Low testosterone doesn’t just affect energy—it can shrink your testicles and slow down fertility.

Research shows that when men have very low testosterone, their sperm count can drop to zero—but when doctors give them hormone treatments to boost it, sperm often reappears, and the size of their testicles tends to increase along with it. Other studies confirm that men with naturally low testosterone, even without being overweight, often have smaller testicles than those with normal levels. It’s not just about feeling tired—your body’s hormone balance directly affects how your reproductive system functions. The connection between low testosterone, reduced sperm, and smaller testicles is consistent across multiple studies, though it’s most clear in men with severe deficiencies.