Katherine Martinko is an expert in sustainable living. She has a degree in English Literature and History from the University of Toronto.

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This is one of the rare periods when we tell you that store purchase is better than homemade!

At TreeHugger, we are loyal supporters of natural skin care products and cosmetics, but not at the expense of severe sunburn. When it comes to sunscreen, whatever Pinterest tells you, it's best to avoid homemade mixtures. This ideal lifestyle site for women is full of homemade sunscreen formulas, but according to a new study just published in the journal Health Communication, these are just formulas for sunburn and skin damage.

Researchers analyzed 189 randomly selected pushpins from Pinterest and found that 95% of them “portrait the effectiveness of homemade sunscreen positively,” while 68% recommended formulas with insufficient SPF protection. Only 35% of the ingredient list contains zinc oxide. Many people claim that its SPF value comes from ingredients such as coconut, raspberry, carrot, olive oil and lavender oil, shea butter and beeswax, all of which have an SPF value below 15. .

According to a detailed article by the Natural Skin Care Institute, homemade sunscreen does not work for many reasons. First, base oils do not have enough SPF levels to provide adequate sun protection, and it is claimed that they are indeed misunderstood because of scientific research.

There are two methods to measure UV absorbance. One is "in vitro", which measures the amount of ultraviolet light absorbed by a certain material (in this case, the carrier oil). The other is "in vivo", which measures "the skin's response to ultraviolet light (redness or erythema), and the amount of ultraviolet light that appears on the skin treated with sunscreen and untreated skin." The latter, in The body is the best test for sun protection.

Second, zinc oxide does not automatically provide sun protection.

After mixing, it clusters together under the microscope, which means it looks smooth and blended, but it actually leaves a space on the skin to burn.

Third, the SPF level needs to be tested to understand what you have applied to the skin.

These are usually carried out on volunteers in the form of in vitro tests and final SPF determination tests. Unless you have these numbers, it is impossible to know how much protection you are truly protected, and eventually you will "play Russian roulette with your skin".

The best and safest option is to buy FDA-tested (and EWG-approved) sunscreens that contain physical sunscreen ingredients such as titanium dioxide or zinc oxide. There are many great products on the market today that can do this job well. In any case, take the time to perfect other DIY skin care recipes, but don't let yourself suffer possible skin damage, and leave the sunscreen making to a professional.

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