A group of curly-haired consumers filed a class-action lawsuit against the maker of a popular haircare brand — claiming use of the products leads to scalp irritation and hair loss.

DevaCurl No-Poo Original conditioner, manufactured by the defendant in the suit, Deva Concepts, is marketed as a sulfate-free alternative to shampoos for customers with curly hair, according to the Manhattan Federal court suit.

But treating your locks with a various number of DevaCurl products, including the conditioner, leads to “scalp irritation, excessive shedding, hair loss, thinning, breakage and/or balding during normal use,” the suit alleges.

The suit, which filed Wednesday, says “thousands of consumers” have reported such adverse effects, with some filing FDA complaints and others voicing their concerns on Facebook.

DevaCurl “provides no warning about these consequences, and in fact makes numerous assertions about the gentle and beneficial nature of the products,” the suit says.

Had DevaCurl users known using the product would cause hair loss, “they would have not purchased” them, according to the suit.

The three lead plaintiffs in the case are Ginger Dixon, of Pennsylvania, Alanna Hall, of Brooklyn, and Cristina Napolotano, of West Babylon.

The trio have all used DevaCurl products within the last four years, experiencing scalp issues and hair loss. Once they switched to other brands, the suit says, their conditions subsided and improved.

They are seeking unspecified monetary damages.

DevaCurl could not immediately be reached for comment.

But the company on Tuesday posted a message intended for “our beloved curl community” addressing customer concerns.

“When some of you first raised concerns about our products, we were laser-focused on our testing as the best way to confirm their safety and quality,” the message read.

“We’ve heard you and recognize that any changes to your hair – for whatever reason – demand a special type of attention that safety tests alone can’t address,” the letter continued.

To better address consumer complaints, the company added, they are now “partnering with medical professionals, dermatologists, industry experts, professional stylists, and members of our curl community.”