As summer approaches, protecting our skin from harmful UV rays during intense and longer stretches of sun exposure becomes a top priority. Sunscreens should be used for activities like hanging out at the beach all day, engaging in water sports, playing a sport for longer durations or for boat rides. Sunscreens are widely used to shield the skin, but not all sunscreens are created equal. In this article, we will delve into the differences between physical sunscreen and chemical sunscreen, highlighting the pros and cons of each option. Additionally, we will discuss the safety concerns associated with chemical sunscreens, providing evidence-based insights to help you make informed decisions about sun protection.

Physical Sunscreen:

Physical sunscreens, also known as mineral sunscreens, work by creating a physical barrier on the skin that reflects or scatters UV radiation. The two main ingredients found in physical sunscreens are zinc oxide and titanium dioxide. These minerals are naturally occurring and provide broad-spectrum protection against both UVA and UVB rays.

Benefits of Physical Sunscreen:

1. Immediate Protection: Physical sunscreens start working as soon as they are applied to the skin, offering immediate protection from the sun’s rays.
2. Broad-Spectrum Protection: Zinc oxide and titanium dioxide provide excellent protection against UVA and UVB rays, reducing the risk of sunburn, premature aging, and skin cancer.
3. Gentle on the Skin: Physical sunscreens are generally well-tolerated by sensitive skin types and are less likely to cause irritation or allergic reactions.

Chemical Sunscreen:

Chemical sunscreens work by absorbing UV radiation and converting it into heat, which is then released from the skin. These sunscreens contain chemical compounds such as oxybenzone, avobenzone, octinoxate, and homosalate.

Safety Concerns with Chemical Sunscreens:

1. Hormone Disruption: Some chemical sunscreen ingredients, such as oxybenzone, have been found to possess hormone-disrupting properties. Studies suggest that these chemicals may interfere with the endocrine system, potentially affecting hormonal balance (1)(2).
2. Skin Irritation: Certain individuals may experience skin irritation or allergic reactions when using chemical sunscreens due to the presence of synthetic ingredients.
3. Environmental Impact: Chemical sunscreens, particularly those containing oxybenzone, can have detrimental effects on coral reefs and marine ecosystems. These chemicals contribute to coral bleaching and impair the growth and development of coral reefs (3).

Choosing the Right Sunscreen:

When selecting a sunscreen, consider the following:

1. Look for Physical Sunscreens: Opt for sunscreens that contain zinc oxide as the active ingredients. These provide effective protection without the potential safety concerns associated with chemical sunscreens. (I do not recommend physical sunscreens containing titanium dioxide; nor do I recommend sunscreen sprays containing zinc oxide nor titanium dioxide; see below).
2. Check the SPF: Choose a sunscreen with a broad-spectrum SPF of 30 or higher to ensure adequate protection against UVA and UVB rays.
3. Consider Your Skin Type: If you have sensitive skin or are prone to skin allergies, physical sunscreens are generally a safer option.

Mineral sunscreens provide a physical barrier to the sun. They reflect the sun, by coating your skin in nanoparticles of silver or titanium dioxide. There is evidence to suggest that nanoparticle titanium dioxide absorbs through the skin (4).

There’s also a potential exposure through inhalation. Inhalation of either zinc oxide or titanium oxide have been linked with pulmonary inflammation and this can lead to fibrotic and proliferative changes in the lungs, including cancer.  [Titanium dioxide nanoparticles–biological effects] – PubMed (nih.gov)

Protecting our skin from harmful UV radiation is essential for maintaining skin health and reducing the risk of skin cancer. While both physical and chemical sunscreens offer sun protection, physical sunscreens, with their immediate and broad-spectrum protection, pose fewer safety concerns. By understanding the differences and considering the potential risks, you can make informed choices about sunscreen products that prioritize both skin safety and environmental sustainability.

1. Krause, M., & Klit, A. (2012). Endocrine Disrupting Effects of UV-Filters. International Journal of Andrology, 35(3), 424-436.
2. Ghazipura, M., et al. (2017). Systematic Review of the Endocrine-Disrupting Effects of Personal Care Products Used by Pregnant Women. Hormones, 16(3), 255-263
3. Downs, C. A., et al. (2016). Toxicopathological Effects of the Sunscreen UV Filter, Oxybenzone (Benzophenone-3), on Coral Planulae and Cultured Primary Cells and Its Environmental Contamination in Hawaii and the U.S. Virgin Islands. Archives of Environmental Contamination and Toxicology, 70(2), 265-288.
4. Schneider, SL, Lim, HW. A review of inorganic UV filters zinc oxide and titanium dioxide. Photodermatol Photoimmunol Photomed. 2019; 35: 442– 446.