Pro-anorexia sites are selling merchandise ranging from weave bracelets in order to "meet" other sufferers and appetite suppressants so users can "become anorexic fast".
Research by The Priory Group, provided exclusively to The Huffington Post UK, revealed websites which actively promote eating disorders are profiting from their vulnerable users.
Although sites selling appetite suppressants, such as the one Louis Tomlinson tweeted about, are nothing new, they usually come with a side-effects warning, and are packaged for diets and weight loss, rather than directly advertised to anorexics.
Pro-anorexia, often dubbed 'pro-ana', website Tangerine Monday contains dozens of adverts and articles promoting a diet suppressant.
One article on the site reads: "So you want to become an anorexic but don’t know where to start? I was in this position a few years ago.. How can I survive without eating was what I thought to myself.. How can a person become anorexic if they cannot stop being hungry..
"..I came across a natural appetite suppressant.. [which] enabled me to become anorexic fast.
"Anorexia dieting is becoming a large phenomenon as almost everyone wants to become skinny. What is more beautiful than a thin women? [sic]"
Another website, My Pro Ana, is selling a "pro ana red weave bracelet". Anorexics can wear the bracelet in order to identify other sufferers, while reminding them to "stay true" to their diet.
One review under the bracelet reads: "This bracelet is worth every single penny. The detail is phenomenal. When I put it on I am constantly reminded that I am never alone and I am strong enough to make it."
A description of the bracelet reads: "Traditionally a red beaded bracelet, the pro ana bracelet is worn as a reminder of staying true to your diet, and also to meet other Ana’s [sic].
"The bracelet is without any logos so you can wear it while maintaining discretion – nothing indicates that it is pro ana."
Perhaps even more worrying is the bracelet is out of stock.
Dr Alexander Yellowlees, Medical Director at the Priory Hospital in Glasgow and consultant psychiatrist specialising in the treatment of eating disorders, believes they place those suffering in a perpetual downward spiral.
"These sites are enormously negative. Particularly if the individual already has this illness. They are definitely designed to help sufferers become more effective in their methods," he told HuffPost UK. "They fuel the pursuit of thinness and encourage the anorexic drive.
“They [the sites] give the individual the idea that anorexia is a legitimate choice – it’s not. Anorexia has the highest mortality rate of all psychiatric conditions – it’s a killer.
“Those suffering often get clinically depressed and commit suicide or die from their physical conditions brought on by the disease, from a cardiac arrest or fit."
He added the websites provide a false sense of community, while fostering and promoting the illness
"It’s like having a drinking club for alcoholics where you can learn how to drink more effectively. They are encouraging anorexia and seem to be trying to make money from the illness, like having a happy hour for alcoholics."
A spokesperson for eating disorder charity B-eat told HuffPost UK: "Eating disorders by their nature are a very secretive illness and by making parts of very harmful and dangerous websites exclusive can fuel the illness.
"Often people use these types of sites to gain acceptance and a sense of understanding and by offering merchandise it’s feeding the idea that this is a community.
"The commercial exploitation of something that is a very serious mental illness is extremely concerning."