Tanning according to science


Even in Sweden, the sun has finally come out of its winter hide-away. Summer is here and white translucent Swedes are spreading themselves out, half-naked, over every bit of grass-covered surface in Stockholm. All fully exposed to the sun’s non-forgiving rays.

Different skin-types

Tanning can be a tremendously bad idea. It can lead to cancers and give you a skin which makes you look like an old dinosaur on crystal meth. The lighter skin-types have here a disadvantage to the darker types since darker skin is more protected against the sun’s radiation due to the pigments. Use a sunscreen!

However, there are obvious benefits to being exposed to light like increased production of vitamin D. This means that it is good to be exposed to light, and does not mean that you should fry yourself like a broiler on a BBQ. That would be very unhealthy. Vitamin D deficiency particularly occurs during winter and is more common in people with darker skin due to a slower production of this vitamin in dark skin. This is probably why you generally find lighter skinned people at higher latitudes (where you have less light).

Just treat your skin well. All skin colours are beautiful.


The sun: never forget that it is a radiating nuclear fusion reactor. Wear sunscreen. NASA [Public domain], via Wikimedia Commons

Your cells are damaged by UV-radiation

Your skin is made up by many types of skin cells. One type is called melanocytes and they are responsible for the production of melanin which can absorb ultraviolet (UV)-radiation and prevent further cell damage. If you become exposed to dangerous UV-radiation, the production of melanin is triggered to make sure that the skin is further protected against radiation damage.


Melanocyte (image credit: Blausen.com staff)

In some people, particularly blondes and redheads another pigment namely phaeomelanin can dominate over melanin. Melanin results in a golden brown colour whereas phaeomelanin is red and explains why some people just do not tan very well.

Did you know that you tan slower with sun glasses?

One funny little detail in all this is that the pituitary gland in your brain can sense that it is light outside since it is linked to the optic nerve. At high light intensities, the pituitary gland starts to produce a hormone: melanocyte-stimulating hormone (MSH) which reaches the melanocytes in the skin through the blood stream and kicks up the production of melanin and you tan more readily. Since this system is depending on light reaching your eyes, you tan more easily if you do not wear sunglasses. However, I know that I prefer a slower tan over looking like a raisin around my eyes or damaging my retina. Wear sunglasses!


The brain and the pituitary gland (the little pea-like structure bottom middle/left). (Image credit: Henry Vandyke Carter)

Natural sunscreens do not cut it – this is why!

As a final note: There is some complete quackery running its rounds on social media right now claiming that coconut oil is a “natural” sun-screen that can replace normal sunscreen. Apart from me growing insane just by hearing the word “natural” in such a nonsensical context, it is straight forward bullshit. Oil is not a sunscreen per se! It is true that some oils have modest sunscreen properties, but these range in SPF (sun protection factor) of 2-8 (see reference *** below), which is not even close to what you need to be out in the sun safely. A good sunscreen should have SPF 15-50. I only ever use SPF 30-50 due to my pale (ghost-like) skin. Children should use an SPF of 50 if pale skinned.

Do not buy into this quackery. Turn on your bullshit deflector and do not gamble with your own or your children’s skin. It is way too precious since you must continue living in it for (hopefully) many years to come.

UV damage to the skin can cause skin cancer. This is because the UV-radiation can mutate the DNA in your cells and result in a cellular havoc. Mutations are generally not particularly good. I will make a post on what a mutation really is. The mutation may cause uncontrolled aggressive growth of your cells and this is cancer. Young skin is very sensitive to this sort of damage and should really be protected.

If you are worried about the toxicity of sunscreens – don’t be. Buy your sunscreen at a proper pharmacy or a reliable shop with as little scent as possible and as high factor as possible. These products are very well tested. Furthermore, you need to put this into a perspective. Say that your sunscreen is a bit “toxic” (which it most likely is not), but what is the alternative? You either put on sunscreen on your kid or expose them to mutagenic cosmic radiation from a gigantous nuclear fusion reactor in space, that might make your kid age prematurely and even develop severe illness. I know what I would choose.

Science Safely!

Dr. Anna of The Imaginarium

...wears sunscreen.

…wears sunscreen.

***In vitro sun protection factor determination of herbal oils used in cosmetics. Chanchal Deep Kaur and Swarnlata Saraf. Pharmacognosy Res. 2010 Jan-Feb; 2(1): 22–25. doi:  10.4103/0974-8490.60586.

Immediate pigment darkening: description, kinetic and biological function. By: Routaboul, C; Denis, A; Vinche, A. EUROPEAN JOURNAL OF DERMATOLOGY  Volume: 9   Issue: 2   Pages: 95-99   Published: MAR 1999

Photoprotective mechanisms in human skin. Modulation by oligonucleotides. By: Hadshiew, IM; Eller, MS; Moll, I; et al.. HAUTARZT  Volume: 53   Issue: 3   Pages: 167-173   Published: MAR 2002

Posted in Biology, Medicine and tagged , , , , , , , .



  1. Hey Anna, really good points here! I also want to raise the flag about the coconut oil’s new potential Rosetta Stone of all affections, and point that also the madness about using it in every single food or cooking only with it, is highly disregarding the fact that coconut oil has a really high saturated fat content and is recommended against by several world health organizations. Although it has mostly short chain fatty acids, it would be still preferable to indulge less in this type of oil, especially as a dietary complement. Also, it’s important to keep in mind that DNA damage, either by UV or other means, is the basic cause of cancer (Brookes and Lawley (1964) Evidence for the Binding of Polynuclear Aromatic Hydrocarbons to the Nucleic Acids of Mouse Skin : Relation between Carcinogenic Power of Hydrocarbons and their Binding to Deoxyribonucleic Acid, Nature 202, 781 – 784 doi:10.1038/202781a0). I’m looking forward to sunny days for some Vitamin D dose and safe tanning! 😉

    • I couldn’t have said it better myself! Thank you for your input!
      These diet fads really have started to annoy me. There are new “superfoods” every week and they are all apparently magic in one way or another. I suppose it is harder to understand that it is all about moderation. That there are no quick-fixes and that there is no magic cure. Maybe it all stems from a complete misunderstanding of how the body works. Maybe, I should make a post about homeostasis… 🙂

      Have a great day!

      Dr. Anna

Leave a Reply

Your email address will not be published. Required fields are marked *