAD+ supplement list explains.

The gap between what the human studies show so far and what they do not is the heart of this page.

Does NAD+ work? What the human studies found

Each trial tested one specific molecule, so read each row on its own.

In plain terms, the trials show that blood levels move and that short-term use was well tolerated. They were small and short, and their main results were blood markers, cholesterol, blood pressure and arterial stiffness. The review’s own authors say larger trials are needed before anyone can say NAD+ treatment works for aging or age-related conditions. If the cholesterol and blood pressure results are what caught your eye, our heart health supplements for seniors guide covers omega-3, CoQ10, magnesium and fiber.

Fortune’s 2026 list says that while early research suggests NAD+ may help with aspects of fatigue, more evidence is needed on cognitive performance and long-term health.

Life Extension’s NAD page makes claims of its own. It says NMN is “shown to increase NAD+ levels in the bloodstream in clinical studies,” and calls NR “one of the most extensively studied nutrients for healthy aging.” Those are the company’s words. The trials above measured blood markers, not the longer-term aging claims.

What are the side effects and downsides of NAD+?

Short-term use in these trials caused few problems. Long-term safety is the open question. Write down how you feel each day, so you have something concrete to bring to your provider.

What should I avoid taking with NAD+?

Fortune notes that NAD+ supplements may interact with medicines or other health conditions, and advises talking with your doctor before starting one. For most older adults, this is the most important safety point. The NIA’s guidance on taking medicines safely as you age says to write down all medicines you take, including OTC drugs, and to include any vitamins or dietary supplements, the amount and the time you take each one. Show that list to every provider, and keep a copy in your wallet.

• Prescription medicines of any kind: ask your pharmacist to check a new supplement against your list.
• Diabetes medicines: ask your pharmacist how any supplement fits with your blood sugar plan before you start.
• Kidney concerns: ask your prescriber whether your kidney function changes what is safe for you.
• Pregnancy: ask your obstetric provider first. A 2023 review in Antioxidants & Redox Signaling covers NAD deficiency in pregnancy. It describes congenital disorders linked to gene mutations and studies in mice, not trials of supplements in pregnant people.

Which form of NAD is better: NMN, NR or NAD+?

No form has been shown to work best, and the trials above did not compare forms side by side. Here is how the names differ on a label.

Fortune also notes that NAD+ is not vitamin B3, though the two are similar, and that NR is a form of vitamin B3.

Is NAD+ like Ozempic?

The trials above tested NAD+ building blocks on their own, not against any prescription medicine, Ozempic included. If you take a prescribed medicine, do not change or swap it because of a supplement. Ask your prescriber first.

Are there best NAD+ supplements for women, men or anti-aging?

Ranking lists can point you to products, but they are shopping guides, not trials. Fortune’s 2026 list scored products on first impressions, taste, swallowing and value, using testers who tried each one. Fortune names one pick for women, one for men and Tru Niagen for aging. Those are the list’s own choices. The research on aging claims is still early, as the review above says.

None of the trials above compared products, or tested them by sex or age. So the choice of a product for women, men or any age group rests on your own goals and your pharmacist’s advice.

What do NAD+ supplements cost, and can you get a refund?

Prices as of November 6, 2026. Fortune’s list gives the cost per serving for each product it reviewed, and Life Extension’s NAD page shows a regular price. Prices change, so check today’s price with each company before you order.

Refund terms differ by company. Fortune lists a 30-day money-back guarantee for Timeline Urolithin A, and notes a multiple-bottle discount for PartiQlar and a subscription price for IM8. Before you pay, ask each company for its refund window in writing, whether shipping is refunded, and what it charges when a subscription renews. Then find the cancellation steps on the order page before the first charge.

Do celebrities take NAD+?

None of the research above names a public figure who uses NAD+, and a celebrity’s routine is not a trial. If an ad names a famous user, treat that as marketing, not research.

Is it safe to buy NAD+ injections?

The trials above tested tablets and capsules taken by mouth. They did not test injections or IV drips, so they cannot answer questions about those. Injections are a separate decision to make with a clinician, and we do not suggest a seller for them.

If you are looking at any online source for a medicine, the NIA’s guidance says to make sure the online pharmacy requires a valid prescription, is licensed in your state, and has a pharmacist available to answer questions. The same guide is at taking medicines safely as you age.

Before you try NAD+: a checklist for you and your provider

Keep a simple daily log. Write the product name, the ingredient on the label, the time you took it, and any nausea, headache, stomach upset, flushing or unusual tiredness. Bring the log and your medicine list to your next visit. Our right time to consider a natural supplement guide walks through the same questions in more detail.

Questions to bring to your pharmacist or prescriber:

• Does this product interact with any of my medicines or supplements?
• Does my kidney function change what is safe for me?
• Is this safe with my health conditions and my age?
• What is the refund window, and how do I cancel a subscription?
• Can the company send the lab report for the exact batch I am buying?

Book a visit soon if tiredness keeps getting in the way of your day, or if you notice new symptoms after starting any supplement.

By the Senior Safety Desk Editorial Team

This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.