Sunscreen provides protection against the harmful effects of exposure to ultraviolet radiation. However, not all sunscreens are made the same. Some use different classes of active ingredients in their formulation. Others can provide broad-spectrum protection against both UVA and UVB rays. There are also sunscreens with different ratings found in their labels.
How to Choose the Right Sunscreen
Physical Sunscreen vs Chemical Sunscreen
Of course, in choosing skincare products, it is better to know the ingredients contained therein. Sunscreen ingredients and formulations are generally categorized according to two: physical sunscreen and chemical sunscreen.
Physical or mineral sunscreens are based on inorganic mineral compounds that work primarily by blocking ultraviolet radiation. They are once called sunblocks. Two compounds approved safe and effective by government regulators, including the U.S. Food and Drug Administration, are titanium dioxide and zinc oxide. Chemical sunscreens, on the other hand, are made with inorganic UV filters that work by absorbing UV radiation.
Each category has their advantage and disadvantages. Physical ones are generally insoluble, thus providing some level of water-resistance. They are also more suitable for sensitive skin because they have less tendency to cause irritations or allergic reactions.
Chemical variants are easier to apply, more transparent, and do not leave a whitish residue. Products made from TiO2 and ZnO are thicker, harder to spread on the skin, and leave a white cast on the skin. Hence, chemical sunscreens are easier to spread throughout the skin. They are also easier to integrate into other skincare products such as facial moisturizers, toners, liquid makeup, and hair leave-on products and hairsprays, among others.
Some formulations combine physical and chemical active ingredients to complement the advantages of each and address their respective drawbacks. For example, some products contain both titanium dioxide and avobenzone to provide broad-spectrum protection.
Factors in Choosing the Right Product
Ingredients are a good starting point in choosing from a selection of different sunscreen products. They define a range of product benefits and features to include the type of production a particular brand provides, the quantity and quality of protection, product form and consistency, and applications or other use-case scenarios, among others.
Ingredients fundamentally tell consumers how sunscreens work. Considering the difference between physical and chemical ingredients take note of the following factors that should be considered when choosing the right sunscreen:
1. Broad-Spectrum UV Protection
There are products, particularly those containing only titanium dioxide, that only protect against UVB rays. The right sunscreen should protect against both UVA and UVB rays. Each subtype of UV radiation affects the skin and overall human health differently.
Product labels can tell a consumer if a particular product provides broad-spectrum protection. However, manufacturers and different jurisdictions use different rating values and standards or systems. Consider the following:
• Sun Protection Factor: The sun protection factor or SPF rating indicates protection against UVB. An SPF rating tells consumers how long it takes before an average person develops sunburn from UVB exposure. The number next to this abbreviation represents a fraction of UVB radiation that reaches the skin. For example, an SPF 30 means that 1/30th of the burning radiation will reach the skin.
An ideal sunscreen should at least have SPF 30. However, it is important to reiterate the fact that an SPF rating only indicates protection from UVB rays. It is still an inadequate information because damages from UVA rays are largely invisible.
• Protection Grade of UVA: Japan and the Asian market use the Protection Grade of UVA or PA system to indicate the capability of specific sunscreen products to protect against UVA radiation.
A product with a PA+ rating has a UVA protection factor of between two and four, while a PA++ rating has between four and eight and a PA+++ rating has more than eight. The specific use-case equivalent of each rating is also descriptive.
Products with a PA+ rating have minimal UVA protection. They are suitable for individuals with minimal sunlight exposure. Those with PA++ are ideal for moderate exposure under medium sunlight while those with PA+++ are appropriate for exposure to intense UVA radiation.
• Star Rating System for UVA: The United Kingdom uses a different rating system that involves using stars. The country has adopted the Boots Star Rating System. The number of stars shown in the product label indicates the percentage of UVA rays that a specific sunscreen could protect in comparison to UVB rays.
The entire system fundamental tells the ratio between the degree of protection afforded by the UVA protection and the UVB protection. It is also related to the SPF rating system. Sunscreens with zero to single star provide minimal protection. Most recommendations suggest using products with four to five stars on the label.
However, because of the relationship between the Star Rating System and the SPF rating system, sunscreens with a high number of stars and low SPF do not provide better UVA protection than those with a lower number of stars and a higher SPF rating. It is essential to choose a product with a high SPF rating and a high number of stars. Recommendations suggest choosing a sunscreen with an SPF 30 and 4 to 5 star ratings.
Specific Applications or Use-Case Scenarios
Sunscreens also come in different forms. Lotions are the most common form. However, within this subcategory, there are different subtypes. There are oil-based lotions, which are ideal for dry skin and cold weather, and there are gel-based lotions, which are ideal for normal-to-dry skin and hot and humid weather. Some sunscreen lotions are water-resistant and suitable for use in activities involving swimming or for users who perspire heavily.
