Does shaving make hair grow back thicker?

A natural hair that has never been cut tapers to the tip: thin, soft, almost transparent at the end. A razor cuts it at its thickest point, at the skin, and leaves a blunt end. When that end emerges a day or two later, you are touching not the soft tip but the cross-section of the hair, which feels hard. The hair has not got thicker; you are simply touching its middle for the first time.

There are three more reasons it seems otherwise:

• Short stubble stands upright and does not lie along the skin like long hair, so it is more visible and it prickles.
• A fresh hair has not yet faded in the sun or rubbed against clothes, so it looks darker than old hair.
• After shaving the hair regrows from zero, and the contrast between "smooth" and "stubble" two days later is far more striking than the slow regrowth after waxing, although the growth rate is the same.

The question has been tested scientifically. In 1928 four men shaved part of their face following the same routine while researchers measured and compared the cut hairs: they found no evidence that shaving speeds up growth. In 1970 the Journal of Investigative Dermatology published "Shaving and hair growth": for several months five men shaved one leg once a week and left the other alone, while scientists measured the regrowing hair. Neither width, coarseness nor growth rate changed with shaving. In 2007 the BMJ, in its review "Medical myths", placed this belief alongside the myths about eight glasses of water a day and reading in dim light. Medical sites such as Healthline, reviewed by clinicians, repeat the same: shaving affects neither thickness nor speed.

Sources: J Invest Dermatol 1970, Shaving and hair growth (PubMed), BMJ 2007, Medical myths (PubMed), Healthline, does shaving make hair thicker

A hair is born in the follicle, deep in the skin, and everything about it is decided there. Thickness and colour are set by genes: some people have thin, light leg hair all their life, others dark and dense hair from their teens. Hormones, above all androgens, switch on growth in the "male" areas: chin, upper lip, belly, chest. That is why women's hair becomes more noticeable at puberty, in pregnancy, with polycystic ovary syndrome, at menopause and on some medications. These events coincide in time with the start of regular shaving, and shaving takes the blame it does not deserve. If hair on the face or belly has genuinely become darker and coarser, the razor is not the cause, hormones are: more in laser hair removal for hirsutism and PCOS.

Sources: NHS, hirsutism, NHS, PMOS (formerly PCOS, polycystic ovary syndrome)

Partly yes, and that is where the second myth comes from. Wax, sugaring and epilators pull the hair out by the root, and in our experience, after many years of that some follicles weaken: the new hair comes out thinner and individual follicles stop working. But it is slow, painful, uneven and causes ingrown hairs, especially in the bikini area. Shaving does not touch the follicle, so it neither weakens it nor damages it: razor burn and ingrown hairs after shaving can be treated, and nothing happens to the skin or the hair itself. How to shave without irritation is covered in razor burn and bumps.

Before laser hair removal and between sessions, shaving is the only method allowed. The laser heats the hair through its pigment and reaches the follicle along it, so the root has to be in place: after wax, tweezers or an epilator the laser has nothing to work on. The body is shaved the day before a visit; between sessions you can shave as often as you like, it does not interfere with the course and removes the feeling that hair is "growing more". The face is not shaved before laser; the specialist trims the hair.

To keep shaving from irritating the skin, the American Academy of Dermatology advises: wet the skin and hair, apply a shaving gel or cream, shave in the direction the hair grows, and change the blade or throw away a disposable razor after 5-7 shaves. Preparation in detail: how to prepare for laser hair removal.

Sources: American Academy of Dermatology, how to shave

Laser can make hair thinner and sparser in a targeted way over large areas: it acts on the follicle itself. It destroys follicles in the growth phase; over a course of 6-10 sessions most of the hair goes, and what remains is thinner and lighter. How many sessions you need and why hair "grows" between them is explained in how many laser hair removal sessions you need and why is hair still growing after laser hair removal. If the goal is to remove hair completely, including light and grey hair that the laser cannot see, there is electrolysis: a fine needle destroys each follicle one by one with a current, and a treated follicle usually does not produce hair again. It is the only method that works on hair without pigment, but on large areas it is slow, painful and expensive, so it is used for what remains after laser or for hair without pigment.

At the consultation we always say: shave without worry, it will not get thicker. Before the course you shave the body the day before your visit, between sessions with a razor whenever it suits you, and you leave the face alone, we trim the hair there ourselves. If after several years of shaving the hair has become darker and coarser, the specialist looks at the area and asks about your hormonal background, because that is usually where the cause is, and it changes the course plan. With every session you shave less often, and after the course most people need only one or two maintenance sessions a year.