Sun Safety

adult putting sunscreen on child

Dermatologist Dr. Yuka Asai answers questions about sunscreen. Click here for a list of sunscreens approved by the Canadian Dermatology Association.

Does a higher SPF make a better sunscreen?

An SPF of 30 is enough, says dermatologist Dr. Yuka Asai:  “The difference between an SPF of 30 and 50 is less than 2% blockage.  Volume and frequency are what really count in obtaining good sun protection.  Use a sunscreen with both UVA and UVB coverage (look for the words “broad spectrum”) and a minimum SPF of 30.  Apply 2mg/cm2 of skin area.  That’s about a ½ tsp. on your face and neck, ½ tsp. on each arm and 1 tsp. on each leg (amounts would vary with the surface area of your face/neck/arms).  When in doubt, more is always better.  Apply 15-30 minutes prior to going out and then reapply often (every two hours).

Do I need to apply sunscreen if I use a face moisturizer with an SPF of 30?

You need to apply at least ½ tsp. on your face and neck, says dermatologist Dr. Yuka Asai:  “Using half that amount (i.e., a pump or two of your moisturizer) gives you only 1/8 the protection, so a daily SPF-enhanced moisturizer is likely not going to provide enough volume of sunscreen.  Two most important things about sunscreen are to use lots and to reapply often (every 2 hours).”

Can I skip moisturizer and just use a sunscreen?

Yes. It’s better to trust your sunscreen since moisturizer and SPF-enhanced makeup are not always applied evenly and often come off easily, says dermatologist Dr. Yuka Asai:  “ You don’t really need a moisturizer if you're using the appropriate volume of sunscreen.  After cleaning your face apply your sunscreen, wait a few minutes and then apply your makeup.  This prevents diluting the sunscreen.”

Does it matter if I use a spray sunscreen versus a lotion?

Spray sunscreen is fine, says dermatologist Dr. Yuka Asai:  “But you need to have a good layer and to rub it in to make sure the droplets actually make contact with the skin surface rather than just sit on top of the body hair.”

Can the sun’s rays penetrate glass

Yes, says dermatologist Dr. Yuka Asai:  “UVA rays, which penetrate deep into the dermis (the skin’s thickest layer), also penetrate window glass, so if you work as a driver or in a glassed-in but very sunny area, keep this in mind and reach for the sunscreen.”