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People with obesity using the drug tirzepatide saw a decrease in blood pressure. Stefa Nikolic/Getty Images
  • People with obesity who took the weight-loss drug tirzepatide for 36 weeks also saw a decrease in their systolic blood pressure, the top number in a blood pressure reading.
  • The blood pressure reduction ranged from 7.4 Hg to 10.6 mm Hg on average, depending on the dose of tirzepatide received.
  • The effect of the drug on blood pressure was seen during measurements taken both in the daytime and at night.

Nearly 500 adults with obesity who took the chronic weight loss drug tirzepatide saw a decrease in their systolic blood pressure, in addition to losing weight, the results of a clinical trial show.

The results of the new research were published February 5 in Hypertension, a journal of the American Heart Association.

Systolic blood pressure, or the top number in a blood pressure reading, is a measure of the force that occurs when the heart pumps blood into the arteries.

When systolic blood pressure is too high over a long time, it increases the risk of heart attack, stroke, irregular heart rhythms and other health problems.

In the study, people taking 5 milligrams of tirzepatide saw an average decrease in systolic blood pressure of 7.4 millimeters of mercury (mm Hg).

For those taking 10 mg of tirzepatide, sold under the brand names Mounjaro and Zepbound, the average reduction was 10.6 mm Hg; and for people taking 15 mg of tirzepatide, the decrease was 8.0 mm Hg on average.

The blood-pressure lowering effects occurred during both daytime and nighttime measurements, which were done over a 24- to 27-hour period.

Dr. Cheng-Han Chen, an interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, Calif., who was not involved in the research, said the results show that tirzepatide can significantly lower blood pressure in patients with obesity.

“While the baseline blood pressures were not particularly high, the drug had blood pressure lowering effects on par with our standard anti-hypertensive medications,” he told Healthline.

Nearly 47% of adults in the United States have high blood pressure or hypertension, and almost 42% have obesity, according to the American Heart Association’s 2024 Heart Disease and Stroke Statistics.

“Since hypertension is a known and common risk factor for cardiovascular disease, these findings suggest a benefit to cardiac health beyond the drug’s effect on blood sugar control and weight loss,” said Chen.

“This study also highlights that treating obesity isn’t about losing weight, but it’s about gaining health,” said Dr. Angela Fitch, chief medical officer at knownwell and current president of the Obesity Medicine Association, who was not involved in the new study.

As a result, “patients deserve access to comprehensive obesity care to improve their health and quality of life,” she told Healthline, “not just access to a medication for weight loss.”

The new research was a sub-study of a larger clinical trial funded by drugmaker Eli Lilly and Company, manufacturer of tirzepatide.

The drug is approved by the U.S. Food and Drug Administration as a treatment for type 2 diabetes (brand name Mounjaro), and for chronic weight management in people with obesity or who are overweight (Zepbound).

Tirzepatide works by mimicking two hormones in the body: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP).

After a person eats, these hormones stimulate the secretion of insulin and increase the body’s sensitivity to insulin. Together, they help regulate blood sugar levels, slow down digestion and reduce appetite.

By activating the GLP-1 and GIP receptors, tirzepatide acts in a similar way, which leads to weight loss. Another chronic weight management drug, semaglutide, activates only the GLP-1 receptor.

In the larger clinical trial for tirzepatide, which included people who were overweight or had obesity, those receiving 5 milligrams of the drug lost 15% of their body weight on average.

Those receiving 10 milligrams lost an average of 20% of their body weight, and those taking 15 milligrams lost 21% of their body weight on average.

“These findings show the effectiveness of these [GLP-1 agonist] medications for weight loss,” said Dr. Mir Ali, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, Calif., who was not involved in the new research.

“Additionally, any form of sustained weight loss will improve most, if not all, health conditions,” he told Healthline.

Fitch pointed out that one clinical trial involving the GLP-1 agonist semaglutide (brand names Ozempic and Wegovy) showed that, in addition to helping people lose weight, the drug had a number of cardiovascular benefits, including lowering blood pressure.

“We have known for years clinically that these newer GLP-1 agonist medications lower blood pressure and we have to be mindful of that when caring for patients,” she told Healthline, “since many patients with overweight or obesity have hypertension and may take medications for blood pressure.”

Ali recommends that people taking one of these medications see their physician regularly because as “their blood pressure improves, their blood pressure medications will likely need to be adjusted.”

One question that remains is whether the improvements in blood pressure are the result of the weight lost or the direct effects of the drug.

In the new sub-study, researchers found that participants’ weight loss was linked with blood pressure reductions.

However, “the data we have to date on GLP-1 agonists suggests that the cardiovascular improvements seen from these medications is not just an effect from weight loss,” said Fitch, “but is also a direct effect of the medication on the cardiovascular system.”

Additional research is needed to understand how much of a direct effect these drugs have on blood pressure, and also what happens if people stop taking the drug. Does their blood pressure remain stable, return to its previous level, or something in between?

“We need more data on the medication effects on cardiovascular outcomes vs. the weight reduction effects,” said Fitch. “It is quite probable that being on these medications long-term is necessary not only for maintenance of weight reduction but also for the cardiovascular benefits.”

The sub-study included 600 participants from the larger clinical trial, which involved adults with obesity but not type 2 diabetes.

Around two-thirds of participants in the sub-study were female, two-thirds were white and one-quarter were Hispanic. The average age of participants was 46 years old.

Participants were randomly assigned to receive tirzepatide in one of three strengths (5 mg, 10 mg or 15 mg) or an inactive placebo.

About one-third of participants had high blood pressure at the beginning of the sub-study. All had blood pressure levels lower than 140/90 millimeters mercury (mm Hg). Around one-third were taking one or more high-blood pressure medications.

The American Heart Association classifies high blood pressure as having a systolic blood pressure greater than or equal to 130 mm Hg, or a diastolic (the bottom number) greater than or equal to 80 mm Hg.

Researchers compared participants’ blood pressure readings at the start of the study to 36 weeks later. Only participants with sufficient valid blood pressure readings at both times were included in the final analysis; this was 494 participants out of 600.

At each time, participants wore a blood pressure monitor over a 24- to 27-hour period. This measured blood pressure every 30 minutes during the day and once an hour at night.

This type of ambulatory blood pressure monitoring is more comprehensive than a single measurement taken in a doctor’s office or at home. However, the measurements were collected only at two time points during the study, and also only once an hour at nighttime.

Another limitation of the study is that researchers did not assess participants’ diet, including sodium intake. As a result, they cannot estimate whether dietary changes contributed to the reductions in systolic blood pressure.

In a study of nearly 500 adults with obesity, people who took the weight-loss drug tirzepatide saw a reduction in their systolic blood pressure, in addition to losing weight.

The blood pressure reductions depended on the dose of tirzepatide that people received, but the reductions occurred during both daytime and nighttime measures.

More research is needed to understand the long-term effects of this blood pressure lowering on the risk of heart attack, heart failure and other cardiovascular outcomes. It is also unknown if the blood pressure will rebound after a person stops taking this medication.