Nicotinamide Mononucleotide (NMN) Research

This is the first randomized controlled trial in humans to test whether oral nicotinamide mononucleotide (NMN) — a precursor the body uses to make NAD⁺ — affects how the body handles insulin. Twenty-five postmenopausal women with prediabetes who were overweight or obese took either 250 mg of NMN daily or an identical placebo for 10 weeks. Neither the participants nor the researchers knew which pill each person received until the trial ended.

After 10 weeks, women taking NMN showed a 25% improvement in how effectively their muscles took up glucose in response to insulin, measured with a hyperinsulinemic-euglycemic clamp — the reference method for assessing insulin sensitivity. Women taking placebo showed no such change. Muscle biopsies confirmed that the insulin-signaling machinery inside the muscle cells (the AKT and mTOR pathways) was working harder after NMN. Gene expression analysis showed that NMN activated hundreds of genes involved in muscle repair and remodeling, including the PDGF signaling pathway.

The improvement was specific to muscle. NMN did not change body weight, body fat, liver fat, blood pressure, fasting glucose, fasting insulin, cholesterol, or how insulin acted on the liver or fat tissue. Muscle strength and endurance did not improve during the 10-week window. NMN was well tolerated, with no adverse events reported and standard blood tests unchanged.