Why applying sunscreen is not enough to protect your skin
April 5th, 2009
What is SPF?
SPF is a measure of UV-B, not UV-A, protection. High SPF sunscreen lotions let you cook more slowly before you get burned. Remember: much damage is done by pre-burn irradiation! As you bake in the belief that SPF 15 or 50 gives you 100% protection, you’re threatened as much by potential skin cancer and premature aging as if you used nothing. Furthermore, many chemicals in sunscreens are absorbed by your body are toxic.
In 2003, the findings of an article published by a team of research physicians included:
SPF 15 does not block UV-B. A sun protection factor (SPF) of 15 was considered to completely block ultraviolet radiation. The logic behind that cutoff point was that sunscreens with this SPF number would always prevent erythema and that preventing erythema prevents the ill effects of UV exposure. Both these assumptions were wrong.
Incorrect sunblock application. These physicians further showed that users apply only “… about one-quarter to one-half thickness of the layer of sunscreen material used to measure the SPF in the laboratory.”
SPF applies to UV-B only. SPF does not protect against UV-A. Therefore, use of an SPF 30 product may only have the effective range of an SPF of 15 or even 7³, if not properly applied. That allows a low-grade attack on the skin, even without any burning or redness. The researchers also clearly noted: “… [a]significant injury, DNA damage, mutations, and carcinogenesis can and do occur with cumulative sub-erythemal UV exposure. Thus, erythema induction, a criterion that defines SPF, is not a good indicator of UV damage. We also need higher SPF values to prevent the damage caused by sub-erythema doses of UV.”
In addition, these physicians noted that there are: “… environmental factors that are not taken into account during SPF measurements in the laboratory, such as sweating, water immersion, rubbing off, and photo-degradation.”
Sunscreens. SPF protection is illusory since pre-burn exposure does much chronic damage. The cumulative effect of ultraviolet bombardment damages genes in a normal cell, eventually making that cell a cancer factory.
The Beach. A beach umbrella blocks sunlight, not ultraviolet radiation. The sand on the beach is also a threat: it reflects UV-A and UV-B rays onto exposed, vulnerable skin.
Clothing. Most light clothing is worthless against exposure; ultraviolet radiation comes from a source that essentially explodes millions of hydrogen bombs every second. Summer clothing is lighter, thinner, and less protective. Some clothing is now SPF-rated, but how does it stand up, wash after wash? (Check Consumer Reports.)
Shade. The shade from the side of a house, for example, offers some protection. The best UV-A and UV-B block comes from full shade under thick foliage. But it’s impossible to stay in the forest all day long, each day of the week.
“Patch test” any skin lotion or sunblock before you use it to ensure its safe and non-allergenic use.
1. Avoid excessive, unprotected exposure to sunlight.
2. Wear a wide-brim hat outdoors.
3. Use a sunblock rated at least SPF 45 - one that blocks UV-A safely as well as UV-B - when outside for prolonged periods.
4. Wear heavier, SPF-rated clothing outdoors.
5. Avoid the use of tanning booths.
Note: The best mitigation against solar ultraviolet exposure is to avoid sunlight between 10:00 A.M. and 3:00 P.M.!