Prosper Junior Bakiny of The Motley Fool recommends Eli Lilly over Viking Therapeutics as the better GLP-1 stock, citing 48% second-quarter revenue growth to $23 billion, Mounjaro and Zepbound momentum, and retatrutide's planned Q1 2027 filing. Viking's VK2735 posted 14.7% mean weight loss at 13…
The Motley Fool has made its pick in the GLP-1 stock race: Eli Lilly over Viking Therapeutics. In an analysis published Aug. 7, 2026, contributing healthcare analyst Prosper Junior Bakiny, a University of Maryland Global Campus graduate, compared the two companies and delivered a direct verdict: "I'd opt for Eli Lilly."
The recommendation rests on two pillars. The first is commercial: Eli Lilly reported second-quarter revenue of $23 billion, up 48% year over year, and the analysis explicitly cites the stock's limited downside risk relative to a development-stage rival. The second is pipeline: Eli Lilly plans to request approval for retatrutide in Q1 2027, and the drug posted outstanding phase 3 results in diabetes and weight loss.
Viking is the contrarian case in the comparison. Its dual GLP-1/GIP agonist VK2735 has generated strong early efficacy data, but the company has no approved products, generates no revenue, and is not profitable. Bakiny's framing is therefore a choice between an incumbent widening its lead and a binary bet on a single candidate.
The verdict is an investment judgment, not a clinical one. It does not claim that Eli Lilly's molecules are superior in a head-to-head sense; it claims that the risk-adjusted case favors the company with marketed products, manufacturing scale, and a funded pipeline. Keeping those two claims separate matters, because efficacy data and stock performance are frequently conflated in coverage of this market.
The financial detail runs deeper than the headline growth rate. Mounjaro , Eli Lilly's tirzepatide brand for diabetes, delivered $9.9 billion in second-quarter sales, up 91% year over year, making it the best-selling medicine in the GLP-1 niche and, in Bakiny's assessment, Eli Lilly's most important growth driver. Zepbound , the weight management brand of the same molecule, contributed $4.9 billion in revenue, up 46%. The company's gross margin stands at 83.40%, and it pays a dividend yield of 0.54%. Eli Lilly also markets Foundayo , an oral GLP-1 product, a sign the company is hedging across delivery formats; the spelling is preserved from the original column and may be a typographical error.
Growth of 91% off a base approaching $10 billion in a single quarter is unusual for a pharmaceutical franchise. It indicates the class is still expanding the number of treated patients rather than merely taking share from competitors. The gross margin of 83.40% and the dividend yield of 0.54% are the mechanical signs of the asymmetry: Lilly generates cash from products already approved, while Viking, with no approved products and no revenue, must fund development through equity markets.
The pick capped a week of unusually dense coverage of the company. On Aug. 3, David Jagielski, CPA, asked whether Eli Lilly stock was running out of steam. On Aug. 4, Lyle Daly published a ranking of the largest healthcare companies by market capitalization, and Thomas Niel noted that Eli Lilly was up 7% in 2026 with major catalysts on the way. On Aug. 5, Joe Tenebruso explained why Eli Lilly stock climbed that day. On Aug. 6, Daly published a second market cap ranking, covering the largest companies regardless of sector. Bakiny's analysis also fixed the regulatory question to a calendar date: the retatrutide filing will come in Q1 2027, timing that a companion Bakiny column the same day framed as a problem for Novo Nordisk.
Bakiny's central claim is that Eli Lilly is a leader in the GLP-1 drug market and is likely to maintain that lead for the foreseeable future. The basis is a deep pipeline in which retatrutide is only the most advanced entry.
The efficacy comparison at the heart of the analysis rests on two numbers that are often placed side by side and should not be read as directly comparable.
Tirzepatide produced an average weight loss of 20.2% in a 72-week phase 3 study. That figure defines the current benchmark for incretin-based obesity therapy and underpins the commercial results above.
Viking's subcutaneous VK2735 produced a maximum mean weight loss of 14.7% in a 13-week phase 2 study, with no plateau observed. The absence of a plateau matters: patients were still losing weight when the measurement window closed, which suggests the figure could understate the drug's effect over a longer horizon. But it also means the two molecules have never met in a head-to-head trial. The analysis itself flags that cross-trial comparisons are subject to the usual caveats.
The two numbers are not measuring the same quantity. The 20.2% figure is an average weight loss at the end of a 72-week program. The 14.7% figure is the maximum mean weight loss recorded within a 13-week window. In this drug class, weight loss trajectories typically continue well beyond three months, so the phase 2 readout almost certainly understates what VK2735 could produce at week 52 or week 72. Yet an understated figure is not a guarantee of reaching 20%. Dose selection, titration speed, and the fraction of patients who complete the trial determine how much of an early trajectory survives contact with a year-long protocol.
Cross-trial comparisons in obesity medicine are also distorted by differences in design. Studies vary in baseline body mass index, in whether they include a lifestyle intervention, in dosing and titration, and in how dropouts are counted. A trial that classifies early discontinuations as non-responders will report a lower mean than one that excludes them. The upshot is that the two figures establish both molecules are active. They do not establish a ranking.
The column does not provide full methodological details for either study. Sample sizes and patient populations are not described, and the trial designs are given only by phase and duration. What the design can show is a signal of efficacy and an early tolerability profile. What it cannot show is whether VK2735 would match tirzepatide's result under the same dose, duration, and patient selection.
