Summary

About 20% of Americans taking a GLP-1 for weight loss are not using an FDA-approved product, according to a recent Gallup survey. Another 12% were unsure what they were taking. Use of these medicines has risen almost fourfold in two years. In May 2026 the FDA proposed a change. Semaglutide, tirzepatide and liraglutide would leave the 503B Bulks List, which permits large-scale compounding. Notably, the shortages that first opened this door closed more than a year ago.

Access Impact

The shortage ended. The substitution did not.

Semaglutide and tirzepatide left the FDA shortage list in late 2024 and early 2025. Compounding was legal while supply was short, and telehealth firms built large businesses on it. Then the shortage designation lapsed. Several sellers moved to “personalised” versions instead. Those are permitted when the approved product does not meet a patient’s needs. Consequently, the volume did not return to the branded channel. At their peak in 2024, compounded versions were estimated at roughly 30% of the market. Manufacturers responded through the courts. Novo Nordisk sued Hims & Hers for patent infringement, and the company later agreed to stop advertising compounded alternatives and to offer Wegovy instead. Even so, the wider pattern held. The domain under pressure is Budget Impact and Resources.

Budget Impact and Resources

Budget impact models rest on one quiet assumption. Treated patients are paid-for patients.

That assumption fails here. A patient using a compounded GLP-1 is treated, counted in prevalence data, and largely invisible to the payer. Therefore, the payer’s spend looks lower than true treatment volume, while the manufacturer’s revenue looks lower than true demand. Moreover, if the 503B proposal is approved, a share of that hidden volume will move back into the funded channel. Budget holders who modelled the current pattern would then face a step change they never forecast. In addition, the timing is hard to plan for. Proposals slip, and budgets are set annually.

Cost-Effectiveness

Price sensitivity is an access variable, not a commercial afterthought. A cost-effectiveness case is built at an assumed net price for an assumed population. However, a fifth of that population declines the price and buys elsewhere. The analysis then describes a narrower market than the one that exists. Specifically, the patients who leave are unlikely to be a random sample. They are the price-sensitive ones, often uninsured or underinsured. As a result, the treated population inside the payer’s data may look healthier and more adherent than the real-world one. Consequently, observed outcomes can flatter the modelled case.

Care-Pathway Integration

Access is a route, not only a price. The compounded channel runs largely through telehealth, which shortens the pathway considerably. A recent JAMA research letter examined online sellers. Notably, orders were often filled without screening for risk factors such as a history of eating disorders. In June the FDA warned that unapproved GLP-1 products are not reviewed for safety, efficacy or quality. By contrast, the approved pathway carries prescriber checks, monitoring, and a documented safety record. Even so, patients keep choosing the shorter route. Convenience is an access factor in its own right. That tells us something about how the funded pathway is experienced.

Risk Signal

Four years. Multiple lawsuits. A federal crackdown. Roughly one in five patients still outside the approved channel.

Forecasts for this class have repeatedly assumed that regulatory action would restore normal market behaviour. Instead, demand adapted each time the rules moved. Notably, the pattern is not unique to obesity. Any class with a high list price, a large eligible population, and a simple molecule invites the same substitution. Moreover, internal models rarely price that risk before launch. Furthermore, two diligence teams reviewing this market today would likely produce different access assumptions. Nothing external exists to reconcile them.

If your uptake forecast for a high-price, high-volume asset is challenged in two years, what independent benchmark stands behind it?

#MarketAccess #HTA #MARArating #Semaglutide

Explore the independent MARA assessment for Semaglutide \(Wegovy\): https://mararating.com/report/wegovy-semaglutide-for-weight-management-in-adults-with-obesity-or-overweight-and-at-least-one-weight-related-comorbidity-as-of-june-2026/

See how Orforglipron was assessed for overweight and obesity: https://mararating.com/report/foundayo-orforglipron-for-managing-overweight-and-obesity-as-of-june-2026/