Increases in the stress hormone cortisol causes hair follicle stem cells to remain in an extending "resting phase" without being able to regenerate the hair follicle, leading to hair loss.

Supplemental selenium protects against obesity in mice and extends lifespan in yeast by 62% by mimicking methionine restriction, which decreases the hormone IGF-1.

The benefits of fish oil depend on your genotype — certain people will see reductions in triglycerides (blood fat), while others increase triglycerides, based on variants of the gene GJB2.

Researchers have uncovered a new function of the gene BMI1, which prevents neurons' DNA from disorganizing into structures called G4, seen in Alzheimer's diseased brains.