SEATTLE, WA (MyBellinghamNow.com) – An Illinois man is taking Costco to court over claims of misleading labelling on one of its products.

Court documents were filed in the U.S. District Court of Western Washington Wednesday, Sept. 30, as the big-box store is headquartered in Issaquah.

Plaintiff Mason Maldonado claims that the store’s Kirkland Signature Hydration Electrolyte Mix, labelled as sugar-free, actually contains allulose.

The Cleveland Clinic defines allulose as a naturally-occurring sugar found in foods like maple syrup and figs.

It’s used in higher amounts as an artificial sweetener, attracting more health-conscious individuals because of its lower caloric content.

Maldonado, who describes himself as a health-conscious individual, says in his lawsuit that he was more compelled to purchase Costco’s electrolyte mix because of its sugar-free label’s claim.

His class-action lawsuit seeks $5 million in damages for other consumers who feel they were duped by Costco.