We don’t pay a lot of attention to vellus hair. This is the fine downy hair that covers a lot of our body, with the exception of the palms of our hands and for some reason, the backs of our ears. It isn’t very visible so the beauty world doesn’t take a lot of notice of it, though to my mind it is quite attractive. But you need to get pretty close to someone to be able to even see it, so it isn’t something you are really aware of except on family members are very close friends.
So what is it for? It turns out that nobody knows for sure, but it is quite likely that it plays a role in temperature regulation. The hairs hold a layer of air close to the skin which acts as a sort of blanket against heat loss. Vellus hair might also affect how efficient sweating is at temperature control, increasing the surface area so more water evapourates.
An intriguing further role might be protection against bacterial infection. The dermatologist Anthony Ormerod from Aberdeen University has proposed that the skin produces small quantities of nitric oxide (NO) that kill germs. If so, the vellus hairs would probably hold the gas in place longer and might make the difference between it working and not working.
I wondered whether the fine hairs might also give some protection against UV radiation. A bit of googling failed to pick up any work on this. I did discover that Caucasians have more vellus hair follicles than Blacks or Asians though – which is the wrong way round if vellus hairs are protective against light. So it is probably heat control that they are mainly there for.
But I think that vellus hairs are one of the things that helps keep our skin in good condition. We don’t need to do much to help them along with this – just let them grow. The only thing to bear in mind is that hair removal products that are strong enough to remove regular hairs are going to make short work of vellus hairs. Although they grow back quickly enough, I have a feeling you don’t want to lose them if you can help it. So if you can avoid getting the hair remover out, I would.
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You might also be inerested in another often overlooked feature of your skin.
Paper where the possible role of NO in skin protection is discussed.
Ethnic variation in vellus hair follicles.
Thanks to Wikipedea for the image of vellus hair.