Introduction
Ozempic alone generated about USD 13.9 billion in 2023 sales and continues to grow. With supply constraints repeatedly reported due to incredible demand, the door opened for the compounding pharmacy industry to enter.
Why compounding surged
Under U.S. law (FDCA 503A/503B), compounders can make "essentially copies" of approved drugs when those drugs appear on FDA's drug shortage list. Semaglutide injections (Ozempic/Wegovy) went into shortage starting in 2022 due to demand.
That shortage status effectively allowed 503A pharmacies and 503B outsourcing facilities to compound semaglutide injection products, which grew rapidly. One estimate suggests roughly 30% of U.S. semaglutide volume was via compounded products at one point.
On February 21, 2025 FDA formally determined the national shortage of semaglutide injection products was resolved and issued guidance ending enforcement discretion:
State-licensed 503A pharmacies must stop compounding semaglutide immediately.
503B outsourcing facilities may continue only until May 22, 2025, after which compounding "copy" semaglutide will again be prohibited.
Novo Nordisk's scale, and Denmark's macro impact
Novo Nordisk's total 2023 sales were around USD 33.7 billion, up 36% year-on-year, with roughly 90% of revenue coming from diabetes and obesity care (including Ozempic and Wegovy), and growth in this franchise continued into 2024 and to this day.
The GLP-1 boom has had macro-level effects on Denmark's economy: analysts at Danske Bank estimated that without the pharmaceutical sector (dominated by Novo Nordisk) Denmark's 1.8% GDP growth in 2023 would have been essentially flat.
Norway's Government Pension Fund Global (the "oil fund") is a huge global investor and holds a small but valuable stake in Novo Nordisk (around 1.8% of the company), worth about USD 5.5 billion as of mid-2025. These are big dollars we're looking at.
What's coming from big pharma
Eli Lilly has Phase 3 trials for their new drug in this arena, a "GLP-3," retatrutide. Most published forecasts see Eli Lilly's total revenue exceeding USD 90–110 billion by 2030, driven largely by its obesity/diabetes franchise, with retatrutide modeled as a future multi-billion-dollar asset that could rival today's largest drugs if phase 3 data translate into broad approvals.
For retatrutide specifically, independent analysts' peak-sales estimates currently cluster in the mid-single-digit billions by 2030. And there is at least one recent forecast going as high as USD 30 billion in annual sales in the 2030s.
What is the difference between a GLP-1 and a "GLP-3"?
GLP stands for glucagon like peptide 1. It is a well-defined human hormone. It is a drug target.
What GLP-1 is
GLP-1 (glucagon-like peptide-1) is an incretin hormone from intestinal L-cells that boosts glucose-dependent insulin secretion, slows gastric emptying, and reduces appetite.
GLP-1 receptor agonist drugs (semaglutide, liraglutide, tirzepatide's GLP-1 component, etc.) exploit this pathway to lower blood glucose and drive clinically meaningful weight loss.
What people mean by "GLP-3"
The term "GLP-3" is mostly a marketing or shorthand label for newer triple-agonist drugs, not a distinct, established hormone system like GLP-1.
In practice, GLP-1 is a single incretin pathway, while "GLP-3" usually refers to compounds that hit three metabolic receptors (for example, GLP-1 + GIP + glucagon), giving broader and often more potent effects but with less long-term human data.
In physiology, GLP-3 is not an established incretin axis on par with GLP-1 and GLP-2; it is a relatively poorly characterized peptide with no approved therapeutics and a limited defined role.
In the peptide/weight-loss space, "GLP-3" is often used informally to describe triple agonists such as retatrutide, Eli Lilly's new drug, that activate GLP-1, GIP, and glucagon receptors simultaneously, hence "three-pathway" signaling.
Where GIP fits
GIP is an incretin hormone from the small intestine that helps the body handle nutrients by stimulating insulin release after you eat, especially after oral glucose or fat. It works alongside GLP-1 but has a somewhat different role in energy storage and, in obesity pharmacology, can be either blocked or activated depending on the drug design.
GIP stands for glucose-dependent insulinotropic polypeptide, historically called gastric inhibitory polypeptide. It is a 42-amino-acid peptide hormone secreted by K-cells in the upper small intestine in response to nutrients, mainly carbohydrates and fats.
GIP amplifies glucose-dependent insulin secretion from pancreatic beta cells, explaining why oral glucose triggers more insulin than IV glucose (the classic incretin effect). It promotes nutrient storage: increasing adipocyte glucose uptake, supporting fatty-acid and triglyceride synthesis, and generally favoring post-prandial energy deposition rather than mobilization.
Why these companies protect the market
With these huge dollars involved, is it any wonder that these companies would go to any lengths to protect that market?
Now, back to the advocates of decentralizing this use of peptides. Would it be a better philosophy and use to microdose peptides for their benefit, and consider adding other small molecules (other peptides and bioregulators) to supplement the benefit and improve the body's function?
The "holistic" framing, and the tradeoff
This holistic approach assumes you've already considered diet, exercise, hormone normalization, and other wellness themes. It also recognizes what triple-agonist drugs are trying to do: layer GLP-1's effects with GIP's insulinotropic actions and glucagon's impact on energy expenditure and fat mobilization. The goal is greater weight loss and metabolic improvement, but the tradeoff is a more complex and less-proven risk–benefit profile.
The bigger picture and the "horror stories"
This is only one piece of a much bigger picture. Much of this discussion ASSUMES you've already addressed the bigger picture of diet, exercise, baseline health, and readiness—that you're not simply jumping straight into peptides. That missing context is one reason, I believe, we hear "horror stories." A small number of people have experienced nasty side effects from large doses of these weight-loss drugs, and in many cases there wasn't enough consideration of where they were starting from or whether they were good candidates for this intervention.
One important MD voice in this space often adds a helpful caveat when talking about side effects: "But what are we talking about here? What is this risk compared to obesity and poor cardiovascular health and near-certain early death?"
Peptides are not an instant solution for weight loss. But they are also not something to be afraid of. They should be considered after more foundational health practices have been tried. Not as your go-to option, but as a next step.