Sunscreen vs. Sunblock: What is the Difference

Sunscreen vs. Sunblock: What is the Difference

There are topical skincare products specifically formulated to protect the skin from the damaging and potentially cancerous effects of the sun.  They work by screening or absorbing ultraviolet radiation to prevent sunburns, photoaging, and skin cancers, among others. Some call these products sunscreens. Others call them sunblock lotions. What exactly is the difference between these two?

Explaining the Difference Between Sunscreen and Sunblock

Outdated Understanding of the Sunblock Label

Most consumers use the words “sunscreen” and “sunblock” interchangeably. Some are more familiar with the latter, while others prefer using the former. Others believed that products labeled as sunblock are more potent than sunscreens.

Several online publications and health blogs have noted that the two labels pertain to the two different ways products can protect the skin from ultraviolet radiation. They noted that a sunblock blocks UVA and UVB rays by forming a physical shield, thus physically blocking the radiation from hitting and penetrating deeper into the skin.

On the other hand, for them, sunscreens work not by physically blocking the radiation but by absorbing them. The described mechanism of action of these products centers on the use of chemicals that create a thin film and readily absorb UVA and UVB rays so that these harmful radiation would not penetrate the skin.

Regulation and Standards On Proper Labeling

The aforesaid explanations regarding the difference between sunscreen and sunblock are obsolete. To be more specific, “sunblock” is already an outdated term. Most manufacturers have dropped this label, and health professionals recommend the use of “sunscreen.”

In fact, the United States Food and Drug Administration has banned manufacturers from using the word “sunblock in their product labeling and marketing since 2011. The agency explained that the term might mislead consumers and encourage them to overestimate the effectiveness of the products so labeled.

Even the documents of regulatory bodies from the European Union and in other countries in Southeast and East Asia, as well as technical and scientific papers, are now using the term “sunscreen” to refer to topical skincare products and formulations intended to protect the skin from ultraviolet radiation.

Physical Sunscreen and Chemical Sunscreen as the Proper Categories

The literature now uses the terms “physical sunscreen” and “chemical sunscreen” to classify to broad categories of sunscreen products based on their mode of action. Those containing inorganic compounds such as zinc oxide and titanium dioxide are called “physical” because they stay on the surface of the skin and deflect UVA and UVB rays.

Chemical sunscreens have organic particulates as active ingredients the protect the skin from the harmful effects of the sun by absorbing ultraviolet radiation. Examples of these ingredients are avobenzone, octisalate, octocrylene, oxybenzone, homosalate, and octinoxate.

These two product categories have additional differences aside from their respective mechanisms of action that can guide consumers in choosing the right sunscreen for themselves. Physical sunscreens are usually thick and opaque. They feel heavier to apply and sometimes leave a white film on the skin. Chemical sunscreens are easier to rub and most transparent. They also come in different formula options, including lotions and liquid sprays, facial moisturizers, and toners.

FURTHER READINGS AND REFERENCES

  • Kuritzky, L. A. and Beecker, J. 2015. “Sunscreens.” Canadian Medical Association Journal. 187(13): E419. DOI: 1503/cmaj.150258
  • S. Food and Drug Administration. 2011. “Questions and Answers: FDA Announces New Requirements for Over-The-Counter Sunscreen Products Marketed in the U.S.” U.S. Food and Drug Administration. Available online
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