Skip to content
ContentLora

    Tip: press / anywhere to search.

    Explainer

    GLP-1 and metabolic medicine in 2026: a crash course

    GLP-1 medicines mimic or extend gut hormones that regulate insulin and appetite, and in trials they have produced average weight loss of about 15% to more than 20%.[1][2] By October 2026 the field had moved beyond weight loss to heart, kidney, liver and sleep-apnea outcomes, daily pills, and fights over price and coverage.[3][4][5]

    Editor reviewedStrict sourcingUpdated GLP-1 and metabolic medicineHealth and medicineLife sciences

    GLP-1 medicines are one of the biggest shifts in medicine in decades. Drugs first built for type 2 diabetes now treat obesity, and large trials show they also cut heart, kidney and liver complications.[3][6][7] This crash course explains the biology, the main drugs and companies, the evidence, and the open arguments as of October 2026. Nothing here is medical advice. It describes evidence and regulatory status only.

    Why it matters

    WHO says more than 1 billion people live with obesity.[8] The FDA says about 70% of American adults have obesity or overweight.[9] Older weight-loss drugs worked modestly. GLP-1 drugs produced average losses of roughly 15–21% in their main trials, against 2–3% on placebo.[1][2] That made it realistic to treat obesity as a chronic disease with medicine, which WHO now recommends.[10][11]

    The field’s centre of gravity has shifted from glycaemic control to multi-organ outcomes. SELECT showed a 20% relative reduction in major adverse cardiovascular events in people without diabetes (HR 0.80).[3] FLOW showed a 24% lower risk of major kidney events in type 2 diabetes with chronic kidney disease.[6] ESSENCE showed MASH resolution in 62.9% versus 34.3% on placebo.[7] Supply is now the smaller constraint. WHO projects these drugs will reach fewer than 10% of people who could benefit by 2030.[12]

    The map of the field

    The field has five overlapping sub-areas:

    • Incretin biology. How gut hormones such as GLP-1 and GIP control insulin and appetite (see semaglutide and the explainer on how the drugs work).[13]
    • Drug design. Longer-acting peptides, multi-receptor agonists like tirzepatide and retatrutide, amylin combinations like cagrisema, and small-molecule pills like orforglipron.[14]
    • Defining obesity. The 2025 Lancet Commission split obesity into “clinical” and “preclinical” forms and moved diagnosis beyond BMI alone.[15][16]
    • Outcome trials. Heart, kidney, liver, sleep apnea, and a failed attempt in Alzheimer’s disease.[17][18]
    • Access and policy. Shortages, compounding, prices, Medicare coverage and generics.[19][5][20]

    Key ideas

    The breakthrough was engineering versions of the hormone that last far longer: semaglutide’s half-life was extended about two-thousand-fold, so one injection a week is enough.[21] Newer drugs hit more than one hormone receptor. Tirzepatide activates both GIP and GLP-1 receptors, and the experimental retatrutide adds a third, the glucagon receptor.[22][23] Head-to-head, tirzepatide produced more weight loss than semaglutide: 20.2% versus 13.7% at 72 weeks.[24]

    Pharmacology has moved along three axes. The first is potency per molecule: GLP-1/GIP co-agonism in tirzepatide, triple agonism in retatrutide (-25.0% at 80 weeks versus -3.9% on placebo in the peer-reviewed TRIUMPH-1 report).[22][25] The second is route: oral peptide semaglutide 25 mg (13.6% at 64 weeks in OASIS 4) and non-peptide orforglipron (11.2% at 72 weeks at 36 mg in ATTAIN-1).[26][27] The third is dosing interval: monthly candidates such as Amgen’s MariTide, which pairs GLP-1 receptor agonism with GIP receptor antagonism.[28] One counter-intuitive finding is that both activating and blocking GIP signalling have produced weight loss when combined with GLP-1 agonism.[22][28]

    Who the main players are

    Two companies dominate. novo-nordisk makes semaglutide (Ozempic, Wegovy, the Wegovy pill). eli-lilly makes tirzepatide (Mounjaro, Zepbound) and orforglipron (Foundayo).[29][30] In the second quarter of 2026, Lilly reported $23.0 billion in revenue, up 48%, led by Mounjaro and Zepbound.[30] In August 2026 Novo forecast 2026 adjusted sales growth of 0% to -6%.[31] Other drugmakers are buying in: Pfizer completed its roughly $7.0 billion acquisition of Metsera in November 2025.[32] Regulators and payers matter as much as companies: the FDA, EMA, CMS and WHO.[33][11]

