If you want to avoid the discomfort of sunburn and protect your skin, you need to lather on the sunscreen. Or wait—is it sunblock? 

The two terms may be used interchangeably, but they actually work in two completely different ways. When it comes to protecting your skin, we believe knowledge is power—so here, we’ll explain the difference between sunblock and sunscreen and how they protect your skin, so you can decide which one is best for your long days out in the sun.

Sunblock

True to its name, sunblock blocks the ultraviolet (UV) rays that come from the sun. Sunblock is usually opaque, and when you apply it onto your skin, it acts as a physical barrier that protects your skin from sunburn.¹ 

Sunblocks, also known as mineral or physical sunscreens, usually contain powerful broad spectrum UV-blocking ingredients—such as zinc oxide and titanium dioxide—which work by scattering and reflecting the sun's rays off your skin, and back into the atmosphere.² 

Where sunblock acts as a physical defense against the sun, sunscreen works more as a chemical defense.

Sunscreen 

Sunscreen is a chemical defense against the sun's harmful UV rays. Unlike sunblock, which creates a physical barrier on top of your skin, sunscreen absorbs into your skin and stops UV radiation before it can reach and damage the deeper layers of your skin.³

Sunscreens often contain chemicals responsible for absorbing UV rays, such as avobenzone, oxybenzone, and para-aminobenzoic acid (PABA). These chemicals neutralize UV radiation by converting it into heat, which is then released from your body.⁴

To choose the right sunblock or sunscreen for your skin, always make sure you consider your skin type and sensitivities. You should also keep in mind that the products will only give you proper sun protection when you apply them as directed, so make sure you follow the steps provided on the label.

Which one is better, sunblock or sunscreen?

It’s difficult to definitively say whether sunblock or sunscreen is better, as both provide protection against the sun's harmful UV rays. 

When comparing sunblock to sunscreen, research shows that sunblock is able to block a higher percentage of light, while sunscreen requires frequent reapplication for maximum efficacy.⁵ On the other hand, sunscreens can increase your skin's tolerance to UV rays, which may be beneficial for you if you spend a lot of time in the sun.⁶ 

Ultimately, the best choice between sunblock and sunscreen depends on your individual preferences and skin type. You can even opt to buy a product that contains a mix of both sunblock and sunscreen to get the best of both worlds. 

Before using a new sun protection product, always read the label to ensure that it offers the level of protection you want and to avoid any ingredients that may cause you skin sensitivities.

Sunblock and sunscreen ingredients

There are some beneficial ingredients that you should look for in sunscreens, and others you should avoid. 

The Food and Drug Administration (FDA) has proposed a ‘Generally Regarded As Safe and Effective (GRASE)’ status for sunblocks containing zinc oxide and titanium dioxide.⁷ Sunblocks that contain these ingredients are often referred to as mineral sunscreens.

On the other hand, the FDA has raised safety concerns about other sunscreen ingredients. For instance, sunscreens containing aminobenzoic acid (PABA) and trolamine salicylate have been proposed to be non-GRASE due to safety issues. 

Studies have shown that these ingredients may pose a risk of skin irritation or allergic reactions. The FDA has also proposed a “no GRASE” status for several other sunscreen ingredients, including cinoxate and avobenzone. These ingredients require further data to be deemed GRASE, and the FDA has requested additional safety information to determine their safety and effectiveness.⁸

When choosing a sunscreen or sunblock, read the labels carefully and choose products with ingredients that are approved and effective. Mineral sunscreens containing zinc oxide and titanium dioxide are a good option, as they are effective at blocking UV rays and are generally less likely to cause skin irritation. Additionally, look for sunblock or sunscreen with a high SPF for optimal sun protection.

Ultimately, the best sunscreen is one that provides you with adequate protection from the sun's harmful rays while minimizing potential risks. 

What is SPF in sunblock and sunscreen? 

SPF, or sun protection factor, is a measure of how well a sunscreen or sunblock can protect your skin from harmful UVB rays that cause sunburn. The SPF number is a numerical indicator of the level of protection a product can offer, with higher numbers indicating greater protection.⁹

The American Academy of Dermatology recommends using sunscreen with an SPF of 30 or higher to protect against sunburn and other skin damage caused by UV radiation. You should also reapply sunscreen generously and frequently, especially when spending a lot of time in the sun. Other sun protection measures such as wearing protective clothing, seeking shade, and avoiding tanning beds are also important to reduce your risk of skin damage.¹⁰

What to look for in a good sunblock or sunscreen 

A good sunblock or sunscreen will not only prevent sunburn but also offer other benefits such as being water-resistant and offering broad-spectrum protection.

