Goop, the lifestyle brand owned by actress Gwyneth Paltrow, has been reported to the U.K.'s trading standards and advertising watchdogs over allegations that it makes misleading claims about its products.

The Good Thinking Society, a non-profit charity that campaigns against pseudoscience, confirmed to CNBC Monday that it had submitted the complaint about Goop to the U.K.'s National Trading Standards and the Advertising Standards Authority. The news was first reported by The Sunday Times newspaper.

The complaint, seen by CNBC, alleges that Goop's "wellness" products are advertised misleadingly and make "potentially harmful" claims. It also holds that Goop's advertising could encourage customers to "use products which could cause direct harm" and that some of the firm's health claims about its supplement products are "unauthorized."

The charity listed 113 examples of Goop's advertising which it says are in breach of the law.

One of Goop's products, called "The Mother Load," lists 110 percent of the "daily value" of vitamin A for adults and children aged four an above, and 69 percent of the daily value for pregnant women. But Britain's National Health Service and the World Health Organization against taking supplements containing vitamin A during pregnancy. The NHS website recommends pregnant women "avoid taking supplements that contain vitamin A."

Susan Beck, senior vice president science and research at Goop, told CNBC on Monday: "When used as recommended, goop's the Mother Load supplements are safe during pregnancy. The Mother Load contains a very moderate 450 mcg (micrograms)," or 1500 IU (international units), "of vitamin A (preformed vitamin A as retinyl palmitate), which is less than the recommended daily intake of 600 mcg per day (per NHS)."

Beck added: "The Mother Load package contains a warning that pregnant women should not consume more than 10,000 IU vitamin A daily due to risk of birth defects. To provide you with more context — All pregnant women need vitamin A."

Goop said it had not been contacted by either National Trading Standards or the Advertising Standards Authority about the complaint.

Paltrow's firm, which was set up in 2008, recently opened its first pop-up store in the U.K., and made its web store available to European customers.

Laura Thomason, project manager at the Good Thinking Society, said in a emailed statement: "It is shocking to see the sheer volume of unproven claims made by Gwyneth Paltrow's Goop about their products, especially given that some of their health advice is potentially dangerous."

Thomason added: "Gwyneth Paltrow may well have good intentions, but she and her company sell products with claims that could clearly mislead customers. Just because Gwyneth has an Academy Award, it does not mean that Goop should be given an easy ride compared to other big corporations."

"Being a celebrity does not exempt someone from abiding by the advertising law here in the U.K., and if Gwyneth Paltrow cannot provide satisfactory evidence behind the claims she makes for her products, she should not be making those claims."

A spokesperson for the Advertising Standards Authority told CNBC: "We are looking into a number of ads appearing in various places, including online. At this point we are assessing the complaints and no investigation has been launched at this stage."

A spokesperson for National Trading Standards told CNBC: "While we have received correspondence from the Good Thinking Society, the regulation of advertising is not within the remit of National Trading Standards. Any complaints about advertising should be directed to the Advertising Standards Authority for consideration under the U.K. Advertising Rules."

It's not the first time Paltrow's Goop has been confronted with legal action. It settled a $145,000 lawsuit with California prosecutors last month over the advertising of a vaginal jade and rose quartz egg which it claimed could balance hormones and regulate menstrual cycles.

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