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How to Pick out a Sunscreen like a Dermatologist

Are you overwhelmed by the number of choices there are for sunscreens at your local drug store? Are you worried that you are not picking a safe sunscreen for yourself or your children? Do you spend way too much time on google trying to decipher the sunscreen lingo that advertisers use to manipulate your choices? Or do you just want an expert to save you the headache and tell you what to choose? In this post, I am going to answer all of your burning questions about sunscreen and make buying your next sunscreen super easy and stress-free!

The following are questions that I get asked OFTEN by my patients, friends, and family. Now I will share my expert answers with all of you. 

What SPF do I buy?

For a long time, patients were told that sunscreens with SPF over 15 or 30 were a waste of money and would not lead to a noticeable improvement in protection from the sun. But now we know better! I want you to educate yourself about the latest recommendations for what SPF to use. First of all, let’s get some facts straight…

SPF stands for sun protection factor. It’s a measure of how much of the sun’s rays reflect off the skin after it is applied in a concentration of 2mg/cm2. When the sun’s rays are reflected, it means that they are NOT absorbed into the skin. From my previous post, we know that the sun’s absorption into the skin causes many ill-effects. Some of the effects include the break down of cellular collagen, which makes the skin look saggy and wrinkled, dark spots and uneven skin tone, and DNA damage that causes skin cancer. Therefore, we must block as much of this radiation as possible with a great broad-spectrum sunscreen that has an appropriate SPF!
The SPF is measured in a number. The higher the SPF, the more sun that is blocked. For example, SPF 15 prevents 93% of the sun’s radiation from penetrating the skin, SPF 30 prevents 97%, and SPF 50 prevents 98% of penetration.  However, no sunscreen blocks 100% of the sun’s rays. Here is an important disclaimer about SPF: The SPF of a sunscreen is determined in a laboratory setting under ideal conditions where it is applied precisely with the dose of 2mg/cm2. If that SAME sunscreen is tested outside, the SPF obtained is LOWER than what is on the label. This means that if you are using that same sunscreen in real-life settings, you won’t be getting a level of protection that is as high as the SPF listed. Further, we know that most users are not applying sunscreen in the concentration tested in the lab. Instead, we are using on average only 50% of this amount which lowers the effective SPF by half!

So, even though lower SPF sunscreens (such as SPF 15) seem to block nearly all of the sun’s harmful radiation while higher SPFs only add a few more percentage points of blocked radiation, we now have scientific evidence that shows the real-life benefit of higher SPF sunscreens is MUCH greater than just a few percentage points. A recent study showed that SPF 100 sunscreen was significantly more effective in protecting against sunburn compared to SPF 50 sunscreen when used in real-life outdoor settings. This was a high-quality study (randomized, double-blind, split-face clinical trial) published in one of the most respected dermatologic journals (JAAD). This is a good illustration of the concept that what happens in the lab does not always translate exactly to what happens in real-world conditions.

It is also important to remember that all SPFs last the same amount of time before they need to be reapplied. A higher number SPF does not allow you to safely spend extra time outdoors without reapplication.

The take-home point here is: higher SPF sunscreens are SIGNIFICANTLY more effective than lower SPF sunscreens. So aim high!

The one-liner: The higher, the better.  SPF 50+!

What’s the difference between a chemical sunscreen and a physical sunscreen?

Sunscreen can be largely divided into two categories: chemical absorbers and physical blockers. Technically, chemical sunscreens are ORGANIC products because they are composed of ingredients that contain carbon molecules.  Physical blockers are INORGANIC because they contain non-carbon ingredients like zinc oxide and titanium dioxide).

Chemical sunscreens contain active ingredients that work by ABSORBING UV radiation in the harmful spectrum and converting it into low energy heat. These ingredients are highly effective at blocking both UVB and UVA sun rays, depending on the chemical. Chemical sunscreen formulations are the most cosmetically elegant to apply and wear. They have the least amount of “white cast,” which is the chalky white look often caused by physical sunscreens. They rub in nicely and evenly and are overall the most user-friendly.

Some common chemical ingredients used in sunscreens in the U.S. are ensulizole, octisalate, homosalate, octocrylene, octinoxate, oxybenzone, and avobenzone. A few of these chemicals have been shown to absorb into our bloodstream when used in high quantities. We are unsure of the significance of this finding on our overall health so more studies must be conducted.  However, some people remain concerned enough about these claims that they are choosing to avoid chemical sunscreens altogether. If you fall into this category, you may opt for a physical (chemical-free) sunblock, which is discussed in more detail below.

Physical sunscreens work by BLOCKING harmful UV radiation and reflecting the rays off the surface of the skin with very little absorption. You can imagine this as a barrier cream sitting on top of the skin. The active ingredients in physical sunscreens are MINERALS zinc oxide and titanium dioxide. Both of these ingredients are classified as “broad-spectrum” meaning they block both UVA and UVB rays.

