I just started my 3rd pen. The only side effect has been feeling tired. My part D insurance would have paid some leaving me with about $2,000 to pay for each 28-day pen. I need the Forteo to build my bones so I can have major back surgery. Thank goodness Lily has the Care Foundation and they are providing the medicine for free. My doctor’s office help coordinate everything after I filled out an application on line. My osteoporosis was undiagnosed because no doctor thought to order a bone scan when I should have had one. Please pass the word to anyone you know who is 65 or older to get a bone scan.