Sources
The research behind what we teach.
Every study behind the guide Before Your Last Dose and our patient education, grouped by the point it supports. Links open the study abstract or source page.
For education, not medical advice. Updated October 2026 · Dr. Tanesha Handy Lloyd, MD, MBA
How many people are on these medications
| The point | Source |
|---|---|
| About 1 in 9 American adults (11%) is currently taking a GLP-1 for weight loss, up from 3% in 2024. Roughly 28 million people, applying 11% to about 258 million U.S. adults. | Gallup. In U.S., GLP-1 usage reaches new high. Survey of 5,065 U.S. adults, May 28–June 5, 2026; updated Sept 8, 2026. news.gallup.com |
Metabolic health in U.S. adults
| The point | Source |
|---|---|
| Only about 12% of U.S. adults met all five markers of optimal metabolic health (waist, blood sugar, blood pressure, triglycerides and HDL cholesterol) without medication. | Araújo J, Cai J, Stevens J. Prevalence of optimal metabolic health in American adults: National Health and Nutrition Examination Survey 2009–2016. Metab Syndr Relat Disord. 2019;17(1):46–52. PubMed 30484738 |
What happens when you stop
| The point | Source |
|---|---|
| In one major withdrawal study, a year after stopping, people had regained about two-thirds of the weight they had lost. Labs and blood pressure also drifted back toward baseline. | Wilding JPH et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553–1564. doi:10.1111/dom.14725 |
| In a tirzepatide withdrawal trial, people switched to placebo regained weight over the following year, while those who stayed on treatment continued to lose weight. | Aronne LJ 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 |
| In semaglutide maintenance data, staying on treatment helped hold the loss, while switching to placebo led to regain. | Rubino D et al. Effect of continued weekly subcutaneous semaglutide vs placebo on weight loss maintenance: the STEP 4 randomized clinical trial. JAMA. 2021;325(14):1414–1425. doi:10.1001/jama.2021.3224 |
30 pounds of what?
| The point | Source |
|---|---|
| In some studies, roughly one out of every four pounds lost was lean mass. In some cohorts, the share was higher. | Batsis JA et al. Effect of incretin-based and nonpharmacologic weight loss on body composition: a systematic review. Ann Intern Med. 2026;179(7):996–1013. doi:10.7326/ANNALS-25-00478 |
| Lean mass often makes up roughly a quarter to a third of weight lost, and resistance training appears to reduce that share. | Eisa N, Barood O. Lean mass changes with incretin therapy versus lifestyle intervention: a systematic review and meta-analysis. Diabetes Obes Metab. 2026;28(6):4818–4827. doi:10.1111/dom.70666 |
| When weight comes back, it often comes back disproportionately as fat. | Beavers KM et al. Is lost lean mass from intentional weight loss recovered during weight regain in postmenopausal women? Am J Clin Nutr. 2011;94(3):767–774. doi:10.3945/ajcn.110.004895 |
The example "10 of her 38 pounds" is a simple illustration based on applying roughly one-quarter to a 38-pound loss.
Why we measure: muscle, metabolism and mobility
These measurements are not experimental. Each one is established in research as a marker of long-term health. They are not yet part of routine care.
