“Shaving makes hair grow back thicker”

Many people have long believed that running a razor over their skin causes hair to return thicker, darker, and more abundant. This common misconception likely stems from the immediate sensation following a shave. When hair is cut at the skin's surface, the razor creates a blunt tip. Unlike the naturally tapered end of virgin hair, this blunt tip can feel coarser and more noticeable as it emerges, leading to the mistaken impression of increased thickness.

Scientifically, this idea has been thoroughly debunked. Hair growth is determined by the follicles located beneath the skin, not by the external act of shaving. Shaving only removes the dead portion of the hair shaft above the skin's surface and has no impact on the hair follicle's activity, the hair's diameter, its growth rate, or its pigmentation. Studies, some dating back to the 1920s, have consistently shown that shaving does not alter these characteristics of hair. What appears to be thicker hair is simply the uniform, blunt edge of the regrowing stubble.

The persistent belief in this myth is largely due to our sensory perception and observational biases. The stubble that emerges after shaving feels rougher because it lacks the soft, tapered tip of un-shaved hair. Additionally, newly grown hair that has not been exposed to sunlight, chemicals, or friction might appear darker and feel firmer than older hair, further reinforcing the illusion. The natural progression of hair growth, such as the transition from fine vellus hair to coarser terminal hair during puberty, can also coincide with the start of shaving, leading individuals to incorrectly attribute the change in hair texture to the act of shaving itself.