Women Lose 57% More Weight Than Men on GLP-1 Drugs, Johns Hopkins Meta-Analysis Finds

GLP-1 receptor agonists work across the demographic spectrum. That’s the headline finding from the most comprehensive meta-analysis to date, published March 2, 2026 in JAMA Internal Medicine by researchers at the Johns Hopkins Bloomberg School of Public Health.

The study examined 64 clinical trials involving tens of thousands of patients taking GLP-1 drugs including semaglutide (Ozempic, Wegovy) and dulaglutide (Trulicity). The conclusion: age, race, ethnicity, starting BMI, and baseline blood sugar levels do not meaningfully predict whether GLP-1 medications will work. They work across the board.

Except for one factor. Women lose significantly more weight than men.

The Sex Difference: 11% vs. 7%

On average across the 64 trials, women who took GLP-1 receptor agonists lost about 11% of their starting body weight. Men lost about 7%. That’s a 57% difference in relative weight loss between the sexes on the same class of medication.

“These results should give clinicians and their patients more confidence that GLP-1 RAs work similarly well across different racial and ethnic populations, and different ages and weights, though they appear to have modestly greater effectiveness among women compared to men,” said senior author Hemal Mehta, an associate professor at the Johns Hopkins Bloomberg School of Public Health’s Department of Epidemiology.

The word “modestly” in Mehta’s statement deserves scrutiny. A 4-percentage-point difference in body weight — 11% versus 7% — is clinically meaningful. On a 200-pound person, that’s 22 pounds lost versus 14 pounds. Over a year of treatment, this adds up to a substantial divergence in outcomes.

Why Do Women Respond Better?

The researchers note that GLP-1 drugs may be more effective in women because of synergistic interactions with estrogen. Estrogen and GLP-1 receptors interact in ways that may amplify appetite suppression and metabolic effects in women, particularly premenopausal women. The exact mechanism isn’t fully established, but the hormonal interaction hypothesis is the leading explanation for the observed sex difference.

This also raises an important clinical question: do postmenopausal women respond differently than premenopausal women? The meta-analysis does not appear to have broken down results by menopausal status, which would be a valuable follow-up analysis. Women on hormonal birth control or HRT may also have different response profiles — this is an open research question.

What the Study Confirms About Equity

The equity finding is significant. GLP-1 drugs were developed and initially trialed in populations that often skewed white and middle-aged. A persistent concern in obesity medicine is whether treatments developed in narrow populations generalize to diverse groups.

The JHU meta-analysis directly addresses that concern. Across racial and ethnic groups, across patients starting at different BMIs (including class III obesity with BMI 40+), across patients with different baseline A1C levels — the effectiveness was statistically comparable. The drugs work for people regardless of these demographic factors.

This matters particularly for Black and Hispanic patients, who are disproportionately affected by obesity-related disease and have historically had less access to effective treatments. The data confirms that when access barriers are removed, biological effectiveness is equivalent.

Age and GLP-1 Effectiveness

The analysis also directly compared outcomes in patients under 65 versus 65 and older — finding comparable effectiveness. This is relevant because older patients are often undertreated for obesity, with clinicians sometimes reluctant to initiate aggressive weight-loss therapy in patients over 65 due to concerns about muscle loss or medication tolerance.

The data suggests age alone should not be a disqualifying factor. Appropriate clinical evaluation of individual health status matters far more than age as a category.

Starting BMI Doesn’t Predict Response

One of the more counterintuitive findings: patients with higher starting BMI did not have meaningfully different response rates than those with lower starting BMI. This challenges an assumption some clinicians hold — that severely obese patients (BMI 40+) may respond poorly because their metabolic dysregulation is more entrenched.

The meta-analysis says no. Whether you start at BMI 27 or BMI 47, the percentage of body weight lost on GLP-1 therapy is similar. The absolute pounds lost will be higher for heavier patients, but the relative response is consistent.

What This Means for Patients

If you’ve been told or assumed that GLP-1 medications “might not work” for you because of your age, race, ethnicity, or starting weight — this study is direct evidence against that assumption. The largest meta-analysis ever conducted on GLP-1 demographic effectiveness says those factors don’t predict response.

If you’re a woman, the data suggests you may benefit somewhat more than average. If you’re a man, 7% body weight loss is still clinically significant — it’s associated with meaningful improvements in blood pressure, blood sugar, sleep apnea, and joint health.

The single best predictor of whether GLP-1 therapy will work for you is not demographics. It’s adherence: staying on the medication, escalating the dose as directed, and maintaining the behavioral changes that compound the pharmacological effect.

Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Consult a licensed healthcare provider to determine if GLP-1 medications are appropriate for your individual health situation. Last updated: March 2026.