Why semaglutide or tirzepatide may stop producing weight loss

A weight-loss plateau is common and does not necessarily mean the medication has stopped working. It usually occurs when calorie intake and energy expenditure reach a new balance. In clinical trials, average weight loss often slowed after roughly 12–18 months, although timing and response vary widely.[1–5] 

THIS IS A COMMON LL MD ISSUE. AND OTHER REASONS  BESIDES THESE.

🧬 Biological and metabolic reasons

1. A normal weight-loss plateau has been reached.
   As weight decreases, the calorie deficit becomes smaller until intake and expenditure match.[1–5]
2. A smaller body requires fewer calories.
   After weight loss, the body needs fewer calories for basic metabolism and movement.
3. Adaptive thermogenesis develops.
   The body may reduce energy expenditure more than expected for the amount of weight lost.[6,7]
4. Appetite-regulating hormones oppose further weight loss.
   Weight loss can increase hunger signals and reduce satiety signals, partially counteracting medication effects.[6]
5. The initial water-weight loss has ended.
   Early glycogen and water changes can make initial loss appear faster than later fat loss.
6. Lean-muscle loss has reduced energy expenditure.
   Some lean tissue is usually lost with substantial weight reduction, especially without resistance exercise or adequate protein.
7. Gastric emptying may slow less.
   Tachyphylaxis can develop to this particular GLP-1 effect, although appetite and metabolic benefits can remain.[8]
8. Individual biological response varies.
   Genetics, brain appetite pathways, gastrointestinal signaling and baseline metabolism produce substantial differences between patients.
9. Type 2 diabetes can reduce the average weight-loss response.
   Trials generally report less weight loss in people with diabetes than in those without diabetes.[9,10]
10. Aging, menopause or sarcopenia may lower energy needs.
    Loss of muscle and hormonal changes can make further weight loss more difficult.

💉 Dose, administration and treatment issues

11. The dose is still a starter or titration dose.
    Low doses are intended mainly to improve tolerability and may not produce the full weight-loss effect.[11–13]
12. There has not been enough time at an effective dose.
    Results should be assessed over months, not several days or weeks.
13. Doses are being missed or delayed.
    Irregular treatment can allow appetite and food intake to rise again.
14. Treatment has been repeatedly interrupted and restarted.
    Shortages, procedures, illness or insurance problems may lead to prolonged periods at lower exposure.
15. Side effects prevent reaching a therapeutic dose.
    Nausea, vomiting, diarrhea, constipation or reflux may limit titration.
16. Oral semaglutide is not being taken correctly.
    It should generally be taken fasting with no more than 4 ounces/120 mL of plain water, followed by at least 30 minutes before food, drink or other oral medicines.[13]
17. The product was stored or administered incorrectly.
    Excess heat, freezing, damaged pens, incomplete injections or leakage can reduce the dose actually received.[11–13]
18. Medication access is inconsistent.
    Shortages, cost or loss of insurance coverage commonly lead to skipped doses or forced dose reductions.
19. The product is counterfeit, improperly compounded or subpotent.
    Unapproved products may contain the wrong concentration, different salt forms or dosing errors.[14,15]
20. Switching drugs required restarting at a low dose.
    Weight loss may temporarily pause during re-titration from semaglutide to tirzepatide or vice versa.

🍽️ Food intake and activity

21. Calorie intake has gradually increased.
    Small increases can erase the reduced calorie deficit after substantial weight loss.
22. Portion sizes have crept upward.
    Appetite may remain lower than before treatment while portions nevertheless become larger over time.
23. Liquid calories are being overlooked.
    Sweetened drinks, specialty coffees, juices and smoothies can add substantial calories without much fullness.
24. Alcohol intake has increased.
    Alcohol contributes calories, reduces dietary restraint and can stimulate eating.
25. Energy-dense or ultra-processed foods are overriding satiety.
    Small amounts can contain enough calories to prevent further loss.
26. Frequent grazing or evening eating has returned.
    Repeated small snacks may add more calories than recognized.
27. Weekend or social eating offsets weekday restriction.
    A weekly calorie balance matters more than a few “good” days.
28. Protein or fiber intake is inadequate.
    This may reduce fullness and make preserving muscle more difficult.
29. Planned physical activity has decreased.
    Injury, fatigue, illness, schedule changes or reduced motivation can lower total expenditure.
30. Non-exercise activity has fallen.
    People often unconsciously sit more, walk less or fidget less during weight loss.
31. Exercise is being compensated for by eating more.
    Increased hunger or “reward” eating can exceed the calories burned.
32. Sleep is inadequate or irregular.
    Sleep loss can increase hunger, cravings and fatigue while reducing activity.
33. Stress, depression, anxiety or emotional eating has increased.
    These can overcome some of the medication’s appetite-reducing effect.

