TABLE OF CONTENTS

The sun is upon us, and whether you want to or not, wearing sunscreen will become a necessity, especially with the many heat waves that some countries around the world have been experiencing, including Jamaica.  Ultra Violet Radiation (UVR) are the main culprit, at least, too much of it, as a little sun is necessary for the synthesis of vitamin D, which is crucial to our health.  However, excessive exposure to UVR has been linked to negative health effects as it is reportedly carcinogenic where human health is concerned.

As such, with the harsh weather, sunscreen will become crucial as part of a healthy skincare and wellness regimen.  Therefore, we must educate ourselves on its use, ingredients, and side effects so that we can choose the best ones for our skin and overall health needs. Let’s discuss!

You can read more about the skin in the articles below:

• Love the Skin you are in!

• What is my Skin Type?

The Discussion

Sunscreens are products with active ingredients to block or minimize the penetration of Ultraviolet Radiation (UVR) on the skin.  Ultraviolet radiation has been linked to the development of most skin cancers, especially basal cell carcinomas and squamous cell carcinomas (Task Force on Community Preventive Services, 2004).   Additionally, ultraviolet Radiation has reportedly been associated with some types of melanomas (skin cancers). The two (2) main types of skin cancers are – melanoma and non-melanoma. 

Melanoma or ‘black tumour’ is the most dangerous type of skin cancer as it can spread to other parts of the body.  As such, it accounts for the highest risk of death (clevelandclinic.org; skincancer.org).  This type of cancer is reported as being the seventeenth (17^th) most common cancer, globally and the thirteenth (13^th) most common cancer in men and fifteenth (15^th) in women [World Cancer Research Fund International (wcrf.org)].   On the other hand, non-melanoma skin cancers are common and are usually treated within general medical care. Both basal cell carcinomas and squamous cell carcinomas are non-melanoma tumours.

A 2020 global report indicated that more than 1.5 million cases of skin cancers were reportedly diagnosed with over One Hundred and Twenty Thousand (120,000) skin cancer-associated deaths (World Health Organization, 2022).   To this extent, the regular use of sunscreen has been shown to reduce the occurrences of skin cancers, both melanoma and non-melanoma (Green A, et al. 1999; Green AC et al. 2011). In fact, sunscreen was recommended to prevent skin cancers by both the Canadian Dermatology Association and the American Academy of Dermatology (Canadian Dermatology Association, 2020; American Academy of Dermatology, 2016).  

Apart from skin cancers, ultraviolet radiation has been associated with other skin concerns such as sunburn and photodamage/photoaging.  Photoaging is one of the main concerns of premature aging.  As such, we must find ways to ensure that we protect our skin from excessive exposure to ultraviolet rays, and sunscreen is one of the main and proven vehicles to do so, worldwide. 

In this article, we will be exploring the workings of sunscreen on the skin, some of the common ingredients found in these products, ingredients to look out for when purchasing sunscreens and those to be cautious of or avoid.  The article will also explore the difference between mineral and chemical sunscreens, and the ‘white cast.’

Five (5) ‘Must-Know’ Facts About Sunscreens:

• How does sunscreen work?
• What are some of the common ingredients in Sunscreens?
• Sunscreens’ best ingredients and what to avoid.
• Difference between Mineral and Chemical Sunscreens.

• Common Side Effects of Sunscreens.

How Does Sunscreen Work?

Sunscreens contain both organic (chemical) and inorganic (physical) substances.  These substances work together to protect the skin from ultraviolet radiation.  While these are often described as not the best characterization for sunscreens, it does help to break down the ingredients that these products contain. For example, sunscreens that are classified as physical (inorganic) usually contain ingredients such as zinc oxide and titanium dioxide while those of the chemical properties are usually all the other ingredients that you will find in a sunscreen.

Ultraviolet radiation is described as short wavelengths of light (non-visible light) (Sander et al. 2020).  The light is further divided into several different ranges, for example, ultraviolet A [UVA1, UVA2], Ultraviolet B [UVB] and Ultraviolet C [UVC] (Sander et al. 2020).

The filters are the active ingredients of sunscreens and provide the necessary protection from the sun’s rays. As indicated above, there are two (2) main filter types, which are usually described as categories of sunscreens – chemical and physical.  Chemical filters include ingredients such as oxybenzone, avobenzone, octocrylene and ecamsule while physical filters include ingredients such as titanium dioxide and zinc oxide. 

Additionally, chemical filters are those compounds that can be absorbed by the skin while physical filters reflect ultraviolet rays from the skin (Geoffrey et al. 2019).  However, there are situations where physical compounds such as titanium dioxide and zinc oxide, will behave like chemical filters and that is, when the particle sizes are very small, such as when the sunscreen has been what is described as ‘micronized.’  (Geoffrey et al. 2019).

As such, your protection from the sun will be dependent on the type of ingredients in the product you purchase and whether it absorbs or reflects ultraviolet radiation (Geoffrey et al. 2019).  Nonetheless, according to research, sunscreen filters typically provide protection against most of the varying rays of the sun such as UVA1, UVA2 and UVB radiation.

What are Some of the Common Ingredients in Sunscreens?

