Novo Nordisk (NVO) and Eli Lilly (LLY)’s Weight-Loss Drugs Still Work at Smaller Doses, Study Finds
On August 31, 2026, Reuters reported on a new study finding that patients who stay on the lowest starter doses of GLP-1 weight-loss drugs still lose weight, though far less than at full recommended doses, and experience less nausea.
Patients on Eli Lilly and Company (NYSE: LLY )'s low-dose tirzepatide lost an average of 5.5% of their body weight over a year, versus 2.2% for Novo Nordisk A/S (NYSE: NVO )'s low-dose semaglutide, compared with 20.2% and 13.7% respectively at the higher, manufacturer-recommended doses seen in earlier trials. The low-dose tirzepatide group also showed higher rates of certain side effects, including constipation and muscle cramps, than the low-dose semaglutide group.
The study supports an overall patient base for both Eli Lilly and Company (NYSE: LLY ) and Novo. Patients who remained on the lowest starter doses still lost weight after one year, with tirzepatide producing average weight loss of 5.5% and semaglutide producing 2.2%. Many patients struggle with cost, tolerability, supply, or their personal weight-loss goals. So evidence that lower doses still work could help more patients remain on treatment.
Tirzepatide's stronger low-dose results solidify Lilly's competitive position. Patients taking the lowest approved dose of tirzepatide lost more than twice as much weight as those taking the lowest semaglutide dose. Lilly already leads the injectable obesity market with Zepbound. Recent Reuters reporting shows Mounjaro is generating strong growth and has gained more cardiovascular approvals in the U.S.
Novo Nordisk A/S (NYSE: NVO ) still has an important opportunity in oral obesity treatments. Novo's Wegovy pill gives the firm a way to compete beyond injections as the global obesity market expands. Analysts expect the obesity-drug market to exceed $100 billion annually by 2030, while Novo's CEO expects pills to become a significant part of GLP-1 use.
Low-dose treatment could reduce revenue per patient if more users avoid higher maintenance doses. The study found substantially less weight loss at the starter doses than at the manufacturer-recommended higher doses, with 5.5% weight loss for low-dose tirzepatide versus 20.2% at higher doses and 2.2% for low-dose semaglutide versus 13.7%. If patients remain on lower doses because of cost, tolerability, or personal preferences, prescription growth may not turn into comparable revenue growth.
The study also shows a difficult trade-off between efficacy and tolerability since patients on the lowest doses experienced less nausea and constipation, but they still faced other adverse events. Eli Lilly and Company (NYSE: LLY )'s low-dose tirzepatide showed higher rates of kidney injury, constipation, and muscle cramps than low-dose semaglutide. Both drugs produced much less weight loss than higher-dose regimens. These differences could influence which drug patients and physicians prefer as competition intensifies.
Novo Nordisk A/S (NYSE: NVO ) remains under pressure from Lilly despite the expanding market. Lilly's tirzepatide is outperforming semaglutide on weight loss, while Novo's CagriSema produced less weight loss than Zepbound in head-to-head testing. Hence, Novo needs its Wegovy pill and next-generation pipeline to get back momentum as Lilly expands its own oral and injectable obesity portfolio.
The hedge fund data tells the same story as the stock charts: Eli Lilly and Company (NYSE: LLY )'s holder count jumped to 152 funds in the second quarter from 132, with position value surging to $17.24 billion from $12.58 billion, while Novo Nordisk A/S (NYSE: NVO ) saw a more modest rise to 59 funds from 55 and $2.00 billion from $1.79 billion. Viking Therapeutics, an earlier-stage obesity-drug developer increasingly mentioned as a future rival to both, saw its holder base grow to 47 funds from 44 and position value rise to $551 million from $441 million, evidence that hedge funds are also starting to look beyond the two incumbents for exposure to the category.
The low-dose study supports the overall use of GLP-1 drugs by showing that patients can achieve measurable weight loss without reaching the highest recommended doses, which could expand treatment access for both Lilly and Novo. However, substantially lower weight loss at starter doses could limit revenue per patient, while differences in efficacy and side effects give Lilly another competitive advantage over Novo. With the obesity market heading toward $100 billion annually, investors should watch whether wider access and prescription growth outweigh the potential pressure on treatment intensity and revenue per patient.
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