🩺 Medications, health conditions and misleading scale changes

34. Another medication is promoting weight gain.
    Examples include insulin, sulfonylureas, thiazolidinediones, corticosteroids, some antipsychotics and antidepressants, gabapentinoids and certain beta-blockers.[16,17]
35. Hypothyroidism is untreated or undertreated.
    It can contribute to fatigue, fluid retention and modest weight gain.
36. Cushing syndrome or chronic glucocorticoid exposure is present.
    Although uncommon, either can cause central weight gain and metabolic dysfunction.
37. Untreated obstructive sleep apnea is interfering with progress.
    Poor sleep, fatigue and metabolic changes can make weight management more difficult.
38. Pregnancy has occurred.
    Pregnancy causes expected weight gain, and weight-loss medications are not recommended during pregnancy. Contact the prescriber promptly.[11,12]
39. Fluid retention or constipation is masking fat loss.
    High sodium intake, menstruation, heart/kidney disease, edema or retained bowel contents can temporarily raise scale weight.
40. Measurement variation or body recomposition is hiding progress.
    Different scales, clothing, time of day, hydration and menstrual-cycle changes can obscure trends. Waist size or body composition may improve even when weight is stable.

✅ What to review with the prescriber

• Look at the 4–8 week weight trend, not single measurements.
• Confirm the exact product, dose, schedule, storage and injection technique.
• Review food intake, alcohol, activity, sleep and constipation.
• Review all medications for weight-promoting effects.
• Consider testing for hypothyroidism or other conditions when symptoms suggest them.
• Discuss protein intake and resistance exercise to preserve muscle.
• Do not increase the dose, combine semaglutide with tirzepatide, or use compounded/counterfeit products without medical supervision.
• Seek prompt medical advice for pregnancy, persistent vomiting, severe abdominal pain, dehydration, or symptoms of gallbladder or pancreatic disease.

References

1. Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine. 2021;384(11):989–1002. doi:10.1056/NEJMoa2032183.
2. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine. 2022;387(3):205–216. doi:10.1056/NEJMoa2206038.
3. Rubino D, Abrahamsson N, Davies M, et al. Effect of continued weekly subcutaneous semaglutide vs placebo on weight-loss maintenance in adults with overweight or obesity: The STEP 4 randomized clinical trial. JAMA. 2021;325(14):1414–1425. doi:10.1001/jama.2021.3224.
4. Wilding JPH, Batterham RL, Davies M, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes, Obesity and Metabolism. 2022;24(8):1553–1564. doi:10.1111/dom.14725.
5. Aronne LJ, Sattar N, Horn DB, et al. Continued treatment with tirzepatide for maintenance of weight reduction in adults with obesity: The SURMOUNT-4 randomized clinical trial. JAMA. 2024;331(1):38–48. doi:10.1001/jama.2023.24945.
6. Sumithran P, Prendergast LA, Delbridge E, et al. Long-term persistence of hormonal adaptations to weight loss. New England Journal of Medicine. 2011;365(17):1597–1604. doi:10.1056/NEJMoa1105816.
7. Rosenbaum M, Leibel RL. Adaptive thermogenesis in humans. International Journal of Obesity. 2010;34(Suppl 1):S47–S55. doi:10.1038/ijo.2010.184.
8. Nauck MA, Kemmeries G, Holst JJ, Meier JJ. Rapid tachyphylaxis of the glucagon-like peptide 1–induced deceleration of gastric emptying in humans. Diabetes. 2011;60(5):1561–1565. doi:10.2337/db10-0474.
9. Davies M, Færch L, Jeppesen OK, et al. Semaglutide 2.4 mg once a week in adults with overweight or obesity and type 2 diabetes: The STEP 2 randomized trial. The Lancet. 2021;397(10278):971–984. doi:10.1016/S0140-6736(21)00213-0.
10. Garvey WT, Frias JP, Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes: SURMOUNT-2. The Lancet. 2023;402(10402):613–626. doi:10.1016/S0140-6736(23)01200-X.
11. Novo Nordisk. Wegovy (semaglutide) injection: US prescribing information. Plainsboro, NJ: Novo Nordisk Inc. Current prescribing information available from: https://www.novo-pi.com/wegovy.pdf (opens in new tab)
12. Eli Lilly and Company. Zepbound (tirzepatide) injection: US prescribing information. Indianapolis, IN: Eli Lilly and Company. Current prescribing information available from: https://pi.lilly.com/us/zepbound-uspi.pdf (opens in new tab)
13. Novo Nordisk. Rybelsus (semaglutide) tablets: US prescribing information. Plainsboro, NJ: Novo Nordisk Inc. Current prescribing information available from: https://www.novo-pi.com/rybelsus.pdf (opens in new tab)
14. U.S. Food and Drug Administration. FDA’s concerns with unapproved GLP-1 drugs used for weight loss. Available from: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss (opens in new tab)
15. U.S. Food and Drug Administration. Medications containing semaglutide marketed for type 2 diabetes or weight loss. Available from: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/medications-containing-semaglutide-marketed-type-2-diabetes-or-weight-loss (opens in new tab)
16. Apovian CM, Aronne LJ, Bessesen DH, et al. Pharmacological management of obesity: An Endocrine Society clinical practice guideline. Journal of Clinical Endocrinology & Metabolism. 2015;100(2):342–362. doi:10.1210/jc.2014-3415.
17. Wharton S, Lau DCW, Vallis M, et al. Obesity in adults: A clinical practice guideline. CMAJ. 2020;192(31):E875–E891. doi:10.1503/cmaj.191707.