Sunscreens contain both organic and inorganic substances.  These substances work together to shield the skin from ultraviolet radiation. Organic ingredients are those that usually make up ‘chemical sunscreens’ while inorganic compounds are those of ‘mineral sunscreens.’  Mineral sunscreen (physical) usually uses ingredients that sit on top of the skin to block UV rays while chemical sunscreens generally use ingredients that are absorbed into the skin.

Overall, several ingredients are present in sunscreen products, varying from mineral brands to chemical ones.  Some of the common ingredients include titanium dioxide (provides UV protection against UVA2), Zinc Oxide (provides UVA1 protection), octinoxate (UVB protection), homosalate (UVB protection), avobenzone (UVA 1 protection), oxybenzone (UVA 2 protection), cinoxate (UVA) and octocrylene (UVA 2 protection), ecamsule (provides both UVA and UVB protection) among others.  Oxybenzone, avobenzone and homosalate can reportedly be absorbed into the skin (Canadian Medicine Association Journal, 2020).

As such, you will see a combination of these ingredients which enables the product to provide against several UV filters. Therefore, you can look for these ingredients in your sunscreen products to ensure that you are protected from varying UV filters.  Further, ensure that you continue further research as to some of these ingredients’ possible effects on the body. This is due in part to the recent research that has now placed the common ingredient – oxybenzone under the radar. 

According to research, oxybenzone, which is usually found in mineral sunscreens, is now reportedly associated with adverse effects on the reproductive system.  Research contends that it may disrupt hormones and cause allergic reactions, especially if you have sensitive skin. However, the study was conducted with fish and thus labelled by those researchers as ‘uninformative.’ (Ghazipura et al. 2017).  

However, a study of both humans and animals found that high levels of oxybenzone during pregnancy may reduce the gestational age of babies. The gestational age is a term used to describe how far along one pregnancy is. It was also said to be associated with a decrease in the birth weight of female babies (Ghazipura et al. 2017). Nonetheless, more studies in this area are recommended

What are the best Sunscreen Ingredients and those to Avoid?

Most sunscreen products have common ingredients that work to block varying UV radiation from the skin.  Most ingredients do this by just laying on top of the surface of the skin.  However, there are a few ingredients that can be absorbed by the skin and those are the ones that can become concerning, especially if they can negatively impact the body and overall health (short or long-term).  

One of those ingredients was mentioned earlier – oxybenzone, which studies have now suggested has become one of the most worrying ingredients in sunscreen.  However, avobenzone, octocrylene and ecamsule reportedly can also be absorbed by the skin, which of course may warrant continuous research (Matta MK et al. 2019).

According to a small randomized controlled trial conducted in 2019, these ingredients were found to be absorbed into the skin and remain there for up to four (4) days.  The level of absorption into the bloodstream by these ingredients was found to exceed the recommended levels established by the United States Food and Drug Administration (FDA).  As such, regular use may cause unwanted build-up in the body (Califf RM and Shinkai K., 2019).  Subsequent research has since confirmed these findings (Matta MK et al. 2020).  Nonetheless, more studies are recommended where these findings are concerned, particularly as they relate to health effects over time. 

Therefore, it is best to look out for products with ingredients such as zinc and titanium oxide as these ingredients sit on the surface of the skin, rather than being absorbed.  These ingredients are usually found in mineral sunscreens. Other ingredients that are mentioned earlier such as oxybenzone and homosalate etc., are typically found in chemical sunscreens and are absorbed by the skin. While research is ongoing as to any potential ill effect on human health where absorption is concerned for many of the ingredients that are usually found in sunscreens, it is best to know the differences among the ingredients so that you will be able to make more informed choices when purchasing.

So, What is the Difference Between Mineral and Chemical Sunscreen?

Mineral sunscreens or what is usually known as physical sunscreens are those that contain active ingredients that typically are not absorbed into the skin.  The active ingredients of mineral sunscreens are zinc oxide and titanium dioxide. Research has shown that the nanoparticles of zinc oxide only penetrate the uppermost layer of the skin (Stratum corneum) and not the lower layer (lower stratum corneum) (Filipe et al. 2009).

Zinc oxide and titanium dioxide are the ingredients that usually cause that white cast (ghost cast 😊) on the skin, and as such, usually not appealing cosmetically.  However, most of these sunscreens are leaving the white cast behind due to more advanced formulations (Rai et al. 2012).  Additionally, according to research, zinc oxide and titanium dioxide are the only ingredients that purportedly are recognized as safe by the FDA.

On the other hand, chemical sunscreens are those that contain ingredients that are usually absorbed by the skin.  As such, these products usually contain active ingredients such as oxybenzone, avobenzone, homosalate ecamsule etc. These ingredients are more cosmetically appealing as they do not typically leave a white cast on the skin as with mineral sunscreens.

Of the two (2) types of sunscreens, mineral sunscreens are usually considered healthier even though they leave a white cast on the skin.  Additionally, it may be the better option for those with sensitive skin or those who are looking for non-chemical options.  Nonetheless, chemical sunscreens are easier to apply and typically require less work in terms of application than mineral ones. However, they may not be safe to use due to the controversies surrounding some of the ingredients used, especially, in the long-term.

