Updated: May 13, 2020
Last month I talked about protecting your skin even in winter and on cloudy days. This month, I’d like to touch on the subject of SPF (sun protection factor).
There is a general belief that sunscreens with a higher SPF gives proportionately more protection. This couldn’t be further from the truth. As can be seen from the graph, a sunscreen with an SPF 15 gives a 93 per cent protection. Increase the SPF to 50 by more than doubling the active ingredients, and you only get an extra five per cent protection. This is a trade-off most people aren’t willing to make once they understand it.
Having more active ingredients in a sunscreen is not always a good thing. These ingredients work by absorbing the UV rays to prevent them hitting the skin cells. In the process of absorbing and neutralising the UV rays, these ingredients turn into free radicals which then present a different set of problems to the skin. So, a good sunscreen should also have a good dose of antioxidants to combat this issue. More on ingredients next month.
Another fact that is not widely known is that the SPF measure only applies to UVB – the shorter UV rays that reach the epidermis (top layer of the skin) that is responsible for redness, inflammation and burns. The measure does not apply to UVA – the longer, more insidious rays that can penetrate the skin down to the dermis damaging collagen and elastin tissues (please see Part I in the last issue). So, choosing a sunscreen based on SPF alone is not enough as you are only protected against UVB. Look for one with a broad spectrum protection guarding against both UVB and UVA.