A bipartisan bill that would require Medicare Part D to cover anti-obesity medications, including GLP-1 receptor agonists like Wegovy and Zepbound, has secured 14 co-sponsors in the U.S. Senate, according to an announcement from the bill's lead sponsors on March 4. The Treat and Reduce Obesity Act (TROA), co-sponsored by Senators Tom Carper (D-DE) and Bill Cassidy (R-LA), would lift a decades-old statutory exclusion that prevents Medicare from covering weight loss drugs.
The bill has picked up five new co-sponsors since January, including Senators from both parties who represent states with high obesity rates. Senator John Fetterman (D-PA) and Senator Markwayne Mullin (R-OK) joined as co-sponsors in February, citing constituent demand.
"My office gets more calls about obesity medication coverage than almost any other health issue," Senator Cassidy, who is also a physician, said during a press conference. "This isn't a cosmetic issue. Obesity is a disease, and Medicare should treat it like one."
Why Medicare Doesn't Cover Weight Loss Drugs
The exclusion dates to 2003, when Congress passed the Medicare Modernization Act that created Part D. At the time, the available weight loss medications had limited efficacy and significant safety concerns. Lawmakers included anti-obesity drugs in a category of excluded medications alongside cosmetic drugs, fertility drugs, and drugs for erectile dysfunction [1].
The pharmaceutical landscape has changed dramatically since then. GLP-1 receptor agonists have demonstrated weight loss of 15-22% in clinical trials, along with cardiovascular benefits, improvements in sleep apnea, and reductions in kidney disease progression. The exclusion, written for a different era of obesity medications, now blocks Medicare beneficiaries from accessing drugs that have strong evidence of clinical benefit.
Currently, approximately 65 million Americans are enrolled in Medicare [2]. The Kaiser Family Foundation estimates that roughly 40% of Medicare beneficiaries have obesity, meaning more than 25 million people are affected by the coverage exclusion [3].
What the Bill Would Change
TROA would amend the Social Security Act to remove anti-obesity medications from the list of Part D excluded drug categories. It would also add obesity screening and counseling as covered benefits under Medicare Part B.
The bill includes several provisions designed to manage costs:
A step therapy requirement would mandate that patients try lifestyle interventions or lower-cost medications before accessing GLP-1 receptor agonists. This approach mirrors what many commercial insurers already require.
The bill authorizes Medicare to negotiate prices for anti-obesity medications under the Inflation Reduction Act's drug negotiation provisions. Semaglutide and tirzepatide would be eligible for Medicare price negotiation once they meet the required time-on-market thresholds.
A budget cap provision would limit total Medicare spending on anti-obesity medications to $35 billion per year for the first five years, with annual adjustments thereafter.
The Cost Debate
Cost is the central tension in the debate. The Congressional Budget Office has not yet scored the current version of TROA, but a 2024 CBO analysis of a similar proposal estimated that covering GLP-1 medications for all eligible Medicare beneficiaries would cost approximately $28 billion per year [4].
Opponents, including some fiscal conservatives and taxpayer advocacy groups, argue the price tag is too high. Americans for Tax Reform called the bill "a blank check for pharmaceutical companies at taxpayer expense" in a February statement.
Supporters counter that the cost analysis fails to account for savings from reduced obesity-related healthcare spending. Obesity drives costs across nearly every medical category: heart disease, diabetes, joint replacements, certain cancers, and dozens of other conditions.
Dr. Lee Kaplan, director of the Obesity, Metabolism, and Nutrition Institute at Massachusetts General Hospital, presented data at a Senate Health Committee hearing in January showing that treating obesity could reduce Medicare spending on related conditions by $15-20 billion annually within five years of coverage implementation.
"The question is not whether Medicare can afford to cover these medications," Dr. Kaplan testified. "The question is whether it can afford not to."
Where the Bill Stands
With 14 co-sponsors, TROA is approaching the level of support that typically triggers a committee vote. The bill has been referred to the Senate Finance Committee, chaired by Senator Ron Wyden (D-OR), who has expressed support for the concept but has raised questions about the budget cap mechanism.
Senate watchers note that bipartisan support does not guarantee passage. The bill would need 60 votes to overcome a filibuster in the full Senate, and the companion House bill has fewer co-sponsors and faces a more skeptical reception from the House Budget Committee.
Advocacy groups, including the Obesity Action Coalition and the Obesity Care Advocacy Network, are organizing constituent campaigns targeting senators who have not yet co-sponsored the bill. The Obesity Action Coalition reported that more than 200,000 Americans have contacted their senators about GLP-1 coverage since January.
What Medicare Beneficiaries Can Do Now
While the legislative process continues, Medicare beneficiaries with obesity have limited but real options:
Medicare Part D covers GLP-1 medications when prescribed for type 2 diabetes, not for weight management. Beneficiaries with both conditions can access these drugs through their diabetes diagnosis.
Some Medicare Advantage plans have begun offering supplemental anti-obesity medication benefits outside the standard Part D framework. These benefits are plan-specific and vary by region.
Medicare beneficiaries can also contact their senators to express support for TROA. The Obesity Action Coalition provides form letters and contact information at its website.
Sources
- Medicare Modernization Act of 2003, Section 1860D-2(e)(2)(A). U.S. Congress.
- CMS. "Medicare Enrollment Dashboard." Updated January 2026.
- Kaiser Family Foundation. "Obesity Among Medicare Beneficiaries." 2025.
- Congressional Budget Office. "Estimated Budget Effects of Covering Anti-Obesity Medications Under Medicare Part D." 2024.