I didn't have any side effects. My problem with the products was remembering to take them all. Not being consistent. I can't say it made a difference because the next time I had a DEXA I was still losing density. But I belive that was due to my not being consisstent with taking them, not eating enough of the right foods, exercising enough with weights and walking. Osteoporosis is so complicated and confusing. He would be the guy to walk a person through it all. In the book he lists many of his case studies and he describes and how he solved their problem. What kind of side effects are you worried about?