How to make natural sunscreen: why DIY is unsafe

Recipes for homemade sunscreen are easy to find online. A 2020 study sampled 189 posts about homemade sunscreen on Pinterest alone, and a third of them claimed a specific SPF. They appeal to people who want fewer ingredients or a more natural product. The problem is simple: nobody can measure the protection of a homemade mix in a kitchen, and when scientists have tested these recipes in a lab, most gave little protection. This guide explains why sunscreen is tested the way it is, what the studies of homemade recipes found, and what to use instead. It is part of Skinli's guide on how to choose a sunscreen for your face.

Sunscreen is a drug in the United States

The FDA says that in the United States, "sunscreens are regulated as drugs, which means they must satisfy the safety and efficacy standards for nonprescription drug products." The American Academy of Dermatology (AAD) says the same: sunscreen products are regulated as over-the-counter drugs by the FDA.

That status has three practical effects:

1. Only listed active ingredients may be used. The FDA keeps a list of permitted sunscreen ingredients and the strength allowed for each. In 2026 it added one, bemotrizinol, and removed two, PABA and trolamine salicylate.
2. Every claim on the front must be tested. The SPF number, the words "Broad Spectrum" and the water resistance time all come from tests set out in federal rules (21 CFR 201.327).
3. The label must carry set directions and warnings, such as applying 15 minutes before sun exposure and reapplying at least every two hours.

A homemade mix has none of these checks.

How the SPF on a label is measured

The SPF test is done on people. Under 21 CFR 201.327:

• A panel of volunteers takes part, with enough people to give at least 10 valid results.
• Sunscreen is spread on marked areas of each person's back at 2 milligrams per square centimeter. That is a thick, even layer.
• After at least 15 minutes, the areas are exposed to measured doses of light from a lamp that copies sunlight.
• The tester compares how much light causes redness on protected and unprotected skin. A standard sunscreen of known strength is tested at the same time to check the method.

The "Broad Spectrum" claim needs a second test. The sunscreen is spread on roughened plastic plates, exposed to light first to see whether it breaks down, then measured across the whole ultraviolet range. The rules state that "the accuracy of the test depends upon the application of a precisely controlled amount of sunscreen product with a uniform distribution."

None of this can be copied at home. A kitchen scale and a mixing bowl cannot tell you how much ultraviolet light gets through a layer on your skin.

What happened when homemade recipes were tested

Two studies looked at homemade sunscreen directly.

A lab test of 15 internet recipes. In a 2021 study in the Journal of Cosmetic Dermatology, researchers in France chose 15 sunscreen recipes from the internet and made each one in a laboratory following its instructions. Then they measured the protection. The abstract reports: "Three of the 15 recipes studied do not contain any sunscreen and therefore constitute a major risk for users in case of exposure to the sun. The other 12 cannot be considered as sun protection products since all of them have an SPF under 6." SPF 6 is the lowest value allowed for a sun protection product in Europe. The authors' conclusion was blunt: the recipes are dangerous, because some give no protection at all and most do not give enough.

A study of Pinterest pins. In a 2020 study in the journal Health Communication, researchers searched Pinterest for "homemade sunscreen" and "natural sunscreen" and studied 189 pins. They found that 95.2 percent described homemade sunscreen as effective, and 68.3 percent recommended recipes that "offered insufficient UV radiation protection." A third of the pins claimed an SPF, ranging from SPF 2 to SPF 50. Some pins had been saved more than 21,000 times. The authors stated the core issue in their abstract: homemade sunscreen products "are not regulated or tested for efficacy like commercial sunscreens."

So the SPF claims in online recipes are guesses. The one lab test of such recipes found none reached SPF 6, while the AAD recommends SPF 30 or higher.

Why adding zinc oxide at home is not enough

If a recipe calls for zinc oxide powder, it is using one of the two ingredients in mineral sunscreen, and it is a real sunscreen ingredient. But the amount of protection depends on how much of it is in the mix, how well it is spread through the cream, and how evenly the cream covers the skin. A clump in one spot and a thin patch in another give uneven protection, and there is no way to see this with the eye.

Store-bought mineral sunscreens are made to a tested formula. The FDA has proposed that sunscreens with zinc oxide or titanium dioxide, at up to 25 percent, are generally recognized as safe and effective. That finding applies to a product whose protection has been measured.

Water, sweat and a homemade mix

Store-bought water-resistant sunscreen is tested in water too. Under 21 CFR 201.327, volunteers wear the sunscreen in a pool or hot tub for 20-minute periods of moderate activity, with rests out of the water, for a total of 40 or 80 minutes in the water. Only then is the SPF measured again. A product that keeps its SPF through that test may print "Water Resistant (40 minutes)" or "(80 minutes)."

A homemade mix has no such test. You have no way to know whether it stays on for five minutes in the sea or washes off at once. The FDA says "all sunscreens eventually wash off," even tested ones.

Buying sunscreen online or from abroad

The same caution applies to products that skip the U.S. rules. The FDA says some countries regulate sunscreen as a cosmetic, and advises reading the label of any sunscreen bought outside the U.S. "to understand any potential differences." The FDA also lists the forms of sunscreen that can be legally sold in the U.S.: lotion, cream, stick, gel, oil, butter, paste, ointment, spray and powder. It says sunscreen in other forms, including wipes, towelettes, body washes and shampoos, "cannot be legally marketed."

What about aloe vera, oils and other "natural" ingredients?

No source Skinli read shows that aloe vera, coconut oil or other kitchen oils give reliable protection from ultraviolet light. None of them is on the FDA's list of sunscreen active ingredients. The AAD mentions aloe vera only for after the damage: it suggests a moisturizer with aloe vera or soy to soothe a sunburn.

If you are drawn to homemade sunscreen because you want a natural product, the closest tested option is a mineral sunscreen whose only active ingredients are zinc oxide, titanium dioxide, or both. Our guide to mineral vs chemical sunscreen explains the difference and where each ingredient stands with the FDA. If your worry is safety, see our guide on whether sunscreen is bad for you.

If you have already used a homemade sunscreen

If you used a homemade mix and your skin turned red or sore, treat it as a sunburn. The AAD suggests getting out of the sun, cool baths or showers, a moisturizer with aloe vera or soy, and drinking extra water. Do not pop blisters; the AAD says blistering means a second-degree sunburn.

See a doctor for a large area of blistered skin, or a sunburn with fever, chills or a headache. The FDA says severe sunburn should be treated as a medical emergency.

For future days outside, switch to a tested sunscreen and use enough of it. The AAD suggests at least 1 teaspoon for the face, enough to cover the length of your index and middle fingers, and reapplying every two hours outdoors. Our guide on how often to reapply sunscreen covers the timing.

What to look for instead

Choose a store-bought sunscreen with these words on the label, as the AAD recommends:

• Broad Spectrum
• SPF 30 or higher
• Water Resistant (40 or 80 minutes)

If you have acne-prone skin, add one more: non-comedogenic, which means the product is made so it does not clog pores. Our guide to sunscreen for acne-prone skin explains why, and Skinli's sample plan shows where sunscreen goes in a morning routine.