Activewear brand Sweaty Betty has become involved in a new dispute over advertising slogans, which a period underwear company claims were copied.

Kelly Newton said Sweaty Betty’s use of two taglines that were very similar to her firm Nixi Body’s “seemed a little off”, and while she could not get them trademarked she felt Sweaty Betty was “taking from” other female founders.

Sweaty Betty said the “No ifs. Just butt.” line had been used by many brands and influencers, but also said it was reviewing all its marketing campaigns.

Ms Newton said she was speaking out after seeing personal trainer Georgina Cox reveal Sweaty Betty had offered her a settlement over a disputed slogan.

Ms Newton, who co-founded Nixi Body in 2019, said the company has advertised its leak-proof period underwear with the lines “Keeping you moving through menstruation, motherhood and menopause” and “No leaks. No ifs. Just butts.” for years.

But late last year a friend alerted her to a Sweaty Betty ad for its femtech range of leak-resistant and maternity leggings with the tagline “Keeping you moving through menstruation, maternity and menopause”.

At first, Ms Newton thought it could have been a coincidence, and said she was annoyed but did not feel there was anything she could do.

That tagline has since been changed on the Sweaty Betty website to “Menstruation. Maternity. Menopause. Together we’re raising the bar for every woman, for any life stage.”

Then, earlier this year, she noticed Sweaty Betty was running a campaign with the line “No ifs. Just butt.”

“I thought ‘oh hang on a second’,” Ms Newton told the BBC.

Again, Ms Newton said she didn’t reach out. She said she had tried to get the “Keeping you moving through menstruation, motherhood and menopause” line trademarked but was unable to do so, and said she knew that legally she had little recourse.

“Legally they were within their rights to use these words, but they’re words that we’ve used for quite a few years.”

It was personal trainer Ms Cox sharing her story about dealing with the brand that made her want to speak out, Ms Newton said.

Last month Ms Cox revealed that Sweaty Betty had offered her £4,000 in exchange for confidentiality and its continued use of the phrase “Wear The Damn Shorts” that she claims was used without crediting her in its latest campaigns.

She told the BBC she came up with the slogan to support her sister in 2020 and it quickly went viral. In 2023, Sweaty Betty approached her to use it in a campaign and paid her £3,500 to promote the campaign in social media posts.

She was also paid for another campaign using it in 2024, but was not approached about it for this year.

Ms Newton said she felt compelled to speak out about her experience after talking to Ms Cox, because she was not the only person affected.

“Your tagline can’t be empowering all women when actually all you’re doing is taking from them,” she said, adding that she was not seeking compensation but rather for Sweaty Betty to be accountable.

“It just feels like for me all the slogans I’m seeing are coming from other female founders.

“I just want them to do the right thing and just morally acknowledging what they’ve done isn’t great and to do better really.”

Sweaty Betty said it chose words “to empower women through fitness” to advertise its femtech range, something many brands try to do, which “sometimes… means the language used by different brands aligns”.

“We have been using the phrase for over a year and Nixi has not been in touch with us about our use of it. The phrase is used by many brands in various forms and that is why no individual or brand can claim exclusive rights to it or trademark it,” the company said in a statement.

“It is never our intent to take credit for the work or creativity of others, particularly from trailblazing women, and we have reached out to Nixi Body directly to convey this. We have also been undertaking a review of all our campaigns and marketing language to fully understand the origins of the phrases we use and will continue to do this.

“We note that such a review was conducted with respect to the ‘Wear the Damn Shorts’ phrase and its origins date back to at least as early as 2019, before either Ms Cox or Sweaty Betty first used the phrase. We continue to work towards a resolution with Ms Cox, as has always been our objective, however this dispute remains ongoing.”