Two possible reasons for Em using “Melatonin” (which is an over-the-counter pill to help promote sleep) instead of the correct word, “Melanin” (which is a pigment that is the primary determinant of skin color)
Proof might have messed up and said Melatonin instead of Melanin when he was talking to Em.
Eminem made a mistake. He might’ve made that mistake because he was just recovering from drug addiction, and Melatonin might’ve been one of the pills he used.
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