Fake batches of a men’s supplement have been found to contain erectile dysfunction medication.

The US Food and Drug Administration issued an alert after counterfeit versions of Green Lumber supplements, which claim to boost confidence, were found to contain the prescription drug tadalafil.

Green Lumber said the fake products were produced by an employee who used legitimate packaging and customer information to create and then distribute the erectile dysfunction medication, disguised as the supplements.

The employee has since been fired.

The FDA warned tadalafil could put people who take nitrates or prescription drugs for heart disease, blood pressure or other conditions at risk of developing life-threatening side-effects.