Londoners sweat it out in cellulite busting hot pants

Already more than 40,000 people have "liked" a Facebook page supporting weight-loss "hot pants", and Dannii Minogue has sworn allegiance to a pair of ankle-length leggings in a bid to make her cankles disappear.

On Twitter, updates for Proskins Slim anti-cellulite leggings have become so frequent that the marketing team has launched a #caffeinepants trend to channel the interest as they continue to shift 15,000 pairs a week at £50 apiece.

On Facebook, the Zaggora Hot Pants page is generating minute-by-minute commentary because of the brand's claim that by making you sweat, your bum heats up, boosts circulation and, after The Two-Week Challenge (14 days of being worn for eight hours a day) they can help you drop a jeans size and reduce cellulite. Already 40,000 pairs have been sold in the UK at £44.99 each and 150,000 pairs worldwide.

"So amazed by the results, have lost one inch in from waist and thighs in a week can't wait to see the final result ... Thankyou Hot Pants," comments one user, Nishu Sharma, while another squawks: "have lost six pounds! I ride my bike in them, wear them at work, sleep in them and run in them! Just love them so much."

But can any garment possibly live up to this kind of hype? For the past few weeks, to put them to the test, I've tried wearing a pair of Zaggoras under my pyjamas while I'm sleeping or at work and Proskins Slims instead of leggings during cycling and ballet.

The Proskins are made from compression fabric to enhance blood flow and keep you warm. They are also impregnated with caffeine particles which, Proskins claims, promote fat destruction, retinol to stimulate collagen and vitamin E to keep skin fresh.

Testing the full-length leggings - black and silky, I barely notice them once they are on. As a replacement for everyday leggings they just aren't sufficiently cool unless, of course, you actually want to look like a wet seal. But they feel encouraging: when I'm not trying to catch an image of my legs in the mirror, I'm springing about desperate to burn some energy. And after just a few sessions, my legs do feel softer - but the skin around my bum hasn't changed.

Wearing the Zaggoras is an altogether less pleasant experience. Aside from being excellent passion killers, I feel like I've been squeezed into a dry wetsuit which is a size too small, swishes loudly as I walk and makes me perspire from the onset. I wake up at 3am bathed in sweat and ferociously thirsty and tear them off.

Dehydration is certainly a side-effect, especially if you plan to complete the two-week challenge - I lasted two days - without a crashing headache.

Hot Pants may have an ecstatic online following but the experts are more ambivalent, suggesting that while you could find yourself fitting into a clingy dress in two weeks' time, much of the success is down to clever marketing.

"They've taken a very old traditional theory and married it with modern technology," says cosmetic surgery expert and author Antonia Mariconda, who also claims to have tried most anti- cellulite products. "These are made of materials that make you sweat. Of course this makes you lose fluid and reduces body mass. But measure it against traditional weight loss methods and these will probably be less effective. In the long run, I'm not so sure about them. In the short-term, sure, you will see some results. But a lot of it is clever wording," she argues.

As for me, I'd rather forego that extra glass and second helping and reach for a body brush than wear pants or leggings for days and nights on end.