5-Amino-1MQ, NAD+, and Methylation: The Biochemistry

What does NNMT actually do?

NNMT transfers a methyl group from SAM onto nicotinamide, producing 1-methylnicotinamide (1-MNA) and S-adenosylhomocysteine. Nicotinamide is also the raw material the NAD+ salvage pathway recycles into NAD+. The rationale for 5-amino-1MQ is that blocking NNMT leaves more nicotinamide for NAD+ salvage and spends less SAM on nicotinamide. That is a hypothesis built on a real reaction.

What do animal studies show?

A mouse study of methylquinolinium NNMT inhibitors, the compound class 5-amino-1MQ belongs to, reported that the inhibitors crossed cell membranes, were selective against related methyltransferases and NAD+ salvage enzymes, and suppressed lipogenesis in fat cells [11]. In high-fat-fed obese mice they reduced body weight, fat mass, adipocyte size and plasma cholesterol without changing food intake [11]. These are mouse and cell results, and they do not measure NAD+ or methylation in people.

Do NAD+ precursors raise NAD+ where it counts?

NAD+ supports cellular energy metabolism and serves as a substrate for sirtuins and PARP enzymes [1]. NMN and NR are NAD+ precursors [6][7]. None of the human trials below tested 5-amino-1MQ.

In a trial of 30 healthy adults, the 15 assigned to NMN 250 mg/day had higher whole-blood NAD+ after 12 weeks [1]. In a 60-day trial of 80 middle-aged adults assigned to placebo or one of three NMN doses (300, 600 or 900 mg/day), blood NAD rose in each NMN group, most at 600 and 900 mg [2]. In a trial of 20 people with Parkinson's disease, the 10 assigned to NR 1,500 mg twice daily had blood NAD+ increases of up to 5-fold over four weeks [3]. In a crossover trial of 24 adults aged 55 to 79, NR 1,000 mg/day for 6 weeks raised NAD+ in blood cells about 60% over placebo [8].

Blood is not muscle. In a 21-day crossover trial of 12 men aged 70 to 80, NR 1 g/day raised markers of NAD+ synthesis in muscle but did not significantly raise total muscle NAD+ (210 vs 197 pmol/mg, p=0.22), and mitochondrial respiration was unchanged [4]. A 2025 meta-analysis found NMN had no significant effect on skeletal muscle index, handgrip strength, gait speed or the 5-times chair stand [9]. A second 2025 meta-analysis of 12 studies and 513 participants found NMN raised blood NAD but most clinical outcomes, such as fasting glucose and blood lipids, were not significantly different from control [10].

What about the methylation side?

The human methylation data come from NAD+ precursor trials, not from an NNMT inhibitor. In the 21-day study of 12 older men, NR raised nicotinamide-methylation products about 5-fold in muscle, which indicates that excess nicotinamide was being cleared through methylation [4]. In the 4-week NR-SAFE trial of 20 people with Parkinson's disease, NR recipients had a slight initial rise in serum homocysteine, and the authors judged the methyl donor pool intact [3].

Is any of this an approved treatment?

NMN and NR are sold in the US as oral dietary supplements, and neither is an FDA-approved drug [5]. No NAD+-precursor product is approved by FDA to treat aging or any disease [5].