When I first stumbled upon this recipe for DIY sunscreen, I was a little wary because the SPF factor is unclear. But, after researching zinc oxide, I've come to find out that it is the best absorbent of both UVA and UVB light and it is photostable (meaning its chemical breakdown is unchanged upon sun exposure). The good news is that the SPF factor is quite high. The bad news is that it leaves a white mark wherever you apply it.
The original recipe doesn't call for an essential oil, but I've tweaked it a bit. I really like the way that just one drop of a powerful botanical oil can cover up that zinc smell. My pick is peppermint, but I'd also recommend rosemary or lavender. Here's what you'll need:
1 tbsp zinc oxide
1 1/2 tsp light sesame oil
1 tbsp rosewater
1 drop essential oil of your choice
For step-by-step directions on how to make your own sunscreen,
STEP 1: Mix the zinc oxide and sesame oil together in a bowl. Then, heat the mixture in a double boiler and stir frequently.
STEP 2: Next, take the pot off of the stove and slowly stir in the rosewater and one drop of your favorite essential oil. Continue to stir even as the ingredients cool.
STEP 3: After about 30 seconds of stirring, pour everything into a Tupperware container, close the lid tightly and place it in the fridge for an hour (at least) to completely cool and settle. This sunscreen is good for about ten days. After that, I recommend discarding any remains.