Health and medical experts have also warned against popular online diet product SkinnyMe tea, which has a laxative effect, saying it can cause ''unrealistic and unhealthy'' weight loss.

Users of the diet tea have reported serious side effects, with one customer hospitalised.

SkinnyMe tea is an Australian online company formed last year. It describes itself as a ''100 per cent natural health supplements company'' and promotes its products almost exclusively through social media, using ''before and after'' pictures.

Its ''colon cleanse'' product, which has caused the most concern among experts, contains the laxative senna.

The Australian Medical Association said using laxative products like this when they are not needed causes electrolyte and fluid loss, as well as the loss of other nutrients needed by the heart and brain to function.

''The Australian Medical Association would absolutely not recommend buying online programs like this in an effort to control weight,'' Brian Morton, a spokesman for the association, said.

''It is unrealistic - and if you are going to use anything, read the label very carefully and get some expert advice from a general practitioner or dietitian.''

Instagram deactivated the company's profile, which was followed by more than 200,000 people, more than a week ago. An Instagram spokeswoman said SkinnyMe tea directly violated its community guidelines.

''While Instagram is a place where people can share their lives with others through photographs, it does not condone the promotion or glorification of self-harm,'' the spokeswoman said.

The company has since set up another profile on Instagram.

SkinnyMe tea is not on the Australian register of therapeutic goods and has not yet been assessed. The Therapeutic Goods Administration said people who wish to use products that are not approved ''should note that no assurance can be given regarding their quality, safety or effectiveness''.

The administration said SkinnyMe tea had advised it will seek to include its products on the register ''as soon as possible''.

Declan Palmer, chief operations manager for SkinnyMe tea's parent company, All Good Incorporated, disagreed with claims that the tea is dangerous and advised those concerned to see a health expert.

''There's nothing wrong with being skinny and looking good,'' Mr Palmer said. ''The colon cleanse is a kick-start and we don't suggest users should be reliant on it.''

The chief executive of eating disorder support group the Butterfly Foundation, Christine Morgan, said she was ''horrified'' by the program and SkinnyMe tea's ''blatant disregard'' for the minds of young people.

''It's buying into this negative body image, which is a scourge amongst young people … that they won't be worthwhile or successful if they are not this idealised 'thin' body shape,'' Ms Morgan said.

''These practices are harmful on their own but if you have a genetic vulnerability to an eating disorder you are like a fuse waiting to explode. It is programs just like this that trigger it and send you down a very dangerous path.''

Madeleine Macintyre, 18, who was admitted to hospital at 17 after taking the colon-cleanse tea, was pleased to see the Instagram account deleted after SkinnyMe tea reportedly blocked her from its page when she complained about the product

''All the success stories made me feel so horrible about myself that I felt the need to be like those girls,'' Ms Macintyre said. ''Out of nowhere I got stomach cramps and they were so bad I was in tears every time I tried to lie down from the pain. My doctor told me my body had gone into mild shock.''

A spokeswoman for the Dietitians Association of Australia, Kate Di Prima, said ''extreme dieting'' was not balanced or healthy.

''I don't think there are any dietitians in Australia who would say it is," she said.

Jessica Maclennan, 19, bought the tea after seeing the extreme before and after photos online and only lasted six days on the program.

''The side effects I couldn't endure and I couldn't go to work,'' she said.

''I was woken at 5am with incredible cramps and was physically sick for about three hours in the morning. By the sixth day, the pain was too intense and I chose to end my 'teatox'.''