Consumers need to take into consideration the solubility of active ingredients. Physical UV blockers such as titanium dioxide and zinc oxide are generally insoluble. Hence, when compared to organic chemicals used in chemical sunscreens, they are ideal for people who swim or are involved in outdoor activities.
Other forms of sunscreens include liquid products and sprays. These products are primarily based on organic UV filters. Compared to lotions based on TiO2 and ZnO, liquid-based and spray-based variants are easier to apply and are more transparent. Organic UV filters are also ideal ingredients for use in makeup products such as foundation, tints, and face powders that provide some degree of UV protection
Consider the following questions when choosing the right sunscreen based on use-case scenarios:
• How long will you stay outdoors and at what time of the day? Longer duration under the Sun from 9:00 in the morning onwards would require a broad-spectrum product with at least SPF 30 and at least PA++ or a 4-star to a 5-star rating. A quick trip outside to buy something or walk in a coffee shop would require between SPF 15 to SPF 30 with average UVA ratings. An average person takes 5 to 10 minutes of exposure to direct sunlight before developing sunburns
• What activities are you going to do outside and how long will it take? Trips that involve strolling at the beach, hiking the mountains, are riding a bicycle following a trail would need sunscreens with above-average protection ratings. Remember that swimming and activities that make a person perspire heavily would need water-resistant sunscreens. Physical ingredients are ideal in these scenarios. A transparent liquid-based product might be more suitable For individuals attending an outdoor daytime event
• Will you be staying indoors and are there windows? Note that a person still needs to wear sunscreen even when indoors during the daytime. Note that this is especially true when staying inside houses and buildings with large windows. Furthermore, this is also applicable in cars. UVB radiation generally does not penetrate unfiltered glass but UVA radiation can. UVA rays are responsible for photoaging and indirect molecular damages that can lead to cancer formation.
Different Skin Types and Health Concerns
Certain ingredients in skincare products are not suitable for all skin types. In sunscreens, there have been concerns over organic ultraviolet radiation filters used in chemical sunscreen formulations. Active ingredients such as oxybenzone and octinoxate can trigger moderate to severe allergic reactions in some individuals.
There are also concerns over the effects of these UV filters. The U.S. FDA published two studies concluding that oxybenzone, octinoxate, octisalate, octocrylene, homosalate, and avobenzone are all systemically absorbed into the body after a single use. Studies revealed further that oxybenzone, octinoxate, and homosalate have the potential to cause hormone disruptions.
Experts also have precautions over mineral compounds such as titanium dioxide and zinc oxide because of the potential for ingestion and inhalation due to their small-sized particles. However, the risk is low because they are readily well-blended in a sunscreen formulation. Studies have also revealed that these two ingredients in physical sunscreens pose a low risk for allergic reaction.
Products containing titanium dioxide and zinc oxide are more suitable for people with sensitive skin. The two also have added benefits, including some antimicrobial activity. However, an electron of titanium dioxide becomes unstable when hit by a photon of UV radiation, thus producing free radicals and raising the possibility for damages due to oxidative stress.
Zinc oxide has the lowest health-related risks among all sunscreen ingredients. Aside from the fact that it is ideal for sensitive skin, it has additional benefits that include soothing mildly irritated skin, relieving rashes and itchiness, and preventing certain skin infections.
FURTHER READINGS AND REFERENCES
- Matta, M. K., Florian, J., Zusterzeel, R., Pilli, N. R., Patel, V., Volpe, D. A., Yang, Y., Oh, L., Bashaw, E., Zineh, I., Sanabria, C., Kemp, S., Godfrey, A., Adah, S., Coelho, S., Wang, J., Furlong, L.-A., Ganley, C., Michele, T., and Strauss, D. G. 2020. “Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients.” JAMA. 323(3): 256. 1001/jama.2019.20747
- Matta, M. K., Zusterzeel, R., Pilli, N. R…Straus, D. G. 2019. “Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial.” JAMA. 321(21): 2082-2091. DOI: 1001/jama.2019.5586
- Schneider, S. L. and Lim, H. W. 2018. “A Review of Inorganic UV Filters Zinc Oxide and Titanium Dioxide.” Photodermatology, Photoimmunology & Photomedicine. 35(6): 442-446. DOI: 1111/phpp.12439
- Smijs, T. and Pavel, S. 2011. “Titanium Dioxide and Zinc Oxide Nanoparticles in Sunscreens: Focus on Their Safety and Effectiveness.” Nanotechnology Science and Applications. 4:95-112. DOI: 2147/nsa.s19419