| The point | Source |
|---|---|
| Grip strength is a simple, inexpensive marker of risk. In about 140,000 adults aged 35 to 70 across 17 countries, each 5 kg lower grip was linked to about 16% higher all-cause mortality, and grip predicted death better than systolic blood pressure. | Leong DP et al. Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. Lancet. 2015;386(9990):266–273. doi:10.1016/S0140-6736(14)62000-662000-6) |
| In half a million adults aged 40 to 69, lower grip strength was linked to higher risk of death from cardiovascular disease, respiratory disease and cancer. Adding grip to a standard office risk score improved its prediction. | Celis-Morales CA et al. Associations of grip strength with cardiovascular, respiratory, and cancer outcomes and all cause mortality: prospective cohort study of half a million UK Biobank participants. BMJ. 2018;361:k1651. doi:10.1136/bmj.k1651 |
| Low muscle strength, measured by grip or chair stands, is the first sign the European sarcopenia consensus looks for. Muscle quantity, measured by body composition, confirms it. Sarcopenia can begin earlier in life, not only in old age. | Cruz-Jentoft AJ et al. Sarcopenia: revised European consensus on definition and diagnosis (EWGSOP2). Age Ageing. 2019;48(1):16–31. doi:10.1093/ageing/afy169 |
| Slower chair stands predicted fracture in older men, independent of standard fracture risk tools. | Harvey NC et al. Measures of physical performance and muscle strength as predictors of fracture risk independent of FRAX, falls, and aBMD: a meta-analysis of the Osteoporotic Fractures in Men (MrOS) study. J Bone Miner Res. 2018;33(12):2150–2157. doi:10.1002/jbmr.3556 |
| More muscle, measured by bioelectrical impedance, was linked to lower all-cause mortality in older adults. Body weight alone could not show this. | Srikanthan P, Karlamangla AS. Muscle mass index as a predictor of longevity in older adults. Am J Med. 2014;127(6):547–553. doi:10.1016/j.amjmed.2014.02.007 |
| Cardiorespiratory fitness predicts all-cause mortality and cardiovascular events. Each 1-MET higher fitness level was linked to about 13% lower all-cause mortality. | Kodama S et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women: a meta-analysis. JAMA. 2009;301(19):2024–2035. doi:10.1001/jama.2009.681 |
| In 122,007 adults, the mortality risk tied to low fitness was comparable to or greater than smoking, diabetes and coronary artery disease. Fitness is a modifiable indicator. | Mandsager K et al. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw Open. 2018;1(6):e183605. doi:10.1001/jamanetworkopen.2018.3605 |
| In people without known heart disease, low heart rate variability was linked to a 32–45% higher risk of a first cardiovascular event. | Hillebrand S et al. Heart rate variability and first cardiovascular event in populations without known cardiovascular disease: meta-analysis and dose-response meta-regression. Europace. 2013;15(5):742–749. doi:10.1093/europace/eus341 |
| Equations that estimate resting metabolism can be off by more than 10% for an individual, especially in groups underrepresented in the original research. Measuring by indirect calorimetry removes that estimation error. | Frankenfield D et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105(5):775–789. doi:10.1016/j.jada.2005.02.005 |
These studies show associations in large populations. They describe risk; they do not predict any one person's future.
What you may have gained beyond the scale
| The point | Source |
|---|---|
| Some of these medications have shown cardiovascular benefit, including fewer heart attacks and strokes in selected populations. | Lincoff AM et al. Semaglutide and cardiovascular outcomes in obesity without diabetes (SELECT). N Engl J Med. 2023;389(24):2221–2232. doi:10.1056/NEJMoa2307563 |
| Tirzepatide has shown benefit for obstructive sleep apnea severity in adults with obesity. | Malhotra A et al. Tirzepatide for the treatment of obstructive sleep apnea and obesity (SURMOUNT-OSA). N Engl J Med. 2024;391(13):1193–1205. doi:10.1056/NEJMoa2404881 |
| Semaglutide has shown benefit for knee pain in people with obesity and knee osteoarthritis. | Bliddal H et al. Once-weekly semaglutide in persons with obesity and knee osteoarthritis (STEP 9). N Engl J Med. 2024;391(17):1573–1583. doi:10.1056/NEJMoa2403664 |
"Quieter food noise" reflects common patient experience; it is not a direct trial endpoint.
