I hope you are well. Here is the second part of my brief sunscreen summary. The first part can be found here. This time I’ll give you recommendations for some of my favourite sunscreens. If you have any questions, feel free to ask.
Is there a safe way to tan?
As it is mentioned, even UVA rays cause cancer so tanning beds aren’t consider a “safe” way of tanning.
However, if you like tanned skin, the safest choice is a self tanner. The majority self tanners in stores are based on Dihydroxyacetonem, a chemical which in reaction with the dead skin cells on the surface creates skin darkening which lasts for approximately 5-10 days.
What is the difference between physical and chemical sunscreen?
Physical sunscreens create a layer which deflects the UV rays from the skin. They are generally stable, but their consistency is thick and they often leave a white cast on the face. They are less likely to irritate the skin and therefore they are appropriate for persons with sensitive skin.
Physical filters are titanium dioxide (protects against UVB and a part of UVA spectrum) and zinc oxide (protects from full UVA and UVB spectrum).
Chemical sunscreens contain filters which absorb the UV rays. They are generally photostable (exception avobenzone), but they can irritate sensitive skin. They are more user-friendly because they can be put in various formulations.
The most common chemical filters are: Octylcrylene, Avobenzone, Octinoxate, Octisalate, Oxybenzone, Homosalate, Helioplex, 4-MBC, Mexoryl SX and XL, Tinosorb S and M, Uvinul T 150 and Uvinul A Plus
What is a SPF?
SPF (skin protection factor) is a number which indicates the amount of time we can spend on sunlight without getting burned. This amount of time depends on how your skin reacts to sun. For example, your skin burns after 5 minutes in the sun (no protection). If you use the right amount of SPF 15 sunscreen, this means that now you can spend 75 minutes out without getting burned (5 minutes * 15); for SPF 30 this is 150 minutes, etc.
SPF number usually indicates protection against UVB rays. UVA protection is on my sunscreens usually indicated just by saying UVA, and it generally is one third of UVB protection.
How much sunscreen do we need to apply?
Sunscreen is really not something you should save and for it the old “a little goes a long way” does not apply. You should apply 2mg of sunscreen for 1 cubic centimeter of your skin. Yes, this means that a 30ml bottle of sunscreen will last you less than a month if you use it daily on the face.
The following example will illustrate how smaller amount diminishes the protection. If you apply half of the recommended amount of SPF50 sunscreen, you won’t get SPF25 protection; rather, you’ll get one square root of SPF50 which is approximately SPF7.
How often should I apply sunscreen?
If you spend a lot of time outside, the sunscreen should be reapplied every two hours or every time after you get out of the water.
Some of my favourite sunscreens:
Chanel UV Essentiel (zinc based sunscreen)
Bioderma Sebium Mat (SPF 30, but works well under make-up)
Uriage Barie Sun Crème Teinte (nice replacement for a tinted moisturizer for lighter skin)
Eucerin Sun Crème SPF 50 (tinted sunscreen for darker skin)
Lavozon (Mueller brand) and Sundance (DM brand) sunscreens for body
Sundance SPF30 lip balm and Sundance SPF 50 stick lip balm
Avene Mineral sunscreen SPF 50 (excellent titanium dioxide waterproof sunscreen)
You can find more information about sunscreen and skin cancer on the following links:
Paula Begoun – Cosmetic Cop
European Union sunscreen guidelines
FDA sunscreen guidelines
I hope that you have found answers to your questions.
DISCLAIMER – I am not a professional dermatologist and this article is based solely on my knowledge of physics and chemistry (It is surprising what one remembers from high school :)).