What You Need To Know When Choosing and Using Sunscreen

Know the Ingredients
This can be divided into compounds that physically block radiation or compounds that absorb radiation.
The radiation blockers are very effective at reducing the exposure of the skin to both UVA and UVB radiation.
Older formulations like zinc oxide are opaque and may be cosmetically unacceptable.
However, a newer formulation of micronized titanium dioxide is not as opaque and provides excellent protection.
The radiation absorbing ingredients are differentiated by the type of radiation they absorb - UVA absorbers and UVB absorbers.
- Picking the Proper Sunscreen
The SPF measures the amount of UVB absorption, but there is no method of reporting the UVA absorption.
The only way to determine if a sunscreen protects against UVA and UVB radiation is to look at the ingredients.
A good broad-spectrum should have an SPF of at least 15 and contain avobenzone, titanium dioxide, or zinc oxide.
- Proper Application When You Wear Sunscreen
Most people wear sunscreen improperly by not applying enough. They apply only 25% to 50% of the recommended amount.
It should be applied liberally enough to all sun-exposed areas that it forms a film when initially applied.
It takes 20-30 minutes for it to be absorbed by the skin, so it should be applied at least a half an hour before going out in the sun.
It should also be the last product applied especially on the face since some it can break down in the presence of water contained in water-based foundations and moisturizers.
- Reapplying Sunscreen
Most instructions on product labels recommend reapplying "frequently", but the definition of "frequently" is vague.
A common instruction is to reapply after 2-4 hours in the sun.
However, one study has shown that reapplying 20 to 30 minutes after being in the sun is more effective than waiting 2 hours.
It is possible that this time period is more effective because most people do not apply enough initially, and this second application approximates the actual amount needed.
Reapplication should also be done after swimming, excessive sweating, or toweling.
- Daily Application
Sunscreen should be applied daily. The daily use of one with low SPF(15) has been shown to be more effective in preventing skin damage than the intermittent use of a higher SPF one.
- Sunscreen and Insect Repellents
Insect repellents reduce the SPF by up to one-third. When using both together, wear sunscreen with a higher SPF and reapply it more often.