Responding to the question about taking l-arginine and feeling like stuck n the chest. Five days ago the same thing happened to me while taking l-arginine. I normally take 5 grams (4 large pills) very late at night/early morning so as not to compete with other aminos (food). On this particular night, after a late night of partying, I took my normal dosage, except, I don t remember exactly what I did and very likely took without much water...AND immediately passed out. The result was a feeling of something stuck in my chest the next morning which I ignored for several days. After an unpleasant visit to a gastroenterologist (is that a word?) today, I was diagnosed with an esophageal ulcer. The diagnosis was that a pill likely burned my esophagus, and in my case, the likely culprit being l-arginine. While it may have occurred with another type of pill taking under my circumstances, in my case it was arginine. I now have a 4-5 week excruciating healing process which means limited meals and even more likely minimal workouts since you can t workout if you can t eat. What I m taking away from this; do NOT take l-arginine, or any other pill supplement, in the middle of the night where you risk it sitting. If and when I m able to start eating normal again, I will take the arginine very early in the morning before my morning workout, and I will crush the pills. Yeah I know there is already likely a powder form, but I have a full bottle of pills. Hope someone can learn from this since although I did much research before using arginine, not a single mention of this. Interestingly, of the 4 doctors I spoke to over the last 2 days, only one had even heard of arginine?