Nowadays, when you go shopping for sunscreen to protect your family during hot summer days, you are faced with a variety of choices that can leave you wondering: which sunscreen should I purchase ?
Sunscreen can block ultraviolet sunlight in the "A range" (UVA) and the "B range" (UVB). It used to be thought that UVA only caused skin aging  and UVB caused skin cancer . Dermatologists  now understand that the UVA can also be a skin cancer causing risk factor, as well!
Many people simply look at the "SPF" rating for sunscreen, which measures how well it protects from UVB. However SPF does not measure how well a sunscreen stops UVA, which is more difficult to block. Thus, a sunscreen that has a lower SPF but blocks UVA well may be better than a very high SPF sunscreen that only blocks UVB.
To date, only three sunscreen ingredients have been approved by the FDA: Zinc Oxide, Titanium Dioxide and Parsol 1789. The best suncreens contain Zinc Oxide or Titanium Dioxide as these physically block both UVA and UVB. You will not see these chemicals as the main ingredient in many sunscreens because they tend to be more expensive. These products may also leave a white hue when applied to darker skin, although some makers apply a tint to prevent any "ashy" appearance.
Parsol 1789 (also called Avobenzone) also reduces the potential harm of UVA, but by absorbing it, not blocking it. This ingredient is very popular in sunscreens, but doesn't last long on the skin. Some companies have developed stabilizing compounds that help it last longer on the skin, but these products are usually the more expensive products. Most dermatologists prefer zinc for UVA blocking.
SPF numbers can be misleading. You might have a sunscreen with 10% zinc in it but it is only an SPF 40. You may have another that has Parsol 1789 in it and it is an SPF 55. Sunscreen with Zinc Oxide provides you with better protection because of the Zinc Oxide lasts longer on the skin. Most dermatologist's recommend at least wearing a sunscreen with at least an SPF of 30.