Can Drugs Like Ozempic and Mounjaro Interfere With Birth Control?

Type 2 diabetes medications including Ozempic, Wegovy, and Mounjaro have all made headlines for their increasingly popular use as weight loss drugs. But a new question has entered the conversation lately: Can these drugs interfere with and reduce the effectiveness of hormonal birth control?

This concern has been buzzing among social media groups in recent weeks, where some users have claimed that they became pregnant while taking one of these weight loss drugs even though they were on hormonal birth control.

These trendy weight loss drugs belong to a class of medications called GLP-1 receptor agonists, which can slow gastric emptying and affect the absorption rate of other oral medications.

While there’s no scientific evidence to prove that these drugs can reduce the effectiveness of birth control, such speculation is valid, according to Laura Purdy, MD, a Nashville-based OB-GYN and chief medical officer of OpenLoop Health, a telehealth services delivery company.

Purdy explained that since GLP-1 medications can slow the rate at which food moves through the digestive system, they might be able to delay the absorption of oral birth control hormones, potentially interfering with ovulation.

“This could lead to irregular periods or changes in the effectiveness of hormonal birth control methods,” Purdy told Verywell. “Additionally, losing weight while taking these medications could also affect hormone levels and potentially reduce the effectiveness of birth control.”

However, according to Sarah McBane, PharmD, a professor at the University of California Irvine School of Pharmacy and Pharmaceutical Sciences, the labeling for Ozempic and Wegovy does not warn of a drug interaction with oral birth control, and she has not heard of any instances of this occurring.

Mounjaro, on the other hand, is different from Ozempic and Wegovy, McBane said. Mounjaro, also known as tirzepatide, acts on a combination of two hormones: GLP-1 and GIP (glucose-dependent insulinotropic polypeptide). Unlike Ozempic and Wegovy, Mounjaro does state in its drug label that the absorption of oral contraceptives may be affected.

“There seems to be something about this combined activity that can have a more dramatic effect on the absorption of medications,” McBane said.

So while Ozempic and Wegovy’s impact is nothing more than a possibility at this point, Mounjaro has demonstrated an ability to have an effect on the absorption of other medications, including birth control.

“People using oral hormonal birth control for contraception should be aware these medications might be less effective and plan to use a backup method of birth control—such as condoms or a non-oral form of contraception—for four weeks after starting Mounjaro and after each dose increase,” McBane said.

Why Do These Drugs Have a 'Reproductive Potential' Warning?

Ozempic, Wegovy, and Mounjaro all contain a “reproductive potential” warning on their labels. According to Purdy, this is a standard warning included on many medications, indicating that the medication could potentially affect fertility or harm a developing fetus.

“Women who are pregnant or planning to become pregnant should talk to their doctor before taking these medications, as the potential risks and benefits need to be carefully considered,” Purdy said.

It’s also important to note that all three of these drugs can cause side effects including nausea and occasionally vomiting. If a person were to vomit a dose of birth control, McBane explained, that would have the same effect as missing a dose and could impact its effectiveness.

“There are many birth control options besides pills. There are patches, rings, implants, IUDs, and barrier methods such as condoms that could be used along with Mounjaro,” McBane said. “With this many alternatives, I encourage health practitioners to have candid conversations with their patients so that appropriate, effective, patient-centered medication choices are made.”