Co-Authored by Janis Leahy
Sunblock. Sunscreen. SPF. It’s all over the news right now as so many companies have been questioned about the safety of their products, and now the FDA is being petitioned to investigate more chemical sunscreen ingredients. But it’s one of the hottest, sunniest times of the year. We’re swimming, hiking, and playing outdoors for extended amounts of time, which – we hope – has you reaching for sunblock.
Sun protection is such a huge category in skincare, and it’s arguably the most important. We are proponents of using it every day, not just during summer outdoor activity. So we felt it was the perfect time to address all your questions around SPF like:
- What’s the difference between UVA & UVB rays and what is broad spectrum?
- What’s the difference between chemical sunscreen and physical/mineral sunblock?
- What does SPF 100 even mean & do you really need such a high number for effective protection?
- What are the hormonal and/or environmental impacts of the SPF formulation you’re putting on?
The Difference UVA & UVB Rays
To understand one of the primary differences of chemical sunscreen and mineral sunblock, it helps to familiarize with the different types of UV Rays. Here in the northern hemisphere we have 2 types of UV rays to contend with when spending time in the sun: UVA and UVB.
UVA rays have a longer wavelength and are most associated with accelerated signs of aging, such as hyperpigmentation, hardening of the skin, and fine lines & wrinkles.
UVB rays have a shorter wavelength and cause sunburn, and are more commonly associated with skin cancer. It’s why chemical sunscreen primarily addresses UVB rays.
However, while we do need some sun exposure to properly synthesize vitamin D, ALL UV rays are associated with increased risk of developing skin cancer. During time in the sun, you are exposed to 500 times more UVA rays than UVB. To properly prevent sun damage, use a broad spectrum SPF daily (broad spectrum means it fights both UVA & UVB rays) – especially during extended exposure. We’ll talk more about broad spectrum SPF later in the article.
The Difference Between Chemical Sunscreen and Physical/Mineral Sunblock
With the exception of Avobenzone, Chemical SPF only protects against UVB rays (whereas all Physical SPFs are broad spectrum). Additionally, the effectiveness of chemical sunscreen diminishes over time. Why? Chemical sunscreen is composed of chemicals that take UVB rays and convert them into heat. During this conversion, chemical sunscreen oxidizes & destabilizes, and through that process loses about half of its potency every hour. This means if you put on an SPF50 at 10AM, by 12PM your protection level has fallen to about an SPF 10, and you must reapply. Furthermore, Chemical SPF degrades in the bottle, so if you’re using a bottle from last summer, there’s no way to tell how effective it still is.
Last, the chemicals used in sunscreen have been linked to hormonal disruption, triggering skin inflammation and acne, and many have been banned in Hawaii and other island nations/cities due to the destruction they cause reefs. Because of the health risks to both humans and the environment, MADEWITH does not sell any products containing chemical sunscreen.
Chemical Sunscreen Examples
- Padimate O
- Para-aminobenzoic acid
- Trolamine salicylate
- Mexoryl SX and XL
- Tinosorb S and M
- Uvinul T 150
- Uvinul A Plus
Physical sunscreens are inert mineral barriers and work like painting a layer over the skin that helps prevent sun rays from penetrating. Physical sunscreen is broad spectrum and blocks both UVA + UVB rays. Unlike chemical sunscreens, physical sunblocks are not absorbed into skin as long as they’re in a non-nano formulation, which is all MADEWITH carries (we explain nano vs. non-nano below). This type of SPF also protects against HEV light – the blue light emitted from electronic screens – which can also cause damage to the skin. As with any sun protection, it also needs to be reapplied if sweat or water causes that barrier to slide or wash away (it is recommended that you reapply every 2 hours if you are being active and/or going into the water).
- Zinc – Zinc is a chemical element with a grey-blue color. It is an incredibly efficient sunblock beloved by outdoor athletes and surfers. It’s anti-inflammatory properties are well-known and help with treating acne, diaper rash, dermatitis and other inflammatory disorders. It is one of only 2 ingredients approved by the FDA to provide both UVA and UVB protection.
- Titanium Dioxide – This chemical compound is produced by crossing oxygen and titanium. It functions in cosmetics as both an effective sunblock and source of white pigment.
