I started using this product completely by accident after a suggestion from a veterinarian I had brought my dog to for a paw injury. I mentioned she was getting older and a little stiff and it was bothering me and probably my dog a whole lot more than me. There are competitive products and I tried one or two since originally getting this and there is no comparison. Within a week or less I saw a dramatic Improvement in my Patti girlies energy and movement. She's older and I am seeing her do things and reach places without the hardship and effort she had prior. Since I purchased this and after exploring another option or two I have to say forget about everything else buy this. The other thing that might be important to mention for people who have dogs that have special needs such as my girl. I have to be careful with her as she is on prescription food and prone to kidney stones, let me tell you every other product has a kidney stone warning somewhere hidden in the labeling or there was a warning about them but this particular product does not. It's hard for me to find things for her and this was the happiest accident ever. No side effects or stomach distress and certainly not a worry about any future kidney stones. Give it a try and you may see a difference in your dog's Mobility and Agility within days or certainly no later than a week or two. It's really important for those of us who consider our dog or other petsin our family's to know of products such as this one which does not cause any harm and it genuinely only helps and 2 just see an older cat or in my case a dog seem to act like she did when she was much younger, was and is just as amazing and heartwarming. I won't mention the name of their largest competitor but I did try them out and I saw no improvement. I saved a few dollars but it wasn't worth it Please go with this you won't regret it and neither will your fur babies young or old if they're showing any signs of arthritic conditions or Mobility problems. This Dasuquin MSM will be with us 4 a lifetime. It's an amazing product with no side effects to date. Trust me if there was going to be something that would impact or make my Patti girl sick I would certainly know it by now and nothing of the kind is happening. Therefore if you have an older dog like a senior don't worry this is the product you want to have just to see what appears to be like evolution in reverse as far as your older dog behaving much more puppyish pretty darn quick. Total breakthrough in a natural supplement as opposed to giving your four-legged family member medications for the obvious signs of Aging and arthritis or general stiffness which could happen in larger dogs even at younger stages of their life.