The oral formulation of VK2735 is where the clinical risk concentrates. Its phase 2 efficacy was highly encouraging, but the trial reported high rates of discontinuation due to side effects. For an oral peptide, that is the central development problem, and late-stage testing will determine whether it can be solved. Discontinuations are not only a safety metric; they are also an efficacy metric, because a drug that works mainly in the patients who tolerate it has a commercial ceiling that mean weight loss alone will not reveal.
Both companies now operate on disclosed timetables. Eli Lilly plans to request approval for retatrutide in Q1 2027. The filing would go to the FDA, the agency named in the title of a related Bakiny column published the same day, and it would follow the established approvals of tirzepatide for diabetes, weight management, and obstructive sleep apnea OSA . A filing is the beginning of a review, not an approval, and the column does not specify the legal basis or regulatory pathway the company will use.
A disclosed filing date carries weight for two audiences. For investors, it converts a regulatory unknown into a calendar item and signals that Eli Lilly considers its retatrutide data package complete enough to submit. For competitors, it starts a countdown. The FDA will set its own review timeline, and the analysis does not say whether the company will seek priority review or which studies the submission will contain. What the disclosure does is narrow the window of regulatory uncertainty from "sometime" to a specific quarter.
The filing plan should be read against the breadth of the retatrutide program. Registry data show phase 3 studies in obesity and overweight with and without type 2 diabetes, a phase 3 master protocol in metabolic dysfunction-associated steatotic liver disease, and a phase 3 study in chronic low back pain. A first approval filed in Q1 2027 would most plausibly cover obesity or overweight; the other indications would extend the product's market if subsequent filings succeed. Tirzepatide is already approved across diabetes, weight loss, and OSA, so retatrutide would enter an existing commercial infrastructure. That is the competitive problem the analysis assigns to Novo Nordisk: the class leader can chain new product launches to an established franchise while later entrants are still generating their first late-stage data.
Viking expects to start late-stage trials for the oral formulation of VK2735 by year-end. That program will have to demonstrate two things: efficacy at doses patients can tolerate, and discontinuation rates regulators find acceptable.
The regulatory scope of the GLP-1 class now extends well beyond its original territory. Tirzepatide's approvals cover metabolic disease and sleep-disordered breathing, and pipeline candidates are being studied in metabolic dysfunction-associated steatotic liver disease MASLD , chronic pain, and cardiovascular conditions. Each new indication widens the patient population and, with it, the commercial stakes the stock analysis is trying to price.
The molecules at the center of this competition are incretin-based peptide therapeutics, and the underlying biology explains both the efficacy numbers and the side effect profiles.
GLP-1 , glucagon-like peptide 1, is released by intestinal L cells after meals. It stimulates glucose-dependent insulin secretion, suppresses glucagon release, slows gastric emptying, and reduces appetite through receptors in the central nervous system. The appetite signal is central as much as peripheral: GLP-1 receptors are expressed in the hypothalamus and brainstem, where they integrate satiety input, which is why nausea, not hypoglycemia, is the dose-limiting side effect of the class.
GIP , glucose-dependent insulinotropic polypeptide, is released by intestinal K cells and acts as the second major incretin, with additional effects on lipid handling in adipose tissue. GIP receptors are found on pancreatic beta cells and adipocytes, and the dual-agonist concept rests on the idea that the two incretins are complementary rather than redundant. Tirzepatide and VK2735 are both dual GLP-1/GIP receptor agonists, and combining the pathways is thought to produce deeper appetite suppression and better metabolic control than engaging GLP-1 alone.
Retatrutide adds a third target, the glucagon receptor. Glucagon signaling drives hepatic glucose output in the fasting state, but in combination with GLP-1 and GIP agonism it is thought to increase energy expenditure. The rationale is to counter the compensatory fall in energy expenditure that normally accompanies weight loss, which is one reason the class's weight-loss curves extend past a year. The phase 3 evidence base for the triple agonist includes TRANSCEND-T2D-1, a double-blind, randomized trial in people with type 2 diabetes published in the Lancet PMID 42250575 ; a systematic review and meta-analysis of randomized controlled trials PMID 42371360 has separately examined retatrutide's effects on blood pressure and lipid levels.
The stubborn problem is delivery. Peptides face enzymatic degradation in the gastrointestinal tract and poor intrinsic absorption, which is why most are injectables. An oral incretin that worked reliably would command a larger market than any injectable, but oral delivery demands formulation strategies, absorption enhancers, and in many cases higher doses to reach systemic exposure comparable to an injection. Higher doses push the molecule toward the gastrointestinal tolerability ceiling, which is exactly the pattern visible in the oral VK2735 phase 2 data: efficacy that is highly encouraging, with discontinuations that will determine whether the oral route is viable at doses that matter.
The…
Peptides referenced: Tirzepatide, Retatrutide, Glucagon, GLP-1.
Related reading: Retatrutide nears the market as physicians map GLP-1 weight-loss options, Durham VA joins national trial testing GLP-1 medications for alcohol use disorder, Starbucks is ending GLP-1 coverage for weight loss as employer costs climb, No Link Between GLP-1 and Hypertensive Disorders of Pregnancy.