Nicotinamide mononucleotide (NMN) supplements are once again available for purchase as dietary supplements following a reversal by the U.S. Food and Drug Administration (FDA). The FDA had previously banned the marketing of NMN as a dietary supplement in 2022 while it was under investigation as a drug, but reversed this decision in 2025, permitting NMN supplements to re-enter the market.
NMN is a direct precursor to nicotinamide adenine dinucleotide (NAD), a crucial coenzyme found in all living organisms. NAD plays a vital role in cellular health, energy production, and DNA repair. As NAD levels naturally decline with age, there has been increased interest in NAD-boosting treatments and supplements.
Dr. Andrew Salzman, Chief Medical Officer of wellness biosciences company Wonderfeel and a physician from Harvard Medical School, explained that NMN, being a smaller molecule than NAD, may have greater potential for cellular uptake. Once inside cells, NMN can convert into NAD, helping to replenish the body's supply.
This regulatory change has led to a proliferation of NMN supplements from thousands of brands, offered in various formulations and with differing standards for testing and production. This availability prompts questions about choosing high-quality supplements, appropriate dosage, timing, and potential side effects.
Potential benefits of NMN supplements, supported by research, include improved mitochondrial function, reduced inflammation, enhanced insulin sensitivity, and better athletic performance. Some studies have indicated that NMN supplementation can improve muscle insulin sensitivity and glucose utilization in individuals with prediabetes. Research has also suggested improvements in aerobic exercise capacity in amateur runners. Additionally, NMN may contribute to healthier skin by increasing hyaluronic acid production, potentially improving hydration, elasticity, and firmness.
While human studies have not yet definitively proven lifespan extension, animal research has shown promising results. A 2023 study indicated that NMN supplementation was associated with longer lifespans in mice, delaying the onset of frailty and increasing median lifespan in female mice. More research is needed to confirm these effects in humans.
NMN supplements are most commonly available in capsule form, which experts like Salzman favor for absorption and conversion into NAD. While NAD injections and intravenous (IV) infusions have gained popularity, the clinical research supporting their efficacy in raising NAD levels within cells remains limited. Some experts express concerns that these methods may not effectively deliver NAD where it's needed, noting that NAD itself lacks a direct mechanism for cellular entry. Studies have shown that a significant portion of intravenously administered NAD can be excreted in urine.
When selecting an NMN supplement, experts advise prioritizing purity, ensuring the product is free from contaminants. Look for supplements manufactured in a Current Good Manufacturing Practice (cGMP)-certified facility and independently tested by a third-party laboratory, with accessible lab results (Certificate of Analysis or COA) for verification. Products should ideally be free of unnecessary binders, fillers, and artificial additives.
Research suggests that higher doses of NMN are more effective at increasing NAD levels. A clinical trial involving 900 milligrams of NMN daily demonstrated notable improvements across various health metrics compared to a placebo. This dosage is also offered by brands like Wonderfeel in their Youngr NMN supplement.
Clinical research generally indicates that NMN supplements are safe and well-tolerated. A 2022 safety evaluation found no side effects at oral doses up to 1250 milligrams, and a 2023 trial using doses up to 2,000 milligrams daily also reported no adverse effects. However, as with any new supplement, consulting a healthcare provider before starting NMN is recommended, particularly for individuals with underlying medical conditions or those taking prescription medications. Pregnant or breastfeeding individuals should avoid NMN until further safety research is available.