The Nature Index 2025 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...

Low levels of total and bioavailable testosterone may be associated with an increased risk of dementia in elderly men, according to French investigators. From a cohort of 3,650 men aged 65 years and ...

Testosterone is the quintessential male hormone (androgen), and it’s a busy one, helping to regulate intimate function, muscle mass, red blood cell count, mood, and more. But not all testosterone in ...

Total testosterone represents the sum of free, or bioavailable, testosterone and a more sizeable proportion bound to sex hormone-binding globulin (SHBG) and albumin. Total testosterone readings may ...

Genetics play a role in low testosterone for some men, but underlying causes vary widely. Many genes influence testosterone ...

Starting around age 40, many men notice the first physical changes that may be related to their hormone levels: Energy wanes ...