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Dr. Raynham Interviews Dr. Henry Lim

Interview between Dr. Helen Raynham and Dr. Henry Lim, the past president of the American Academy of Dermatology

Dr. Lim and Dr. Raynham


Dr. Raynham: How would you recommend a person apply sunscreen when they are going to be going out of the office during lunch time? Do you think it’s ok to apply it in the morning before they go to work and stay in the office all day? Or do you recommend they apply it immediately before leaving the office at lunch time?

Dr. Lim: Depending on how long they are going to be out, if they are going out to their car, picking up some lunch and then coming back they should be applying it before they go to work in the morning. That should be fine, there should be enough sunscreen on the skin that should be able to protect the skin. However, if you’re going to be sitting outdoors in the sun for an hour during your lunch break then I think definitely sunscreen should be applied before then.

Dr. Raynham: As far as how much time they should take to apply the sunscreen before they leave. In other words, should they apply the sunscreen 20 minutes before going outside? Half an hour? Or could they apply that sunscreen immediately before going outside?

Dr. Lim: Sunscreen will work as soon as it is applied. However, our recommendation is to apply 20 minutes before. That would allow the individual to apply leisurely, to apply evenly, to apply sufficiently rather than having to rush through the application of the sunscreen.

Dr. Raynham: And is there any study that’s being written about applying it 20 minutes beforehand going outside versus right before going outside?

Dr. Lim: There are no studies that have done that. The purpose of the application of sunscreen 20 minutes before is so that one can apply it without being rushed so that the application can be done properly.

Dr. Raynham: I understand. Now, many women and men have been given the option of chemical sunscreen or physical sunscreen in their moisturizer and in their makeup. My question to you is, if patients put on their moisturizer which has sunscreen in it and then go outside at lunch time does it make a difference if they wear a physical sunscreen or a chemical sunscreen?

Dr. Lim: There is no data on that but I would expect that it would not make any difference. As long as the sunscreen is the appropriate SPF; the same SPF and the same broad-spectrum coverage, I don’t expect there would be any difference.

Dr. Raynham: What I’m understanding is that physical sunscreen and chemical sunscreen break down at a similar rate or become less effective at a similar rate when you are indoors at the office?

Dr. Lim: That’s correct.

Dr. Raynham: And then when one is outside, the FDA tells you that when you are outside you have to reapply sunscreen every two hours in order to maintain it’s efficacy. Is there any difference based on chemical versus physical sunscreen when you are outside?

Dr. Lim: There is no difference.

So to summarize: here are our sunscreen recommendations.

If playing or working outside, apply generous amounts of sunscreen SPF 30 or higher, with UVA and UVB protection (broadspectrum).  Reapply after 2 hours.

If you work indoors, apply moisturizer with sunscreen in the morning before work.  By lunchtime your sunscreen will still be effective whilst you run errands or grab a lunch.  However, if you are planning on spending your entire 1 hours lunchbreak outdoors we recommend applying sunscreen. 

  • If your skin is irritated or your eyes burn from the sunscreen, we recommend using a physical sunscreen rather than a chemical sunscreen.  Pure physical sunscreens have titanium dioxide and zinc oxide and do not contain chemicals such as avobenzone, oxybenzone, octocrylene, octisalate, ecamsule and octinoxate.