Introduction
In this blog we will be delving into the nitty gritty of sunscreen and sun damage. We will discuss why it’s important to wear sunscreen, the different types of UV radiation we are exposed to and the effects of them. We will discuss the different types of sunscreen available on the market and what should be used in order to sufficiently protect yourself from the damage inflicted by the suns UV radiation.
Why is it important to wear sunscreen?
In the US, more than 9,500 people are diagnosed with skin cancer every day. More than two people die of the disease every hour. (Cancer Facts & Figures, 2024). The most common skin cancers are the keratinocyte carcinomas and squamous cell carcinoma, which result in significant morbidity and need for healthcare. The most deadly skin cancers include melanoma, merkel cell carcinoma, and squamous cell carcinomas of the ears and lips. Although melanoma accounts for only about 1 percent of all skin cancers, most skin cancer deaths are from melanoma. UVA and UVB are omitted by the sun, and both associated with skin cancer, with UVA also being associated with photo ageing and UVB being associated with sunburn. (National Academy of Sciences, Engineering and Medicine 2022). In short unprotected sun exposure can lead to skin cancer, wearing sunscreen significantly reduces this risk.
Facts about skin cancer:
1 in 5 Americans will develop skin cancer by the age of 70.
More than 2 people die of skin cancer in the U.S. every hour.
Having 5 or more sunburns doubles your risk for melanoma.
When detected early, the 5-year survival rate for melanoma is 99 percent.
(Skin Cancer Foundation, 2024).
Difference between UVA & UVB
When it comes to sun protection there are two forms of radiation your sunscreen should be protecting you from:
UVA stands for Ultraviolet A. It is a type of ultraviolet radiation omitted by the sun, they have longer wavelength comparative to UVB. This radiation is present at all hours of the daylight they are very powerful and can penetrate through clouds and even windows! They penetrate the skin more deeply than UVB rays, resulting in wrinkles, sun spots and leathery skin, they also cause long term damage including different types of skin cancer.
UVB stands for Ultraviolet B. Comparative to UVA they have shorter wavelengths. These rays primarily affect the out layer of the skin (epidermis) and are the primary cause of sunburn. UVB rays also play the greatest role in causing skin cancers, including the deadly black mole form of skin cancer - malignant melanoma. (University of Iowa, 2018)
What is SPF?
SPF is an acronym which stands for ‘Sun Protection Factor’. The SPF relates only to the ability of a sunscreen to block sunburning UVB rays. The SPF number does not relate to the ability of a sunscreen to block UVA rays. Sunscreens provide different levels of protection for example SPF 15, or SPF 30, or SPF 50 at the maximum. The numbers associated with SPF eg. SPF 30 or SPF 50 indicates the time you are protected by UVB rays comparative to no protection. It tells you how long the suns UVB radiation would take to redden your skin when using the product exactly as directed versus the amount of time without any sunscreen, for example with SPF 30 it would take 30 times longer to burn than if you wasn’t wearing it. (Steven Q. Wang, 2023)
Because SPF only protects us from UVB radiation it is important to use a broad spectrum sunscreen that can also protect you from UVA rays. So when you are shopping for sunscreen make sure it states UVA/UVB protection on the label this indicates that you are using a broad spectrum sunscreen. I would also recommend using a water resistant sunscreen as this provides continuous protection during water related activities. That being said always reapply after coming into contact with water to ensure protection.
What are UVA star ratings?
Many forms of sun protection carry a UVA star rating on the bottle - Boots developed this rating system in 1992, and it was Europe’s first measurement system for UVA protection. Ranging from 0 to 5, this rating indicates the percentage of UVA radiation that’s absorbed by that particular sun protection, compared to UVB. The higher the star rating, the better the protection against UVA rays. The lowest recommended star rating for UVA protection is 4. (Boots Pharmacy, 2022).
What kind of sunscreen should you use?
A broad spectrum water resistant sunscreen, with a minimum SPF rating of 30 along with a UVA rating of 4 or 5 stars. If you spend a lot of time outdoors use an SPF rating of 50+, do not however compromise on the UVA rating as mentioned above a higher SPF number does not automatically mean better protection.
How often should I be wearing sunscreen?
Every single day. It doesn’t matter if you live in a hot or cold climate, if it’s cloudy or rainy or if you’re inside all day. As mentioned above UVA rays are extremely powerful and can penetrate through clouds and glass, they can also reflect of snow so even the freezing cold does not protect you from the wrath of UV radiation.
How often should I re apply?
Generally, sunscreen should be reapplied generously every two hours, especially after swimming or sweating. Apply 30 minutes before exposing yourself to the sun to give it time to work. Keep in mind that no sunscreen is perfect. Wear wide-brimmed hats, sunglasses or other protective clothing, and seek shade whenever possible. (Anna Chien, 2024).
