What does SPF measure?
SPF or 'Sun Protection Factor', is a measure of a sunscreen's ability to prevent UVB rays from damaging the skin. If, for example, it takes 20 minutes for your unprotected skin to start turning red, using an SPF 15 sunscreen theoretically means it takes 15 times longer – about five hours – for your skin to redden.
While higher-energy UVB rays are the primary cause of sunburns and pre-cancerous DNA mutations, UVA rays cause more subtle damage. They penetrate deeper into skin tissue and are most responsible for generating free radicals – energized molecules that are highly reactive and can damage DNA and skin cells, promote skin aging and cause skin cancer. However, the SPF rating gives no indication of the sunscreen's ability to protect the skin from UVA rays.
Sunscreens To Avoid!
Today, the market is flooded with a very diverse range of sunscreens. Ever tried spray sunscreens? Sunscreens with SPF over 100? How about sunscreen towelettes and sunscreens combined with insect repellents? Ingenious as these products may seem, they do present health hazards that you should be aware of.
- Avoid Spray Sunscreens - Aerosolized sunscreens may seem like a godsend when you need to apply sunscreen on your squirming reluctant child. However, there is growing concern that these sprays pose serious inhalation risks. Sprays also do not apply evenly, so there is a likelihood that you may underapply or miss some spots.
- Avoid SPFs over 50+ - Sunscreens with sky-high SPFs may protect against sunburn caused by UVB rays, but could leave your skin over-exposed to damaging UVA rays. How so? SPF or 'sun protection factor' refers only to protection against the skin-burning UVB rays. It however gives no indication of protection against UVA rays which penetrate deep into the skin, suppress the immune system, accelerate skin ageing, and possibly cause skin cancer. High SPF products give people a false sense of protection, tempting them to stay longer in the sun, and not reapply often. Some countries have placed a limit on SPF claims to 50+ in view of such concerns.
- Avoid Combined Sunscreen/Insect Repellents - Sunscreens and insect repellents don't really need to be combined as insects are usually not a problem during peak UV exposure hours. Studies have also indicated that such combinations could instead lead to increased skin absorption of insect repellent ingredients. Definitely not what we want for ourselves or our children!
- Avoid Sunscreen Towelettes - Towelettes may seem like a convenient and ultra space-saving option, but efficacy is a huge problem as you probably will not get enough of the sunscreen on your skin to make a difference. Environmentally, towelettes also add to waste! The FDA has in fact prohibited the sale of sunscreen wipes and towelettes in 2011.
- Avoid Oxybenzone - Oxybenzone is commonly used in chemical sunscreens. However, this chemical is able to penetrate the skin, enter the bloodstream and act like estrogen in the body. It has also been found to trigger allergic reactions in some people.
- Avoid Retinyl Palmitate - Retinyl Palmitate is a form of Vitamin A used in night creams for its anti-aging effects. However, when used on sun-exposed skin, it may accelerate the development of skin tumours and lesions.