Further, an SPF (Sun Protection Factor) value of 15 is considered safe and effective for sun protection, but those of a higher spectrum will provide more protection.  Importantly, the effectiveness of the sunscreen will be dependent on the way it is applied as well as how much is applied. As such, always try to use your product as described for maximum protection.

What are the Side Effects of Sunscreens?

Most of the side effects of using sunscreens are irritation such as stinging and burning.  However, some may cause allergic reactions such as dermatitis and photo-allergic contact dermatitis. Nonetheless, the latter is usually considered rare and may be due to the inclusion of ingredients such as octocrylene, oxybenzone and octyl methoxycinnamate (Rodríguez et al. 2006).

Illustrative Summary

Here is an illustrative summary of the Five (5) ‘must-know’ facts about Sunscreens!

Let’s Sum Up!

Sunscreens are becoming a must-have item both cosmetically and health-wise.  This is due to the increasing incidences of skin cancers as well as the overall damage to the skin and anti-aging effects of the sun’s harmful rays.

While sunscreens are becoming more popular, ongoing research is exploring some of the possible damaging effects of certain ingredients especially those found in chemical sunscreens.  This is because these ingredients are usually absorbed into the skin, for example, oxybenzone.

Nonetheless, while you need to review your ingredients for safety, SPF value must be taken into consideration.  The lowest recommended SPF value is 15. As such, look out for products with a SPF value of 15 or higher.

For years, I was never a fan of sunscreen. Not because it wasn’t important, I just could not find one that didn’t let me look ‘whiteout’ (You know what I mean?). But, for the past year or so, I have found one that has ingredients that I have been looking for, but most importantly left no ‘white cast’, and I am super happy and saddened a bit, that I did not start using sunscreen earlier and more consistently.  Now, if I could wear it to bed, I would 😊!), just because of the difference it has made to my skincare regimen.

So, now that you have explored sunscreens, the types of ingredients and some of the common side effects, what will your choice be?  Do you use a Sunscreen? Or will you now include one in your skin and health and wellness routine?

You can read more about the skin and some awesome ingredients to look out for in the articles below:

• Love the Skin you are in

• What is my Skin Type?

• Hyaluronic acid – Antiaging Here or Fad?

• Vitamin D and the Skin.

References

• Califf RM, Shinkai K. Filling in the evidence about sunscreen. JAMA 2019;321:2077–9.
• Canadian Dermatology Association’s position statement sun protection and sunscreen use. Ottawa: Canadian Dermatology Association; 2020. Available: https:// dermatology.ca/wp-content/uploads/2020/02/Sun-Protection-and-Sunscreen -Use-Position-Statement-EN.pdf (accessed 2020 Mar. 15).
• CMAJ 2020 December 14;192:E1802-8. doi: 10.1503/cmaj.201085.
• Filipe P, Silva JN, Silva R, et al. Stratum corneum is an effective barrier to TiO2 and ZnO nanoparticle percutaneous absorption. Skin Pharmacol Physiol 2009;22:266-75.
• Geoffrey K, Mwangi AN, Maru SM. Sunscreen products: rationale for use, formulation development and regulatory considerations. Saudi Pharm J 2019;27:1009-18.
• Ghazipura M, McGowan R, Arslan A, et al. Exposure to benzophenone-3 and reproductive toxicity: a systematic review of human and animal studies. Reprod Toxicol 2017;73:175-83.
• Green A, Williams G, Neale R, et al. Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial. Lancet 1999;354:723-9.
• Green AC, Williams GM, Logan V, et al. Reduced melanoma after regular sunscreen use: randomized trial follow-up. J Clin Oncol 2011;29:257-63.
• Matta MK, Zusterzeel R, Pilli NR, et al. Effect of sunscreen application under maximal use conditions on plasma concentration of sunscreen active ingredients: a randomized clinical trial. JAMA 2019;321:2082-91.
• Matta MK, Florian J, Zusterzeel R, et al. Effect of sunscreen application on plasma concentration of sunscreen active ingredients: a randomized clinical trial. JAMA 2020;323:256-67.
• Prevent skin cancer. Schaumburg (IL): American Academy of Dermatology; 2016:1. Available: www.aad.org/public/diseases/skin-cancer/prevent/how (accessed 2020 Mar. 15).
• Rai R, Shanmuga SC, Srinivas C. Update on photoprotection. Indian J Dermatol 2012;57:335-42.
• Rodríguez E, Valbuena MC, Rey M, et al. Causal agents of photoallergic contact dermatitis diagnosed in the national institute of dermatology of Colombia. Photodermatol Photoimmunol Photomed 2006;22:189-92.
• Sander M, Sander M, Burbidge T, Beecker J. The efficacy and safety of sunscreen use for the prevention of skin cancer. CMAJ. 2020 Dec 14;192(50):E1802-E1808. doi: 10.1503/cmaj.201085. PMID: 33318091; PMCID: PMC7759112.
• Task Force on Community Preventive Services. Recommendations to prevent skin cancer by reducing exposure to ultraviolet radiation. Am J Prev Med 2004; 27:467-470.