Ask just about any skin expert and she or he will say sunscreen is a non-negotiable essential for healthy skin. While some are still looking at the SPF number as the main factor in choosing a sunscreen, there's so much more than that in choosing truly effective sun protection.
1. Let's Start With SPF
SPF stands for Sun Protection Factor and is a measure of a sunscreen's ability to protect from UVB rays. These are shorter UV rays that cause sunburns (B for burning) and possibly skin cancer. The American Academy of Dermatology recommends at least an SPF 30 for daily wear, which is estimated to provide about 97% of protection against UVB rays. For those with fair skin, an SPF 50 is recommended with an estimated 98% protection. This does noes not mean going with an even higher SPF will block 100% of the sun's rays. There is absolutely no evidence of such.
It's important to know that the same SPF does not provide the same protection for everyone. How can you figure out the length of protection an SPF is estimated to give you? For example, let's say it takes you around 10 minutes for your skin to start to turn red. An SPF 30 is estimated to keep you protected for 300 minutes (10 x 30).
Please remember that an SPF number refers to UVB protection and does not account for UVA protection (A for aging, the rays that goes deeper to cause harm before a burn even shows, including loss of firmness, wrinkles, dark spots...and yes, potentially skin cancer).
2. Broad Spectrum
Make sure you see these two words on the label of your sunscreens. If they are from the U.S., sunscreens should have "broad-spectrum" indicated on labels to indicate that its active ingredients provide protection from both UVA & UVB rays. Even if a sunscreen protect is labeled with high SPF, without the broad-spectrum label, it cannot assure adequate UVA protection.
3. Active Ingredients
Active sunscreen ingredients are considered over-the-counter drugs in the U.S. and there are two categories of approved broad-spectrum active ingredients. The two categories care physical and chemical sunscreens. For today's purposes, I will only be discussing those approved for use in the U.S. I am often asked by clients which is better, and before I give my answer, let me clarify some key differences as well as pros and cons between the two categories.
Physical (or mineral) sunBLOCKS (zinc oxide & titanium dioxide) work by sitting on top of the skin to reflect the sun's rays. These tend to be less irritating for sensitive skin. They also tend to be more stable and do not degrade in the sun as fast as chemical sunscreens. However, many are difficult to blend in the skin and often leave an unflattering white cast. They can rub and/or sweat off easily and many are also very heavy feeling. Depending on what the sunblock is layered with, it can increase potential for breakouts.
Chemical sunscreens approved in the United States (which include avobenzone, octinoxate and oxybenzone) work by absorbing UV rays, converting them into heat, and then releasing them from the body. Chemical sunscreens tend to be more cosmetically pleasing and work well in water- and/or sweat-resistant formulas. Less is needed than physical sunscreens to protect the skin because you don't risk leaving spaces between the sunscreen molecules like with physical sunblocks. However, chemical sunscreens can degrade in the sun faster than physical sunblocks so many people have a false sense of security feeling that they are protected and not reapply. You are advised to wait at least 15 minutes after application of chemical sunscreens before exposure and to reapply every two hours.
I advise not to go by simply a comparison of the percentages of active ingredients to determine if one product offers more protection than another. The amount and quality of protection depends greatly on the supporting cast and how it is stabilized.
So which is the best sun protection to use? If you ask most skin experts, they will likely say either as long as it gets you to use sun protection. I agree. Physical and chemical sun protection does not have to be exclusive from one another, however, as their combination may enhance qualities of the other. My personal favorite is actually a mixture of zinc oxide (physical) and octinoxate (chemical) protection called Hydrative Day UV+ Environmental Defense Moisture Cream Broad-Spectrum SPF 40. Not only does it offer very high FDA approved level of broad-spectrum protection that is super-stable (very important), but it offers superior skin care benefits including lasting hydration, environmental & free radical damage + hyperpigmentation defense with cathepsin G (degrades skin) inhibitors in a patented multi-level delivery system. It has none of that thick, pasty sunscreen appearance and feel, goes on like a luxurious yet light moisturizer (without pore blockers or commonly proven irritants) and helps the skin to look naturally "lit-from-within" immediately and long-term. I have tried many formulas in my years as an esthetician, but since this was developed, I can't go a day without it!
Whatever sunscreen you choose, be sure to apply liberal amounts daily, rain or shine, to protect the health of your skin.