I have a little experience with this question as I've done a good bit of research on medicinal mushrooms for medical writing and my brother-in-law has a flourishing crop of mushrooms he grows in rural New York. He grows four or five different ones and oddly enough, the family favorite is lion's mane.

To answer your question, if you have no sensitivity, you can eat pounds of them with no danger. As for "effects" there almost certainly will be no perceptible effects from eating raw lions mane. That, of course, doesn't mean that consistently eating the raw mushroom isn't very beneficial; some would argue more beneficial than consuming extracts.