One completely random study result[0] supporting that couch + testosterone leads to bigger muscles. Maybe it is some puritanical thing, but not sure why this myth persists. Exercise + juice results in even bigger gains, but it is possible to increase muscle mass without hard work.

  ...The men in the testosterone groups had significant increases in the cross-sectional areas of the triceps and the quadriceps (Table 4); the group assigned to testosterone without exercise had a significantly greater increase in the cross-sectional area of the quadriceps than the placebo-alone group

[0] https://www.nejm.org/doi/full/10.1056/NEJM199607043350101