The Chemicals in Your Sunscreen

Lucy Bell-Young

by Lucy Bell-Young

13th June 2018

After months of bitter cold and relentless rain, summer has finally arrived in the UK. But before you whip out that barbecue or book that much-needed holiday, it’s time to trade in your umbrella for some sunscreen.

Properties of Sunscreen

We all want that golden tan, but protecting your skin from powerful UV rays should be at the top of your priority list.

Sunscreens are specifically designed to give you the best protection against our sizzling sun, and they also have a variety of properties that make them safe for topical application and accidental ingestion. In general, sunscreen:

  • Should not contain ingredients that are skin-irritants
  • Should not contain ingredients that are harmful to internal organs
  • Should be able to withstand UV radiation without losing effectiveness
  • Should be stable so that it doesn’t form harmful breakdown products

Some sunscreens often contain penetration enhancers. These help other ingredients penetrate the skin. But this also means that a lot of chemicals from sunscreen are getting absorbed into our bodies. In fact, many ingredients present in sunscreen can be measured in blood samples, urine samples and even breast milk.

Before we start slathering on the lotion, then, it’s important to ask ourselves: what chemicals are actually in sunscreens?

An aerial shot of people on a beach

Before you go on that holiday you’ve been craving since the year started, make sure you’ve found the sunscreen that works best for you. There are two different types of sunscreen and they both contain different chemicals that may affect how you use them or how your body reacts to them.

Know your Sunscreen

Different types of sunscreens are composed of different types of chemicals. In general, there are 2 sunscreen categories: physical blockers and chemical absorbers. While they both do the same thing – protect your skin from the sun – they each use different mechanisms and ingredients.

Physical Blockers

Also known as mineral or physical sunscreen, blockers contain natural minerals like titanium dioxide and zinc oxide. These substances are generally considered safe to use.

Physical blockers are reflectors. They work by sitting on top of the skin where they deflect and scatter UV rays. Mineral sunscreens are characterised by their thick consistency and the semi-opaque white gloss they leave on your skin – you know the one.

Because it sits on top of your skin rather than being absorbed into it, physical blockers do have the potential to clog pores. They can also be easily rubbed off or sweated away, meaning that if you’re engaging in a physical activity you would have to frequently reapply your sunscreen.

They do have many advantages, though. Mineral sunscreens:

  • Protect against a broad spectrum of UV light, including UVA and UVB
  • Protect immediately after application, so there’s no waiting around
  • Last longer when you’re in direct UV light, like sunbathing
  • Are better for sensitive or heat-activated skin because they contain natural ingredients

Chemical Absorbers

Also known as chemical sunscreens, these products contain synthetic, carbon-based compounds like avobenzone and, most notoriously, oxybenzone.

Chemical sunscreens are absorbers. They can change electromagnetic radiation by absorbing UV rays into the skin and releasing them from the skin as infrared rays (heat). Unlike physical blockers, they are usually completely absorbed into the skin.

While this means that you don’t get that sticky white sheen coating your body, there are a few disadvantages you should be aware of when using a chemical absorber:

  • They require at least 20 minutes after application to become effective
  • They increase the chance of skin irritation because of the number of chemical ingredients
  • For those who have heat sensitive or rosacea-prone skin, chemical absorbers increase the risk of redness as they convert UV rays into heat

It is also worth noting that the higher the SPF number, the higher the likelihood is of skin irritation. In fact, the Food and Drugs Administration (FDA) is considering banning all sunscreen products with an SPF that is greater than 50. This is because there is no scientific proof that these products give more protection than lower SPF ratings – so don’t judge a sunscreen by its label!

A boy and girl sunbathing on a beach

While mineral sunscreen can easily rub off, it lasts longer than chemical sunscreen when in direct UV light. Chemical absorbers are better for when you’re doing physical activity because they absorb into your skin and won’t sweat off. So if you’re planning to do some tanning this summer, mineral sunscreen is your best bet – even if it is a little sticky!

