[T]he greatest danger of sunscreen appears to be the false confidence many people have in its protective powers. People often burn because they don't reapply as recommended after swimming or because they don't use enough sunscreen to begin with - you need at least one ounce (enough to fill a shot glass) to completely cover exposed areas of the body. ~ Dr. Andrew Weil




Steps

1. List any needs or concerns that you might have about the use of sunscreen. This list might include such things as:
   
   
   • Potential allergens
   • Potential carcinogens
   • Effectiveness of sunscreen
   • Duration of effectiveness
   • Suitability for different age groups etc.
2. Read over the label on a sunscreen in your bathroom cabinet. See which ingredients you are already familiar with and those that don't mean much to you at all. The following list provides some of the key sunscreen ingredients, along with an explanation of what they are:
   
   
   • SPF - this is the indicator level of how much "Sun Protection Factor" is in the sunscreen. The rating is an attempt to show how long you are protected from the sun's UVB rays, and the higher the SPF, the longer the protection lasts. However, increased SPF comes at a cost - do not let it fool you into thinking you can stay out in the sun longer and not take other sensible sun protection measures. That will only end in sunburn and premature skin aging. Also, the higher the SPF, the more chemical barriers you are being exposed to. And finally, SPF only measures sun-protections against UVB, not against UVA - see the article Understand the Effects of Different UV Rays for an explanation of the different effects of the rays. As such, the indicator is only telling half the story of how long it will take to redden your skin and you may redden much sooner!
   • Titanium dioxide and zinc oxide - these minute metal particles that reflect and scatter UV light. These do not penetrate your skin, which makes a sunscreen with these elements ideal for sensitive skin, children and those who do not like using chemical versions. Note that titanium dioxide has been classified as possibly carcinogenic to humans by the International Agency for Research on Cancer. Concerns have also been raised about the use of nanoparticles of zinc oxide and titanium dioxide as possibly increasing the risk of skin cell damage but studies are as yet inconclusive.
   • Chemical blocks - If there is a phrase on your sunscreen that says the sunscreen protects you against UV radiation and both UVA and UVB rays, then it contains chemical blocks. Some chemicals tackle UVB and some UVA, so many products tend to contain a combination of both. Chemical blocks may cause skin reactions (rashes etc.) and for some people, there are questions about the safety of some chemicals in sunscreens who are concerned that the chemicals might penetrate the skin barrier and increase photocarcinogenic proprerties. If this is a concern for you, practice safe sun precautions (see "Tips" below).
   • Broad spectrum - this means that the sunscreen will protect against both UVB and UVA. However, some broad spectrums are better than others, as some sunscreens do not adequately block UVA. MedicineNet notes that "a good broad-spectrum sunscreen should contain avobenzone, ecamsule (Mexoryl), titanium dioxide, or zinc oxide for significant UVA protection."
   • PABA-free - most sunscreens carry this message now. PABA (para-aminobenzoic acid) caused a spate of skin rash reactions, so few manufacturers include it now. It is also implicated in increasing the chance of skin cancer. Modern sunscreens rely on derivatives of PABA which are considered to be safer, such as PABA esters (glyceryl, padimate A and padimate O). Although these derivatives are considered to be safer, there are still side effects for some users.
   • Waterproof or water resistant - this lets you know that the sunscreen will stay on as you swim. Water resistant generally stays on for about 40 minutes, with waterproof generally providing coverage for up to 80 minutes. However, no sunscreen is really waterproof and will eventually wash off. It is generally recommended that you reapply such sunscreen every 2 hours when you are swimming.
   • Baby or child sunscreen - this indicates a more skin sensitive formula that has been manufactured to suit babies and children.
   • Expiry date - pay attention to this one; old sunscreen won't be able to protect you as the ingredients break down and their effectiveness wears off. It isn't helped by the fact that we tend to leave sunscreens in the heat, fastening their demise. Replace regularly, at least every year.
   • Extracts and scents - mere window dressing to make the product more palatable. These can be irritants, so take care.
3. Make an informed choice. Next time you purchase a sunscreen, keep this list in mind and be guided by the needs and concerns that you listed in Step one. Follow up any concerns that you might have with the retailer and the manufacturer. You can also ask your local health professional for more information and advice.

Tips

• Scented sunscreens are best avoided; they don't do anything to improve the screening ability of a sunscreen, the scents can often result in allergic reactions and they can be an annoyance to others who have to smell it!
• Sun safe tips include:
  
  
  • Wear broad brimmed hats
  • Keep out of the sun between 10 am and 3pm
  • Wear long-sleeved and long-legged clothes
  • Don't stay in the sun for long periods of time
  • Wear UV blocking clothing (specially manufactured clothing)