Health Canada says Fluffy Unicorn — an unauthorized natural health product promoted as a workout supplement — may pose serious health risks.

Health Canada says laboratory testing on product seized from a shop in Laval, Que., found that it contains undeclared synephrine and higher levels of caffeine than declared on the label.

When combined, synephrine and caffeine can cause serious side effects ranging from dizziness, tremors, headaches and irregularities in heart rate to seizures, psychosis, heart attacks and stroke.

Health Canada says consumers should stop using the product and consult with a health care professional if they have used Fluffy Unicorn and have any health concerns.

Should additional retailers or distributors be identified, Health Canada says it will take appropriate action.