As to which type of guitar capo will best suit your playing, you will need to match the capo to your guitar, the primary factor being whether you have a flat fretboard, like a nylon-stringed classical or some steel-string acoustics, or if the fretboard is curved, like on most steel-stringed acoustics and electrics.
However, note that other causes of the symptom 'Muscle mass loss' may be possible. Research the causes of these symptoms that are more broader types of symptom than Muscle mass loss: Muscle atrophy (351 causes)
Losing muscle is highly undesirable because your metabolism will decrease and aesthetically, you may not look leaner even if you do lose weight. Lean body mass is also your set point to determine how much fat you should lose and what your body fat percentage will be if you lose a certain amount of fat. You can check out the Ideal Body Weight Formula, which takes into account your lean body mass to arrive at your ideal weight.