Wondering how sunscreen works or which one to choose? You’re not alone. From confusing SPF numbers to new ingredients making headlines, it can be hard to know what actually matters.
Here’s what dermatologists want you to know — including an important new development that could change how you shop for sunscreen.
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“It’s exciting because it protects against both UVA and UVB rays and is more stable in sunlight than older ingredients.”
Allison Lee, MD, dermatologist
A new sunscreen ingredient is making headlines
A recently approved ingredient called bemotrizinol (also known as BEMT) will soon appear in U.S. sunscreens — and it’s a big step forward in sun protection.
“It’s exciting because it protects against both UVA and UVB rays and is more stable in sunlight than older ingredients,” says Alison Lee, MD, a dermatologist and Mohs surgeon who specializes in skin cancers at Emory Healthcare.
Why it matters:
Provides broad-spectrum protection in a single ingredient
More photo-stable, so it lasts longer in sunlight
Already widely used in Europe and Asia
May allow for developing sunscreens that feel lighter and less greasy than those already on the market in the US.
It’s also classified by the FDA as “generally regarded as safe and effective for adults and children starting from 6 months of age,” based on extensive testing.
Sunscreens with bemotrizinol are expected to start appearing in the U.S. in late 2026
under the name of PARSOL® Shield.
In the meantime, dermatologists recommend continuing to use a broad-spectrum sunscreen with SPF 30 or higher as part of your daily routine.
“It’s never too late to start getting in the habit of smart sun protection.”
Allison Lee, MD, dermatologist
Why sunscreen matters for your health
Sunscreen does more than prevent sunburn.
Dermatologists recommend it because it helps protect your skin from both short- and long-term damage, including:
Skin cancer: UV radiation is a leading cause of common skin cancers
Premature aging: Sun exposure leads to wrinkles, sagging and uneven skin tone
Discoloration: Conditions like melasma and dark spots can worsen with sun exposure
Sensitive skin conditions: Including rosacea and lupus
"As a dermatologist, we really advocate for sunscreen because it plays such an important role in many different skin conditions,” Dr. Lee says. “It’s never too late to start getting in the habit of smart sun protection.”
What does SPF mean?
SPF, or sun protection factor, measures how well a sunscreen protects your skin from UVB rays, which cause sunburn.
Here’s a simple way to think about it:
SPF 15 blocks about 93% of UVB rays
SPF 30 blocks about 97%
SPF 50 blocks about 98%
So which SPF is right for you?
Higher numbers offer more protection, but not in a straight line. Though it appears that there’s only a small difference between SPF 50 and 30 in terms of total protection from UVB rays, most people don’t apply enough sunscreen and typically won’t meet the full labeled protective dose as labeled on the sunscreen. That’s why dermatologists recommend choosing at least SPF 30 — and ideally SPF 50 when possible.
UVA vs. UVB: Why both matter
Sunlight includes two types of ultraviolet rays that can harm your skin:
UVB rays cause sunburn and play a major role in skin cancer development, particularly non-melanoma skin cancers like basal cell carcinomas and squamous cell carcinomas.
UVA rays penetrate deeper, causing wrinkles, aging and discoloration
Some research also suggests UVA rays may contribute to the development of melanoma, the most serious type of skin cancer.
That’s why it’s important to choose a sunscreen labeled broad-spectrum, which protects against both types.
“The best sunscreen is the one you’ll use consistently.”
Allison Lee, MD, dermatologist
How sunscreen works to protect your skin
Sunscreen forms a protective layer on your skin that helps block harmful ultraviolet radiation.
There are two main types:
Chemical sunscreens absorb UV rays and convert them into heat
Mineral sunscreens (like zinc oxide and titanium dioxide) also absorb most UV rays and reflect a small amount
A common myth is that mineral sunscreens only sit on top of the skin and reflect sunlight. In reality, both types work in similar ways by absorbing most UV radiation.
Dr. Lee’s suggestion on how to pick the best sunscreen? “The best sunscreen is the one you’ll use consistently, so find a formula- chemical or mineral or a mix of the two- that you enjoy applying, in a format you enjoy using.”
Are you using enough sunscreen?
Probably not. Most people apply much less sunscreen than needed, which lowers its effectiveness.
To get the full protection listed on the bottle:
Use about 2 teaspoons for your face and neck
Use about 2 to 3 tablespoons for your entire body
“That’s more than most people expect, but it’s what you need to get the full SPF,” Dr. Lee says.
How to apply sunscreen correctly
To protect your skin:
Apply sunscreen 15 minutes before going outside
Use a broad-spectrum SPF 30 or higher
Reapply every two hours
Reapply after swimming or sweating
Don’t forget easy-to-miss areas like your ears, neck and feet (if wearing open-toed shoes)
“Think of putting it next to your toothpaste and making it part of your daily routine.”
Allison Lee, MD, dermatologist
Do you really need sunscreen every day?
Yes — even if you spend most of your time indoors.
That’s because UVA rays can pass through windows, exposing your skin while you’re driving or sitting near natural light.
“Think of putting it next to your toothpaste and making it part of your morning routine,” Dr. Lee says.
Common sunscreen myths — cleared up
Myth: Higher SPF means all-day protection
Not true. You still need to reapply every two hours.
Myth: You only need sunscreen at the beach
Daily use offers the best protection.
Myth: Makeup with SPF is enough
You likely aren’t applying enough to get full protection, so layer it over sunscreen.
Myth: Spray sunscreen works better than lotion
Both can be effective, but only if applied correctly. Sprays are easy to miss spots or apply too lightly, so be sure to spray generously and rub it in. Lotions can offer more even coverage, especially for the face.
Myth: Darker skin doesn’t need sunscreen
Everyone benefits from protection against skin damage, aging and discoloration.
Simple ways to protect your skin
Sunscreen works best when combined with other sun-safe habits:
Wear wide-brim hats and UV-protective clothing
Seek shade, especially between 10 a.m. and 4 p.m.
Be mindful near water, sand and pavement, which reflect sunlight
Sun protection doesn’t have to be complicated. With new innovations like bemotrizinol, sunscreen options are becoming more effective — and more wearable — than ever.
The most important step is simply this:
Find a sunscreen you like and use it every day.
How to treat a sunburn
Sunburn is a sign of skin damage from spending too much time outdoors without wearing a protective sunscreen. If you find yourself with a sunburn, here are a few ways you can find relief:
Taking an over-the-counter anti-inflammatory medication (such as ibuprofen or aspirin) and applying cold compresses or ice packs can provide some pain relief.
Taking cool baths or showers frequently may also help.
After a bath or shower, gently pat yourself dry, but leave some water on your skin and apply a moisturizer. The use of moisturizing creams and lotions, including aloe vera, will also help prevent drying and cracking.
If a blister does form, leave it intact for a faster healing process.
If you have a sunburn, stay out of the sun for a few days in a cool, shaded or indoor space and drink plenty of water.
What is sun poisoning?
When an itchy, red rash appears on your skin after it’s been exposed to sunlight, this is called sun poisoning – you may also know it as a sun allergy. It may take only minutes for signs of sun poisoning to appear after exposure to the sun. You could experience redness, itchiness or pain, elevated red patches, blisters, scaling or even bleeding.
Take the next step for your skin health
Daily sun protection can help reduce your risk of skin cancer and keep your skin healthier over time.
Have questions about your skin or sun exposure?
Schedule an appointment with an Emory dermatologist or talk to your primary care provider.
This article was originally published on June 24, 2024 and has since been updated.
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