I think you should notice something within the first month.

Depending on your situation and how much you needed it in the first place. It works on metabolic issues, and those can take time to change things.

I don't have major PN issues now, it is mostly arthritis for me these days, so I didn't notice much change in my PN pain.
I think I have fewer days of burning however.

Where my effects show up is in blood work... A1C is lower and blood glucose levels better. That is my major reason for using it.

Amazon carries it now -- the Doctor's Best brand. It is easier to make that free $25 shipping offer there than at iherb.

Many people over the years here have found lipoic acid helpful. It is really nice now to have the improved form and also that is affordable as well, and can be delivered to your door for convenience by the mail.