What product would be best for putting weight on and building muscles?
The best product is called "Elbow Grease". You can buy it at the
gym for about $39 a month, maybe less if you can find a discount.
Once you buy this product (they might have different brands, called
"Memberships"), you must apply it to a variety of apparatuses and
to your body on a regular basis. This product works best when you
synergize it with a healthy, protein-rich diet and some advice from
your physician, dietitian, and the optionally-included personal
trainer.