Do Sunscreens Cause Cancer? What the Science Says

One of the claims most often encountered on social media and the internet in recent years is that sunscreens can cause cancer. These claims lead many people to avoid using sunscreen, and some even come to believe that sun protection is unnecessary.

So do sunscreens really cause cancer?

The short answer: No. There is currently no reliable scientific evidence to support this claim.

The sun's rays are one of the most important causes of skin cancer

The scientific evidence available today shows that ultraviolet (UV) rays are the most important environmental risk factor not only in skin ageing but also in the development of skin cancers such as basal cell carcinoma, squamous cell carcinoma and melanoma.

Intense sunburns in childhood and adolescence in particular increase the risk of developing melanoma later in life. Sun exposure sustained throughout the day over many years (chronic sun exposure), meanwhile, is an important risk factor mainly for skin cancers such as squamous cell carcinoma. Sun protection is therefore one of the basic steps in protecting against skin cancer.

So where did these claims come from?

In recent years, studies have been published showing that the organic (chemical) UV filters found in some sunscreen products can be absorbed through the skin in certain amounts. In addition, laboratory and animal studies of some filters have reported findings suggesting that they need to be investigated more thoroughly for safety — through mechanisms such as hormonal effects, oxidative stress and DNA damage at high doses. These studies have raised public concern that sunscreens might cause cancer.

However, a significant proportion of these findings were obtained at doses far higher than those to which people using sunscreen in daily life are exposed, or under experimental conditions that do not fully reflect human use. In the clinical and epidemiological studies carried out to date, no reliable evidence has been produced to show that sunscreens increase cancer risk in people under normal conditions of use.

Another important point is that benzene contamination was detected in some sunscreen products in past years. Benzene is a chemical known to be carcinogenic; however, the problem here is not the sunscreen filters themselves but contamination occurring during the manufacturing process. These products were withdrawn from the market by the relevant health authorities and the necessary measures were taken.

Today, international dermatology associations and health authorities are in agreement that, in the light of the current scientific evidence, using approved sunscreens as directed is safe, and that the benefits provided by sun protection far outweigh the theoretical risks that remain unproven to date.

Is there a difference between chemical and mineral sunscreens?

Sunscreens are broadly divided into two groups:

• Chemical (organic) filters absorb UV rays and neutralise them.
• Mineral (physical) filters contain substances such as zinc oxide and titanium dioxide; they reflect and scatter UV rays.

Both groups are safe and effective when formulated correctly. Today, many products contain different combinations of these filters.

Do sunscreens harm the body?

Sunscreens have been used by millions of people around the world for many years. The large-scale scientific studies carried out to date have not shown that approved sunscreens increase cancer risk when used as directed.

By contrast, it has been established by very strong scientific evidence that not protecting oneself from the sun increases the risk of developing skin cancer. In the light of current scientific knowledge, therefore, the benefit of using sunscreen far outweighs the theoretical and unproven risks.

Does using sunscreen lead to vitamin D deficiency?

This is another frequently asked question. Because sunscreens are not applied in daily life as perfectly as under ideal laboratory conditions, a certain amount of UV still reaches the skin. Studies show that sunscreen use does not cause clinically significant vitamin D deficiency in most people.

In people found to have a vitamin D deficiency, the most appropriate approach is to take suitable vitamin D supplementation on a doctor's advice, rather than uncontrolled sunbathing.

What to bear in mind when using sunscreen

• Products of at least SPF 30, preferably SPF 50+, should be chosen.
• The product should be applied about 15–20 minutes before going out in the sun.
• A sufficient amount of product should be used for the face and neck.
• It should be reapplied after sweating, swimming or towel-drying.
• Reapplication about every 2–3 hours during the day is recommended.
• Using sunscreen does not replace other protective measures such as a hat, sunglasses, protective clothing and, especially, avoiding the sun during the midday hours.

Conclusion

The scientific evidence available today shows that there is no proof that approved sunscreens cause cancer, and that, on the contrary, the sun's rays are one of the most important environmental risk factors in the development of skin cancers.

For this reason, we should trust scientific evidence rather than the unverified claims about sunscreens circulating on social media. A regular sun-protection habit, as recommended by a dermatologist, is one of the most effective ways both to reduce the risk of skin cancer and to prevent premature sun-related skin ageing.