Would you like to prevent aging? A study published June 3 in the Annals of Internal Medicine showed that there is a lotion that, if used daily for about five years will, reduce skin aging by almost 25 percent! What is that magic lotion?

It's sunscreen!

You may know sunscreen by its former name, "sunblock." However, the name "sunblock" has been forbidden by the Food & Drug Administration (FDA), since there is no lotion that truly blocks the harmful effects of the sun's rays.

The sun's rays reach the earth in two different wavelengths that affect the skin: UVA and UVB. UVB rays cause sunburn, whereas both UVA and UVB contribute to skin aging and cancer. These rays are invisible, and they occur even on cloudy days. In fact, up to 40 percent of the sun's ultraviolet rays reach the earth, even on a completely cloudy day.

Sunscreen strength is measured in SPF, or "sun protection factor." The SPF is a measure of UVB protection, and sunscreen ranges from 2 to 50+ SPF. This is what the SPF number means: if it would normally take unprotected skin 10 minutes to burn and start to turn red, then SPF 15 would prevent a burn for 15 times longer, which is 150 minutes. The amount of time it takes for a burn to occur depends partly on the UV Index, which you can check out for your ZIP code on any given day on the Environmental Protection Agency (EPA) website.

When choosing a sunscreen, consider the following: SPF 15 filters out 93 percent of UVB rays, SPF 30 filters out 97 percent and SPF 50 filters out 98 percent. (There is no sunscreen that filters out 100 percent, i.e. no "sunblock.")

It is important to protect your skin from the sun, not only to prevent aging, but also to prevent skin cancer. The majority of the most common skin cancers – squamous cell and basal cell carcinomas of the skin – are caused by accumulated sun damage. Sun exposure also increases the likelihood of developing malignant melanoma, which is a deadly skin cancer. In fact, even one bad (blistering, or second-degree) sunburn as a child more than doubles your risk of developing melanoma later in life, according to the Skin Cancer Foundation.

So here is how to protect your skin with sunscreen:

• Buy at least SPF 15, preferably SPF 30. In fact, Consumer Reports (which previously recommended SPF 30) is now recommending SPF 40 based on its 2013 product testing.
• Make sure your sunscreen is labeled "broad spectrum" – this means that it protects against both UVA and UVB rays.
• Apply sunscreen liberally to all the sun-exposed areas of your skin. That means using at least two to three tablespoons of sunscreen. (Most people don't use enough to be protective!)
• Apply 15-30 minutes prior to sun exposure, and reapply every two hours (sooner if you are swimming or sweating heavily).
• Do not use sunscreen on infants under 6 months. Rather, infants should be kept out of the sun completely.
• Avoid using sunscreen sprays on children; the FDA is looking into whether sprays pose risk when inhaled, and they typically do not cover the skin as effectively as lotions do. If you choose to use a spray, do not spray it on the face; instead, spray it on the hands and rub onto the face. Also be aware that the sprays are flammable.
• If your sunscreen is three years old or beyond the expiration date on the bottle, throw it away and buy a new bottle.

Be especially careful to protect your skin between the hours of 10 a.m. and 2 p.m. when the sun's rays are strongest. Hats and sleeves work even better than sunscreen. Windows filter out UVB rays, but not UVA – so you can still experience photo-aging of the skin and a higher risk of skin cancer via sun exposure through a car or house window.

The FDA has issued some new regulations for sunscreen makers as of June 2012 which fully take effect for this sun season. Key points include:

• Any sunscreens that are not broad spectrum, or are broad spectrum but have an SPF of less than 15, must display a "skin cancer/skin aging alert."
• Several misleading terms on sunscreen are now forbidden, including "sunblock," "instant protection," protection of more than 24 hours and "waterproof."
• Claims of water resistance are now limited to either 40 minutes or 80 minutes. This is the maximum amount of time, according to tests, that you can expect the sunscreen to protect your skin at the declared SPF level.
• Any SPF greater than 50 will just be called "50+" since there is no real advantage to higher SPF than 50.

I hope you find this information helpful as you prepare to protect your family and enjoy time together outdoors this summer!