My girl has been wearing a collar for about 5wks now, its hard to say, but i put it on her anyway, some people notice it helps straight away, others say a few months, she limps quite bad on her front legs, not at the same time! I put the same blog on another site i am in, and got 11replies back, 8 said it helped their dogs, 3 said no change, but, the orthapeadic surgeon that was treating my dog, told me to put 1 on her and just forget about it, so i do, worth a try i say, but then i would try anything as would most dog owners!!!