What Is the Difference Between Tymlos and Forteo?


What is the difference between Tymlos and Forteo?


PTH stimulates the production of new bone tissue, and these two drugs both replicate the bone-producing effects of PTH. Both medications are delivered through self-administered injection once per day. Because these medications only work to build bone, physicians recommend following up with a bisphosphonate medication. Bisphosphonates decrease the rate that bone is destroyed, which slows down the rate of bone loss.

Forteo was first approved by the FDA to treat osteoporosis in 2002. Tymlos came onto the scene later, and was approved in 2017. Both drugs were only approved for patients with severe osteoporosis who had exhausted all other treatments, or could not try other treatment options. This includes women and men that have a history of osteoporotic fractures, which are fractures that usually occur in the spine, hip, or wrists that were not caused by force and have painful symptoms.  

Side Effects

Tymlos and Forteo share similar side effects. Both can cause your blood pressure to drop and can cause dizziness, nausea, and palpitations (faster heartbeat). You may also experience pain or swelling where you injected the medication. Both medications can also cause you to have too much calcium in your blood which can lead to kidney stones and interfere with heart and brain function. Forteo also lists joint pain and leg cramps as potential side effects on its website.

Tymlos and Forteo both have a label warning that they can cause osteosarcoma (bone cancer).  During the drug testing periods they were shown to cause bone cancer in animal studies. Both medications are only prescribed for two years, after which the drugs’ effectiveness stalls and the risks increase.


Tymlos is marketed as a better version of Forteo, boasting that it reduces the relative risk of nonvertebral fractures by 43%. But, relative risk can be a deceivingly inflated statistic. In actuality, for both drugs there was just a 2-4% reduction in absolute risk of non vertebral fractures.    


Tymlos and Forteo are delivered in the same way through an injection pen. Forteo needs to be refrigerated, but a month’s worth of Tymlos doses does not. Without insurance, Tymlos costs about $1,800 per pen (30 doses) and Forteo costs about $3,270 per pen (28 doses). Most Medicare plans cover Forteo while only about half cover Tymlos.

For more information on osteoporosis treatments check out our Osteoporosis Treatment Fact Sheet.

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