Classically, physical sunscreens have a reputation for creating a white cast on the skin (think of the white lifeguard nose) and being difficult to rub in. These disadvantages are due to the large particle size in the product formulation. However, the field of nanotechnology has revolutionized the formulation of these products by shrinking the particle size down to nano-particles. This micronized form allows the sunscreen to be more transparent, rub in more easily, and appear smooth under makeup application. Further, many physical sunscreens also come in a “tinted” version which adds skin-colored pigment to camouflage this white appearance.

Because physical blockers tend to look more white when applied to the skin, users may opt to apply a lesser quantity than a chemical sunscreen. Be cautious about this as improper application lowers the SPF and puts the user at greater risk of sun damage.

The one-liner: Physical sunscreens reflect sunlight, whereas chemical sunscreens absorb sunlight. Both are effective broad-spectrum products, and each has its pros and cons.

How can I tell if a sunscreen is chemical or physical?

Look at the ingredients label on the back of the sunscreen product. In the “active ingredients” section, you will see either chemicals or minerals listed (or a combination of both). If you want to be sure you are using a chemical-free (a.k.a. physical/mineral) sunscreen, the active ingredients should have ONLY zinc oxide and/or titanium dioxide minerals listed. You will find some products that have both chemicals and minerals in them, and I consider these in the chemical category.

Here are the most common chemicals used in the U.S. in sunscreens: ensulizole, octisalate, homosalate, octocrylene, octinoxate, oxybenzone, and avobenzone. If you see any of these on the active ingredient list, then you know you are looking at an organic chemical sunscreen. This is true regardless of whether or not zinc or titanium is also listed.

It’s essential to understand this concept and learn how to read the labels on the sunscreen packaging. This way, you can most easily avoid falling for confusing marketing ploys on sunscreen bottles. Skip the fancy packaging, colors, logos, etc. and go straight to the label!

The one-liner: If a sunscreen has ONLY zinc oxide and/or titanium dioxide on the active ingredient list, it is a chemical-free physical blocker.

What does broad-spectrum mean?

Broad-spectrum refers to the ability of a sunscreen to protect against both UVA and UVB rays. This is an essential property of the sunscreen and one that you should always look for when choosing a product.

UVB rays are responsible for causing the characteristic red sunburn and causing cellular damage that leads to skin cancer.

UVA rays penetrate deeper into the skin (where the collage resides) and are the leading cause of skin aging from the sun.  UVA rays have also been found to cause DNA damage that leads to skin cancer.

Remember, the SPF is a measure of how well the product protects against UVB specifically. In addition to this important label, you want to see that the product is broad-spectrum to avoid the harmful effects of UVA rays as well. 

The one-liner: Broad-spectrum means the product protects against both UVA and UVB rays.

What’s the deal with waterproof sunscreen?

I’m sorry to burst your bubble, but NO sunscreen in “waterproof.” In fact, you will not legally find this term on sunscreen product labeling in the U.S. because it has been deemed misleading by the FDA. Sunscreens that are formulated to hold up better in water are termed either: “water-resistant” or “very water-resistant.”
Water-resistant means a sunscreen will maintain its SPF after 40 minutes of water immersion testing. Very water-resistant means it will hold up after 80 minutes of water immersion testing.

This testing is conducted in an indoor, freshwater pool. The subject is immersed in water in 20-minute intervals (up to 40 minutes or 80 minutes) with a 15-minute rest out of water in between each interval. During this 15 minute rest, the subject does NOT towel off to dry. It is very important to understand how this is tested in order to interpret these claims in a real-life setting such as the salt-water ocean at the beach or in a chlorinated pool or hot tub.  Because these products are not tested in various water conditions and most people do towel off when getting out of the water, it is unlikely that these water-resistant products are as protective as the research shows.

To make a sunscreen resistant to water, certain ingredients must be added to the formulation to make it more readily adhere to the skin so it doesn’t wash off easily in the water. This can be achieved with added components such as waxes, oils, or polymers like dimethicone. These can potentially change how the sunscreen feels on the skin and can be a bit thicker to rub in.

The same recommendations for reapplication apply to sunscreens in this category. All water-resistant and very water-resistant products must be reapplied every 2 hours or when getting out of the water.

The one-liner: Waterproof sunscreens do not exist!

Should I buy lotion, spray, or stick sunscreen?

Sunscreens are widely available in a variety of vehicles including creams, lotions, gels, sprays/aerosols, and semi-solid sticks.

Creams/lotions: This variety is best for use on the face and on dry skin. It also offers the easiest way to ensure you are applying enough of the product to be effective.  I highly recommend sunscreens in creams and lotions compared to all other vehicles.

Gels: Sunscreens in gel formulations are great for the scalp and hairy areas of the body, such as a man’s chest. Gels can be drying, so it is best to avoid this type of sunscreen on dry or irritated skin.

Sprays: Although sunscreen sprays are typically the easiest to apply of all the formulations, they are the LEAST effective! Therefore, I never recommend using sunscreen sprays. It is difficult to know if you are spraying enough on to the skin to be effective. If a spray is going to be used, it is preferred to spray the product onto the palm and then apply it to the skin. However, this tip effectively eliminates the purpose of a spray. I tell patients to never use these on the face due to the risk of inhalation. And these should never be used in babies or children as it is harder for these age groups to hold their breath during application which further increases their risk of inhalation.

