CompetitorsWide moat

Eli Lilly (LLY) — moat facet

Two companies hold 87% of the market, a third competitor was removed by the FDA rather than by Lilly, and the rest of the industry is buying its way in.

The head-to-head with Novo Nordisk has its own root threat on this company. What these pages add is the shape of the competitive field around it, which is more unusual than a two-horse race.

Prescription weight-management revenueEli Lilly — 53%Novo Nordisk — 35%Everyone else ~13% of the wider category — 12%Lilly and Novo together hold ~87% of the category. Shares are estimates.
Two companies, an enormous growing market, and no third participant of consequence.

Start with the arithmetic: Lilly and Novo together control roughly 87% of prescription weight-management revenue, split about 60/40 in Lilly's favour1. Two companies, an enormous and growing market, and no third participant of consequence — that is a duopoly, and duopolists in a market growing this fast compete for share of growth rather than for each other's installed base.

The other three relationships are stranger. Compounding pharmacies became a meaningful competitor by selling copies of Lilly's molecule during shortage, and were removed not by Lilly but by the FDA, which in April 2026 proposed permanently excluding tirzepatide and semaglutide from the list of ingredients large compounders may use2. Pfizer, having abandoned its own oral candidate, bought its way back into the category through Metsera3. And the shift to pills is changing who the customer is — a meaningful share of oral prescriptions is flowing through cash-pay channels rather than insurance4, which is the subject of the Major Clients pages.

Watch Lilly's share of new prescriptions rather than total prescriptions. Total scripts reflect who won last year; new-to-brand share is the leading indicator, and it is where the oral products are currently being decided.

Moat trajectory: Widening

Lilly's competitive position strengthened on every front this year. It holds about 60% of a duopoly controlling 87% of the category, the compounding threat was removed by regulators, and the rivals attempting to enter are buying clinical-stage assets rather than fielding approved products. The only genuinely new competitive dynamic — the cash-pay oral market — is one Lilly is currently leading.

The number that tests this moat
Third-party estimate
Lilly and Novo's combined share of the category
~87%, split about 60/40

Two companies, an enormous growing market and no third participant of consequence. Watch Lilly's share of NEW prescriptions rather than total: total scripts reflect who won last year, and new-to-brand is where the oral products are being decided.

Source: Third-party obesity market share analysis ↗
Dig deeper
DIG DEEPER 01
Novo Nordisk: A Duopoly, Not a War
When demand grows faster than either company can manufacture, share comes from the untreated rather than from each other — that is a duopoly, not a…
DIG DEEPER 02
The Compounders the FDA Removed
Compounders sold copies of Lilly's own molecule at scale within two years; the defence was the FDA, not anything Lilly built.
DIG DEEPER 03
Pfizer and the Companies Buying Their Way In
Capital arrives quickly and competition does not — an acquired Phase 2 asset is a press release, not a rival.
DIG DEEPER 04
The Pill Race, Where the Buyer Changes
Oral drugs sold for cash replace the benefit manager with the patient, which changes what competing even means.
References
  1. Third-party estimateLilly and Novo Nordisk together hold roughly 87% of prescription weight-management revenue, split about 60/40 to Lilly.
    Third-party obesity market analysis — the prescription weight-management market splits approximately 60.1% to Eli Lilly and 39.9% to Novo Nordisk, with roughly six of every ten US obesity prescriptions written for a Lilly medicine; the two companies together control approximately 87% of prescription weight-management drug revenue — 2026 · publ. 2026 · source ↗
  2. ReportedThe FDA proposed in April 2026 permanently excluding tirzepatide and semaglutide from the 503B Bulks List.
    FDA compounding policy reporting — on April 30, 2026 the FDA proposed permanently excluding semaglutide, tirzepatide and liraglutide from the 503B Bulks List, the ingredients large-scale compounding facilities may legally use; by May 31, 2026 there were 990 adverse event reports associated with compounded semaglutide and more than 730 associated with compounded tirzepatide — 2026 · publ. 2026 · source ↗
  3. Third-party estimatePfizer abandoned its own oral candidate and re-entered obesity by acquiring Metsera.
    Industry analysis of obesity-asset acquisitions — Pfizer discontinued its in-house oral GLP-1 receptor agonist danuglipron in April 2025 following liver enzyme elevations, and re-entered the obesity category by acquiring Metsera; AstraZeneca, Regor Therapeutics and others are evaluating oral GLP-1 candidates — 2025-2026 · publ. 2026 · source ↗
  4. Third-party estimateA majority of oral GLP-1 volume is flowing through cash-pay channels rather than insurance.
    Oral GLP-1 launch tracking — two oral GLP-1 products have FDA approval, Novo Nordisk's Wegovy pill (December 2025) and Eli Lilly's Foundayo (April 2026); Wegovy pill prescriptions eased to about 163,000 from a peak near 172,000 while Foundayo rose to 38,928 from a prior record of 34,219; within eight weeks oral Wegovy captured around a third of new-to-brand prescriptions, with the majority of volume flowing through cash-pay channels — 2026 · publ. 2026 · source ↗
Sources
Generated September 23, 2026