I have tried this product a few times. It has worked for me, but at the expense of ripping headaches. Maybe this is why?
http://scienceblogs.com/terrasig/200...ts_no_more.php
"In the case of Stiff Nights, following a consumer complaint, the FDA determined that the product contains sulfoaildenafil. This is a chemical similar to sildenafil, the active ingredient in Viagra. Sulfoaildenafil may interact with prescription drugs known as nitrates, including nitroglycerin, and cause dangerously low blood pressure."
This stuff is nothing to play with, and is not regulated. Check Here too:
http://www.mensblogtalk.com/index.php For reviews on supplements