I have suffered with canker sores my whole life. I am now 58 and canker sore free. I was getting them really bad last year and always had at least 2 in my mouth or under my tongue. I was in misery. Believe me I tried all the "remedies" however it was my dr that suggested that I start taking L Lycine. I had nothing to loose so started taking 500 Milligrams per day. It helped but wasn't there yet. I then doubled the dose and found that when I remembered to take my iron pill in conjunction I was canker sore free. I have found that not all L Lycine tablets are created the same. I was using the Target brand because the tablets were small. I would still get a few now and then but definitely better. When I switched to the mini GNC brand I rarely get an outbreak and if I did feel one coming on it usually just goes away before breaking the skin. I think it may be important to mention that I take a B12 supplement as well. Since these are so painful I thought it important to share. Thanks and best of luck!