US GLP-1 prescriptions pass 2.5 million a month before demand inflects

US prescriptions for GLP-1 medicines, a class that includes semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), had climbed to roughly 2.5 million per month before October 2022, according to IQVIA data ^[1]. That month, Elon Musk posted on Twitter (now X) that taking Wegovy was his secret for looking "fit and healthy." The post went viral, and GLP-1 prescription volume more than doubled over the following year ^[1].

The timing mattered. Mounjaro, Eli Lilly's tirzepatide product, had launched only four months earlier, in mid-2022 ^[1]. IQVIA describes Musk's post as "a pivotal moment" that sparked "widespread curiosity around GLP-1s and their effectiveness on weight loss" ^[1]. By the end of 2024, total GLP-1 prescription volume had surpassed 9 million per month, up from the roughly 2.5 million recorded before the Musk post ^[1].

The surge in interest was not limited to social media chatter. IQVIA reports that between August 2021 and July 2024, social media mentions of obesity treatment brands topped 1.4 million, a 740% increase over the prior three-year period, alongside 53 million searches for obesity as a disease over that span ^[1]. Drugmakers also ramped up spending: in the month before Mounjaro's launch, GLP-1 promotional spend stood at $1.8 billion; by mid-2025 it had grown to more than $7 billion across the class ^[1].

Patient uptake tracked this attention. Before 2022, only about 1.8% of people diagnosed with obesity, roughly 1.6 million patients, had started any anti-obesity treatment ^[1]. After Mounjaro's launch, the number of patients on GLP-1 therapy jumped 200% within 12 months ^[1]. By the second quarter of 2025, an estimated 11 million unique patients were using a GLP-1 drug across all indications, including diabetes and obesity ^[1].

Why it matters for patients

The scale of this shift helps explain much of what patients have experienced since 2022: long waitlists, periodic shortages, and a flood of advertising and social media discussion about these drugs. IQVIA's data suggest that patient demand, not just clinical trial results, drove much of the early surge, with search and social activity rising sharply around the same time prescriptions took off ^[1].

The growth in prescribing also came with a large jump in the number of prescribers involved. IQVIA found that by 12 months after launch, Mounjaro and Zepbound had reached four times as many unique prescribers as Ozempic and Wegovy had at the same point in their own launches ^[1]. That faster spread across providers likely made it easier for more patients to find someone willing to prescribe a GLP-1 drug, though the sources do not detail how prescribing patterns varied by specialty or region.

Even with this rapid growth, IQVIA notes that the roughly 11 million patients on GLP-1 therapy as of mid-2025 represent only a small share of the US population diagnosed with obesity, meaning there is, in the firm's words, "a lot of room to grow in this class" ^[1]. The sources do not say what share of current users are being treated for obesity specifically versus diabetes or other approved uses, nor do they address cost, insurance coverage, or supply issues in detail.

What happens next

IQVIA's analysis, published in September 2025, frames the 2022 inflection as a turning point that has continued to shape the market. Mounjaro was selling about $3 billion a month roughly three years after its 2022 launch, and Zepbound was on pace to exceed that figure within a few months of the report ^[1]. The sources do not provide specific forward-looking dates beyond these figures, so how prescription volume, promotional spending, or patient counts will change from here is not yet known based on the material reviewed.