Shaving hair from the skin has no impact on hair growth rate.
There are several myths regarding shaving or removing body hair. A common misconception is that shaved hair grows back faster or thicker afterwards. In fact, hair is little more than a residue formed from excess protein and keratin, the same substance found in nails. It has no nerve endings and no other way of signaling a faster growth rate to the glands that excreted it. Hair grows at a specific and constant rate for each person, although there may be a slight increase during the summer.
Shaving removes the ends of the hair.
Shaving only removes the ends of hair at or slightly below skin level. The actual hair roots remain in the deeper follicles or pores of the skin. When the shaved hair starts to grow back at its normal rate, the first part of the hair to emerge is the anterior root, not a tapered shaft. As the hair root is thicker than the hair removed, it appears thicker to the human eye. What makes it appear to grow faster is its darker appearance against bare skin.
Shaving the air from the armpit does not affect the actual growth rate, but the irritation when the hair grows back may be more noticeable.
Soon after male teenagers begin to develop facial hair, many of them will quickly shave it off, believing that shaved hair will grow back thicker and faster. In some cases, there is measurable growth in facial hair, but shaving is not the root cause. As more and more adult hormones are released into the teenager’s body, there is an increase in the number of active hair follicles. More facial hair appears, but it is not growing faster than any previous beard or mustache.
Shaving your chest hair will not make it grow back any faster.
The same theory also applies to the growth of other body hair. Some people may have faster hair growth rates than others because of their diets or an inherited genetic factor, but shaved hair itself has no control over that rate. Women who shave their legs frequently may feel a stubble sensation as the root hairs grow, but they are not forcing more hairs to appear or making them grow faster. Shaving your armpit, pectoral, or pubic hair doesn’t affect the actual growth rate either, but the skin irritation and itchiness when the hair comes out can cause some people to notice these shaved areas a little more than usual.