Pharma's $8 Billion DTC Ad Spend Fails to Translate Into AI Citation Share, 5W Index Finds
Key Insights
Eli Lilly leads the Pharma / Rx AI Visibility Index 2026 with an estimated 12.5% AI citation share, followed by Novo Nordisk at 11.5%, driven by GLP-1 receptor agonists (search) Ozempic, Wegovy, Mounjaro, and Zepbound.
The U.S. pharmaceutical industry spent an estimated $8 billion on direct-to-consumer advertising in 2024, yet ad spend shows no correlation with AI engine citation share across ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews.
Merck (search), maker of the world's best-selling drug Keytruda, ranks only fifth in AI citations, while AbbVie (search)'s heavily advertised Humira franchise ranks sixth at 5.0%.
Eli Lilly and Novo Nordisk dominate the artificial intelligence answer surface for pharmaceutical queries, capturing a combined 24% of all AI citations despite not being the industry's largest direct-to-consumer advertisers, according to the newly released Pharma / Rx AI Visibility Index 2026 from 5W AI Communications.
The Index, published June 19, 2026, ranks the top 25 pharmaceutical companies by AI citation share across more than 60 patient and consumer prompts run in Q2 2026 — five times per engine, in clean sessions — across ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews. The findings expose a structural disconnect between where the pharmaceutical industry invests its advertising dollars and where AI-powered search engines direct patient attention.
Eli Lilly holds the top position with an estimated 12.5% citation share, while Novo Nordisk follows closely at 11.5%, propelled by the consumer research footprint of their GLP-1 receptor agonist franchises — Ozempic, Wegovy, Mounjaro, and Zepbound — which together generated approximately $70 billion in combined 2025 sales. Pfizer ranks third at 8.5%, Johnson & Johnson fourth at 7.0%, and Merck (search) rounds out the top five at 6.0%, despite producing Keytruda, the best-selling prescription drug globally.
The DTC Spending Disconnect
The U.S. pharmaceutical industry spent an estimated $8 billion on direct-to-consumer advertising in 2024, making it the largest category-level DTC ad commitment in the country. Yet the Index demonstrates that scale of spend does not translate into proportional AI citation share.
AbbVie (search), historically among the highest individual DTC spenders through its Humira franchise, ranks sixth at an estimated 5.0% citation share. Merck (search), despite Keytruda's commercial dominance, lands at fifth. "AbbVie spent the most. Merck makes the best-selling drug on earth. Neither is the answer the chatbox returns," said Ronn Torossian, Founder and Chairman of 5W AI Communications.
The mechanism underlying this gap, according to the Index, is the structural difference between paid attention and the AI-retrievable record. "A 30-second TV spot can move share-of-voice for a quarter. A peer-reviewed trial readout in The New England Journal of Medicine, followed by sustained Reuters, STAT, and Fierce Pharma coverage, moves the answer surface for years," the report states. "The engines retrieve the durable record, not the campaign."
Six Structural Truths
The Index documents six structural findings that reshape how pharmaceutical corporate communications should be understood in the AI era. First, revenue rank does not predict citation rank — the highest-earning drugmakers are not the most-cited. Second, a blockbuster drug pulls the company name with it, as Ozempic and Mounjaro made Novo Nordisk and Eli Lilly household names. Third, self-researched conditions drive citations: weight, diabetes, and immunology generate significant citation volume, while specialist-prescribed oncology does not.
Fourth, DTC advertising compounds into citations only when it feeds the editorial record — the spot itself is not retrievable; the coverage it generates is. Fifth, diffuse corporate structure dilutes citation share, with conglomerates and private companies under-indexing. Sixth, patients now research before the appointment, meaning corporate citation share sits upstream of the prescription conversation.
"The buyer is in the chatbox, asking ChatGPT to compare Ozempic and Mounjaro," Torossian said. "The companies that built the AI-retrievable record around those names own that answer. The ones still buying spots and hoping it carries through to the engines are funding the wrong channel."
Methodology and Scope
5W analyzed more than 60 common patient and consumer prompts across six pharmaceutical market sub-categories: metabolic and GLP-1, oncology, immunology and inflammation, vaccines and antivirals, cardiovascular and specialty, and generics and biosimilars. Citation sources tracked include the business and health editorial press — Reuters, Bloomberg, Fierce Pharma, STAT — reference sources such as company filings, Wikipedia, and Drugs.com, as well as brand-owned corporate content.
The complete top fifteen includes AstraZeneca (4.0%), Moderna (3.5%), Amgen (3.0%), Novartis (2.6%), Bristol Myers Squibb (2.3%), GSK (2.0%), Sanofi (1.8%), Gilead Sciences (1.5%), and Roche (1.3%). Remaining citation volume splits across ranks 16 through 25 and unranked companies.
The Index measures AI citation share for corporate communications and marketing strategy purposes only and does not rank drugs or companies on safety, efficacy, side effects, or clinical value. Eli Lilly's brief crossing of the $1 trillion market cap milestone — the first healthcare company to do so — and the estimated $5.6 trillion global pharmaceutical market provide additional context for the commercial stakes involved in AI visibility.