Nicole Kenney
June 20, 2016

Like so many mom’s concerned with both sun protection and the safety of what I use on my children’s sensitive skin, I once looked into DIY sunscreen. The thought is so appealing. I mean, how easy does something like this sound?

-¼ cup shea butter

-2 tbsp. zinc oxide powder (non-nano zinc oxide)

-¼ cup coconut oil

-¼ cup beeswax granules

-20 drops carrot seed oil

-1 tsp. raspberry seed oil

-1 tsp. vitamin E oil

Mix it all up and BAM! You’ve got yourself some sunscreen with an SPF of 30-50…except you probably don’t.

First, let’s assume the oils being used are essential oils. There are no essential oils that meaningfully filter UV rays (Dr. Robert Tisserand). If it’s the carrot seed FATTY oil, then perhaps you’re getting a small amount over SPF coverage (closer to 2-4 SPF). Carrot seed oil is often claimed as having a 38-40 SPF factor. This is based off of a misused and misrepresented 2009 study that you can find here. The formula that many people correlate with carrot seed oil is only identified as HS3 and contains carrot seed, symplocos, and wheat germ (this is an incomplete list of ingredients because the study was only listing the herbal components). Now, some people have done a bit of digging and think they have found the sunscreen that was labeled HS3, Bio Carrot SPF 40 Sunscreen, of which the full ingredient list includes zinc. This is circumstantial of course, but of the known ingredients it was the only one to contain the three mentioned above in its formula. So knowing what we do about zinc, it makes it highly more likely that the SPF rating is derived mainly from the zinc and other possible actives.

Next, while some of these ingredients do provide a small amount of protection you can’t just add up their combined SPFs to get your total rating. It’s, unfortunately, not that simple because some constituents negate or react poorly with others. This study explains why it’s not so easy to just throw some ingredients together and get an effective sunscreen:

“To develop sunscreens with better safety and high SPF, the formulator must understand the physicochemical principle, not only the UV absorbance of the actives but also vehicle components, such as esters, emollients, emulsifiers and fragrances used in the formulation, since sunscreens can interact with other components of the vehicle, and these interactions can affect the efficacy of sunscreens.”

Now like me you’ll probably think, “but what about the zinc oxide? That is a known natural sunscreen!?!” Well, yes, you’re correct. What isn’t commonly known is that zinc oxide is extremely hard to disperse, and keep dispersed, even while using specialized equipment. It naturally acts like a magnet and wants to bond with other zinc molecules. This means that you get clumps, not necessarily visible clumps either but ones that can only be seen under a microscope. What this means is that you have holes in your sunscreen that can actually magnify the sun’s rays as they come through the sunscreen. Without proper equipment it is nearly impossible to create a sunscreen that is properly dispersed and, unfortunately, a blender (even a high powered one) isn’t enough.

Amanda at the Realize Beauty blog has written an incredible article explaining her own journey and process. It is a few years old but was recently updated and she is still active in the comments and answering questions. She is a cosmetic chemist who deals closely
with creating natural sunscreens and has tried many formulations over the years.

One thing Amanda says that sticks out for me is that you may be lucky and hit the sunscreen formulation jackpot on your first try. That’s amazing! If you feel like you’ve got a winner then please have your sunscreen tested. Especially if you plan to use it on children, or take it to market. Laboratory testing runs about $300 per subject and at minimum you’ll want 3 people (sunscreen testing is done in vivo, which means it is tested on living human subjects).




You may be wondering where that leaves you. There are several sunscreens that are natural and HAVE gone through testing to make sure you’re getting the coverage you need. There are a few that I recommend, these all have an EWG rating of 1.

Adorable Baby Clear Baby Sunscreen Lotion, SPF 30+

Badger Baby Sunscreen Cream, Chamomile & Calendula, SPF 30

Butterbean Original Sunscreen, SPF 30

Kiss My Face Organics Mineral Sunscreen, SPF 30

You’ll notice that all of the sunscreens I listed have an SPF of 30. Why not look for higher SPF? It’s a little complicated as you can read over at the Skin Cancer Foundation but simply put, SPF 30 blocks nearly 97% of UVB radiation while SPF 50 blocks approximately 98%. After that, it increases so marginally that it’s pretty much insignificant. Something else to consider is that using such a high SPF tends to make people feel over confident and negligent when it comes to other sun protection measures. Such as, seeking shade and wearing sun protective clothing. Then there’s the false sense of security so we tend to stay in the sun longer without reapplying. With that in mind, it would seem an SPF range of 30-50 is plenty adequate. Remember though, for babies under 6 months of age you want to avoid using sunscreens. Even the natural ones are best avoided. Not only is there concern about infants absorbing sunscreen ingredients through the skin more easily and possible dehydration, there is also the chance of babies licking and ingesting the applied sunscreen. Instead use alternative sun protection like, clothing, hats, seeking shade, and sunglasses.


So while you’re out enjoying the sun this summer, remember DIY doesn’t always equal best, natural is possible but look for something that’s been tested, and don’t forget to keep covered and reapply your sunscreen frequently.