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How Safe is Your Sunscreen?

Updated: Jul 18, 2022

Summer is upon us! What are your sun protection strategies?

What is more effective than sunscreen? Avoiding the midday sun, finding shade, covering up with clothing, hats and sunglasses are great options, however they may not be feasible depending on the activities you do. There are days when we are exposed to the sun for much longer than we need to make vitamin D. In this case, choosing the right sunscreen is really important to prevent sunburn, skin damage and limit the risk of skin cancer.

Sunscreen safety and efficacy As you slather a high SPF sunscreen all over your face and body, or slab thick layers of the lotion over your children, do you ever wonder about sunscreen efficacy and safety?

  • How much sun protection are you getting from your sunscreen?

  • What are the chemicals and their potential impact on your health?

  • Are any of the ingredients absorbed through the skin?

  • How long do these chemicals stick around?

  • How do they affect pregnant women, breastfeeding mothers, teenagers and everyone else?

  • What is the potential environmental impact on the marine ecosystem?

Unfortunately, many over-the-counter products are not what you think they are. Let's take a look at SPF and a few potential toxic ingredients. Let's figure out how to choose a sunscreen free of harmful chemicals.

UV Spectrum

Sunlight is the main source of ultraviolet (UV) radiation, which is invisible to the eyes. They come in the form of UVA and UVB.

  • Ultraviolet B (UVB) have slightly more energy than UVA rays and are responsible for sunburn and skin damage.

  • Ultraviolet A (UVA) rays can (1) cause our skin to age and form wrinkles, (2) damage our DNA from free radicals, (3) impact melanoma production, and (4) suppress our immune functions.

What does SPF mean? SFP stands for sun protection factor and primarily protects us from sunburn-causing UVB, but not UVA. SPF values can be misleading (explained below). Doubling the SPF provides a marginal increase in UVB protection, and typically at the cost of lower UVA protection. For example,

  • SPF 15 blocks 93% of UVB rays

  • SPF 30 blocks 97% of UVB rays

  • SPF 50 blocks 98% of UVB rays.

Broad Spectrum If you are buying sunscreen made in the US, look out for broad spectrum that can block both UVA and UVB rays. European sunscreen manufacturers follow stricter regulations and their products usually provide UVA protection of at least one third of the SPF on the label. For example, a European sunscreen with SPF 30 should have an UVA protection of at least 10. SPF values from the labs do not reflect real life applications The SPF value on the label is based on tests done inside a lab, the number does not necessarily reflect the protection we get when using outdoors. SPF measurements are very sensitive to testing conditions and thickness application, especially for higher SPFs (50+). In other words, you may not be getting the same level of protection as advertised on the label, particularly if the SPF is 50 or higher. The trouble with high SPF products

  1. Poor balance. Higher SPF provides higher protection against sunburn from UVB at the expense of UVA rays. Even though UVA may not cause sunburn, studies suggest UVA is associated with higher risk of ageing, DNA damage, and skin cancer.

  2. Misuse. Sunbathers using higher SPF tend to have a false sense of security. High SPF users typically spend more time in the sun and reapply less frequently, consequently overexposing themselves to UVA and UVB radiation. People who use lower SPF are likely to go indoor earlier, stay under the shade or cover themselves as more effective means of protection.

  3. SPF values are misunderstood. SPF 100 does not offer twice the protection from SPF50. A correctly applied SPF 50 sunscreen blocks 98% of UVB, and a SPF 100 sunscreen blocks 99% of UVB, which is only 1% more.

  4. SPF values indicate the level of protection NOT the amount of time one can be protected from the sun. Reapply your sunscreen regularly, especially if you swim or sweat after application.

  5. Higher concentrations of chemicals. In order achieve a higher SPF, higher concentration of sun-filtering chemicals are needed, which can have their own side effects such as skin allergies, absorption into the body and endocrine disruption.

According to the EWG, studies do not show that higher SPF provide better protection against skin damage or cancer, so it is not worth the risk of extra chemical exposure from higher SPF products, plus all the other pitfalls described earlier. Therefore, using a SPF 30 is likely more sensible than SPF 70.

Chemicals/ Active Ingredients Recognising a few chemicals can be helpful because sunscreen is meant to be worn all year round, all over the body and even multiple times a day when we are outside in the summer. Sunscreen isn’t like shampoo or shower gel, which gets rinsed off after a few minutes. According to the studies published by the FDA, many sunscreen chemical ingredients are absorbed into the skin, some are found on the skin and in the blood weeks after application, even in amniotic fluid, breast milk, and urine samples. Organic UV filters Watch out for organic UV filters in chemical sunscreens, being organic doesn't mean they are safe to use. Some of these can penetrate the skin and cause hormone disruption, affect pregnancy and birth weight, increase the risk of breast cancer and endometriosis. Ingredients of Concern


  • is one of the most widely used UV filters in chemical sunscreen.

