To date, we know of only two things that can reverse the effects of aging: caloric restriction and extensive exercise. But in a recent experiment, researchers applied a new compound to 2-year old mice, causing their muscles to regenerate to 6-month old levels. Incredibly, human trials may start next year.
The new compound, nicotinamide mono nucleotide (NMN), worked surprisingly quickly when tested on mice. When administered early enough in the aging process, it was found to work within one week; the muscles of older 2-year old mice were "indistinguishable" from the younger 6-month old animals. It improved muscle wastage, restored mitochondrial function and communication, and improved inflammation and insulin resistance, both of which are known causes of aging.
To put it into perspective, this result was like regenerating the muscles of a 60-year old human to those of a 20-year old.
Quite obviously, this comparison should be taken with a grain of salt; human aging and metabolism is quite different from that of mice. What's more, muscle strength did not improve (though the researchers are hoping to correct that). It's also an example of partial age reversal; the mice still have other age-related problems, like neurodegenerative decline and the shortening of telomeres.