[Help] Any supplement(s) that I should get for my 9 year old lab's health? Particularly for joints/hips

I have a 9 year old female labrador.She groans sometimes when she lays down (although sometimes it seems like it may be out of frustration/disappointment that we wouldn't give her food/more of her munchies/treats after begging) and I believe that groaning is related to her hips or joints. I know that at least 1 of her back legs trembles a bit sometimes, usually while laying down.I bought a supplement off Amazon for her but I might return it (haven't used it) since a lot of the reviews seemed fake and leads me to believe the product may be more of an overpriced snake oil with known ingredients that could be purchased much cheaper elsewhere: http://ift.tt/2qHdPVw recommendations for supplements that aren't 'snake oils'? via /r/dogs http://ift.tt/2rcUq2l