I'm going to sound like a commercial but... I was skeptical but desperate so I decided to give Flexacil Ultra a try. It took roughly 3 weeks to feel the effects and it was amazing. I have had crippling back pain for years and this product has made it almost disappear. I quit taking anti-inflammatories and only take Flexacil now. I accidentally ran out when I thought I had another bottle still. I ordered more right away but had to go without for about a week. The pain came back within about 3 days. But it went away again after a few days back on Flexacil. I will be certain to not run out again. I highly recommend this product.