The off-ramp discussion
| The point | Source |
|---|---|
| Stay on: in maintenance trials, people who stayed on treatment generally held more of their loss, and some continued losing. | STEP 4 (Rubino 2021) and SURMOUNT-4 (Aronne 2024), above. |
| Change the treatment plan: in one maintenance trial, people moved to a lower dose kept more of their loss than people switched to placebo. | Horn DB et al. Tirzepatide for maintenance of bodyweight reduction in people with obesity in the USA (SURMOUNT-MAINTAIN). Lancet. 2026;407(10545):2305–2318. doi:10.1016/S0140-6736(26)00656-2 |
| Come off with a plan: cycling off without a plan raises the risk that weight returns with a higher fat share. | Beavers KM et al. Am J Clin Nutr. 2011;94(3):767–774. doi:10.3945/ajcn.110.004895 |
The right off-ramp is individualized. For some people that means staying on, for some changing the treatment plan, and for some coming off with a plan.
Hair, nutrients, and protein intake
| The point | Source |
|---|---|
| Hair shedding appears to be reported more often during GLP-1 treatment; nutrition gaps are one proposed contributor. | Viquez Burboa GU et al. GLP-1 receptor agonists and alopecia: a systematic review and meta-analysis. Skin Appendage Disord. 2026. doi:10.1159/000553070 |
| People on GLP-1 therapy may fall short on protein and may need monitoring for selected micronutrients such as vitamin D, iron, and magnesium. | Sibal R et al. Macronutrient, micronutrient supplementation and monitoring for patients on GLP-1 agonists. Nutrients. 2025;17(23):3659. doi:10.3390/nu17233659 |
Changes in the face
| The point | Source |
|---|---|
| In patients on GLP-1 medications, midface volume fell a median of 9%, mostly in the superficial fat pads, about 7% for every 10 kg lost. | Sharma RK et al. Radiographic midfacial volume changes in patients on GLP-1 agonists. Otolaryngol Head Neck Surg. 2025;173(2):360–366. doi:10.1002/ohn.1209 |
| The cheeks, the area under the eyes and the temples are where facial volume loss is most often described. Similar changes follow other large weight losses. | Yoo KH. GLP-1 receptor agonist-associated facial changes: a comprehensive review. Aesthet Surg J. 2026. doi:10.1093/asj/sjag230 |
| Facial volume loss and loose skin are reported more often with greater weight loss. | Santiago Mangual KP et al. Aesthetic, muscle, and dermatologic effects of medical weight management. Int J Womens Dermatol. 2026;12(3):e283. doi:10.1097/JW9.0000000000000283 |
The five pillars: muscle building, nutrition, sleep, stress, hormones
| The point | Source |
|---|---|
| During active weight loss, practical protein targets often fall around 1.2 to 1.6 g/kg/day, which commonly lands near 80 to 120 g/day for many adults. | Mozaffarian D et al. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from ACLM, ASN, OMA and TOS. Obesity. 2025;33(8):1475–1503. doi:10.1002/oby.24336 |
| Resistance training appears to give the best lean-mass profile during weight loss. | Eisa N, Barood O. Diabetes Obes Metab. 2026;28(6):4818–4827. doi:10.1111/dom.70666 |
| Creatine monohydrate, commonly 3 to 5 g/day, has an established evidence base for safety and efficacy in appropriate adults. | Kreider RB et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation. J Int Soc Sports Nutr. 2017;14:18. doi:10.1186/s12970-017-0173-z |
| Short sleep can shift weight loss toward lean mass loss and can increase hunger. | Nedeltcheva AV et al. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. 2010;153(7):435–441. doi:10.7326/0003-4819-153-7-201010050-00006 |
| Stress raises cortisol, and higher cortisol responders ate more after stress, especially sweet foods. | Epel E et al. Stress may add bite to appetite in women. Psychoneuroendocrinology. 2001;26(1):37–49. doi:10.1016/S0306-4530(00)00035-400035-4) |
| A gradual pace such as 1 to 2 pounds per week remains a practical public-health benchmark for weight loss. | Centers for Disease Control and Prevention. Steps for Losing Weight |
Notes
This page is educational and is not individualized medical advice.
Trial populations, durations, and outcomes differ across studies.
Clinical decisions about continuing, tapering, changing, or stopping treatment should be individualized.