What Chemicals Are in Absorbing Sunscreens?

If you’re into your physical blockers, then you can rest easy. In general, the ingredients contained in these types of sunscreens are pretty harmless.

Chemical absorbers, as the name suggests, do contain a number of synthetic compounds that you might want to keep an eye on.

  1. Oxybenzone

One of the most prolific ingredients in chemical sunscreens is oxybenzone. Also known as benzophenone-3, this is a pale yellow, organic compound that belongs to the class of aromatic ketones known as benzophenones.

Oxybenzone is used in sunscreen as a penetration enhancer. It is a widely criticised ingredient because it is a contact allergen and has been classified by toxicology experts as an endocrine system disruptor. However, these statements have been widely debated.

In excessive quantities, oxybenzone has the potential to:

  • Cause skin reactions like eczema
  • Mimic, block and alter hormone levels by disrupting the endocrine system
  • Accumulate in the body faster than it can be removed
  • Cause endometriosis in women
  • Pose a risk to reproductive organs
  • Increase the threat of hormone-related cancer

And if that information wasn’t enough, in 2014 oxybenzone was actually named by the American Contact Dermatitis Society as “Allergen of the Year.”

  1. Octinoxate

Octinoxate, also known by its catchy nickname octyl methoxycinnamate, is another organic compound that is commonly found in chemical absorbers as well as lip balms.

Appearing as a soluble clear liquid, it is an ester formed from methoxycinnamic acid and 2-ethylhexanol. Like oxybenzone, octinoxate has a reputation for hormone disruption, including oestrogen and thyroid hormone systems.

While sunscreens are advertised to us under a guise of anti-ageing formulations, the presence of octinoxate in chemical sunscreen actually does the exact opposite.

Octinoxate increases the appearance of ageing because it releases lots of free radicals. These are tiny reactive molecules that damage skin cells, collagen production and even DNA. Over time, this damage manifests itself in wrinkles, sagging, roughness, and all other hallmarks of premature ageing.

A bottle of sunscreen on a poolside

When looking for what SPF to choose, stay clear of ones that are over 50. This is because there is no evidence to show that these are more protective than lower numbers, and a higher SPF rating is likely to increase the chances of skin irritation.

  1. Avobenzone

The third ingredient in this trifecta of controversial sunscreen chemicals is avobenzone. This is a white-yellowish crystalline solid that is soluble in oil and has a weak odour.

Avobenzone is used in chemical absorbers because it has the ability to absorb UV light over a range of wavelengths. This has led to its widespread commercial use in sunscreens, where it helps to absorb the full spectrum of UV rays.

Although this compound is a great UV ray absorber, its stability under light exposure has been called into question a number of times. The FDA noted a 36% decrease in avobenzone’s UV absorption efficiency after just 1 hour of being exposed to the sun.

When avobenzone degrades under light exposure, it can transfer harmful energy to other areas of the body by releasing free radicals. These not only increase signs of ageing, they can actually increase risks of cancer.

Should You Be Worried?

You’ve taken in a lot of scary information just now, and maybe you’re considering swearing off sunscreen lotion altogether. But really, there is no need to worry.

The potentially harmful chemicals found in sunscreen aren’t present in high enough concentrations to do any considerable damage. They also don’t penetrate the skin sufficiently enough to cause significant toxicity. So if you’re worried about that SPF 60 chemical sunscreen you’ve been using for the past year, don’t be – you’re absolutely fine.

However, it all depends on your own particular circumstances and skin-type. People react differently to different compounds, and a sunscreen that works great for one person isn’t necessarily going to be the same for another.

A love heart drawn into some white lotion on a person's knee

It’s always worth doing a little bit of research before you start caking your skin in a bottle of chemicals, whether they’re natural or synthetic. Luckily, ReAgent are always here to stay ahead of the curve and keep you updated on what chemicals you can expect to encounter in your everyday life.


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