How to Choose the Best Sunscreen

May 15, 2019

Choosing the best sunscreen

By now most of us are aware that we need to protect our skin from the sun. However, while sunscreen is commonly seen by the pool or at the beach, recent data shows that most American adults do not use it regularly throughout the year, if at all. The confusion is real. Which sunscreen is best? Which sunscreen does not irritate my skin or cause me to break out? Should I use a water-resistant sunscreen, a physical blocker or a chemical blocker? How often should I apply and reapply? Do I needed it if I am indoors all day? Do I need SPF 15 or SPF 100? Do I need sunscreen in the winter or when it is cloudy outside? What about Vitamin D levels? And last but not least, my most favorite question: Isn’t the SPF in my makeup enough?

Let’s discuss some common misconceptions and try to understand what would be the best sunscreen for you individually.

What is Sunscreen?

Sunscreen is a product that contains ingredients which prevent the UV rays of the sun from damaging our skin. Sunlight is made of two types of harmful UV rays: UVA and UVB which over time can cause premature aging of the skin, skin cancer, eye damage (cataracts) and sun damage (brown spots). UV rays damage the DNA of your skin cells and over time, genetic mutations can lead to skin cancer.

UVA vs. UVB Rays

  • UVA rays are long-wave and penetrate the skin deeper. They not only cause premature aging but also play a role in the formation of skin cancer. These are the rays that are emitted by tanning booths as well.
  • UVB rays are shortwave and they contribute to sunburns. Even though they are most intense between 10 a.m. and 4 p.m., at high altitudes like here in Colorado, and on reflective surfaces like snow and water, they can damage your skin all year round.

Physical Sunscreen vs. Chemical Sunscreen

There are two types of sunscreens on the market that can protect us from UV light: physical blockers and chemical blockers. Each uses a different mechanism for protecting the skin and maintaining stability in the sun.

  • Physical sunscreen contains titanium dioxide and zinc oxide. These are opaque inorganic compounds that reflect or scatter the sun's rays. These sunscreens give us a ghost-like "white" look, but they are also the least irritating ones to our skin.
  • Chemical sunscreens are organic compounds that absorb the sun’s rays and convert them into heat, preventing them from penetrating the skin. They contain oxybenzone, avobenzone, octinoxate and octisalate. These sunscreens are more cosmetically elegant because they get absorbed by our skin. However, they are also the most irritating ones for people with sensitive and allergy-prone skin.


Physical sunscreens are better if you have sensitive skin and chemical sunscreens are better if you are swimming, you sweat a lot and if you want the sunscreen to absorb fast into the skin so you can apply make up on top.

For acne-prone and sensitive skin, you can look for sunscreens that contain niacinamide. This ingredient is also known as Vitamin B3 and nicotinomide. It works with the natural substances of your skin to improve the appearance of enlarged pores, uneven skin tone and it fights free radicals. One affordable brand that contains it that I recommend to my patients is CeraVe SPF 50 face lotion.

Sunscreen SPF: What is It and How High a Number is Needed?

  • The SPF number that you see on sunscreens indicates how long it will take for UVB rays to burn your skin if using the product as directed versus the amount of time it would take to burn without sunscreen.
  • For example: SPF 15 will take 15 times longer for your skin to burn than if you were not wearing the sunscreen. 
  • Do not let a higher SPF number give you a false sense of security. Studies show that people who use a higher SPF tend to reapply sunscreen less frequently and stay out in the sun for much longer periods of time without protection.
  • The Skin Cancer Foundation recommends a water-resistant, broad spectrum sunscreen with an SPF of 30 or higher.
  • Most people do not apply sunscreen thick enough to get the protection claimed by the SPF factor. Your makeup with SPF is simply not enough to protect you from the sun for that same reason.
  • You need to apply one ounce of sunscreen, which is two tablespoons, 30 minutes before going outside and you need to reapply it every two hours or immediately after sweating or swimming.
  • For those of us who spend most of the day indoors, apply sunscreen in the morning and then reapply in the afternoon.


Sunscreen is only one part of a comprehensive strategy to protect your skin from UV damage. Remember that wide-brimmed hats, UV-blocking sun glasses, sun protective clothing, seeking shade and staying under umbrellas are just as important.

What About Vitamin D?

There is no doubt that Vitamin D is important for our health. When your skin is exposed to the sun it manufactures Vitamin D. Unfortunately many people think that the only way to get Vitamin D is through the sun and unprotected sun exposure. 

The risks of exposing the skin to the sun without protection are however too high and not worth it especially since you can get your Vitamin D from many food sources without causing damage to your skin. Even though proponents of unprotected sun exposure recommend no more than 10-15 min a day of exposure, this is enough time to cause DNA damage to the skin. UVB rays that contribute to the synthesis of Vitamin D are also the same rays that cause sunburn and lead to skin cancer.

The safer option is to get Vitamin D from food and dietary supplements. 

Additionally, it has not been found that sunscreen use leads to a Vitamin D deficiency. In fact, people who use sunscreen daily can maintain healthy levels of the vitamin in their system. No matter how much sunscreen you use, a small amount of UV rays are still able to get to your skin.

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Categories: Dermatology