MasXtreme is sold in blister packs containing one capsule. It is considered a dietary supplement, and does not require a prescription. The recall specifically involves Lot #911035.
The FDA has found that MasXtreme contains aildenafil, which is similar in structure to sildenafil used in the prescription medication Viagra to treat erectile dysfunction.
The second problematic ingredient is an alpha-adrenergic blocker called phentolamine, used to prevent or control hypertensive episodes.