19 September 2008

Sunscreen IngredientsThere are two basic types of skin cream or lotion protection :
  1. absorb and deflect (or reflect) the sun's rays via a chemical reaction.
  2. blocks : zinc oxide and titanium dioxide (which create a physical barrier against rays).
PABA
  • Though rarely used now in sunscreens, beware of products that contain the ingredient.
    40 % of the population is sensitive to it, experiencing red, itchy skin.
Benzophenone (benzophenone-3), homosalate, and octy-methoxycinnamate (octinoxate)
  • They have shown estrogenic activity; shown to disrupt hormones, affecting the development of the brain (particularly the hypothalamo-pituitary-gonadal system) and reproductive organs in laboratory rats.
  • Because people are exposed simply by eating fish (where benzophenone accumulates in the fat), using sunscreen containing these chemicals unduly increases the exposure.
Parabens (butyl-, ethyl-, methyl-, and propyl-)
  • Parabens may also mimic estrogen, but because they are common in sunscreens, avoiding them may prove difficult.
Padimate-O and Parsol 1789 (2-ethylhexyl-4-dimethylaminobenzoic acid and avobenzone)
  • These chemicals have the potential to damage DNA when illuminated with sunlight.
  • On the skin's surface, these chemicals do protect from UV damage; however, once absorbed into the skin, these same chemicals can prove destructive.
  • Padimate-O and Parsol 1789 are excited by the UV energy which they absorb and become reactive, acquiring the potential to attack cellular components, including DNA.
  • DNA damage inflicted by an excited sunscreen is much less capable of being repaired by naturally occurring repair mechanisms than the DNA damage inflicted by UV alone.
Although insect repellents with sunscreen may seem like an easy option, Doctors recommend avoiding them because of the dangers of overexposure to DEET, which can cause eye and skin irritations, headaches, nausea, when the product is reapplied after swimming or exercise.

Most titanium dioxide used in sunscreens is coated with materials that reduce its photoactivity. According to current evidence titanium dioxide is much less likely than other chemical sunscreens to penetrate human skin.

0 comments:

Post a Comment

Search