The use of sunscreen has significantly peaked in the past decades. That is hardly surprising when both doctors and media are shouting from the rooftops that wearing a good sunscreen cuts down your risk of sunburns and skin cancer. Sounds like a good strategy: if only things were as simple as that.
Did you know there is no clear cut scientific evidence that sunscreens can prevent skin cancer? And how about the fact that most products don’t filter out UVA rays that cause premature wrinkling and skin cancer! On the contrary, popular sunscreens are loaded with a slew of dangerous ingredients that may be doing more harm than good.
In this two-part series, we will closely review what is so troubling about commonly used chemical sunscreens and how they may be damaging your health on the sly. What’s more, a surprising finding suggests that these harsh chemicals are taking a huge toll on marine life too. In the end, we will share a few sun smart hints to keep you well-protected and also some tips on choosing sunscreen products that are safer and still provide good sun protection.
According to the 2017 report from Environmental Working Group (EWG), the majority of the sunscreens:
- Protects from sunburn but don’t provide sufficient protection against all types of sun damage.
- Contain potentially harmful ingredients which disrupt hormones, cause skin allergies and ironically some are even implicated in causing skin cancer.
A lot it seems.
Contains dangerous chemicals
Most chemical sunscreens contain oxybenzone, avobenzone, Vitamin A derivatives like retinyl palmitate, parabens and other chemical ingredients. These damaging chemicals cross the skin barrier and have been detected in people’s blood, urine and even mothers’ breast milk. Pregnant women, infants and young children are especially prone to their adverse effects.
In addition, many sunscreens also contain methylisothiazolinone, an inactive ingredient that was named “allergen of the year” by American Contact Dermatitis Society in 2014.
In an experiment conducted by the Center for Disease Control and Prevention in 2008, oxybenzone was found in 96.8% of the human urine samples that were surveyed. A 2002 study showed that oxybenzone penetrates the skin and gets stored in the body. The researchers recommended that parents shouldn’t use sunscreens that contain oxybenzone on young children as they haven’t yet fully developed the enzymes involved in breaking down the by-products of this dangerous chemical. 
Why should you be concerned about oxybenzone? The EWG rates oxybenzone as one of the most harmful ingredients present in cosmetic products, giving it a rating of 8. Increasing evidence suggests that oxybenzone is an endocrine disruptor and mimics estrogen in the body. Animal studies hint that the chemical may be associated with:
- Infertility and reducing sperm count in men
- Low testosterone levels in adolescent boys
- Endometriosis in women
- Causing early puberty in girls
- Allergies and eczema (In 2014, it was named Allergen of the Year” by the American Contact Dermatitis Society )
- Recent rise of skin cancer (melanoma) in people using sunscreen. (It is known to damage DNA in skin cells.)
Vitamin A derivatives like retinyl palmitate
Many sunscreens contain vitamin A or retinyl palmitate, a form of vitamin A. The National Toxicology Program (NTP) study linked retinyl palmitate with an increased risk of skin cancer. It is believed that this vitamin A derivative may accelerate the development of skin tumors and lesions when used in the presence of sunlight.
While the verdict is still divided whether vitamin A or its derivatives are actually safe or not, the fact is these compounds degrade fast and lose their efficiency when exposed to sun, making them a useless addition to sunscreen creams or lotions anyway.
A very common sun blocking chemical, avobenzone is known to effectively guard against UVA rays, unlike most other sunscreens. While it may not be a toxic ingredient in itself, it is pretty unstable and disintegrates rapidly in the sun, offering little protection.
In addition, a recent 2017 study suggests avobenzone may react with chlorinated water in swimming pools and break down into hazardous chemicals that can trigger abnormal functioning of the liver and kidneys, as well as nervous system disorders. 
The use of spray-on sunscreens is on the rise as they are easy to apply. But are they safe? Spray on products often contains zinc oxide and titanium dioxide. When used topically as creams and lotions, mineral sunscreens offer good protection. And they are considered safer to use as there is no risk of skin penetration, as long as these products do not contain nano-sized (ultrafine) particles.
But spray on sunscreens carry inhalation risks. When inhaled, these minerals can cause inflammation in the lung tissues and are particularly risky for children. The International Agency for Research on Cancer (IARC) classifies titanium dioxide as a group 2B carcinogen “possibly carcinogenic to humans”, when inhaled in high doses. Consumer reports recommend not using the spray-on sunscreens on children as you would be directing potentially toxic chemicals into their lungs.
It is true we need more solid human studies that could substantially back these side effects. But the clarity that these chemicals are safe is missing too. While we await more proof, it is sensible to avoid sunscreens containing potentially toxic ingredients, especially when you have better options.
We will continue talking about other side effects of using sunscreens and discuss safer and more effective ways to prevent sunburn and other skin problems associated with over exposure to UV rays. Stay tuned for Part 2 in the series.
- Gustavsson Gonzalez, H., Farbrot, A. and Larkö, O. Percutaneous absorption of benzophenone-3, a common component of topical sunscreens. Clinical and Experimental Dermatology. 2002.
- C Wang et al. Stability and removal of selected avobenzone's chlorination products. Chemosphere. 2017.