Some experts argue that the sunscreen we use to protect us might be doing more harm than help. Is this true?
One of the biggest causes of both skin aging and skin cancer is sunburn, so anything we can do to prevent it the better. Having said that, there have been concerns about some sunscreen and skincare ingredients – of those used in cosmetics, I’d avoid these chemicals:
Parabens, formaldehyde donors, urea derivatives or isothiazolinones; of specific sunscreen ingredients, I wrote in my book, Dermocracy (Harper Collins, 2015): PABA was widely used because of its effectiveness against UVB, but many people developed allergies to it. These days, few manufacturers still use this ingredient. I’d definitely avoid PABA-containing sun-blocks. The other issue to note is that many manufacturers use antioxidants, i.e., either botanicals and vitamins in sunscreens to help scavenge free radicals. But some botanicals, like bergamot, are well known to cause pigmentation in brown skin. From a pure sun protection point of view, these afford no benefit (although they may help repair UV damage later); so I’d definitely avoid sunscreens containing bergamot.
And most sunscreens contain UV-absorbing chemicals and some of these can affect hormones -- chemicals such as oxybenzone, octocrylene, homosalate etc. I also personally prefer to avoid such UV-absorbing chemicals and nanoparticles in sunscreen. Some manufacturers formulate nanoparticle-sized zinc as it is less whitening. But nanoparticles can damage coral reefs and also be potentially harmful to our cells.
How often should people apply sunscreen? And how much?
Ideally the guideline I use when I teach skin cancer doctors is “one ounce i.e. one shot glass” is the amount needed to cover the exposed areas of the body for a standard adult. And we should re-apply sunscreen every 2 hours.
Beyond sunscreen, what else should be considered when it comes to summer skin care?
One should understand what SPF (Sun Protection Factor) is. In my previous book, Skin a Biography (4th Estate, 2013) I had an explanation of sun-protection and SPF. Firstly, let’s understand the Fitzpatrick skin types we use in dermatology:
Always burns, never tans (like the typical Irish redhead
or platinum blonde)
Burns easily, tans with difficulty (usually blonde and
Rarely burns, tans easily (usually brown-black-haired
Sometimes burns, tans easily (Mediterranean, Spanish
or lighter Indian skin)
Dark brown skin that never burns, but tans easily
(darker Indian skin, some North African skin)
Black African skin (skin that has abundant melanin
and does not burn, but tans easily, although this darkening is
often not visible due to the extremely dark skin tone)
From a practical point of view, knowing your Fitzpatrick skin
type and the UV index we discussed earlier is very useful if you are
trying to calculate safe sun exposure.
‘Burn time’ of different skin types
Skin type 1 Maximum time in the sun = 67 minutes / UV index
Skin type 2 Maximum time in the sun = 100 minutes / UV index
Skin type 3 Maximum time in the sun = 200 minutes / UV index
Skin type 4 Maximum time in the sun = 300 minutes / UV index
For example, using the modified Fitzpatrick chart above, we know
that Type 4 Indian sub-continental skin can have safe sun exposure of 300 minutes/UV index of the day. For someone with Type 1 Celtic skin living in New Zealand, where the UV index can get up to 12, the maximum time in the sun (without burning) would be 67 minutes/12, or just over five minutes. Using a sunscreen with an SPF rating of 20 would increase this to around 100 minutes.
There’s an interesting bit of myth-busting I’d like to do here regarding SPF ratings. Unlike popular perception, an SPF of 30 in your sunscreen filters out only 4 per cent more UV when compared to an SPF of 15: i.e. 97 per cent versus 93 per cent. The higher you increase the SPF, the smaller the increase; an SPF 50 only filters out 98 per cent of UV rays. Essentially, higher SPF levels do not mean incrementally higher UV filtering effect. In fact, the US Food and Drug Administration’s recent guidelines prohibit sunscreens or cosmetics from claiming a SPF >50 as it gives users a false sense of security.
I tell my students that the easy way to remember this is that SPF 15 lets in one in 15 harmful sunrays, while SPF 30 lets in one in 30, and SPF 50 lets in one in 50.
Here's a guide to protect you from harmful burns?
The above guide helps us plan our sun-exposure and SPF rating. However, there are other things that we can do to protect from harmful burns as I’ve illustrated in my video below:
Are companies developing better sun-exposure products?
Many companies, including my own lab are trying to remove harmful ingredients and make sunscreens more effective and environmentally friendly. I myself have formulated mineral sunscreens that are free of nanoparticles and has no harmful chemicals. It is currently available only in New Zealand.
How can people see the signs of skin cancer? And when should we consult a doctor?
The main symptom of non-melanoma skin cancer is the appearance of a lump or discoloured patch on the skin that doesn't heal as one would expect from an injury. The main features of the more dangerous melanoma are a new dark spot on skin or growth or a change in an already existing mole.