Summer SPF and Suncare Questions Answered by Boots Suncare Scientific Adviser, Mike Brown

It's been a hectic week: a meeting with Boots Suncare Scientific Adviser, Mike Brown, was in the diary, and I was woefully under-prepared.

When stuck for time, turn to Twitter. You lot did my question-based research for me, thusly resulting in a benefit that was two-fold: a pile of questions to put to Mike and a resulting load of answers to said questions that you all actually want to know the results to. Huzzah!

So, without further ado, lets get to the meat and bones of the post, shall we?

@leannewoodfull for pale skin, what is the minimum spf you should be wearing? and what spf should you wear on your face daily? thanks

Mike's very practical about the whole SPF thing and knows it has to be easy and something you can work into your daily life. "The accepted advice is that the minimum is 15," he confirms, and recommends you get this in your daily moisturiser. Lazy arses might take heed from the next thing he said, though.  "But in the dead of winter, well, really, in a country like Ireland you can get away with none. Aim for SPF from March to October."

In our climate, the maximum we'll need is 30 - when we're away, he advises us to double the protection. In reality, that means a factor 50 when in a sunny climate. So, why is it so important to protect your face anyway? "Well," Mike says, "it's the one part of our bodies - along with our hands - that we don't cover with clothes, so it really does need that protection."

@Makeup_Savvy a bit of an odd Q - but would love to know how long a standard bottle should last - as in how many full body applications. Thanks

An easy one: "we test for this," smiles Mike. "A 200ml bottle should provide about seven full-body applications." I was thinking ahead though - what if you're a leprechaun, or Giant Haystacks? "On the average person," he qualifies, laughing. "We base this on a surface area of 1.8 square metres of skin. Clearly, if you're petite or very tall, you'll use a little more or less, depending.

@eliza64 Where is the sun?

Ask a scientist a smart Alec question and you'll get a smart Alec reply. "It's at the centre of the solar system," deadpans Mike.

@LandersOutdoor does a high spf show "whiter" in photographs?

"No, it shouldn't do," says Mike. Most products use conventional filters - or what you may have heard referred to as chemical filters - and these shouldn't necessarily show whiter, in fact they're transparent. The protection strength has no bearing on the problem, but the ingredients can do. Synthesised materials in sunscreens are fine, but the white cast can come from the inclusion of titanium dioxide. "This is the one that produces that white bloom," he confirms.

While there is a small amount of titanium dioxide in Soltan Face, Mike says Boots has formulated the product with the inclusion of manganese too. That has the effect of changing to brown and neutralising the white effect - so no more Casper the Friendly Ghost when you're in pictures. Hurrah! Well done that man.

@likemamuse2bake Are good quality sunglasses enough protection for the eye area because I find sun cream too heavy there?

"Most sunglasses these days are very good," Mike confirms. But he has a warning for us: "The big round ones can lead to ... you know ... sort of panda eyes." I seize on this eagerly. "You mean REVERSE PANDA, Mike," I screech. "Yes, ok," he smiles politely.

Anyway, I too was interested in this question because despite having a complexion with the approximate tolerance of that of a rhino, I can't use pure SPF products right up to my eyes. "That's often caused by the product 'creeping'." Mike says, but he points out that while Boots doesn't have a specific eye SPF product, Soltan Face is designed for use right up to the eye area, and is very gentle.

@ lil_fairy_doll how many months can you still use a botttle of sun cream after purchase before it loses its benefits?
@JenKen74 how long do sun products last safely please! From sunny Lanzarote!

Lets deal with this pair of questions together because they're very much interconnected. "There are two ways to look at this," he grins. "Number one is that there is a legal requirement that cosmetic products must have a shelf-life of 36 months," Mike says.  If the shelf-life will be less than that then it must be indicated on the packaging - by use of the little 'pot' symbol, for example.

However, it's likely that a product may be on shelf for a while before you buy it, but Mike says in terms of suncreams, it's generally not an issue. "Because Boots formulates all its own product in Nottingham, we can control production really well," so they don't tend to have product left over, and that means that stocks in stores are always fairly fresh.

And the second thing? "Well, there's the practical reality too," he says. Basically, sunscreen chemicals don't break down. The protection factor doesn't diminish - sure, the emulsion it's suspended in might, because after all, it's an oil-in-water mix and they are prone to separation. The chemicals that do the protection job will be fine. So as a rule of thumb, if it looks fine, smells fine and remains a glossy, smooth emulsion, chances are it's grand. If it's separated, smelly, giving you backchat or glowing, chuck it toot sweet.

If you have product left over after holidays, keep it somewhere cool and it'll be fine for next year. And if you've product from a couple of summers ago? "Then you're clearly not using enough sunscreen," laughs Mike.

And here ends today's adventures in SPFs. I have several more questions that Mike has given his considerable consideration to, and we'll take a look at those on Monday.