Why does the hair on my arms stop growing but head

Hair growth is determined by genetics, hormones, and age.

Genetics: The hair follicles on your arms and head are programmed to grow at different rates. The hair on your arms typically grows slower than the hair on your head.

Hormones: The hormone testosterone plays a role in hair growth. Men have higher levels of testosterone than women, which is why they tend to have more hair growth. Women may experience increased hair growth on their arms during pregnancy or menopause, when their hormone levels fluctuate.

Age: As we age, our hair growth slows down. This is due to a decrease in hormone production and changes in the hair follicles.

It's important to note that hair growth can vary from person to person. Some people may have more or less hair growth on their arms than others, and the rate of hair growth may change over time. If you're concerned about your hair growth, talk to your doctor.