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Specialist Advice — 7 minutes

Sunscreens: Thoughtful protection for you and the planet

June 20, 2025

Raymond Lepage, PhD, Doctor in Biochemistry
Raymond Lepage, PhD, Doctor in Biochemistry
Science popularizer

With our very hot summers, the rise in outdoor activities, such as cycling and water sports, and the increasing popularity of vacations down South, Quebecers seem to be spending more time in the sun all year long.

Vacations and relaxing moments encourage us to take full advantage of lakes, pools, patios and a multitude of outdoor activities. A wonderful time to enjoy, even though we know that extended exposure to the sun can increase the risk of skin cancer.

So, wearing protective clothing and using sunscreen are essential. That said, does the available information help everyone clearly understand the hazards associated with these products, not only for our health but also for the environment? And above all, are they being used correctly?

nose sunscreen

What are UVA rays, UVB rays and SPF?

The sun mainly emits two types of rays that can cause changes in the skin.

UVB rays, the strongest ones, are closely associated with skin cancers, particularly melanoma. All sunscreens block these rays, and their degree of protection is indicated by the sun protection factor, commonly referred to as “SPF”. For example, an SPF of 30 means that by wearing that screen, you would need 30 times the exposure to the sun to achieve the same tanning effect as without it.

As for UVA rays, they are less powerful than UVB rays, but they make up 95% of the UV rays that reach us all year long. They are responsible for the aging of the skin, worsening the damage done by the UVB rays and increasing the risk of melanoma or other skin cancers.[1]

Plus, only sunscreens claiming broad-spectrum protection or whose packaging has the UVA or CDA logo effectively protect against these two types of rays.

What is the difference between mineral and chemical sunscreens?

There are two types of sunscreens: mineral agents, also called blocks, which reflect UV rays, and chemical agents, which neutralize them by converting them into heat.

Mineral agents

First-generation zinc oxide and titanium dioxide often evoke the image of a white nose at the beach! Despite this sometimes aesthetically awkward appearance, these agents are generally recognized as being effective and not harmful to our health or the environment. Today, thanks to nanoparticles, clear mineral sunscreens are available, and they don’t leave behind any white streaks.

Chemical agents

Ingredients such as avobenzone, oxybenzone, and octocrylene are the most common active ingredients in chemical sunscreens. They come in the form of creams, ointments, lotions, balms or sticks and provide SPF protection equivalent to that of mineral sunscreens.

Ingredients to watch for when it comes to health

Many studies have shown that these chemical products, when applied generously to the skin, can quickly enter our bloodstream. Once inside the body, these substances could accumulate, act as endocrine disrupters and even present a cancer risk.[2]

Agents like oxybenzone, which absorb UV rays, react to light and form chemical subproducts – free radicals – that could be harmful to our health… and the environment.

What about the environment?

Sunscreens also raise environmental concerns, particularly when it comes to coral reefs, which are already weakened by ocean warming. And it’s precisely in those warm waters where we like to swim that those corals are most present.

Many laboratory studies have shown that ingredients like oxybenzone are toxic to corals, but at very high doses and in artificial conditions.[4] In a natural setting, the effects are more difficult to measure due to the high level of dilution in seawater, currents, and the poor solubility of many products.

As a precaution, regions like the state of Hawaii and Key West, Florida, have decided to ban some sunscreens containing ingredients that are considered concerning, such as oxybenzone.[5]

How to properly use sunscreens

One thing is clear: the benefits of sunscreens in preventing skin cancers significantly outweigh their potential adverse effects on our health or the environment, provided they are used correctly!

And yet, with over 80,000 new cases of skin cancer diagnosed each year in Canada, that seems far from being the case.[6] According to Dr. Dawn Davis, a dermatologist at the renowned Mayo Clinic, two tablespoons (30 mL) of sunscreen are sufficient to protect the face, neck, and backs of the hands, and even more when wearing a swimsuit. The product should also be reapplied every two hours, and more often after swimming.[7] And caution: drying off with a towel can wipe away some of the protection.

What FPS should I choose?

The Canadian Dermatology Association recommends an FPS of at least 30, because it blocks 96% of UVB rays.[6] With an FPS above 50, the gain in protection is minimal.[7] And remember: UV rays pass through clouds and are reflected by water, snow, and other surfaces. So, it’s essential to protect yourself all year round, whether it’s sunny or

“Natural” sunscreens

When environmental concerns related to conventional sunscreens are raised, the industry and many consumers turn to so-called “natural” options. These products are generally copper oxide or titanium dioxide-based mineral agents, sometimes combined with vegetable oil, such as coconut oil.

Natural products often mean homemade products that we can make ourselves using relatively accessible ingredients.[10] However, be cautious: these preparations are rarely tested, and their efficacy, especially when in contact with water, is difficult to guarantee.

Whether they are homemade or purchased, remember that aside from environmental or economic considerations, the primary role of a sunscreen is to protect against UV rays adequately.

Protection… beyond sunscreen

Even at the beach, clothing can provide excellent protection. Hats, caps, anti-UV clothing, a beach umbrella or tent; there are many effective and sustainable options.

The sun is a valuable ally: it produces vitamin D, promotes plant growth and has a remarkable impact on mood. However, we must expose ourselves to it with caution. Throughout their life, one in five North Americans will be impacted by skin cancer, caused mainly by exposure to UV rays.[7]

Whether we choose a mineral sunscreen or a chemical one, or whether we prefer shaded areas, protective clothing, and umbrellas, we have several available strategies to enjoy the sun safely. Finally, remember to check the UV index for the day… and to wear your sunscreen!

This revised edition reflects an updated version from the original version published on our website. We have incorporated recent facts to offer you current and pertinent information.

Sources8
  1. Collective. What is Ultraviolet Radiation? AIM at Melanoma Foundation. https://www.aimatmelanoma.org/melanoma-101/prevention/what-is-ultraviolet-uv-radiation/. Accessed on June 19, 2025.
  2. M Sander, M Sander, T Burbidge, et J Beecker. « The efficacy and safety of sunscreen use for the prevention of skin cancer ». JAMC. 14 déc. 2020; 192(50): E1802–E1808. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7759112/
  3. Collectif. « Crème solaire et coraux ne font pas bon ménage ». Québec Science, August 18, 2022. https://www.quebecscience.qc.ca/14-17-ans/encyclo/creme-solaire-et-coraux-ne-font-pas-bon-menage/
  4. Scientifique en chef du Québec. « La crème solaire endommage les coraux? Incertain ». July 18, 202. https://www.scientifique-en-chef.gouv.qc.ca/impact-recherche/la-creme-solaire-endommage-les-coraux-incertain/
  5. M. Sander, M. Sander, T. Burbidge, and J. Beecker. “Efficacy and safety of sunscreen for the prevention of skin cancer.” CMAJ, March 8, 2021; 193(10): E348–E354. https://pmc.ncbi.nlm.nih.gov/articles/PMC8034319/
  6. L. Torborg. “Mayo Clinic Q & A: Sunscreen Best Practices.” Mayo Clinic. https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-apply-sunscreen-generously-and-frequently-for-full-protection/
  7. Collective. “Sunscreens.” Canadian Dermatology Association. https://dermatology.ca/public-patients/recognized-products/sunscreen/. Accessed June 18, 2025.
  8. Collective. “Is it Possible to Make a Safe and Effective Sunscreen from Scratch?” Healthline, July 10, 2019. https://www.healthline.com/health/homemade-sunscreen#diy-recipes