Let’s think about this from a high-level POV. The sun is a bright ball of burning gas. That fire emits a lot of heat and light and ultraviolet (UV) radiation. Said heat, light and radiation hits our little rock a few million miles away and some of it bounces off our atmosphere and some of it enters into our world. If we’re outside in the daylight, that stuff hits our skin, like it has for a long, long time. And the skin understands this! It’s good. Our bodies convert that exposure into Vitamin D, which helps form our bones. The sun and us, we evolved together. Like plants, the sun helps us grow.
Of course, once we are fully grown, we continue to live a long time — longer than ever before! Even past peak reproductive age, we live for many, many more years. As we age, our cells stop trying as hard and sometimes those cells get tired and sloppy with reproducing. That sloppy reproduction contributes to cell mutations, which we call skin cancer.
The Science of Skin Disease
In scientific terms, “chronic exposure to ultraviolet radiation present in sunlight is responsible for the induction of most nonmelanoma skin cancer (NMSC) in humans.” Basically, UV light from the sun causes the skin to “burn” by producing more melanin. The skin works to repair this burn quickly, with new skin cells rising to the surface. The more repairs, the more the repairs may go wrong. DNA damage occurs from this stress and “occasional mistakes during the repair of this damage leads to the incorporation of wrong bases into the genetic material.” These wrong bases lead to mutations.
From this in-depth report, here’s some more bad news: “ultraviolet radiation is classified as a ‘complete carcinogen’ because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter.” And, “UV is epidemiologically and molecularly linked to the three most common types of skin cancer, basal cell carcinoma, squamous cell carcinoma and malignant melanoma.” PLUS, that UV does some visually less-than-desirable stuff to your skin including “atrophy, pigmentary changes, wrinkling and malignancy.”
UV also damages collagen fibers, hurts the skin’s natural vitamin A levels, and leads to less elasticity in the skin. Which, depending on who you are as a person, is maybe not exactly what you want.
What to Watch For
It’s worth noting that where you live, where you’re from, and what you do makes a big difference. Ambient UV exposure varies geographically, with the equator getting the most direct sunlight and highest UV doses. High altitude and places with minimal cloud cover also increase UV exposure — and don’t forget that sand, snow, water and even concrete can reflect UV to increase rates of exposure. Skin pigmentation also makes a notable difference (see the handy Table 1). People whose unexposed skin is brown or black and have dark eyes and hair (typically of East Indian, Native American, Latino, African or Aboriginal descent) are far less at risk for cancer than people with white and fair skin. And, naturally, people who work outside also receive far more exposure and are at a higher risk of skin related diseases.
In the history of humans, we have primarily been exposed to UV radiation though doing things to survive — chasing prey, gathering food and fuel, or building, farming and other work. More recently, as many people work inside structures, our exposure is now more oriented around leisure activities, like going on a hike or to the beach. Overall, this means less UV exposure. And, with education and proper skin safety, you can reduce harmful effects significantly. In the lab, UV protection does work. It’s just a matter of following best practices in real life.
Best Practices of Sun Protection
The word to focus on here is “strategy.” Have a sun protection strategy. Good SPF is not the cure all. A strategy ensures there’s not a false sense of security from one aspect. It needs to be a holistic approach. Here are a few best practices of sun protection:
- Cover up. Clothing, hats, sunglasses — the better covered you are, the less UV hits your skin.
- Stay in the shade. Umbrellas, trees, indoors — staying out of direct sunlight is a great way of reducing UV exposure.
- Limit exposure. Keep direct sun exposure short — and avoid peak UV times (between 10:00am and 4:00pm).
- Wear a broad spectrum sunscreen of at least 30 SPF — and re-apply throughout the day if consistently outside.
- Apply everywhere that’s exposed to the sun — don’t forget the ears, neck, scalp, hands and feet.
Broad spectrum sunscreen protects against both UVA and UVB rays. Here’s the UVA vs UVB shorthand: UVA are far more prevalent than UVB and penetrate deeper into the skin. UVA rays can lead to skin damage that includes tanning and premature aging and wrinkles. UVB rays affect the surface of the skin more, causing sunburn and playing a key role in developing skin cancer. Use a broad spectrum SPF. They’re widely available. And they protect better.
As for the number on an SPF, that refers to the time the UV radiation would take to burn or redden your skin versus if you left it unprotected (given that you use the product correctly). A perfect application of SPF 30 would keep you from burning 30 times longer than zero sunscreen. It also means that an SPF 30 allows about 3% of UVB rays to hit your skin. SPF 50 allows 2% — an increase of 50%. But keep in mind, this is for ideal conditions and real-world application can be less than ideal (you may apply too little or it may be rubbed off). Re-application is key, every two hours or after swimming or sweating. And reapplying is not only to boost areas the sunscreen strength may have waned or have been washed off, but also because reapplication typically involves a more thorough area covered — you hit spots you may have missed the first time. Still, don’t forget the entire strategy. Don’t simply use a higher SPF and avoid other precautions. Use a high-SPF and follow a complete strategy and then you’re working with best-case-scenario sun protection.
Why We Don’t Have a Moisturizer with SPF
The main reason here is that you should use a moisturizer and SPF differently. In a perfect world, you use a good moisturizer and a good SPF and you use each correctly. Moisturizer and SPF are different products for different jobs. A hybrid is better than nothing, but it's not the best approach for your skin — and we’re in the business of the best approach for your skin.
You should apply moisturizer in the morning after you shower and/or cleanse. You don't really need to reapply throughout the day. Then, before you head into the sun, apply a sunscreen. If you work from home and you're not sitting by a window, you don't need to apply sunscreen until you go outside. While for skin cancer purposes the rule is better-safe-than-sorry, for skin health purposes, it’s better to avoid applying unnecessary ingredients to your skin if you don’t need them. If your commute is sunny, then put on sunscreen — and reapply before you head out in the sun later in the day. Apply to your arms, neck, ears and hands — anywhere you have sun exposure.
The other reason is that we use different moisturizers and different sunscreens for different purposes. In winter, a more robust moisturizer may be best for your skin — not a mild moisturizer + SPF hybrid. And in a humid summer, you may want to skip a moisturizer and focus only on a serum. For daily use, a nice, light SPF 50 may be best for your face. But if you’re going hiking, you’ll want to apply a sweatproof sunscreen. Different tools for different purposes. A hybrid can make you lazy — and lazy is not great when the quality and health of your skin is at stake.
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