We try the new St Tropez Self Tan that keeps selling out online

When a product sells out online within hours of launch, I pay attention. When that same product is re-stocked and immediately flies out again, I won’t rest until I can get my hands on a sample and see what all the palaver is about.

Call it professional diligence, call it an inability to resist hype – either way I was pretty darn excited when a bottle of St Tropez Purity Bronzing Water Gel, £28, arrived at my desk after news that it had sold out twice on Boots online and LookFantastic.

You might remember the Purity range launching last year – essentially these are self tanners in light transparent formulas that smell of tropical fruit, not biscuits. There was a body mousse and a face mist, which I was especially enamoured of as it could be sprayed on over or under makeup for a believable glow without muddy guide colour.

The new kid in the range is also clear and fruitily fragranced, but is a thicker gel. Sweep it on to your body with a mitt and it’ll develop into a tan – a tad deeper than last year’s mist and mousse – in around three hours. Notably, the formula contains tons of Hyaluronic Acid, skincare’s top hydrating ingredient, so promises soft skin as well as bronzing effects.

As a seasoned self tanner my thoughts were thus: This sounds amazingly life-friendly, as I could put on in the morning then get on with my day, no worrying about looking mucky or having to wash it off.

Then again, surely the lack of colour could make application a little tricky? How will I know where it’s going? Will I end up streaky, overly saturated or with one leg doubled-up and deep mahogany and one forgotten and peely-wally? I needn’t have worried.

While it may not have a guide colour per-say it leaves enough of a sheen on skin to show exactly where it’s been and where it needs to go. The formula glides on nicely, it feels a bit like a posh after sun – quenching and gel like but with no stickiness whatsoever – then just sinks in and does its thing. I forgot it was there after 10 minutes and went about my day until I looked in the mirror a few hours on and noticed my face, arms and shoulders had a lovely healthy glow.

Buy it now, £28.50, at Boots.com

I can see why this has proven so popular, it basically does away with all the faff and mess associated with tanning at home. The lack of traditional tan smell will win it plenty of fans too (weirdly, I’ve never minded the digestive biscuit aroma, but that’s just me).

If you’re incredibly nervous first time tanner I’d recommend sticking with something with a guide colour while you work on your mitt skills and if you want nothing less than hardcore, super-deep bronze I’d say a spray tan is still your man. Otherwise, this is a clever, user friendly innovation that is worth a giving whirl as we enter ‘yikes, I have to get my legs out’ season. If you can get your hands on a bottle before it sells out again, that is.