    Where the frontier is (October 2026)

    • Pills. Novo launched the Wegovy pill in January 2026, and US weekly prescriptions passed 265,000 by July. The FDA approved Lilly’s Foundayo in April 2026.[34][35][4]
    • Next-generation injectables. Lilly plans to file retatrutide in early 2027.[36] An FDA decision on Novo’s CagriSema is expected by late 2026, after CagriSema missed non-inferiority against tirzepatide in REDEFINE 4.[37][38]
    • Coverage. Medicare’s temporary GLP-1 Bridge has offered certain obesity drugs for $50 a month since 1 July 2026. Negotiated Medicare prices for semaglutide take effect in 2027.[5][39]
    • Open questions. Weight returns after stopping, and the long-term effects on muscle and nutrition are still being studied.[40][41] These are covered in the debate pages and the tracker.

    How to use this course

    Read the three fundamentals first, then the drug and company pages, the two debates and, last, the tracker of recent milestones.

    Questions readers ask

    What does a GLP-1 drug actually do?

    GLP-1 is a gut hormone that boosts insulin release, suppresses glucagon, slows stomach emptying and reduces food intake. GLP-1 drugs activate the same receptor for much longer than the natural hormone does.[13][21]

    How much weight do people lose on these drugs in trials?

    Average losses were 14.9% with semaglutide 2.4 mg at 68 weeks in STEP 1 and up to 20.9% with tirzepatide 15 mg at 72 weeks in SURMOUNT-1. Placebo groups lost 2–3%.[1][2]

    Are there GLP-1 pills for weight loss?

    Yes. As of October 2026 the FDA has approved two. The Wegovy pill (oral semaglutide 25 mg) was approved in December 2025, and Lilly's orforglipron (Foundayo) in April 2026.[29][4]

    Do the benefits last if treatment stops?

    In withdrawal studies, most people regained much of the lost weight after stopping. A 2026 BMJ meta-analysis found cardiometabolic markers were projected to return to baseline within about 1.4 years.[42][40]

    Sources

    Each numbered claim is a statement we checked against the sources listed with it. Status shows how well established it is.

    1. [1]

      In the STEP 1 trial, weekly semaglutide 2.4 mg plus lifestyle intervention produced a mean 14.9% weight loss at 68 weeks versus 2.4% with placebo. confirmedas of 2021-02-10

    2. [2]

      In SURMOUNT-1, which enrolled 2,539 adults with obesity or overweight and no diabetes, weekly tirzepatide produced mean weight changes of -15.0%, -19.5% and -20.9% at doses of 5, 10 and 15 mg at 72 weeks, versus -3.1% with placebo. confirmedas of 2022-06-04

    3. [3]

      In the SELECT trial of 17,604 adults aged 45 or older with cardiovascular disease and overweight or obesity but no diabetes, semaglutide 2.4 mg reduced cardiovascular death, heart attack or stroke to 6.5% versus 8.0% on placebo (hazard ratio 0.80). confirmedas of 2023-11-11

    4. [4]

      On 1 April 2026 the FDA approved Lilly's orforglipron, branded Foundayo, for adults with obesity or overweight with weight-related conditions, under the National Priority Voucher pilot about 50 days after filing. confirmedas of 2026-04-01

    5. [5]

      CMS's Medicare GLP-1 Bridge, a time-limited demonstration, gives eligible Part D enrollees certain GLP-1 medicines for $50 a month from 1 July 2026 through 31 December 2027. confirmedas of 2026-05-06

    6. [6]

      In the FLOW trial of 3,533 people with type 2 diabetes and chronic kidney disease, semaglutide lowered the risk of major kidney events or kidney- or cardiovascular-related death by 24% (hazard ratio 0.76); the trial stopped early at a prespecified interim analysis after a median 3.4 years of follow-up. confirmedas of 2024-05-24

    7. [7]

      In part 1 of the ESSENCE trial in people with MASH and moderate or advanced liver fibrosis, steatohepatitis resolved without worsening fibrosis in 62.9% on semaglutide versus 34.3% on placebo at 72 weeks, in a planned interim analysis of the ongoing 240-week trial based on liver histology. confirmedas of 2025-04-30

    8. [8]

      According to WHO, obesity affects more than 1 billion people and was linked to 3.7 million deaths in 2024. confirmedas of 2025-12-01