Sticks: Sunscreen sticks are particularly useful for around the eyes, the backs of the hands, and hard to reach spots. These products can be effective if applied in several passes over the skin. To improve their efficacy, I recommend rubbing it in after application. These are great for on-the-go and traveling.

The one-liner: Creams and lotions offer the most effective and reliable protection.

Do I need to worry about the inactive ingredients in sunscreens?

Yes. Inactive ingredients make up 50 to 70% of the bulk of a sunscreen product. They are listed on the back of the sunscreen product in alphabetical order. These ingredients are mixed into the product to help preserve, emulsify, moisturize, condition, and make the product overall cosmetically pleasing.

Methylisothiazolinone is a common inactive ingredient found in many sunscreens. It is a preservative and common skin allergen that causes frequent rashes for patients with both sensitive and non-sensitive skin. Surprisingly, this ingredient may even be in products labeled “hypoallergenic.” The fact that it is in many sunscreens is problematic because sunscreens are applied to a large surface area of our body and reapplied often. This proper application increases the risk of developing a serious reaction to the sunscreen product.

When choosing a sunscreen, I recommend checking the inactive ingredient section to make sure you are selecting a product that is free of methylisothiazolinone, paraben-free, oil-free (to reduce acne breakouts) and fragrance-free.

The one-liner: Choose sunscreens that are free of methylisothiazolinone, parabens, oils, and fragrances.

What other sunscreen lingo should I understand?

You may find that after ALL those decisions, you are still left with a handful of product choices. Among those, you will see a variety of labels and claims on the packaging, which are all typically marketing ploys to make that particular brand or product stand out.

Common claims on the packaging include:

For sensitive skin: This typically means the product does not contain common skin allergens or skin sensitizers such as fragrances, parabens, and methylisothiazolinone. However, this is not a regulated term with any standard by which companies have to abide. Therefore, I recommend you read both the active and inactive ingredient list to make sure you select a product free from particular ingredients you want to avoid.

Sport: The term “sport” is not FDA regulated and does not require the product to meet any certain standard. This is typically a term used to make the consumer believe the product is “sweatproof” or water-resistant to some degree. In fact, there is no product that is legally allowed to claim “sweatproof” as a guarantee as this is misleading to the consumer. If you want sunscreen to hold up in the water, look for the terms “water-resistant” or “very water-resistant” rather than relying on the term “sport” as they are not synonymous!

Face sunscreen: This typically means it is lighter in the formulation and will wear better under makeup. Usually, these are chemical sunscreens and are formulated in a way to decrease the risk of breakouts.
Body sunscreen: In general, these are a bit thicker to apply and are found in higher SPFs.

Organic: Technically, organic means a chemical sunscreen (which is made of carbon-containing compounds). Many consumers who are swayed by products labeled organic are searching for a chemical-free or all-natural product. Therefore, this term often misleads consumers. Check the ingredient list to ensure you are selecting a product without chemicals if that is your preference.

Mineral: This refers to zinc oxide and titanium dioxide, which are the two minerals found in physical sunscreens. Just because a package is labeled as a “mineral” sunscreen does not mean that it may not also include chemicals in the active ingredient list. Again, check the active ingredient list to see the full list of compounds contained in the product. If you are looking for a 100% mineral sunscreen, select one with ONLY zinc oxide and/or titanium dioxide listed under the active ingredients.

For babies: In general, this marketing term is used for sunscreens that are physical sunscreens containing only zinc oxide and titanium dioxide. You must check both the active and inactive ingredient list on sunscreens to be used on babies to reassure there are no added chemicals in the active ingredient list and no allergens or skin sensitizers in the inactive ingredient list.

From these above descriptions, you can understand that the sunscreen terminology on packaging can be frequently misleading. By following these recommendations, you can quickly sort through the abundance of options available to you.

The one-liner: Do not fall for marketing terminology on sunscreen packaging. Always check the label for FDA-approved terms and the ingredient list for reassurance.

As you can see, there is a lot that goes into selecting the best sunscreen for yourself. This information should empower you to easily sift through the many options and avoid marketing scams to find an effective and cosmetically pleasing product.

Here is your quick checklist to keep in mind when buying your next sunscreen:

  1. Choose between a chemical or physical sunscreen. You can base this decision on the pros and cons of each type as well as your personal preference. Check the active ingredients to make sure you are correctly selecting the type you want.
  2. Choose a high SPF, preferably 50 or greater.
  3. Make sure your product has “broad-spectrum” on the label. Remember, broad-spectrum prevents sunburn, skin cancer, and photoaging.
  4. Decide if you need the extra protection of a water-resistant product. Opt for the “very water-resistant” label if available.
  5. Choose the vehicle that you prefer (cream, lotion, stick, spray, etc.). I almost always recommend creams which are the most effective and reliable.
  6. Lastly, check the inactive ingredients to avoid common skin sensitizers and allergens.

And that’s it!

Above all, the best sunscreen is one that you will use effectively and use often. It may take trial and error with a few different brands or types before you find what works best for your skin and your preferences. The good news is that there are SO many options that you can most certainly find one that works for you and your family.