Let's talk about DIY sunscreen
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As someone who is in the business of making soaps, salves and deodorants, I sometimes get asked if I offer any sunscreen products. I've been on the all natural train for a while and am not afraid of a little chemistry, so many years ago, I did try my hand at homemade sunscreen.
Do DIY Sunscreen Recipes Work?
In short no, or at least not consistently enough to depend on them for real sun protection.
I tried many different sunscreen formulations, mostly recipes that featured zinc oxide as the main SPF-providing ingredient. There are many zinc oxide sunscreens produced commercially with great SPF ratings, so I figured it must be something I could make at home! Since I have very pale skin, I have the advantage of being an excellent test subject for sunscreen. But no matter how dedicated I was to consistent reapplication, these sunscreens never seemed to work for me. I was always getting burnt.
So I hit the internet again to find out what was going on. Why did commercial zinc oxide sunscreens work but mine didn't?
A Stick Blender Just isn't Going to Cut it
It turns out that an effective sunscreen is about more than just the ingredients. How the ingredients are mixed has a huge impact on how much sun protection the product can provide. Michelle Wong is a cosmetic chemist with a chemistry PhD who runs the website Labmuffin Beauty Science. Her article: Fact-check: Don't Get Burnt by DIY Sunscreen [1] gives a great explanation about how it just isn't possible to achieve reliable, consistent SPF protection with homemade formulations.
Commercial mineral sunscreens (zinc and/or titanium oxides) are mixed with specialized machinery that makes sure the minerals are evenly and smoothly mixed, down to a microscopic level (and no, we're not talking about nano minerals here). Without this specialized mixing, the minerals will clump in ways that may not be visible to the eye but result in inconsistent protection from the sun.
Another article by cosmetic chemist Amanda Foxon-Hill details her experiments with homemade sunscreen recipes [2]. To have a certified SPF rating, products must go through third party testing, which can be expensive. Foxon-Hill lab tested several of her formulations and each time the actual tested SPF was much lower than the recipe claimed and often inconsistent batch to batch, even with the same recipe.
After several years of recipe testing and investment in some specialized equipment, Foxon-Hill was able to create several different products with SPF ratings consistently around 15, which I think is a great accomplishment! However, I think it just further proves the point that this is not something you can easily achieve at home with a recipe you found online.
But I Make My Own Sunscreen and I Don't Get Burnt!
The problem with using "do I get sunburned?" as the marker of whether or not a sunscreen works, is that much of the sun damage we should be concerned about is not visible as a burn. The sun has two types of skin-damaging radiation that we should be concerned about, UVA and UVB rays. UVB rays cause burns, tanning and some DNA damage to skin cells. [3]
UVA rays don't cause visible burns but they penetrate the skin more deeply and exposure over time causes DNA damage in your skin that can result in melanoma and other skin cancers (as well as accelerating wrinkles and visible skin ageing). And while paler skin tones will alert you to UVB over exposure by burning, you won't know that you've gotten too much UVA exposure until your first visit to a dermatologist for that funny looking mole...
So even if you've managed a homemade sunscreen that protects you from visible burns, without testing there's no way to know if it's effectively blocking UVA.
But I Don't Even Need Sunscreen Because I Don't Burn!
Let's be honest, most people are more gifted in the melanin production department than I am! If you have a darker skin tone or tan easily, you may be tempted to ditch sunscreen altogether. But skin damage still happens, even if you don't burn.
Darker skin is still subject to cancer risks, premature aging and hyper-pigmentation as a result of sun exposure, even if you never visibly burn [4]. While tanning is your skin's reaction to UVB damage and melanin provides some protection from UVB rays, it does nothing to stop UVA.
If you can't find an SPF tested natural sunscreen that you like, remember that no matter what the latest online scaremongering may say about this and that ingredient, the leading cause of skin cancer is THE SUN. Damage to your cells' DNA from UV rays is far worse than anything possibly caused by a chemical UV blocker or a preservative.