    9. [9]

      The FDA states that approximately 70% of American adults have obesity or overweight. confirmedas of 2023-11-08

    10. [10]

      WHO's 2025 guideline describes obesity as a chronic, relapsing disease that needs comprehensive, lifelong care rather than medication alone. confirmedas of 2025-12-01

    11. [11]

      On 1 December 2025 WHO issued its first guideline on GLP-1 medicines for obesity, with conditional recommendations that adults may use them for long-term treatment alongside behavioural interventions. confirmedas of 2025-12-01

    12. [12]

      WHO projects that even with expanded production, GLP-1 therapies will reach fewer than 10% of those who could benefit by 2030. confirmedas of 2025-12-01

    13. [13]

      GLP-1 is a hormone released from gut enteroendocrine cells that augments insulin secretion, inhibits glucagon secretion, slows gastric emptying and reduces food intake. confirmedas of 2026-10-10

    14. [14]

      Efforts to refine GLP-1 therapies have driven development of orally available agonists, allosteric modulators and single molecules that act on several receptors (multi-agonists). confirmedas of 2026-10-10

    15. [15]

      The Lancet Diabetes & Endocrinology Commission defines clinical obesity as a chronic, systemic illness in which excess or abnormal body fat alters the function of tissues, organs or the person. confirmedas of 2025-01-14

    16. [16]

      The Commission says BMI should serve as a population-level risk surrogate or screening tool, and that excess fat in individuals should be confirmed by direct fat measurement or at least one other body measurement such as waist circumference, partly because a high BMI can reflect muscle rather than fat. confirmedas of 2025-01-14

    17. [17]

      On 20 December 2024 the FDA approved Zepbound for moderate to severe obstructive sleep apnea in adults with obesity, the first drug treatment for the condition. confirmedas of 2024-12-20

    18. [18]

      On 24 November 2025 Novo Nordisk reported that the evoke and evoke+ trials in 3,808 adults with early Alzheimer's disease did not show that semaglutide slowed disease progression, although Alzheimer's biomarkers improved. confirmedas of 2025-11-24

    19. [19]

      The FDA determined on 21 February 2025 that the US shortage of semaglutide injection products was resolved, ending temporary leeway for compounders to make copies after set grace periods. confirmedas of 2025-02-21

    20. [20]

      Novo Nordisk reported that loss of exclusivity for semaglutide in Canada and certain other international markets, together with the US most-favoured-nation agreement, lowered its realised prices in 2026. confirmedas of 2026-08-04

    21. [21]

      Novo Nordisk scientists developed liraglutide and then semaglutide, whose half-life was extended about two-thousand-fold, allowing once-weekly injection; semaglutide was approved in the US for diabetes in 2017 and for weight loss in 2021. confirmedas of 2026-10-10

    22. [22]

      Tirzepatide is a single molecule that activates both the GIP and GLP-1 receptors. confirmedas of 2026-10-10

    23. [23]

      Retatrutide is an investigational agonist of three receptors, GIP, GLP-1 and glucagon. confirmedas of 2026-10-10

    24. [24]

      In the open-label SURMOUNT-5 trial, people with obesity but without diabetes lost a mean 20.2% of body weight on tirzepatide versus 13.7% on semaglutide at 72 weeks. confirmedas of 2025-05-11

    25. [25]

      The peer-reviewed TRIUMPH-1 report (NEJM, 29 September 2026) gave mean weight changes at 80 weeks of -17.6%, -23.7% and -25.0% with retatrutide 4, 9 and 12 mg versus -3.9% with placebo under the treatment-regimen (intention-to-treat) estimand; Lilly's May topline figures of 19.0%, 25.9% and 28.3% used the efficacy estimand. confirmedas of 2026-09-29

    26. [26]

      In the OASIS 4 trial, once-daily oral semaglutide 25 mg produced a mean 13.6% weight loss at 64 weeks versus 2.2% with placebo; Novo Nordisk reports 16.6% among people who adhered to treatment. confirmedas of 2025-12-22

    27. [27]

      In the phase 3 ATTAIN-1 trial of 3,127 adults with obesity without diabetes, orforglipron produced mean weight changes of -7.5%, -8.4% and -11.2% at 6, 12 and 36 mg at 72 weeks, versus -2.1% with placebo, with improvements in waist circumference, systolic blood pressure, triglycerides and non-HDL cholesterol. confirmedas of 2025-09-16