Water-resistant sun protection

While the FDA no longer allows manufacturers to claim their products are waterproof, they do allow for the labeling of water-resistant products. It's important to use sunblock or sunscreen that’s water-resistant, especially when spending time in or near water. 

A water-resistant product means that the protection offered by the sunblock or sunscreen will remain effective for a certain amount of time in the water before reapplication is necessary. 

According to the FDA, products labeled “water-resistant” will typically offer protection for up to 40 minutes in the water, while those labeled as “very water-resistant” can last up to 80 minutes in the water.¹¹

It's important to note that even with water-resistant products, reapplication is necessary after the specified time limit. This means that if you’re spending an extended amount of time in the water, or if you’re sweating heavily, you should reapply your sunblock or sunscreen at regular intervals to ensure continued protection.

Broad spectrum sun protection

Aside from looking for water-resistant sun protection, look for sunblock and sunscreen that is broad spectrum. Broad spectrum sunblock or sunscreen is designed to protect against both types of ultraviolet (UV) radiation: UVA and UVB. 

UVA radiation has a longer wavelength than UVB radiation and is associated with skin aging, while UVB radiation has a shorter wavelength and is associated with skin burning.¹²

By using a broad-spectrum sunblock or sunscreen, you can protect your skin from both types of UV radiation and reduce your risk of skin damage. It's vital to read the label carefully and choose a sun protection product that hasn't expired and specifically states it offers broad-spectrum protection.

Protect your skin with Curology 

If you're looking for a high-quality sunscreen that provides broad-spectrum protection and won't leave your skin feeling greasy or weighed down, then Curology’s The Sunscreen might be the one for you.

Get your personalized skincare routine with Curology

Get your personalized skincare routine with Curology

Start your skin quiz

The lightweight formula is designed to provide broad-spectrum protection against both UVA and UVB rays, which helps prevent skin damage and aging caused by sun exposure. 

With its lightweight formula and skin-nourishing ingredients, it's a great addition to any skincare routine—Try it today! 

P.S. We did the homework so you don’t have to:

1. Latha, M.S., et al. Sunscreening Agents: A Review. J Clin Aesthet Dermatol. (January 2013).

2. Geoffrey, K., et al. Sunscreen products: Rationale for use, formulation development and regulatory considerations. Saudi Pharm J. (November 2019).

3. Latha, M.S., et al. Sunscreening Agents: A Review. J Clin Aesthet Dermatol. Ibid.

4. Geoffrey, K., et al. Sunscreen products: Rationale for use, formulation development and regulatory considerations. Saudi Pharm J. Ibid. 

5. Latha, M.S., et al. Sunscreening Agents: A Review. J Clin Aesthet Dermatol. Ibid.

6. Yuan, C., et al. Effects of sunscreen on human skin's ultraviolet radiation tolerance. J Cosmet Dermatol. (December 2010).

7. U.S. Food & Drug Administration. Questions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen. (2022, December 16).

8. U.S. Food & Drug Administration. Questions and Answers: FDA posts deemed final order and proposed order for over-the-counter sunscreen. Ibid.

9. U.S. Food & Drug Administration. Sun Protection Factor (SPF). (2017, July 14).

10. American Academy of Dermatology Association. Sunscreen FAQs. (2023, February 17).

11. U.S. Food & Drug Administration. CFR - Code of Federal Regulations Title 21. (2023, March 28).

12. Gabros, S., et al. Sunscreens And Photoprotection. StatPearls. (2023, March 7).

13. Latha, M.S., et al. Sunscreening Agents: A Review. J Clin Aesthet Dermatol. Ibid.

14. Wilson, B.D., et al. Comprehensive Review of Ultraviolet Radiation and the Current Status on Sunscreens. J Clin Aesthet Dermatol. (September 2012).

Meredith Hartle is a board-certified Family Medicine physician at Curology. She earned her medical degree at Kirksville College of Osteopathic Medicine in Kirksville, MO.

Written by

Curology Team

Medically reviewed by

Meredith Hartle, DO