At the same time, sunscreen shouldn't be your only protection from the sun. I spend a lot of time outside in all seasons and I am a big fan of hats, sunglasses, and long sleeves/long pants, even in the summer! Sunscreen isn't perfect but neither are hats and long sleeves. The more layers there are to your sun protection, the more complete that protection will be. Have you ever looked at the UV index on your weather app? Most people will burn in a UV index of 3 or higher (and that number can be increased by water and snow reflection).
Where to Find Good Natural Sunscreens
(UPDATE March 2026: Turns out the idea of "reef safe" sunscreens may actually be based on bad science! Read more here: https://labmuffin.com/is-your-sunscreen-killing-coral-the-science-with-video/)
There are a lot of good natural sunscreens out there that are SPF tested. A great logo to look for is "reef safe" sunscreens. These are free of various sunblock chemicals that can cause coral bleaching, including the nano versions of zinc and titanium oxide. (The non-nano versions of these minerals are safe for people and coral and work very well)
Sunscreens that come in metal tins or cardboard push-up tubes are great for reducing plastic waste, though this type of packaging can sometimes be hard to find.
Healthline has a round up of the best sunscreens for dark skin. (If you are looking for a natural option, look at the products labeled "mineral" rather than "chemical".)
The Environmental Working Group (EWG) also has a great sunscreen guide. This organization maintains an excellent database about the safety of consumer product ingredients. The more I read about skin care from sources with backgrounds in chemistry and medical research, the more I hear that the EWG are more into scaremongering than actual research. In fact they have a "EWG seal program" that they profit from, so are they really a neutral source of information? Or are they using fear-based marketing to drum up support for their product? Check out some thoughts on EWG here: https://www.theecowell.com/blog/ewgsunscreenguide
References:
[1] https://labmuffin.com/fact-check-dont-get-burnt-diy-sunscreen/
[2] https://realizebeauty.wordpress.com/2012/12/30/the-trouble-with-making-your-own-sunscreen/
5 comments
Great to hear that your melanoma hasn’t returned! I would however be very cautious in depending on dietary changes to protect you from the sun. Especially when the source for this type of advice is often (though not always, unfortunately) someone with no medical or cancer research background. There will always be individuals who, for example, smoke their whole life but don’t get lung cancer. This doesn’t change data that is based on large populations.
Sun exposure absolutely increases risk of skin cancer and blocking UV rays with a combination of shade, clothing, sunscreen and avoiding high UV index times is the best way to reduce the risk. This idea is ingrained into the culture in Australia, for example, and they have actually managed to reduce melanoma rates in their population over the past several decades, likely due in part to their “Sun Smart” preventative program: https://www.cancer.org.au/about-us/policy-and-advocacy/prevention/uv-radiation/related-resources/skin-cancer-incidence-and-mortality
Here is great article (with link to a video version if that’s more your thing) from an Australian science educator and chemistry PhD answering some common questions about sunscreen https://labmuffin.com/answering-almost-all-your-sunscreen-questions-with-video/
She also has a ton of great articles addressing sunscreen myths: https://labmuffin.com/sunscreen-myth-directory/#more-15882
Caroline, you are correct, thanks for catching my mistake! UVB causes burning and tanning, while UVA is the main culprit in skin cancer, wrinkles and ageing. I’ve corrected the article to reflect this.
I thought it was UVB that caused burns – https://www.paulaschoice.co.uk/the-difference-between-uva-and-uvb-rays
Very interesting read – thank you! Diet has a lot to do with burning as well. I first heard about a drastic change in tendency to burn from Tucker Goodrich. I tried it myself and have since seen many others say the same – stop consuming high amounts of linoleic acid (which oxidizes easily) and you’ll stop burning. High amounts of linoleic acid are found in seed oils. So this is my main “sunscreen” now. I had melanoma at 21 (I’m very pale, freckled, lots of moles, red hair). Funny thing is I was wearing sunscreen daily then! I’m 44 now and the melanoma never came back, but my diet changed a lot since my mid-20s (so much more red meat, for one thing – and I removed seed oils from my kitchen at 29). My skincare routine also consists of next to nothing now, but when I was 21 I used many products. Go figure, eh?
As always, very informative. I like your articles because they are informative without being too long.