THE ‘IMMUNE-BOOSTING’ POTION THAT COSTS £4,300

SAMSIDAE PREMIUM KOREAN BLACK GINSENG EXTRACT

£4,300 for one month’s supply

THE CLAIM This mysterious-looking black liquid, developed exclusively for Harrods, claims to ‘improve the immune system and sexual performance’, ‘sharpen memory’ and ‘control blood sugar levels’.

WHAT’S IN IT? Just ginseng – the root of a plant found in China – which has been steamed, dried and liquidised. Samsidae’s ginseng is harvested every six years for ‘optimum potency’.

THE VERDICT Samsidae isn’t clear about why its so expensive, but there are cheaper ‘pure’ ginseng equivalents. The Mail on Sunday found one bottle by German Pharma that offers the same dosage for £14.99 per two months’ supply.

DOES IT WORK? ‘There is significant research that tiny compounds in ginseng stimulate the release of insulin – which converts the sugars in our food to energy,’ says Dr Ward.

‘But studies show that a cup of English breakfast tea has just as significant an effect on insulin. If you drink three cups of tea every day, you’re probably getting the same benefit.’