Sunblock vs. Sunscreen: What's the Difference and Which One Should You Use?

Sunblock and sunscreen are two different types of sun protection that work in different ways. Sunscreen is a chemical blocker that filters the sun's ultraviolet (UV) rays, while sunblock (a term used here to describe physical blockers) reflects the sun's rays away from the skin.

Both forms are effective at protecting the skin from sunburn and preventing UV skin damage, but the ingredients are different. Sunscreen formulas often include fragrances, insect repellent, or other chemicals. Sunblocks often use ingredients that deliver thicker coverage on the skin.

Sunscreen vs. Sunblock

Sunscreen is the more commonly used type of sun protection. It filters or screens the sun's UV rays. It keeps most rays out but lets some in. It may also be called a chemical sunscreen.

Sunblock, on the other hand, blocks the sun's rays by sitting on top of the skin and reflecting them away. It may be called a physical sunscreen.

Choosing Between Sunscreen vs. Sunblock

Sunscreen and sunblock are both excellent forms of sun protection. The American Academy of Dermatology (AAD) doesn't advise using one over the other. The AAD does recommend that you choose one that offers:

• Broad-spectrum coverage (protects against UVA and UVB rays)
• SPF 30 or higher
• Water resistance

Broad spectrum sunblocks and sunscreens will prevent tanning and premature aging as well as sunburn.

Be sure that sun protection is correctly applied. Sunscreen or sunblock will only protect your skin when it's used the right way. A study of 101 women in Brazil, where UV exposure is quite high, looked at the actual amounts of SPF 30 to SPF 45 sunscreen they applied to their faces.

The researchers then calculated how much UV ray protection the women actually had, based on how the products were applied. Because the sunscreens weren't applied correctly, the women did not have the protection the products were supposed to provide.

Difference in Ingredients

Each type of sunscreen or sunblock uses different ingredients. They both protect the skin against the sun's damaging UV rays, but they do it in different ways.

Sunblock Ingredients

Most sunblocks contain titanium dioxide or zinc oxide as the active ingredient. This is why the formula seems thicker and traditionally you couldn't see through it, although some blends are now lighter. Nanoparticles are a common ingredient in newer sunblocks.

Some people find it harder to spread sunblock all over the body. They also may not like the look and feel of a product that can be seen on their skin. For example, you may notice people wearing sunblock at the beach, because they have a streak on their nose or parts of their face.

There are some brands, like Neutrogena, that offer a less visible sunblock. Baby sunblocks contain only titanium dioxide and/or zinc oxide. They are appropriate for children aged six months or older.

Sunscreen Ingredients

Sunscreens use a variety of chemicals that work to absorb harmful UV rays before they penetrate your skin. Some have active ingredients, including oxybenzone or avobenzone.

Some people are sensitive to or allergic to certain ingredients in sunscreen like PABA (para-aminobenzoic acid). They may choose to use sunblock instead of sunscreen.

You may want to avoid fragrances or oils that are added to sunscreens. Products may also be a blend of sunscreen and sunblock, so it's important to check the label if you are sensitive to certain chemicals.

Sunscreens may include insect repellant, either a natural type or one that includes artificial chemicals. The AAD doesn't recommend using these because sunscreen should be applied liberally and reapplied often. Insect repellant, though, should be used sparingly and less often. 

Is Sunscreen or Sunblock Better?

Either sunscreen or sunblock can be used by most people, so it's best to choose a product that you will use correctly and consistently. You also should read labels to understand what you're using, and check expiration dates. The product can't hurt you, but expired products won't work.

Talk with your healthcare provider if you have concerns about sunscreens or sunblocks. For example, there's concern about the ingredient oxybenzone because it may interfere with hormone function when absorbed across the skin. Yet studies suggest it remains safe to use.

Tips for Sun Protection

Hybrid products are now available, offering features of both chemical and physical sun protection. But keep in mind that some of the best UV protections are chemical-free prevention steps, such as:

• Wearing a hat
• Covering exposed skin, and choosing reflective colors and textures
• Staying out of the sun during peak midday hours
• Avoiding tanning beds

Remember to reapply your sun protection every few hours or after water exposure. Follow the product manufacturer directions for use.

Summary

Both sunscreen and sunblock provide protection against the sun. They rely on different chemicals to do so and don't look the same when they're applied.

Unless you have an allergy to a specific ingredient, you can choose any effective product. Check the labels to be sure that they're broad-spectrum products with an SPF of at least 30, and that they're water-resistant.