The suns rays are strongest between the hours of 10am and 4pm, you should therefore take extra care during these hours. Use extra caution near water, snow, and sand. They reflect the damaging rays of the sun. This can increase your chances of sunburn. Do not use tanning beds. Ultraviolet light from the sun and tanning beds can cause skin cancer and wrinkling. If you want to look tan, try using a self-tanning product. But also use sunscreen with it.
What is the difference between organic and inorganic sunscreens?
Organic sunscreens also known as chemical sunscreen use organic (carbon based) compounds to absorb and dissipate UV radiation. These sunscreens work by converting UV radiation into heat, which is then released from the skin. Some common examples of organic / chemical UV filters include: Avobenzone, octocrylene, octinoxate, homosalate, octisalate. Usually an individual UV filter does not provide protection against the entire UV wavelength range. Therefore most commercially available sunscreens contain mixtures of UV filters to offer broad spectrum coverage. Only the inorganic UV filters can provide broad spectrum coverage on their own. (National Academy of Sciences, Engineering and Medicine 2022).
Inorganic sunscreens also known as mineral sunscreens or natural sunscreens contain active mineral ingredients that work by forming a protective barrier on the skin's surface to deflect and scatter UV radiation away from the skin. The two main minerals used in inorganic sunscreens are:
Zinc Oxide: Zinc oxide is a mineral compound that provides broad-spectrum protection against both UVA and UVB radiation. It works by reflecting and scattering UV rays away from the skin. Zinc oxide is known for its stability and compatibility with sensitive skin, making it suitable for use in sunscreen formulations for individuals with allergies or skin sensitivities.
Titanium Dioxide: Titanium dioxide is another mineral compound that offers broad-spectrum protection against UVA and UVB radiation. Like zinc oxide, titanium dioxide forms a protective barrier on the skin's surface, reflecting and scattering UV rays. Titanium dioxide is also generally well-tolerated by sensitive skin.
Traditionally mineral sunscreens were not preferred by the consumer due to the white cast it leaves, resulting in the increasing popularity of organic chemical sunscreens which provides sensory application preferred by many consumers. However in recent times there have been concerns regarding the safety of the of the chemical UV filters used in organic sunscreens. Resulting in the come back of mineral sunscreens, improvements to the mineral filters used in formulas have improved sensory application another reason mineral sunscreens are once more becoming popular with the consumer. The matter of which type of sunscreen is better is fiercely debated amongst scientists and dermatologists, ultimately it is down to you which type of sunscreen you prefer to use just make sure whatever your using does provide broad spectrum protection and has undergone the necessary testing to back up any claims that are made, otherwise you risk comprising the health of your skin.
Conclusion
In this blog we have discussed skin cancer and how wearing broad spectrum sun protection can significantly reduce the risk of getting it. We took a look at some shocking facts and figures pertaining to skin cancer. We established the difference between UVA and UVB, and discussed what SPF means and the numbers that are associated with it. We took at a look at what kind of sunscreen you should be wearing, how often it should be applied in addition to some other precautions that you can take to protect yourself from UV radiation. Lastly we discussed the difference between organic and inorganic sunscreens and the most common type of UV filters used and how they work. I hope this blog has impressed upon you the importance of wearing sunscreen and helped demystify some of the confusion when it comes to the different types of sunscreens and how to effectively protect yourself from UV radiation.
References
Boots Pharmacy Team. (2022). UVA, UVB & SPF - what you need to know. Date Accessed [15/01/2024]. Available at: https://www.boots.com/sun-and-holiday-inspiration/suncare-advice/spf-factors-uva-and-uvb
Cancer Facts and Figures. (2024). American Cancer Society. Date Accessed [15/01/2024]. Available at: https://www.cancer.org/research/cancer-facts-statistics/all-cancer-facts-figures/2024-cancer-facts-figures.html. Accessed January 17, 2024.
Chien, Anna Lien-Lun. (2024). Sunscreen and Your Morning Routine. Date Accessed [15/01/2024]. Available at: https://www.hopkinsmedicine.org/health/wellness-and-prevention/sunscreen-and-your-morning routine#:~:text=Generally%2C%20sunscreen%20should%20be%20reapplied,desk%20just%20to%20be%20safe.
National Academies of Sciences, Engineering, and Medicine. (2022). Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health. Date Accessed [15/01/2024]. Available at: https://nap.nationalacademies.org/catalog/26381/review-of-fate-exposure-and-effects-of-sunscreens-in-aquatic-environments-and-implications-for-sunscreen-usage-and-human-health
Skin Cancer Foundation. (2024). Skin Cancer Facts & Statistics. Date Accessed [15/01/2024]. Available at: https://www.skincancer.org/skin-cancer-information/skin-cancer-facts/
University of Iowa health care. (2018). What is the difference between UVA and UVB rays. Date Accessed [15/01/2024]. Available at: https://uihc.org/health-topics/what-difference-between-uva-and-uvb-rays
Wang, Steven Q. (2023). Ask the expert: does high SPF protect my skin better. Date Accessed [15/01/2024]. Available at: https://www.skincancer.org/blog/ask-the-expert-does-a-high-spf-protect-my-skin-better/