Dermalogica describes itself as "the world's number one professional skincare brand" and we only have to look around us and see the company's pleasingly understated packaging lined up in windows here, there and everywhere to sense its ubiquity. It might therefore be considered remarkable (if not quite earth-shattering) that I haven't been 'face mapped' until now. Face mapping is Dermalogica-speak for skin analysis, either offered by stockists for free or by a beauty therapist as part of a Dermalogica facial, after which products are prescribed for use at home.

"But zat is all bull-sheet, no?" says a French friend when I tell her about it, which is a bit rich given that she also claims the effect of her iridescent eye-shadow is "illuminating".

So no, as it goes. It's not. Dermalogica's huge range of highly specific products aimed at individual skin properties goes at least some way towards explaining its unprecedented profile in the beauty salon environment.

It doesn't take a genius to spot the broken capillaries (cheeks and nose), dehydration (forehead) and odd blocked pore (ahem) that my sun-starved, pollution-ravaged complexion is prone to. It is good to know, though, that skincare aimed solely at dry and damaged skin is, in fact, too rich for me. And there I was thinking that I gave the most desiccated autumn foliage a run for its money. Also noteworthy and without wishing to crow: "You're less than averagely congested as a matter of fact," my Dermalogica therapist tells me. It's the people who don't think they have a problem the diligent beauty professional has to watch, apparently. Deep down, you know who you are.

Anyway, after an hour-long, simple but effective and highly pleasurable facial (£60 – not unreasonable given the three-figure sums that not infrequently go with the territory), I come away with three of Dermalogica's (also reasonably priced) top-selling products: Daily Microfoliant, Precleanse, left, and Intensive Eye Repair.

Susannah Frankel is Fashion Editor of 'The Independent'