Homemade sunscreens are nonsense. Let’s just start there.
A few years ago, fearmongering became huge in the beauty industry. Although the EWG is technically comprised of scientists, several things that the EWG has said, particularly surrounding sunscreen, were later refuted by dermatologists and other skin care experts. For instance, its claim that retinyl palmitate is dangerous in 2010 got millions of consumers to steer clear of vitamin A in sunscreen. However, in an August 2011 review, Safety of retinyl palmitate in sunscreens: A critical study, published in the Journal of the American Academy of Dermatology, this was altogether refuted. In the report, Dr. Steven Q. Wang, M.D., director of dermatologic surgery at Memorial-Sloan Kettering Cancer Center in New York, explains retinyl palmitate is safe and there is no evidence to prove retinyl palmitate increases the risk of skin cancer in humans.
The reasons? The studies were primarily conducted on animals, not humans. And the studies were on isolates of retinyl palmitate: “Despite the concerns raised by these non-human studies, retinyl palmitate operates within the skin as only one component of a complex antioxidant network,” said Dr. Wang. “For example, when a sunscreen with retinyl palmitate is applied to the skin, a number of antioxidants work together to alleviate the risk of free radical formation seen in these in vitro experiments. If studied on its own – outside of this environment – its antioxidant properties can rapidly be exhausted, allowing the production of oxygen radicals. In these non-human studies, retinyl palmitate was the only compound studied – making the biological relevance of these findings to humans unclear.”
And it goes further than retinyl palmitate. Nowadays, people are using coconut oil, almond oil, raspberry seed oil, and shea butter on their skin as “sunscreens” — yet, nothing could be more damaging to your skin! In fact, New York-based dermatologist Whitney Bowe told MailOnline that making and using your own sunscreen is ‘effectively putting your skin at risk for melanoma.’ (source)
I agree completely – Here’s why.
Raspberry Seed Oil: Not a Sunscreen At All
In the journal Photochemical and Photobiological Sciences, a formulation containing raspberry seed oil was found to permit only 7-9% of UVA and UVB rays through — which means that it has an SPF of approximately SPF 7 to SPF 11.
However, upon close inspection of the oft-misquoted study, it turns out that the researchers weren’t applying pure raspberry seed oil to their faces, arms, and legs. Instead, the researchers were applying “raspberry-oil based nanocarriers” — i.e., a combination of raspberry seed oil, rice bran oil, and, most importantly, 3.5% of the chemical sunscreens butyl-methoxydibenzoylmethane and octocrylene — a concentration that isn’t much different than sunscreens you might buy off of the shelf.
I repeat, NOT 100% raspberry seed oil, and not 100% rice bran oil, but a chemical sunscreen composition with both of these ingredients in it. Raspberry seed oil isn’t a sunscreen at all, but rather the other ingredients in this formulation are.
Coconut Oil: Not a Sunscreen, Either
The reason why natural product bloggers will tell you that coconut oil is a sunscreen is because one study cites that coconut oil has a natural SPF of 7 when used in vitro, or in a petri dish (Chanchal Deep Kaur et al.). However, another study uses nearly the same methods and concludes coconut oil would not even have an SPF of 1 (International Journal of Cosmetic Science, 2016).
It should also be noted that both studies examine coconut oil on cells in vitro, or in a petri dish. In order for a chemical to be classified as a sunscreen, it must be applied on human skin in vivo, or on living cells. True SPF can only be measured by applying sunscreen to the skin of a volunteer and measuring how long it takes before sunburn occurs when exposed to an artificial sunlight source. In the US, such an in vivo test is required by the FDA.
Almond Oil: Not a Reliable Source of UV Protection
There one oft-quoted study that demonstrates applying almond oil to the skin before going outside may reduce the risk of sunburn (Journal of Cosmetic Dermatology). However, this study was conducted on mice, not on people.
The truly disconcerting part about using almond oil is also that the UV protective abilities of almond oil depend heavily on its harvest time and storage conditions — really, its UV protective antioxidant properties come down to the source and timing of the oil (Journal of the Science of Food and Agriculture, 2003). Considering that almond oil doesn’t seem to be that UV protective to begin with, with just one singular mouse study to support its use, the fact it isn’t consistent depending on source makes me further skeptical.
Bottom Line
Take it from Joshua Zeichner, MD, a dermatologist in New York, who once explained to Allure that oils ‘can actually absorb light, making UV rays penetrate the skin more.’ Oils are not adequate sun protection.
Look, I get it — I wish that there was a guaranteed-safe remedy to protect your skin (and your family’s skin) from damaging UV rays too. That said, if you put homemade DIY sunscreen oils on your skin, you may actually be asking for sunburns and actually increasing your chances of UV damage. If you are concerned about safety, I highly recommend using zinc oxides and titanium oxides, which penetrate your skin less than chemical sunscreens, and washing them off thoroughly following sun exposure in the evening.