it's a very expensive product to use!! you would be better off feeding a conditioning cube, and a good alfalfa chaff, to help with the weightgain and correct work will build up muscles, bodybuilder is great however, for horses that have lost their appetite, they seem to love the smell! also good for youngstock in poor condition.
I used it last year briefly did the job when in Feb my horse was not putting on any weight despite being on conditioning everything. I did not think it that expensive but only lasts about 10-14 days a tub for a 17hh horse.
Yes and it's fantastic stuff! Used it on Otto last winter just to add a bit of muscle (and to be fair I was working him too) but he really picked up. Worked better then conditioning cubes for us but then every horse is different.