I found this little comment many years ago somewhere on the Internet.

"After ingestion, aspartame is broken down into aspartic acid,
phenylalanine, and methanol.

Methanol is oxidized into formaldehyde and then to
formic acid, which is considered responsible
for the toxic effects of methanol.

Despite arguments that aspartame intake should not affect
blood methanol concentrations, animal studies have
reported the accumulation of formaldehyde adducts derived
from aspartame in tissue components.

This might be one explaining factor for reports on headaches
linked to the intake of aspartame."

jackD


p.s. The phenylalanine might be good for MS folks - I am still looking into this.