Your skin is much more than what people see. The skin is a whole system that acts as a barrier to protect the inside of your body from the outside world. It is vital that we do what we can to protect it. 

What is sunscreen and why is it important? 

Sunscreen is a substance that is applied to the skin to prevent damage by the ultraviolet (UV) rays the sun emits. It is important to use sunscreen because UV exposure is a known carcinogen, meaning it can cause cancer

UV rays also cause darkening of the skin and deterioration of collagen within your skin. This can lead to brown spots, wrinkles, and fragile skin, and affects the skin’s ability to function as a barrier against the environment.

What is SPF? 

The sun emits different kinds of radiation, including UVA and UVB rays. These are types of ultraviolet rays that can damage our skin. 

Sun protection factor, known commonly as SPF, is a number that is used to tell you how effective a sunscreen is in blocking radiation from the UVB rays, not the UVA rays. 

Which sunscreen is best? 

Many people ask which sunscreen is better, SPF 30 or 50? The answer is, it’s complicated! They can both be effective, and the highest SPF doesn’t necessarily give you more protection.

High-number SPFs block slightly more of the sun’s UVB rays; they do not inform you about protection against UVA rays. Moreover, high-number SPFs last the same amount of time as low-number SPFs; both need to be reapplied every two to three hours. 

Current guidelines from the American Academy of Dermatology call for using a “broad spectrum” sunscreen with an SPF of 30 or higher. Broad-spectrum means you are getting protection from both UVA and UVB rays. Most commercially available sunscreens today are broad spectrum, but you should always read the label to be sure. 

Types of sunscreens and sunscreen safety 

There are two different kinds of sunscreens. When shopping for sunscreen, be an educated consumer. Turn over the bottle and look for the active ingredients. 

Mineral sunscreens. The first is mineral sunscreens. The active ingredients in this type of sunscreen are made from minerals, specifically zinc oxide and titanium oxide. They are designed to stay on top of your skin and deflect the UV rays from penetrating through your skin. For this reason, mineral sunscreens are sometimes referred to as “physical” sunscreens. Mineral sunscreens are often recommended for children and those with sensitive skin. 

Chemical sunscreens. The second is chemical sunscreens. While these may contain minerals, they also contain other ingredients such as oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate. This type of sunscreen is designed to absorb the sun’s rays, like a sponge; they can also be absorbed into the body. These types of sunscreens can sometimes be irritating to those with sensitive skin. 

In 2019, the FDA announced that it will reevaluate the safety of every ingredient used in chemical sunscreens to determine whether its absorption into the bloodstream has any effects on a person’s health. 

When to use sunscreen 

Just like brushing your teeth, sunscreen should be a regular part of your daily routine. Wake up, brush your teeth, and apply sunscreen to your face, ears, and neck, and other areas that will get regular exposure to sunlight. It is important to remember that UVA rays penetrate through car windows. 

Answers to common questions about sunscreen 

How often should you reapply sunscreen? 

The key to using sunscreen correctly is that it needs to be applied liberally and frequently. You should reapply every two to three hours, and more often if you are in the water or are sweating during sports or other activities. No sunscreen is “waterproof” or “sweatproof,” and any sunscreen that is labeled as “water resistant” will also display either 40 minutes or 80 minutes of effective time on the label. 

Is SPF 15 enough for daily face protection? 

SPF 30 is the minimum recommendation for all exposed areas, including your face. Many moisturizers and make-ups have built in sunscreen – check to make sure it contains an SPF 30. 

Do you need sunscreen indoors too?     

Yes! The goal is to minimize the cumulative sun exposure you receive over a lifetime. That means every exposure counts. 

If you’re someone who works indoors, you should still apply sunscreen daily. Even if you spend most of your day inside, you still travel to and from your car throughout the day, go for a walk, eat lunch outside, or sit by a window, which all contribute to cumulative exposure. 

Do I need sunscreen during the winter? 

YES! The sun shines 365 days a year. You can still get a sunburn on a cloudy day or on a ski slope in the middle of winter. 

Do sunscreens expire? 

Yes. Sunscreens are regulated by the FDA, which requires that all sunscreens last for at least three years. So go ahead and use that bottle from last year. But if you notice the sunscreen has become watery, changed color, or has an odor, don’t risk getting burned – get a new bottle. 

How to always protect your skin 

A tan is not healthy. It is a sign your skin is reacting to ultraviolet exposure. You should always opt for multiple layers of protection from the sun. 

  • Shade your skin. Use hats, clothing, or umbrellas to protect your skin from the sun’s rays. 
  • Avoid the sun when you can. Seek shady spots when possible. 
  • Use sunscreen. It is one step in your overall skin protection, but it’s not the only way to protect your skin. 
  • Get regular check-ups. Just like getting an annual physical, your skin also needs regular exams by a medical professional to look for any new or changing spots, moles, or other causes for concern. 

Learn more about dermatology services at Lifespan by visiting us online.

Elnaz F. Firoz, MD

Elnaz Firoz, MD, is a dermatologist and the medical director of dermatology at The Miriam Hospital.