I know that Citrulline is generally seen as the most effective in studies, but is there any benefit in taking it in combination with another NO activator?
edit: Agmatine?
Rather than give an answer to your question, I'd ask you a question instead, which might make you look very differently at your ultimate destination, i.e. NO. Here's my question: are you getting headaches from your NO supplements, or whatever other supplement that claims to activate a NO effect? If your answer is no to NO's headache effect, I'd change product until I get one that gives me at least a slight headache. A headache in and of itself is not the major issue in the context of what I'm discussing here, my issue is why I am or I am not getting a headache.
NO causes your blood vessels to dilate (vasodilation), that's where the forearm vascularity promise on the supplement label comes from. But it's a catch 22 here. Either you're getting the roadmap look on your forearms and the great pump in your muscles from NO (due to its working mechanism in dilating your blood vessels),
and with that a headache. Or, you're not getting a headache and none of the pumps and popping veins promised by the supplement, indicating it has no NO, or an activator of it. Or perhaps you are getting a massive pump and vascular arms,
without a headache, in which case I'd look closer at the ingredients that are written on the label and credit them with your results and not NO. Why is that so?
Because there are some people who are prone to headaches when they exert themselves in small bouts of high intensity training, when others suffer no headaches at all. Upon examination, you'd find that those who've gotten the headaches had a higher level of NO in their bodies when compared with those who did not get any headaches
http://www.webmd.com/migraines-headaches/news/20010702/does-exercise-trigger-your-migraines
The point I'm making here, is NO is
not without its commonly known side effect, a headache or a migraine. Of course the supplement company would not wish for you to know that, for more reasons than one.