Most people have heard that coca cola contained some cocaine from 1886 to 1929, but did you know that 7up also contained some medicinal products?
7up's seven original ingredients contained sugar, carbonated water, essences of lemon and lime oils, citric acid, sodium citrate, and lithium citrate (1924-1948).
Wait... lithium citrate... yes Lithium the mood stabilization medication. No wonder consumers may have felt more mellow after consumptions.
This is probably just coincidence but the molecular mass of lithium is 6.94 amu, but no one would put that on the bottle, so round up to 7up!
Bottoms up
References
Rodengen, Jeffrey. The Legend of Dr. Pepper/7Up. Fort Lauderdale: Write Stuff Syndicate, 1995. ISBN 0-945903-49-9.
Gielen, Marcel; Edward R. T. Tiekink (2005). Metallotherapeutic drugs and metal-based diagnostic agents: The use of metals in medicine. John Wiley and Sons. p. 3. ISBN 0-470-86403-6.
https://www.huffingtonpost.com/2014/09/17/7up-history_n_5836322.html