Sunscreen works by protecting our skin from the sun’s invisible ultraviolet light - specifically UVA and UVB rays. UVB rays are responsible for glowing tans and blistering sunburn whilst UVA rays penetrate more deeply into the skin causing photo ageing and immune-suppression. Overexposure to these rays can ultimately damage our living tissue, specifically the DNA, and cause genetic mutations that can develop into skin cancer.
So what are our options for protecting ourselves from these damaging rays?
Chemical Filter Sunscreens
These are the most commonly available sunscreens and they work by partially penetrating the skin and absorbing the sun’s harmful rays so that our skin doesn’t have to. Chemical filter sunscreens are usually are made of two or more of the following ingredients oxybenzone, octinoxate, avobenzone, homosalate, octisalate and octocrylene. Oxybenzone and octinoxate are particularly omnipresent in sunscreens as up to 70% currently on the U.S. market are said to include one of these chemicals.
Pros of Chemical Filter Sunscreens
• Oxybenzone and octinoxate are said to be effective at preventing skin cancer, so when applied properly, chemical filter sunscreens are a good line of defence against sun damage.
• They’re said to offer more coverage against UVA and UVB rays.
• They blend more easily and often invisibly into the skin.
• They’re easier to find and buy.
Cons of Chemical Filter Sunscreens• Chemical filter sunscreens often include chemicals that aid skin penetration to help the product to stay on the skin. As a result, many of these ingredients are absorbed into the body where they can be measured in blood, breast milk and urine samples for up to two days after just one application.
• These sunscreens are said to contain some controversial ingredients. The Environmental Working Group who publish an annual sunscreen guide claim that oxybenzone may cause hormonal disruption and cell damage, which can lead to cancer. A study by US government scientists suggest that vitamin A derivative, retinyl palmitate which can also be found in some chemical filter sunscreens, may speed up malignant cell growth and the spread of skin cancer when applied to skin in sunlight. Many medical professional disagree with these claims stating that the scientific evidence is not definitive.
• According to several environmental studies, oxybenzone and octinoxate, are thought to play a factor in the bleaching of coral reefs and the decimation of new coral growths. They’re also thought to accumulate in sea creatures and the environment, disrupting the hormones of fish and amphibians. This is unsurprising when you think that an estimated 4,000 to 6,000 metric tons of sunscreen washes off swimmers’ bodies annually. In July 2018 in an effort to protect its marine life, Hawaii banned sunscreens containing these harmful chemicals.
• Frequent use of chemical sunscreen is leading to a rise in cases of contact allergic dermatitis. This is being linked to the powerful chemicals like oxybenzone, added preservatives, fragrances, and lanolin that are being used by some brands. Patch testing is often recommended by dermatologists.
Mineral Filter Sunscreens
Mineral sunscreens work by sitting on the surface of the skin to deflect the sun’s rays. They usually contain zinc oxide, titanium oxide or both together. These sunscreens are generally considered to contain ingredients that are less toxic for the environment and safer for use on children and those with sensitive skins. They’re also thought to be safer to use in marine and reef environments.
Pros of Mineral Filter Sunscreens
• Zinc oxide offers strong protection from UVA rays. Titanium oxide’s protection isn’t as strong, but it’s better than most other active ingredients.
• They provide sun protection as soon as they’re applied to the skin, they don’t break down in the sun and they come with few health concerns.
• Physical sun blocking agents such as titanium dioxide and zinc oxide may be more suitable for people with sensitive skin than their chemical filter alternatives.
• They don’t exhibit any evidence of hormone disruption.
• They’ve demonstrated less that 0.01% to zero skin penetration to living tissues.
Cons of Mineral Filter Sunscreens
• Mineral sunscreens don’t blend very well. Instead they often leave a vampiric chalky white residue on the skin. Some brands are changing their formulations to address this by using finer micronised zinc oxide-based creams.
• As they sit on the surface of the skin, mineral filter sunscreens can be rubbed or sweated off the skin more easily. To maintain their effectiveness, frequent and generous application is advised.
• Read the label carefully as some mineral sunscreens also contain some chemical filters ingredients.
And Another Thing…
Whichever sunscreen formulation you decide to use, one application in a day is unlikely to protect you. Most sunscreens must be applied liberally, every few hours. Be aware that some can take up to thirty minutes to be effective. Swimming and sweating will mean more frequent reapplication is needed. Read the instructions on your bottle for further advice.
Dispose of your sunscreen when it expires as its protective properties do fade and it may give you a nasty skin irritation.
The Sun Protection Factor (SPF) numbers on sunscreens tell us how well the sunscreen protects against UVB radiation (There’s no current standard for listing the blocking abilities of UVA rays). The general recommendation is to use a lotion that has an SPF of 15 to 50 but numbers can be deceiving. Whilst SPFs can’t block 100% of UV rays, according to the Mayo clinic, an SPF 15 sunscreen will protect against 93% of UVB rays and an SPF 30 will protects against 97%.
Concerns have been voiced that our use of sunscreens inhibit the body’s ability to make vitamin D (which is essential for our bone health) from the sun. However, clinical studies have never found that daily sunscreen use leads to insufficient levels of vitamin D. This may be because most people use sunscreen intermittently and even if a (rare) person puts on the required amount of sunscreen, no sunscreen exists that can block out 100% of UV rays. Hold this up against the fact that just 10 to 15 minutes spent in the sun without protecting your skin can lead to proven accumulative DNA damage that can increase your risk of skin cancer and wearing sunscreen just seems like the wiser, more responsible choice.
Vitamin D can also be taken via food and supplements without the associated risks from sun exposure but anyone concerned about having vitamin D deficiency - particularly people with darker skins, the elderly, people living in higher latitudes, people with digestive, liver or kidney disorders and the housebound – should consult their doctor for advice.
Sunscreens are a really great defence against UV rays but they’re not the only solution. There are many more things that we can do to protect our skin and health.
• Avoid situations that may lead you to getting sunburn such as falling asleep on a lounger in the sun.
• Clothing made of tightly woven fabric can offer a decent level of sun protection so do cover up. Wide brimmed sun hats, short and long sleeved tops are all recommended. Large wraparound sunglasses are also important as UV radiation can cause cataracts.
• If you plan on spending time outside, avoid the harsh midday sun and instead opt for early morning or afternoon when the sun is at a low peak.
• Sit in the shade. A tree, umbrella, parasol or building will do.
• Avoid reflected rays on sand, snow and by the water.