So what is this SPF and what does it mean as far as sun care?
Well it stands for “Sun Protection Factor”. Remember factors? It is multiplicative, so if you are very pale like me and basically burn in 10 min in the sun, then with an SPF for 45 I would burn in 450 min instead. Essentially, you can stay in the sun 45 times longer. There are many factors included in this calculation such as skin type and whether you use the correct amount. As you probably have heard, SPF ratings are largely inaccurate with typical use, as most people don’t use the amount that they should.
UVA (Ultraviolet A) and UVB (Ultraviolet B) are the frequencies of solar energy that cause damage to our skin. UVB is the more shallow penetrating ultraviolet radiation that causes sunburn and DNA damage. UVA, while it does not cause a sun burn, is the UV radiation associated with tanning. UVA also causes damage to DNA and penetrates deeper into the skin. Tanning is the response of your skin to DNA damage from the sun and is a way to reduce further damage to your DNA.
When it comes to sunscreen there are basically two types.
1: The chemical type: these are the active ingredients such as avobenzone. Basically these work by absorbing ultraviolet rays, mostly UVB, and converting them into heat. My favorite here.
Pros: Effective when used properly and typically more inexpensive. These are the most common sunscreen available.
Cons: Need to be reapplied and typically more greasy. They may not cover or only minimally cover UVA. Look for brands that say “broad spectrum” but be aware that they may not completely protect against UVA.
Of note, you may have heard about sunscreens being damaging to coral. The ones below have been shown to damage coral:
– Oxybenzone (Benzophenone-3, BP-3)
– Butylparaben
– Octinoxate (Ethylhexyl methoxycinnamate)
– 4-methylbenzylidene camphor (4MBC)
- The barrier, reflective, or mineral type: these sunscreens work as the name implies, by reflecting the UV light. These are products that have aluminum, zinc, or titanium oxides. My favorite here.
Pros: Do not need to reapplied unless wiped off, typically less greasy. Reflect both UVA and UVB.
Cons: More expensive. Can sometimes leave a “white film” *But see my post on my favorite sunscreens for my recommendation there.