Does 100 SPF work better than 50?
After that, the difference in protection is small. SPF 50 blocks 98%, and SPF 100 stops 99% of UVB rays from reaching your skin.
Experts say sunscreens with an SPF higher than 50 aren't worth buying. They only offer marginally better protection. They might also encourage you to stay out in the sun longer. Instead, choose an SPF between 15 and 50, apply liberally, and reapply often.
So ideally, with SPF 30 it would take you 30 times longer to burn than if you weren't wearing sunscreen. An SPF 30 allows about 3 percent of UVB rays to hit your skin. An SPF of 50 allows about 2 percent of those rays through.
Sort of, but it's more nuanced than that. Let's first break down how the SPF system works: "SPF 15 guards against 93 percent of UVB rays, SPF 30 protects against 97 percent, SPF 50 is about 98 percent, and SPF 100 blocks 99 percent," Joshua Zeichner MD, a board-certified dermatologist from New York City, tells Allure.
Sunburn protection is only marginally better.
Sunbathers often assume they get twice as much protection from SPF 100 sunscreen as from SPF 50. But the extra protection is negligible. Properly applied SPF 50 sunscreen blocks 98 percent of UVB rays; SPF 100 blocks 99 percent.
Sunscreens with SPF higher than 50 might seem like your best bet, but they could backfire. People who use them may think they can stay out in the sun longer, skip reapplication, and neglect other protective measures like seeking shade, according to the Skin Cancer Foundation.
If you are particularly prone to getting sunburn, getting a sunscreen with SPF 100 might be worth it. However, according to the major health authorities, most of us will do just fine with SPF 30 and above. Regardless of what SPF you use, you still need to reapply every two hours.
The American Academy of Dermatology recommends using a sunscreen with an SPF of at least 30, which blocks 97% of the sun's UVB rays. The highest SPF is 100 and blocks out 99% of UVB rays.
A sunscreen with an SPF 100 index means the same person would be protected for more than 24 hours. The formula below explains how the SPF index works.
The Skin Cancer Foundation recommends choosing a sunscreen that's in the SPF 15-50 range. SPF 15 is best for those who spend most of their time indoors or will spend a short amount of time in the sun. If you'll be outside for longer, opt for something closer to SPF 30+.
How many hours will SPF 50 last?
A sunscreen's sun protection factor (SPF) is only fully effective for two hours after you put it on. Experts recommend carrying a bottle of SPF 30 to SPF 50 sunscreen around with you, even on cloudy or rainy summer days, so you can throw some on if the sun comes out.
What kind of sunscreen is best for the face? Ensuring that you're applying enough SPF is also crucial. “I recommend looking for a broad-spectrum SPF of 30 or higher, and re-applying it every two hours,” says Dr. Gohara.
An SPF 50 sunscreen should block about 98 percent of sunburn rays (primarily UVB rays) and an SPF 100 product should block 99 percent. The key word is “should,” since, in the real world, products with high SPFs on the label rarely achieve the protection they claim.
In general, you should reapply sunscreen every two hours for consistent protection. However, there is an exception to the rule—if you're sweating or swimming you need to apply more often. To make sure you're protected even when you're active, you should reapply sunscreen at least every 80 minutes.
There are no direct adverse effects of applying a higher SPF, but it can lead to a sun protection routine that is incomplete and needing more. While a product with SPF 50 might give you better protection against UVB rays due to its photochemistry, it might have less UVA protection. Both radiations are equally harmful.
For day-to-day use, pick a sunscreen with an SPF of at least 30. If you spend time outdoors, choose a product with SPF 60 or greater. In reality, most people do not use as much sunscreen as they should, and this higher SPF helps compensate for the reduced application.
Everyone, regardless of age, gender or race, should use sun protection factor (SPF) of 30 or higher. But what's in your sunscreen may be just as important as the SPF number. While SPF 85 sounds like it offers more protection, higher SPF numbers can be misleading.
"SPF 100 creates a physical barrier that blocks 99% of UVB rays (responsible for sunburn and skin cancer) from penetrating the skin," says Dr Laftah. "Its biggest limitation is the opaque white tint.
Generally, SPF 100 is the highest protection you can buy, but it's not necessarily the best protection against a sunburn. According to Penn State Prevention Research Center, proper and repeated application of sunscreen is more important than the SPF number.
But there's a bigger reason why you need to reapply your sunscreen every couple of hours. “Chemical sunscreens absorb UV rays and disperse them, but the active ingredients don't stay on the skin and continue doing their job,” says dermatologist Anthony Rossi.
