Testicular atrophy is when the testes shrink. In the case of testicular atrophy, the testes get smaller due to a loss of some of the germ cells and Leydig cells.

Germ cells produce sperm while Leydig cells produce testosterone.

If the testes shrink, a person could have a lower sperm count, lower testosterone levels, or both, due to the loss of these cells.

Testicular atrophy differs from the shrinking that occurs due to cold temperatures. In cooler temperatures, the scrotum retracts or shrinks, pulling the testes closer to the body to maintain warmth. In warmer temperatures, it loosens, allowing the testes to cool.

However, testicular atrophy refers to shrinkage in your actual testicles, not your scrotum. This can be due to several things, including an injury, an underlying condition, or exposure to certain chemicals.

Testicular atrophy can occur due to inflammation caused by viral or bacterial infections, age, and injury, among other causes. Treatment depend on the underlying cause.