I happened to find this product at my local pet store & the trial size was a good price. I have been looking for something that was a good price & easy to give to our girl. She was starting to lose her mobility in her back legs when going up stairs. So we tried this for a month & are happy to say she is back to her old self, running around like shes a pup with her brother & sister (4 legged). She will be 11 yrs this Sept.