I wish I had read all the ingredients before buying. If you have HSV 1 (or 2) you will know that L-argenine can trigger a cold sore. I couldn't understand why I was having constant break outs until I read the ingredients. I ceased to take it and all back to normal but an expensive mistake on my part. I was taking carefully measured doses 3 x 1/4 teaspoon per day for 2-3 weeks. I suppose, in a personally negative way, this shows it was having an effect. But a good lesson to carefully read the ingredients not just reviews.It is difficult to give a rating as I'm sure this would be effective for some people.