It is the drink that celebrities swear by and the staple of any detox diet.
But while hot water with lemon may be a fashionable way to start the day, experts now warn it can damage our teeth.
The drink – touted by celebrities such as Gwyneth Paltrow, Jennifer Aniston and Claudia Schiffer – has been linked to a myriad of health benefits.
Advocates say it wakes up the liver so it flushes out toxins, stimulates digestion, supports weight loss and soothes an upset tummy.
But dentists are warning that the drinks’ acidity can erode away tooth enamel and lead to mottled and discoloured teeth.
Professor Damien Walmsley, the British Dental Association’s scientific adviser, said a number of studies show the more acidic a drink is, the more it erodes the teeth.
He warned that lemon juice is particularly damaging, especially when combined with hot water.
He told MailOnline: ‘Lemon juice, for example, has a pH of between 2 and 3 is therefore highly acidic.
‘The temperature of the water can exacerbate this effect because erosion is more severe at higher temperatures.
‘Studies also suggest that the incidence of this type of tooth wear, particularly among children and adolescents, is more prevalent than in the past.’
And Dr Nigel Carter, chief executive of the British Dental Health Foundation, agreed that lemon in hot water can cause tooth erosion.
He told MailOnline: ‘Lemon in hot water may be a good way of getting some vitamin C but it can play havoc with your teeth.
‘The problem is the acidity of the drink which, if taken regularly, will lead to a softening and wearing away of the enamel surface of the tooth known as dental erosion.
‘This can lead to discolouration as the darker dentine [the harder tooth matter below the enamel] starts to shine through the tooth.’
And the problem is increasing, he added.
‘Dentists are seeing a great rise in levels of dental erosion largely due to acidic fizzy drinks.’
In order to reduce the effects of erosion, he recommends drinking through a straw so that the liquid bypasses the teeth.