GLP-1 Obesity Drug Stocks: NVO vs LLY and the Broader Landscape

June 5, 2026 · 8 min read

Ozempic, Wegovy, Mounjaro, Zepbound — the GLP-1 drug class may be the most important pharmaceutical investment theme of this decade. Here is how to analyse the key stocks.

Why GLP-1 drugs are the most important pharma theme right now

GLP-1 receptor agonists (glucagon-like peptide-1 drugs) were developed as diabetes treatments. Then clinical trials showed they produced substantial, sustained weight loss — and suddenly the addressable market expanded from hundreds of millions of type 2 diabetes patients to over a billion people globally who are clinically obese.

The scale of this market is genuinely transformative. Obesity is associated with type 2 diabetes, heart disease, sleep apnoea, joint disease, certain cancers, and many other chronic conditions. A drug that durably treats obesity could be worth hundreds of billions in revenue annually — and the two leading companies (Novo Nordisk and Eli Lilly) are already well on their way.

The key GLP-1 drugs explained

Ozempic(NVO — Novo Nordisk)
Type 2 diabetes (once-weekly injection)

Semaglutide GLP-1 agonist. The highest-prescribed GLP-1 drug globally, generating over $14 billion annually. Has become shorthand for the entire GLP-1 drug class despite only being approved for diabetes, not obesity.

Wegovy(NVO — Novo Nordisk)
Obesity (higher-dose semaglutide)

Higher-dose version of semaglutide approved specifically for chronic weight management. Supply constraints have limited prescription growth, creating an opportunity for Eli Lilly's Zepbound to capture market share.

Mounjaro(LLY — Eli Lilly)
Type 2 diabetes (tirzepatide)

Dual GIP and GLP-1 receptor agonist (tirzepatide). Clinical trials show greater average weight loss than semaglutide, making this Novo Nordisk's most significant competitive threat.

Zepbound(LLY — Eli Lilly)
Obesity (tirzepatide)

The same tirzepatide molecule as Mounjaro, approved for obesity. Growing rapidly as supply ramps up. Head-to-head SURMOUNT-5 trial showed superior weight loss versus Wegovy in direct comparison.

Rybelsus(NVO — Novo Nordisk)
Type 2 diabetes (oral semaglutide)

First oral GLP-1 approved. Lower weight loss than injectable versions but much easier to administer. Important for expanding the addressable market to patients who will not self-inject.

Novo Nordisk vs Eli Lilly — the key differences

NVO strength

Larger GLP-1 installed base, manufacturing scale, oral semaglutide progress, lower valuation

LLY strength

Clinically superior tirzepatide, broader pipeline (Alzheimer's, oncology), US market access

Key NVO risk

CagriSema next-gen trial underperformance; supply constraints allowing Lilly to take share

Key LLY risk

Extreme valuation requires sustained multi-drug execution; single-drug risk if tirzepatide faces setbacks

The broader GLP-1 investment ecosystem

Beyond NVO and LLY, the GLP-1 theme has second-order effects across multiple industries:

  • Medical devices — DXCM (Dexcom) and ISRG may face headwinds as better diabetes control reduces complications; RMD (ResMed) faces sleep apnoea device pressure
  • Food and beverage — KO, PEP, and food companies face long-term volume pressure if GLP-1 adoption broadly reduces caloric intake
  • Compounding pharmacies — a US-specific phenomenon where compounded semaglutide became available during the Wegovy shortage; FDA has moved to restrict this
  • Pharmaceutical R&D — dozens of companies (AMGN, PFE, AZN) have GLP-1 programmes in development; next-gen oral GLP-1s could dramatically expand market access

Key metrics to watch for GLP-1 stocks

  • Prescription volume growth by drug — weekly IMS/IQVIA data tracks new and total prescriptions for each drug
  • Gross-to-net discount rates — payer rebates significantly reduce realised revenue versus list price
  • Manufacturing capacity additions — both companies are spending billions on new production capacity
  • Pipeline clinical trial results — next-generation molecules (CagriSema, orforglipron, retatrutide) will determine long-term competitive positioning
  • Pricing and reimbursement — US Medicare and Medicaid coverage expansion or restriction significantly affects addressable volume

Compare NVO vs LLY side by side

See the full comparison of Novo Nordisk and Eli Lilly including AI scores, valuation, performance, analyst targets, and investor profiles.

NVO vs LLY ComparisonGLP-1 Stocks Theme