Elon Musk credits Wegovy for his weight loss on Twitter

Elon Musk, responding to a question on Twitter about how he had slimmed down, wrote a one-word reply: "Fasting" ^[1]. About 11 hours later he added a second post: "And Wegovy" ^[1]. The two messages, posted October 1 and 2, 2022 (UTC), are widely treated as the moment a GLP-1 weight-loss drug entered mainstream celebrity conversation ^[1][2].

The scale of the audience was part of the story. The "Fasting" post drew roughly 82,978 likes and 3,360 retweets, while the follow-up naming Wegovy collected about 1,543 likes and 65 retweets ^[1]. Musk runs SpaceX and Tesla and, at the time, was finalizing his purchase of Twitter after a lengthy legal fight ^[2].

What Wegovy actually is

Wegovy is Novo Nordisk's injectable form of the GLP-1 drug semaglutide — the same molecule in the company's diabetes products Ozempic and Rybelsus ^[2]. The FDA approved Wegovy in the summer of 2021 for chronic weight management in adults with obesity, or in adults who are overweight with a BMI of 27 or more plus at least one weight-related condition such as high blood pressure, type 2 diabetes or high cholesterol, or in people with a BMI of 30 or greater ^[2].

Fierce Pharma noted that it was not clear whether Musk would meet those approval criteria, which is one reason unsolicited celebrity endorsements can cut both ways for drugmakers ^[2]. Musk is not a spokesperson for Novo Nordisk, and a company spokesperson told Fierce Pharma Marketing, "we were not aware of Elon Musk's use of Wegovy before he shared this information publicly" ^[2].

The post also landed in a moment when semaglutide's off-label use was already being reported. Earlier in 2022, Variety reported that a number of celebrities were paying large sums to use Ozempic — the diabetes-branded version of semaglutide — at a somewhat different dose to get its weight-loss effects ^[2].

The competitive backdrop

At the time of Musk's posts, obesity drugs were a market that had long disappointed. Heart-safety concerns had derailed many weight-loss medicines over the previous two decades, but Wegovy appeared to be bucking that trend and was projected to become a blockbuster later in the decade ^[2].

Competition was already visible. Eli Lilly's tirzepatide had been approved earlier in 2022 for type 2 diabetes under the brand name Mounjaro, and in October 2022 Lilly began a rolling submission to the FDA seeking approval of tirzepatide for obesity ^[2]. That obesity version would later be branded Zepbound.

Why it matters for patients

A single celebrity post does not change what a drug does, who it is approved for, or what it costs. But it can change demand — and demand affects patients in concrete ways, including pharmacy supply and how clinicians and insurers field requests.

The gap the sources highlight is between the label and the buzz. Wegovy's FDA approval is tied to specific BMI thresholds and, in the overweight category, the presence of a weight-related health condition ^[2]. Public disclosures from people who may or may not meet those criteria can blur the line between medical treatment for obesity — a chronic condition — and cosmetic weight loss. Reporting from 2022 already described celebrities seeking the diabetes-branded Ozempic at adjusted doses for weight loss, which is use outside the labeled indication ^[2].

It is also worth noting what the sources do not say. Musk did not describe his dose, how long he used Wegovy, any side effects, or how much weight he lost ^[1]. Novo Nordisk said it had no advance knowledge of his use ^[2]. The sources contain no information on whether fasting, the drug, or both accounted for his results, and no safety data specific to combining the two. Those details are not known from this reporting.

What happens next

October 1–2, 2022: Musk's two posts appear on Twitter ^[1]. October 2022: Eli Lilly's rolling FDA submission for tirzepatide in obesity is underway ^[2]. October 13, 2022: Fierce Pharma publishes Novo Nordisk's response, confirming Musk is not a company spokesperson ^[2].

For readers weighing these medicines, questions about eligibility, coverage and side effects are decisions to work through with a licensed clinician rather than a social media feed.