Does SPF 50 mean you have to put it on every 50 min?
It's much easier for people to understand the need to reapply at least every 2 hours. You should reapply every 40 or 80 minutes while swimming or sweating, depending on the product.
With the rule of nines, the body's surface area is divided into 11 areas, each representing roughly 9% of the total (box). Sunscreen can be applied to each of these areas at a dose of 2 mg/cm2 if two strips of sunscreen are squeezed out on to both the index and middle fingers from the palmar crease to the fingertips.
Ultraviolet light from the sun can increase your risk of skin cancer and skin aging. Many safe and effective sunscreens are available, and it's important to use them the right way. Using sunscreen every day — no matter where you live or what color your skin — can protect you from sun damage.
Sunscreen is a must-have skincare product in your daily skincare regime. However, you must know that it has to be rinsed off from your skin before you go to sleep which otherwise might give rise to multiple skin concerns.
However, the SPF in sunscreen is a large molecule, which when applied to the skin during sleep at night will create larger pores. Therefore, it is important in skin care with sunscreen to apply it during the day but always wash it off before going to bed.
SPF 30 or higher
The American Cancer Society recommends using a sunscreen that's at least SPF 30. A 2012 review suggests that when used properly, SPF 30 sunscreen will block about 97 percent of UVB rays.
Ideally, any sunscreen with sun protection factor (SPF) between 15 to 25+ will help protect you from daily sun exposure. However, if you are staying outdoors for a longer period of time, then opt for a higher SPF. Also, choose a sunscreen which is non-sticky or non-greasy, as this will not make your skin too sweaty.
Experts unequivocally say no. "The benefit is that it affords us about 1 percent more coverage from the UVB burning rays than an SPF of 50," says Ciraldo. "But the risk is not worth it." Instead, for safe, effective sunscreens, select any SPF 30 to 50 with 20 to 25 percent zinc oxide, says Dudley.
The primary reason that so many of us burn so easily is that we simply aren't applying our sunscreen liberally enough. You don't get the protection listed on the label unless you wear the correct amount, so a quick spritz over each limb isn't going to keep you sufficiently shielded from the sun.
Verify your sunscreen offers broad-spectrum protection against both UVA and UVB rays. Aim to apply a minimum of SPF 30 every day, no matter what. The FDA warns that excessively high SPF claims give consumers a false sense of protection, so be skeptical of anything labeled over 60.
What happens if you use too high SPF?
Higher SPF sunscreens contains higher concentrations of chemical sunscreen ingredients. It is scientifically shown that chemical (organic) sunscreen ingredients can be absorbed into the skin, and when struck by UV radiation, these can become quite aggressive free radicals, increasing the risk of damage.
However, in fact, some cases are reversed: the more you use sunscreen, the darker your skin, even some people have premature aging such as wrinkles, larger pores, acne and even aging.
"SPF measures how much of the sun's UVB rays are blocked, but layering products doesn't improve the amount of active ingredients in the cream," she explained. "The only way to change the SPF is to change the amount of active ingredients within the formulation. Applying more on top doesn't add any extra coverage."
Protection isn't much better than low-SPF sunscreens
Building off of our last point, SPF 100 blocks about 99% of UVB radiation while SPF 50 blocks around 98%. Meaning that despite having twice as much SPF, it's only 1% more effective. There's not as much of a difference in protection as you'd think!
Dermatologists recommend using an SPF of at least 30, which Adarsh Vijay Mudgil, MD, a dermatologist practicing in New York, calls "the magic number". SPF 15 blocks about 93 percent of UVB rays, while SPF 30 blocks about 97 percent of UVB rays. The ADA recommends an SPF of 30 or higher.
A sunscreen's sun protection factor (SPF) is only fully effective for two hours after you put it on. Experts recommend carrying a bottle of SPF 30 to SPF 50 sunscreen around with you, even on cloudy or rainy summer days, so you can throw some on if the sun comes out.
A SPF indicates how much longer it will take to burn with sun protection e.g. the skin should take 30 times longer for it to burn with an SPF30, than without. The higher the SPF, the higher the concentration of chemical sunscreen ingredients, in fact, high levels of chemicals induce higher risk of free radical damage.
Generally, sunscreen should be reapplied every two hours, especially after swimming or sweating. If you work indoors and sit away from windows, you may not need a second application.
"In the winter, if you are out in bright but cold climates, such as when skiing, opt for SPF50 minimum, as UV rays reflect off surfaces such as snow and water, and reapply regularly as you would in the summer.” With that in mind, below are the best sunscreens you can buy right now to protect your skin this winter.