I have used this product for 12 days so for I had a knee injury where I was limping after runs. However, after 5 days of taking my limp had stopped and now I have run on it 3 days doing 10Km without pain or issues. I am back to where a month ago in timing and pace. After 3 runs which is brilliant, "Yes, this does what it says on the tin". I feel stronger, fitter with a better well being.