    28. [28]

      Amgen's maridebart cafraglutide (MariTide), a monthly peptide-antibody conjugate that activates the GLP-1 receptor and blocks the GIP receptor, produced mean weight loss of 12.3% to 16.2% at 52 weeks versus 2.5% with placebo in a phase 2 obesity trial. confirmedas of 2026-10-10

    29. [29]

      On 22 December 2025 the FDA approved the Wegovy pill (once-daily oral semaglutide 25 mg), the first oral GLP-1 receptor agonist approved for weight management, including to reduce cardiovascular risk. confirmedas of 2025-12-22

    30. [30]

      Lilly's second-quarter 2026 revenue rose 48% to $23.0 billion, including $9.9 billion from Mounjaro, $4.9 billion from Zepbound and $98 million from Foundayo. confirmedas of 2026-08-05

    31. [31]

      On 4 August 2026 Novo Nordisk raised its 2026 outlook to adjusted sales growth of 0% to -6% at constant exchange rates, from -4% to -12%, citing higher expected GLP-1 sales. confirmedas of 2026-08-04

    32. [32]

      Pfizer completed its acquisition of obesity-drug developer Metsera on 13 November 2025 at about $7.0 billion enterprise value plus contingent payments tied to its monthly injectable GLP-1 candidate MET-097i and amylin analogue MET-233i. confirmedas of 2025-11-13

    33. [33]

      On 30 April 2026 the FDA proposed excluding semaglutide, tirzepatide and liraglutide from the 503B bulks list, which would bar outsourcing facilities from compounding them from bulk ingredients; comments were accepted until 29 June 2026. confirmedas of 2026-04-30

    34. [34]

      Novo Nordisk launched the Wegovy pill in the US on 5 January 2026. confirmedas of 2026-02-03

    35. [35]

      By mid-July 2026, US weekly prescriptions for the Wegovy pill exceeded 265,000, with more than 5 million prescriptions since launch. confirmedas of 2026-08-04

    36. [36]

      As of August 2026, Lilly said three additional phase 3 retatrutide obesity trials were positive, that the data package was complete for obesity, obstructive sleep apnea and knee osteoarthritis pain, and that it plans to submit a Biologics License Application to the FDA in the first quarter of 2027. confirmedas of 2026-08-05

    37. [37]

      Novo Nordisk submitted CagriSema to the US FDA in December 2025 based on REDEFINE 1 and 2, with a decision anticipated by late 2026. confirmedas of 2026-09-21

    38. [38]

      On 23 February 2026 Novo Nordisk reported that CagriSema failed to show non-inferiority to tirzepatide 15 mg in the open-label REDEFINE 4 trial, with weight loss of 20.2% versus 23.6% at 84 weeks under the treatment-regimen estimand. confirmedas of 2026-02-23

    39. [39]

      Under the Medicare Drug Price Negotiation Program, CMS set a negotiated 30-day price of $274 for Ozempic, Rybelsus and Wegovy, against a 2024 list price of $959, effective 1 January 2027. confirmedas of 2025-11-25

    40. [40]

      A 2026 BMJ meta-analysis of 37 studies found average weight regain of 0.4 kg per month after stopping weight-management medicines, with cardiometabolic markers projected to return to baseline within 1.4 years, faster than after behavioural programmes. confirmedas of 2026-01-07

    41. [41]

      A 2026 narrative review concluded that nutritional and muscle effects of GLP-1-based therapy vary between people, and that routine supplementation is not supported for all patients but a risk-based approach is appropriate for groups such as older adults. confirmedas of 2026-08-23

    42. [42]

      One year after stopping semaglutide and lifestyle intervention in the STEP 1 extension, participants had regained about two-thirds of their prior weight loss, and most cardiometabolic improvements reverted toward baseline. confirmedas of 2022-05-19

    Revision history (2)
    1. Page created.
    2. Refresh: updated retatrutide figure to the peer-reviewed TRIUMPH-1 result.

    Created Oct 10, 2026. Last reviewed by an editor on Oct 10, 2026. Next scheduled review: Jan 10, 2027.

    Cite this page

    "GLP-1 and metabolic medicine in 2026: a crash course." ContentLora, updated Oct 10, 2026. https://contentlora.com/explain/metabolic-medicine

    Spotted an error? Suggest a correction or emailcorrections@contentlora.com.

    Keep exploring

    ☰ Contents