Girl shaving arms?

The idea that hair will grow back thicker and darker if you shave it is absolutely, 100% false. The strange thing about this myth is that 90% of people believe it, and it shows no signs of going away.

The hair that you see is composed of dead cells. The section that grows is under the skin, well out of reach of your razor. Shaving or cutting the dead section is not going to have any effect on the section that is alive. Your fingernails are the same and are composed of the same material, and the section we trim is long dead. Does trimming your fingernails cause the nail to grow back faster, thicker, a different color? No, of course not.

The myth gets perpetuated by the fact that when men start shaving their faces and girls their legs as teenagers, very soon after, the fine hair they started with begins to grow in thicker and darker. This has to do with hormonal changes in your body, NOT with the fact that you started shaving. If you had not started shaving, rest assured the hair would have started growing in thicker anyway. It is a correlation, not a causation.