When 7 Up was originally placed on the market (In 1929), it was named Bib-Label Lithiated Lemon-Lime Soda- a much less catchy, though more descriptive name. The ‘lithiated’ in the name came from the soda’s ingredient lithium citrate, a compound used to treat patients with mental health problems like bipolar disorder, depression or mania.
The soda went through a name change to 7 Up Lithiated Lemon Soda, before finally settling on just 7 Up, and a formula with no added lithium. The 7 in the name has no confirmed source, but several theories about its origin. Some soda fans claim that it is derived from the 7 ingredients used in the original recipe, others from the soda having a pH of 7 (which is not true), and others think that the 7 originates from the lithium in the original formula, as this element has an atomic mass of ~7.