  • is absorbed through the skin

  • can cause allergic skin reactions, endocrine disruption, e.g. metabolism, thyroid function

  • potentially more harmful to children

  • can increase the risk of breast cancer and endometriosis

  • is capped at 2.2% by the European Commission but allowed to reach 6% in the US

  • is banned by Hawaii because of its impact on the marine ecosystem


  • is another widely used organic UV filter

  • insufficient data to support its safety and effectiveness (FDA)

  • can penetrate the skin, disrupt hormones and produce toxic by-products

  • capped at 1.4% by the European Commission but is allowed to reach up to 15% in the US.


  • is readily absorbed through the skin

  • there is insufficient data to support its safety and effectiveness (FDA)

  • causes relatively high rates of skin allergies

  • is linked to aquatic toxicity, potentially harmful to coral

  • is capped at 10% by European Commission, due to potential to disrupt endocrine system.


  • is a widely used organic UV filter

  • must be paired with stabilisers to prevent breakdown in the sun

  • can cause allergic reactions

  • can disrupt endocrine system and block effects of testosterone

Octinoxate (octyl methoxycinnamate, or OMC, or ethylhexyl methoxy-cinnamate)

  • is an organic UV filter that protects from UVB but not UVA rays

  • is readily absorbed into skin, it can be found in breast milk, urine and blood

  • can affect our metabolic system and thyroid hormone production

  • is banned by Hawaii because of its impact on marine ecosystem including coral reefs.

European vs US sunscreen In general, European sunscreens contain lower concentrations of these active ingredients compared to their American counterparts. For instance, oxybenzone is capped at 2.2% by the European Commission but is allowed to reach 6% in the US. Homosalate is limited to a concentration of 1.4% by the EC but can reach up to 10% in the US.

The Safest Ingredients - Titanium dioxide and Zinc oxide Currently titanium dioxide and zinc oxide are considered the safest sunscreen ingredients by the FDA and the EWG. Both are known as mineral sunscreen and act as a physical barrier, meaning they stay on your skin surface and not absorbed into your skin. These molecules are not found to penetrate the skin or cause hormonal disruptions.

Sprays and powders Sprays and powders may increase the risk of inhalation and swallowing. Besides, many people may not apply a thick enough layer to protect the skin from the sun. The FDA is currently proposing new safety rules (i.e. they aren’t in place yet), you are best off avoiding all sprays and powders for the time being.

Nanoparticles Some manufacturers use nanoparticles of titanium dioxide and zinc oxide to improve clarity and get to a higher SPF. Many studies have been done and found NO evidence to suggest these nanoparticles can cross the skin in great amounts. It is true that their impact on human or environmental health is not fully known. If you want to be cautious, avoid sprays, powders and sunscreens that contain nanoparticles. There is more information on nanoparticles on EWG.

Where to find sunscreen I don't have any associations with any brands, but here is a list of recreational sunscreens from the EWG website. Earlier this year, the EWG published its 15th annual sunscreen guide, which covers more than 1,800 sunscreen products. Unfortunately only 25% of them provide sufficient protection and free of harmful ingredients. Based on available studies and current guidance, mineral sunscreen seems to be the best option. If you really prefer non-mineral sunscreens, there is another list recommended by the EWG.

Sunscreen is not the only sun protection tool Thanks for getting this far, I still don't expect anyone to remember all the chemicals and impact. Just remember that there are other effective forms of sun protection, e.g. avoiding the midday sun, finding shade, covering up with appropriate clothing, hats and sunglasses. Always wear sunscreen if you are going out into the sun, preferably a mineral sunscreen, not spray or powder, follow the instructions and re-apply regularly. Enjoy the summer!


EWG's Guide to Sunscreens


Tips to Stay Safe in the Sun: From Sunscreen to Sunglasses Matta, M.K. et al. Effect of \Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients: A Randomised Clinical Trial. (2020), JAMA, 323 (3), 256-267. Matta, M.K., et al. Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients: A Randomised Clinical Trial. (2019), JAMA, 321 (21), 2082-2091. Suh, S., Pham, C., Smith, J., Mesinkovska, N.A., The banned sunscreen ingredients and their impact on human health: a systematic review. (2020), International Journal of Dermatology, 59 (9), 1033-1042.

Battie, C., Jitsukawa, S., Bernerd, F., Del Bino, S., Marionnet, C,, Verschoore, M., New Insights in Photoageing, UVA induced damage and skin types. (2014), Experimental Dermatology,23 Supplement 1, 7-12

Khan, A.Q., Travers, J.B., Kemp, M. G., Roles of UVA radiation and DNA damage responses in melanoma pathogenesis. (2018), Environmental and Molecular Mutahgenesis, 59 (5), 438-460

UV Radiation & Your Skin Opinion on Benzophenone-3 (Oxybenzone), Scientific Committee on Consumer Safety, March 2021.

Opinion on Homosalate. Scientific Committee on Consumer Safety (SCCS) October 2020

Opinion on Octocrylene. Scientific Committee on Consumer Safety (SCCS) March 2021

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