Sunscreen 101: What You Need to Know About Sun Protection

Sunscreen 101: What You Need to Know About Sun Protection

Woman applying sunscreen


Everyone needs sunscreen! Sun protection is for all ages, all genders, and all races. The damage from the sun can affect everyone, and the sun’s UV rays can cause premature aging, unwanted pigmentation, and skin cancer. Although we can do a lot with topical medications and products, premature aging from sun damage can take a long time to reverse or may not be reversible. Regular sunscreen use will help protect your skin from these factors.


Table of contents

  • What type of sunscreen should I use?
  • Broad spectrum sunscreen protects against UVA and UVB rays; what is the difference?
  • When should I use sunscreen?
  • What is visible light? How do I protect my skin against it?
  • What is the difference between chemical sunscreen and physical sunscreen?
  • Final thoughts
  • FAQ



Generally, the best sunscreen is the sunscreen you can use every day! I recommend people use a broad spectrum sunscreen, which means it blocks UVA and UVB rays. I also recommend a sunscreen that is SPF 30 or higher. It should be noted that the SPF rating only applies to how well it blocks UVB.

There is no equivalent rating scheme for UVA; unfortunately, the UVA spectrum is much broader and, therefore, more challenging to block UVB completely. A good rule of thumb is to look for high levels of zinc oxide in your product, as this chemical blocks UVA and UVB quite well!



The sun’s light contains two types of harmful rays that reach planet earth. These rays are UVA rays and UVB rays. Too much exposure to these rays can cause many concerns in the skin. Here is the difference between these two rays:

  •       UVA rays (aging rays) prematurely age your skin. These rays cause fine lines, wrinkles, age spots, and these rays can pass through windows and clouds.
  •       UVB rays (burning rays) are the main culprit of sunburns
Woman applying sunscreen to her cheek

The United States Department of Health & Human Services and the World Health Organization’s International Agency of Research on Cancer have declared UV radiation from the sun and artificial sources, such as tanning beds and sun lamps, a known carcinogen (cancer-causing substance). Tanning your skin in the sun or tanning beds damages your skin, and as this damage builds, you speed up the natural aging process and increase your risk of skin cancer.



Everyone should use sunscreen every day, and it is encouraged to reapply your sunscreen throughout the day regardless of the weather or time of the year. Suppose you are outside most of the day. You will be around water or doing a strenuous activity that may cause you to sweat. In those cases, it is important to reapply your sunscreen every two hours throughout the day. Skin cancer can also form on the lips; to protect them, use a lip balm or lipstick containing a sunscreen of SPF of 30 or higher.


What is visible light? How do I protect my skin from it?

Woman looking at label on bottle in store

Visible light is defined as any light that the human eye can see. Visible light emanates from nature, ceiling lights, cell phones, computers, TVs, etc. “Visible light can induce erythema in light-skinned individuals and pigmentation in dark-skinned individuals. Broad-spectrum sunscreens protect against ultraviolet radiation but do not adequately protect against visible light. For a sunscreen to protect against visible light, it must be visible on the skin” (Lyons et al. 2021). You can save your skin against visible light by using a broad-spectrum sunscreen that says “tinted” on the label and has an SPF of 30 or higher.



The difference between chemical and physical sunscreens is when chemical sunscreens are applied, the sunscreen sinks into your skin and acts like a sponge. In contrast, physical sunscreens sit on the surface of your skin and act like a shield. The formulation of chemical sunscreens tends to be easier to rub into the skin without leaving a white residue.

Although physical sunscreens, also known as mineral sunscreen, often leave a white residue, this sunscreen is better for people with sensitive skin. The best way to avoid the white residue in a physical sunscreen is to find one that is tinted. The ingredients for a chemical sunscreen are Oxybenzone, Avobenzone, Octisalte, Homosalate, Octocrylene, and Octinoxate. Physical or mineral sunscreens ingredients would include Zinc oxide and Titanium dioxide.



As mentioned before, everyone needs sunscreen every day. Reguardless of age, race, gender, time of the year, or the weather. One of the best things to do for your skin is to apply sunscreen daily to protect it from the sun's harmful rays.

Think about how you brush your teeth every day to protect your teeth from tooth decay and gum disease. We apply sunscreen daily to protect our skin from premature aging and sun cancer. Many companies offer many different types of sunscreens. It is essential to remember your skin only needs a broad spectrum sunscreen to protect it against UVA and UVB rays and an SPF rating of 30 or higher.



Sunscreen on woman's back on the beach


Does sunscreen lose strength? Can I use the same sunscreen I bought last summer?

The FDA requires sunscreens to retain their original strength for at least three years. But you should apply sunscreen every day and reapply it throughout the day. If you follow this recommendation, it is unlikely that you will hold on to the same bottle for a year. You can check the expiration date on the label or review the actual product for discoloration or consistency changes.

Is a high number SPF better than a lower number one?

The higher SPF, the more it protects us from UVB rays. An SPF of 30 will allow 3% of UVB rays to hit your skin, while an SPF of 50 will allow 2% of UVB rays to hit your skin. Some people may look at a higher SPF sunscreen and think they will only need to apply it once, thinking it will protect them better. This understanding is false. It is important to reapply your sunscreen no matter how high the SPF is.



Food and Drug Administration. Sunscreen: How to Help Protect Your Skin from the Sun. Accessed February 10, 2021

Lyons AB, Trullas C, Kohli I, Hamzavi IH, Lim HW. Photoprotection beyond ultraviolet radiation: A review of tinted sunscreens. J Am Acad Dermatol. 2021 May;84(5):1393-1397. doi: 10.1016/j.jaad.2020.04.079. Epub 2020 Apr 23. PMID: 32335182.

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