The studies lasted 3 to 24 weeks. NMN and NR were given in dosages of 250 to 2,000 mg per day.

The average ages of the participants across all studies ranged from 61 to 83.

NMN supplementation did not improve the skeletal muscle mass index (limb muscle mass adjusted for height) or any measures of muscle strength or physical function. These outcomes are covered in the table below.

Effect of nicotinamide mononucleotide (NMN) supplementation on muscle mass, muscle strength, and physical function in older adults

Outcome	Number of trials	Outcome
Skeletal muscle mass index	3	No effect
Handgrip strength	3	No effect
Gait speed	4	No effect
Five times sit-to-stand test performance (a test of leg strength in older adults)	2	No effect
30-second sit-to-stand performance (a test of leg strength and endurance in older adults)	1	No effect
Knee extension (a measure of hamstring strength)	1	No effect
Short physical performance battery (a test of physical capabilities)	1	No effect
Chest press (1RM + reps to failure at 80% 1RM)	1	No effect (both measures)
Leg press (1RM + reps to failure at 80% 1RM)	1	No effect (1RM); decrease (reps to failure)*
Thigh muscle mass	1	↓70 grams*

*The NMN group lost weight (–1.9 kg/–4.2 pounds). Some muscle/strength loss is anticipated with weight loss.

NR supplementation improved one measure of aerobic capacity in one study but otherwise did not improve any measures of muscle strength or physical function. These findings are covered in the table below.

Effect of nicotinamide riboside (NR) supplementation on muscle strength and physical function in older adults

Outcome	Number of Studies	Effect of nicotinamide riboside
6-Minute walking distance (a measure of aerobic capacity)	2	Improved performance in 1 study; no effect in 1 study
Short physical performance battery (a test of physical capabilities)	2	Worsened performance in 1 study; no effect in 1 study
Handgrip strength	2	No effect in any study
Five times sit-to-stand test (a measure of lower extremity strength)	2	Less improvement than placebo in 1 study; no effect in 1 study

Can supplementation with NMN and NR rejuvenate aging muscles? Original paper