Do you know what's in your sunscreen?

Melanoma rates have risen 40% in the last decade — and California's numbers are even more concerning. Before you head outside, make sure you know what's in your sunscreen, how it works, and whether it's the right choice for your family.

According to the National Institutes of Health, melanoma rates in the U.S. have risen by 40% in the last decade. The increase is even more concerning here in California. Exposure to UV radiation is the main cause of the most common skin cancers: basal cell carcinoma, squamous cell carcinoma and melanoma. We all enjoy being outdoors on a beautiful sunny day, but practicing sun safety is essential, and that means protecting your skin with sunblock or sunscreen.

What is the difference between sunblock and sunscreen?

Sunblock and sunscreen protect you from the sun in different ways. As its name implies, sunblock literally blocks UV light. It does so by reflecting and scattering the light, so it doesn’t penetrate your skin. Sunblock is generally referred to as “mineral” or “inorganic” because it contains mineral blockers such as titanium dioxide or zinc oxide. Sunscreen, sometimes called chemical or “organic” sunscreen, interacts with UV rays and deactivates them before they can burn your skin. Sunscreens contain ingredients such as avobenzone, oxybenzone and octinoxate.

What is “organic” about sunscreen compared to sunblock?

This terminology can be confusing! In this context, the terms “organic” and “inorganic” come from chemistry classification and have nothing to do with health and wellness. The “inorganic” filters in sunblock are mineral compounds such as zinc oxide or titanium dioxide. Further adding to the confusion, the FDA banned the use of “sunblock” on packaging in 2011 because these products don’t literally “block” the sun. But that certainly doesn’t mean they don’t do a great job of protecting your skin. Organic filters, found in many sunscreens, are carbon-based molecules that absorb ultraviolet light, such as avobenzone, octinoxate, oxybenzone and octocrylene.

Can you tell me more about the ingredients in sunscreen?

In 2017, the FDA took 12 common sunscreen ingredients off the list of products rated “Generally Recognized as Safe and Effective,” (GRASE). Only zinc oxide and titanium dioxide still had enough evidence to remain clearly GRASE. Because they are absorbed by the bloodstream, 12 common chemical sunscreen ingredients were moved into a category needing more safety data. It’s important to understand that this is not a formal ban. The move was due to insufficient research and data, not proof of harm. Below are the chemicals commonly used in sunscreen and the potential drawbacks:

• Avobenzone can irritate sensitive skin, but many dermatologists still consider avobenzone acceptable and effective.
• Fragrance and preservatives are a common trigger for allergic reactions and should be avoided by people with eczema, rosacea or sensitive skin. Fragrance also often contains phthalates, which are known endocrine disruptors. They can mimic or block hormones like testosterone and estrogen and may affect genital development in male fetuses. Phthalates are also possibly linked to low sperm counts in adult men.
• Homosalate is strongly restricted in the European Union due to hormone-related effects at high-level exposure. The restriction ruling determined that homosalate was not safe at the typical 10% concentration. The maximum permitted concentration is now 7.34%.
• Methylisothiazolinone is a preservative many sunscreen manufacturers have stopped using because it is linked to allergic skin reactions.
• Octinoxate showed possible endocrine disruption in animal/lab research and can be damaging to marine ecosystems. You may also find it listed as ethylhexyl methoxycinnamate.
• Octocrylene is a chemical used to stabilize other sunscreen ingredients. It may irritate sensitive skin. Over time, it degrades into benzophenone, a hormone disruptor and possible carcinogen. Many sunscreen and cosmetics companies no longer use this chemical.
• Oxybenzone can cause allergic skin reactions in some people and has impacted hormone activity in some lab and animal studies. This chemical has been linked to lower fertility in men. Its use is also restricted or banned around coral reefs due to damage to the coral. Oxybenzone may also show up on your ingredient list as benzophenone-3 or BP-3.
• Titanium dioxide and zinc oxide are generally regarded as safe when used as lotions. However, these compounds are best used in lotion or cream form, as the spray or powder versions release nanoparticles that can be inhaled.

Which type of sun protection is best?

This is mostly a matter of personal preference. If you’re worried about absorbing sunscreen ingredients through the skin, choose sunblock. It offers slightly better protection and generally does not cause irritation or allergic reactions in people with sensitive skin. If you opt for a mineral compound read the ingredients to look for zinc and/or titanium. And remember that the label won’t actually say “sunblock”.

Don’t like the white, greasy appearance of sunblocks? Sunscreens are clear and easy to apply. However, they are more likely to cause irritation and allergic reactions. They are also absorbed by the skin and end up in the bloodstream. Sunscreens are available as topical creams, sprays and powders. It’s harder to get complete coverage with sprays or powders, especially on windy days, and these can be inhaled or get into your eyes. You may also want to choose unscented sunscreens to avoid allergic reactions to fragrances.

Today, many sunscreens combine physical blockers and chemical absorbers to reduce the downsides of each. Whatever type of sun protection you choose, it should:

• Have an SPF of 30 or higher
• Protect against both UVA and UVB rays
• Be water-resistant
• Be labeled “broad spectrum.” Broad-spectrum products block both UVA rays, which cause dark spots, sagging and wrinkles, and UVB rays, which can cause skin cancer.

Apply sunscreen or sunblock liberally every two hours or after swimming or sweating. Check the label for any special instructions. It’s best to slather on sun protection at least 30 minutes before playing sports, swimming or sweating.

Do not use any type of sunscreen or sunblock on children under 6 months old — just cover baby up and keep them in the shade. Only use mineral sunblock on babies 6-12 months old. If you are pregnant or nursing, consider sticking to sunblock, which is not absorbed into the skin.

Do sunblock or sunscreen keep me from getting vitamin D from the sun?

People sometimes raise the concern that using sunblock or sunscreen interferes with the body’s ability to make vitamin D, which we mostly get from sun exposure. Doctors say this is not the case. In 2018, an international expert panel of physicians and scientists convened for a review titled “The effect of sunscreen on vitamin D.” They concluded that sunscreen and sunblock did not affect vitamin D levels in healthy adults.

What else can I do to protect myself and my family from the sun?

If you’re not planning on swimming or sitting on a beach, opt for clothing labeled with an ultraviolet protection factor, or UPF. Wear sunglasses and a hat, and don’t forget to slather sunscreen or sunblock on your ears, face and neck. Keep an eye on the clock — it’s best to stay in the shade during midday when the sun is most intense.

This article first appeared in the June 2026 edition of the HealthPerks newsletter.