Definitely try upping the dose of V. Double your dose. If it works, taper it back until you find the sweetspot. If it doesn't work, google to see the safe maximum dose and try that.
I used to get some help from Arginine but it doesn't do anything for me anymore.
Those are the only ones I've used. Arginine's cheap and you can take it as needed, but it works even better if you take it regularly as well as taking it as needed.