[vedant]

The main breakdown products of aspartame are aspartic acid and phenylalanine. You may have been born with a genetic mutation that makes it possible for you to taste phenylalanine, which tastes bad.

[vpeters25]

As a completely anecdotal fact with zero scientific value, I think i am among the people that can taste aspartame.

It also gives me headaches, to the point the rare occasions I drink soda, I rather have HFCS than aspartame.

[ejstronge]

I hadn't heard about this before. Are there any published studies on aspartame breakdown and taste?

It seems impressive that aspartame would be broken down quickly enough in the mouth to reliably produce a bad taste.