SPF - Sun Protection Factor
Physical (Mineral) Sunblock made with Zinc Oxide is the best and cleanest SPF option.
Broad Spectrum SPF 30 or higher is the best sunscreen choice as it protects against UVA & UVB rays.
Zinc oxide works well in preventing hyperpigmentation & melasma.
Terms
Broad spectrum - means it protects against UVA & UVB rays.
Water resistant - is suitable if your going in the water, but no product is waterproof. You must reapply all sunscreen every two hours to avoid getting burnt.
Tips
Don't forget
Protect your lips, ears, hairline, neck, top of feet, ankles, back of hands, lower eyelids, and upper lip area.
Touch up - you must apply every 2 hours when you’re out in the sun.
Always apply SPF under makeup. Moisturizers or foundations with SPF are a good idea. Power touch-up with SPF works well over makeup.
Lips - avoid lip products with a shiny finish when out in the sun; they tend to attract more sun rays.
SPF’s over 50 add in more chemicals, and it gives a false sense of protection.
You should always patch-test sunscreen before applying it over your whole body if you have sensitive skin, especially with kids.
Don’t sock pile sunscreen; they lose their abilities over time - always check expiration dates.
How much SPF do you need?
The two-finger technique is a good rule of thumb - make a peace sign on those two fingers, put SPF down the length of each finger apply it to your face; that should be just the right amount for all your body parts, neck, arms, etc.
Types of Sunscreen
Physical - Mineral based
It sits on top of the skin and reflects the sun's rays and UV.
Contains active ingredients such as titanium dioxide and zinc oxide, these minerals help deflect UVA and UVB rays.
It works right away.
Not damaging to the coral reef can be used in Hawaii.
Chemical
It absorbs the sun's rays and acts like a sponge.
When applied, it triggers a chemical reaction that absorbs the sun's rays and turns them into heat before releasing it from the body.
Some other ingredients have been linked to endocrine disruption - CDC has noted oxybenzone for links to endometriosis in women and lower testosterone in teenage boys.
It needs to be applied more often because it break’s down more with UV light.
UV filters from chemical SPF, usually Oxybenzone, Octinoxate, Homosalate, Octisalate, Octocrylene, and Avobenzone, can stay in the body for a long time. They have been shown to end up in breast milk and urine.
Oxybenzone can bleach coral reefs.
Issues with sunscreen
You apply this to yourself everyday, if you go out in the sun. So it's super important to have effective and clean products, so you're not continuously dousing yourself in hormone-disrupting chemicals.
The problem with sprays - is they can contain benzene or even safe ingredients like titanium dioxide that can be okay when applied to the skin in lotion form yet become carcinogenic if inhaled. Lungs have trouble clearing small particles, and they can pass from the lungs into the bloodstream. If you do want to use sprays, try to spray them outside.
The issue with Nano sunscreen - They need to be studied more. They are often used to reduce the white cast of SPF. Some studies have shown that nanoparticles can be absorbed through the skin and have a toxic effect.
What to avoid
Oxybenzone - contributes to coral bleaching and is an endocrine disruptor.
EWG recommends avoiding - oxybenzone, homosalate, oxalate, and retinyl palmitate as they are hormone disruptors.
Avoid Benzene - unsafe at any level. It's in sun sprays, lotions, and gel-based products it's recognized as a carcinogen. It has been taken out of most sunscreens but can sneak its way back in.
In general, its safer to stick to mineral-based SPF.
References
https://www.ewg.org/sunscreen/report/does-europe-have-better-sunscreens/
https://greatist.com/health/best-sunscreen#Slather-up!
https://www.aad.org/public/everyday-care/sun-protection/shade-clothing-sunscreen/sunscreen-faqs