We spoke with Cassie Beisel, Senior Advocacy Officer at the Melanoma Research Foundation, and a Stage IIIc melanoma survivor who shared this article that says “1. Wear sunscreen every day… even on cloudy days – Use a broad spectrum sunscreen of at least SPF 30. “Broad spectrum” means that the sunscreen protects against both types of UV radiation – UVA and UVB.” 
SPF Ratings & Water Resistance – How Much is Just for Marketing?
SPF 30, 60, 100 – what does it mean? Simply put, it’s the multiplier of seconds it takes you to burn. For example, if it takes you 1 minute to burn without SPF, an SPF 30 should protect you for 30 minutes. But there are many other factors that come into play when that’s being calculated such as how well you’re applying, the time of day, etc.
As a general rule it’s recommended to wear a non-nano Zinc or Titanium based SPF every day to get broad spectrum protection. For daily wear, an SPF 20-30 is recommended. For extended exposure and outdoor sports, it’s recommended to wear an SPF 30-50. Anything over 50 really has very little improved protection. The SPF rating system is sadly convoluted. It’s so convoluted, that the US Surgeon General has recommended that the FDA change the SPF rating scale. Proposed future legislation includes a scale that does not exceed SPF 60.
Waterproof vs. Water-Resistant
This is another marketing ploy. There is nothing made for personal care in the entire world that is truly waterproof. This language offers a false sense of security when using a product, especially for sun safety. Furthermore, “water” generally means plain old purified water, and doesn’t account for heavy chlorine, salt, or solvents. This goes for sweat-proof too. It’s probably more appropriate to call them water-resistant or sport-resistant.
Please reapply every 80 minutes for optimum protection. It might seem like a lot, but it might mean the difference between safer sun exposure and dangerous squamous cell damage (which can lead to cancer); not to mention, the difference between looking and feeling like a boiled lobster or just needing a little extra body lotion after your shower that night.
Hormonal and/or Environmental Impact of the SPF Formulation You’re Using
Prime tourist destinations with delicate reef systems like Hawaii, Aruba, Mexico, The US Virgin Islands, Palau, Bonaire, and Key West are banning chemical sunscreens. Why? Because there are different studies linking damage to corals and/or the flora & fauna that make them their home. Chemical SPFs can cause hormonal damage to fish in lakes and streams too, triggering birth defects or breeding issues, in addition to potentially disrupting the ecosystem.
Hormonal Impact in Humans
Have you ever heard someone say they can’t use SPF because it breaks them out, makes them oily, or causes an allergic reaction? This is almost always due to a hormonal response to chemical SPFs. Zinc acts as an anti-inflammatory, and is unlikely to trigger sensitivities in most people (that’s why you see incredibly high percentages of it in diaper rash treatments).
Nano vs. Non-nano
Some brands decided the easiest way to get around the problem of the chalkier white cast of mineral formulations was to go small – like super minuscule – nano. Making things incredibly tiny seemed like the perfect way to solve the visibility issue, but the problems that come with this type of formulation are HUGE. These incredibly tiny particles can’t protect you if they’re too small to create a barrier, making them useless as sunblock. Additionally, at that size, they get absorbed by plants, animals, humans, and reefs. We already know that chemicals have environmental and hormonal impacts; breaking down mineral SPF into these tiny particles can cause just as many. When you’re buying mineral/physical SPF, make sure it is non-nano.
In closing, do you really need SPF every single day? You do, especially when it comes to your face. And we recommend it not only to prevent skin cancer, but damage like hyperpigmentation, fine lines, and wrinkles. Sun and light damage is all around us, from your drive to work to the screens we stare at all day. If you wear makeup there are lots of great SPF options that act as primers. If you’re on the oily side there are powder options. If you’re doing heavy duty sports, there’s great formulations specific for you. There’s a formulation for everyone, so make sure to tell your mentor the kind of activities you use SPF for, and they can guide you in the right direction.
To learn more follow the links below:
- The Never MadeWith List: https://info.madewith.com/never-madewith-list/chemical-spf-sunscreens/
- Melanoma Prevention: https://melanoma.org/melanoma-education/melanoma-prevention/older-adult-prevention/