I have a bottle of B vitamins at home. 250 mg Thiamin HCL, 250 mg Pyridoxine HCL and 1 mg Cyanocobalamin. Its expiry date was on 2019, it's been 2 years since it passed. Should I throw it off or is it OK to take it? How much potency it loses? Also I'm a bit worried about whether if it possible that excipients could be broken down into toxic byproducts by the time.