all right! because @maaaaaaayuri and @zgriptsor asked for it: shaving does not make your hair grow back thicker, faster, or darker! So if that’s the case, what is the difference between shaving and waxing? (1/9)

First, a primer on hair growth: the hair growth cycle has 3 stages. In anagen, the cells divide and mature into the cell types necessary for hair growth. In catagen, the hair follicle regresses and the actual movement of the hair shaft occurs. Telogen is a resting phase. (2/9)

So, what does shaving do? It cuts the hair but leaves everything below the skin intact. In mice, shaving shifts all of the hair shafts from wherever they are in the cycle to the beginning of anagen. This where the myth of faster hair growth after shaving comes from. (3/9)

Hair *seems* to grow back faster because you’ve essentially put your hair through a timeskip; shaving shunts the hair forward in time to the beginning of a new growth cycle. But you’re not actually changing the *rate* of hair growth at all! (4/9)

Shaving also changes the tip of your hair from a naturally tapered tip to a blunt tip, which gives the illusion of thicker, darker hair. However, shaving does not actually stimulate new hair growth, nor does it affect hair coloration. (5/9)

So, how is waxing different? It plucks your hair out from the root. This seems to last longer than shaving because the few cells that are left behind take 4-8 weeks to grow back into a visible hair shaft that pokes above the skin. But that’s not the full story. (6/9)

Waxing growing hairs shortens their next anagen by 4 days because it removes a hair growth inhibitor molecule along with the hair. For telogen hairs, waxing makes the next anagen cycle longer. (7/9)

After repeated waxes, your hairs will all be in the same stage of growth, at which point the goal is to wax while they are in telogen. Waxing can also damage hair follicles, leading to thinner hair growth (and pain). (8/9)

Here's the abstracts for the studies I read while making this thread! Unfortunately, the actual articles are behind paywalls :(

https://dev.biologists.org/content/12/3/465
https://www.sciencedirect.com/science/article/abs/pii/S0190962299701817 (9/9)