A friend tipped me of, but my google-fu gives me a range of opinions and not very good sources. I take about 40-80 grams a day.
ETA: I don’t seem to get headaches from it.
It’s a fine source of protein, and fairly easy to digest quickly, hence its utility in association with exercise, especially training for muscle hypertrophy. Timing of protein ingestion matters: having it in your system during the “anabolic window” of a few hours after a work-out helps, so either before or immediately after exercise (and after may be easier). Huge above normal daily protein ingestion does not really provide any benefit. Why are you taking that quantity? Do you not eat protein form other sources?
I know of no real literature on problems from it above and beyond that hypothesized for any extremely high protein ingestion.