Weird Tales of the Future #2

In the year 2552 a scientist is disgusted that due to advanced technology, humans have entropied bodies with no muscle since no one does anything remotely physical anymore. He creates a serum that will devolve humans to the point when they had muscles. His serum is too powerful though and his assistant Luga devolves into a savage caveman. Luga gives the serum to others and the savages take over the city. Ultimately the scientist is able to kill Luga, and assures the rest will return to normal. He then administers a weaker dose of the serum to the population to make them strong.