The way I understood it creatine by itself doesn't promote muscle gain all that much. It's the fact that you can potentially do one to three more reps which does. But that still means you have to do the reps. https://leangains.com/supplements-you-might-actually-find-us...
After the 7-day wash-in, both groups followed the same RT program that comprising 3 full-body sessions a week for 12 weeks (Supplementary Materials, Table S1). All sessions were supervised by tertiary qualified exercise physiologists and commenced with a standardised warm-up of dynamic flexibility exercises. Each session consisted of 5 exercises: 2 compound movements each for the upper and lower body, and 1 isolation movement for the upper body. Four sets were prescribed for all movements to ensure an adequate weekly training volume for hypertrophy [32]. Training intensities were 6 to 12 repetition maximums (RM) with 60 and 120 s of rest between sets and exercises, respectively. To adhere to the prescribed RM, an individual’s rating of perceived exertion (RPE) on a Likert scale of 1–10 was recorded. RPE corresponds to the number of repetitions an individual perceives they will be able to perform after the set is complete, where an RPE 5 equates to 5 reps more, RPE 6 is 4 reps more, RPE 7 is 3 reps more, and so on [33]. When a RPE of 8 or lower was recorded, the external load (kg) was adjusted on successive sets to ensure that subjects achieved the target RM. The RM method was used to ensure that training intensities were relative to the individual’s abilities while also standardising the training intensity across all participants [34].