In the world of sunscreens, we talk about chemical vs. mineral protection. Lets talk about both.
Chemical
(avobenzone, octisalate, octocrylene, oxybenzone, octinoxate)
Chemical UV blockers offer UV protection by penetrating into your skin and then absorbing the UV radiation from the sun and converting it into heat. Recall that the sun emits UV-A radiation, which is associated with photoaging and melanoma, and UV-B radiation, which is more associated with burns, melanoma, basal and squamous cell skin cancers. The most common chemicals available in the US used include azobenzone (absorbs UV-A), octisalate (UV-B), octocrylene (UV-A & UV-B), oxybenzone (UV-A & UV-B), and octinoxate (UV-B).
Chemical based sunscreens tend to be more cosmetically elegant than mineral based sunscreens because they can be absorbed with minimal residue left on the skin. The downside is that this absorption can lead to unintended consequences. Most notably, they have possible hormonal effects that could cause changes in our endocrine system. They are also being increasingly detected in waterways with possible negative consequences to ecosystems and drinking water.
A study that was published in the JAMA in 2019 showed that when we apply sunscreen to our entire body we absorb more of the active chemical ingredients than we thought AND we don’t know what that means. It does not mean that chemical sunscreens are bad for us, just that our blood levels of the active chemical are higher than we thought or previously identified as safe. We need additional studies to show that even at higher levels, these chemicals are still safe. The FDA has asked sunscreen companies to do this and those studies are going on now.
Physical or Mineral:
(zinc and titanium)
These work by creating a physical barrier on the skin's surface to reflect and scatter UV radiation from the sun as well as absorbing UV. The main minerals used for this are zinc oxide and titanium dioxide. Mineral sunscreens are considered non-toxic and have the advantage of well-documented safety and effectiveness. They are the only sunscreen ingredients in the United States labeled as Generally Recognized As Safe (GRAS). They are also more photostable, meaning they remain effective longer when exposed to sunlight unlike many chemical sunscreens, which start to break down as soon as they are exposed to UV. They still need to be reapplied every two hours.
Generally considered to be gentle on the skin, they are less likely to cause irritation or allergic reactions compared to chemical sunscreens. They are also less likely to cause irritation or allergy than chemical UV blockers making them more for sensitive skin and children. Zinc in higher percentages (over 10%) offers broad spectrum protection against both UVA and UVB. Titanium provides UVB protection. Made from naturally occuring minerals, physical sunscreens are more environmentally friendly. The downside is they can be less cosmetically elegant by leaving a white residue on the skin and contributing to block pores.
Combination
These contain both chemical and physical blockers that have historically be called out in the active ingredient list. But there is a newer category of these sunscreens in the US that feature zinc oxide as a key ingredient, claim 100% mineral but include chemical UV blockers as well. These are included to reach a higher SPF claim and make the zinc more spreadable. Historically, both types of UV blockers (chemical and physical) were highlighted on the active ingredient list, but more recently, this somewhat controversial step of sunscreen "doping" is happening where chemicals are being included in mineral sunscreens that are nearly identical to the regulated chemical filters but are not being disclosed because they are not regulated in the US. Ingredients to look for include butyloctyl salicylate (nearly identical to octisalate), ethyl ferulate (similar to octocrylene), diethylhexyl syringylidenemalonate (octinoxate) and tridecyl salicylate (octisalate). The take home point is when you are trying to avoid chemical sunscreens, look out for these ingredients even if the sunscreen says 100% mineral sunscreen.
Remember: Any sunscreen is better than no sunscreen! Find the right one for you and use it. Understanding the differences between mineral and chemical sunscreen can help you decide which is best for you and your skin.
|
Mineral Sunscreen |
Chemical Sunscreen |
|
|
Active Ingredients |
Zinc Oxide; Titanium Dioxide |
Avobenzone, Octisalate, Octocrylene, Oxybenzone, Octinoxate |
|
Method of Protection |
Forms physical barrier that reflects and scatters UV rays away from the skin and absorbs UV to convert into heat. |
Converts UV radiation into heat which then dissipates from the skin |
|
Effectiveness |
Immediately effective upon application |
Requires approximately 15 to 30 minutes to become fully effective after application |
|
Skin Sensitivity |
Well-tolerated by those with sensitive skin |
Higher risk of allergic reaction and may worsen melasma or rosacea |
|
Bodily Impact |
Can leave a white cast and may contribute to breakouts in people prone to acne |
Oxybenzone, octinoxate and homosalate have all been shown to accumulate in the body over time |
|
Environmental Impact |
Considered reef and earth-friendly |
Accumulate in waterways and linked to coral reef damage |
I prefer mineral sunscreens that contain zinc oxide. Zinc provides protection against both UVB rays that cause burns and UVA rays that are longer, come through windows and cause brown spots and wrinkles. It has a reputation for being thick and white, making people look ghost-like, but now many of the sunscreens with zinc are cosmetically elegant. Unlike the chemical sunscreen ingredients, zinc is a natural mineral and not absorbed by your body. Titanium dioxide is another good physical sunscreen but it only protects from UVB rays, so products need to have both titanium dioxide and zinc oxide to provide broad spectrum protection.
As sunscreen should be an important part of your skin care routine you will need more than one product. I recommend having several:
- A daily face sunscreen that can have tint.
- A powder sunscreen for easy reapplication during the day.
- A body sunscreen for neck, chests, arms during summer days at work.
- A sunscreen that is water resistant for exercise and water play.
If you do get a sunburn, our Restore Healing Balm can help soothe redness and help the recovery process. For a full list of my sunscreens check out this blog.
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References
https://www.aad.org/public/spot-skin-cancer/learn-about-skin-cancer/prevent/is-sunsceen-safe
Researchers Say Oxybenzone Kills Baby Coral And Contributes To Reef Decline.
Reuters (10/21, Liston) reports that a study published Oct. 20 in the Archives of Environmental Contamination and Toxicology suggests that oxybenzone, a chemical commonly found in sunscreen that filters UVA and UVB rays, kills baby coral and is implicated in global coral reef decline. The chemical, which acts as an endocrine disruptor, also increases coral’s susceptibility to bleaching. According to the American Academy of Dermatology, no data exist demonstrating that the chemical is hazardous to human health.
Note: Heather D. Rogers, MD is not sponsored or financially compensated by any brands she recommends. Her recommendations are thoroughly researched, focusing on effectiveness and safety. She prioritizes your skin and health over external pressures or personal gains.
