Young Dog Viscosity has every ingredient that Sound Dog Viscosity has to promote joint health, minus herbs like yucca, curcumin, corydalis, and frankincense. Those herbs give older dogs additional support to manage discomfort from everyday activities. Young dogs can, of course, have aches and pains from fierce, frequent play, but Young Dog Viscosity has MSM to manage that discomfort for a quick recovery.
And if they overdo it, you've always got Comfort Aches on hand.