Sun Protection – Everything you need to know by Dr Johanna Ward
The sun is 4.5 billion years old and is the main source of ultraviolet radiation in our environment. The sun emits two different types of ultraviolet rays (UVA & UVB) that are harmful and damaging to the skin. Exposure to ultraviolet radiation is a major risk factor for most skin cancers and is the primary cause of skin ageing.
READ: SKIN CANCER: The Darker Side of the Sun
UVA rays can penetrate through clouds, windows and glass. These rays penetrate into the skin’s dermis (the deeper layer) and harm the skin by causing ageing and photodamage. Most sun beds have large amounts of UVA which is why sunbeams users get accelerated ageing.
UVB rays are more potent than UVA rays as they can directly damage DNA. These rays are the main rays that cause sunburn. UVB rays are thought to cause most skin cancers.
Most modern day sunscreens are broad spectrum which means that they protect from both UVA and UVB rays. Current advice is that sun protection should be worn throughout the year for anti-ageing and for protection against skin cancer.
Physical versus chemical sunscreens
Physical sunscreens work by sitting on top of the skin and deflecting or scattering UV rays away from the skin. They contain ingredients like zinc oxide or titanium oxide or a combination of both. These are good (esp. zinc oxide) for anyone with acne prone or sensitive skin e.g. eczema or rosacea and are recommended for use in children. Modern physical sunscreens no longer feel heavy, thick and white on the skin.
Chemical sunscreens contain organic compounds like oxybenzone, avobenzone and octinoxate that create a chemical reaction that changes the UV rays into heat which then gets released by the skin. Chemical sunscreens often feel nicer on the skin and often have the added benefit of peptides, antioxidants and hydrators in their formulation so they are nicer for daily use but they can sting the eyes and are more likely to cause allergic reactions.
What does SPF mean?
SPF stands for Sun Protection Factor. It is a measure of UVB rays only and refers to the theoretical amount of time that you can be in the sun without getting sunburned. For example, an SPF 15 will allow you to be in the sun 15 times longer than if you were without protection. SPF 15 protects against 93% of UVB rays, whilst an SPF 30 will protect against 97% of UVB rays and an SPF 50 protects against 98%.
How much sunscreen should I wear?
Most of us don’t wear enough sun protection to get the full benefit of the product. The standard rule is that you need to use an ounce (or a shot glass full) of sunscreen if you want all over coverage. For the face you need on average the size of a 10pence coin (product depending) spread evenly over the face. You should not rely on make up powders with SPF or foundation with SPF alone as an your sun protection as most of us don’t apply these in liberal enough quantities to make them protective.
When should I apply sunscreen?
Sun protection should always be the last thing you apply to the skin. Any moisturiser or lotion applied to the skin after sunscreen will dilute its protection. You can of course layer your sunscreen and use a pressed make up powder SPF afterwards.No sunscreen can be entirely waterproof so for best protection reapply your sunscreen after water exposure, heavy sweating or after 2 hours.
Is a moisturiser that has SPF in it as effective as a sunscreen?
A moisturising SPF is a fantastic investment as it gives sun protection as well as providing hydration for the skin. Find yourself a moisturising SPF that applies nicely onto the skin and it will be your best anti-aging investment ever.
MEET THE TA MAG EXPERT
Dr Johanna Ward MBBS DRCOG MRCGP Dip ClinDerm
Dr Ward is an Award Winning Skin Doctor, Gp and presenter. She runs two private skin and laser clinics and is regarded as one of the UK’s leading skincare experts. She is passionate about everything to do with dermatology and is a founder of the ZENii skincare and wellness range.