How Skinny Fat Affects GLP-1 (Ozempic) Weight Loss & Muscle Mass

Glucagon-like peptide-1 (GLP-1) drugs (1, 2, 3, 4), more commonly known as semaglutide or Ozempic, Wegovy, and Rybelsus, were originally prescribed for diabetes but have become very popular regular white/yellow fat (body fat/adipose tissue) weight loss tools. Two of the many reported negative side effects are Ozempic face (5) and muscle mass (lean body mass) loss. Do GLP-1 weight loss drugs like Ozempic cause muscle mass loss?

Body composition is currently scientifically/medically defined by lean body mass (LBM)(6, 7, 8, 9, 10) — sometimes referred to as fat-free mass (FFM) — versus body fat (adipose tissue/regular white/yellow fat)(11). Lean body mass includes muscle tissue (skeletal muscle, smooth muscle, and cardiac muscle) along with organs, ligaments, tendons, bones, and bodily fluid. To calculate lean body mass you subtract total body fat from total body weight.

Although no official standard currently exists to accurately calculate total body fat, popular methods (12) include body circumference measurements (13), hip-to-waist ratio (14),  and body fat percentage calculations (15). However, no body fat calculation method accounts for genetic skinny fat tissue (thin fat, cellulite)(16), and the only technology that currently exists to determine skinny fat tissue is the Scientific Body Type One Quiz (17). Just as no official standard exists to accurately calculate muscle mass (18, 19). Thus, body fat and lean body mass calculations are not particularly accurate and are more of a guideline.

How Skinny Fat Affects GLP-1 (Ozempic) Weight Loss & Muscle Mass

Yet, the vast majority of scientific studies (20, 21, 22) use known inaccurate body fat and lean body mass methods when attempting to determine how much GLP-1 weight loss drugs like Ozempic affect muscle mass loss. Some of the conclusions indicate high muscle mass loss, with estimates ranging from 30% to 60% (20, 23, 24, 25, 26). While in seeming contradiction, one American Heart Association Journal study generally concluded (27) that “GLP-1 RA treatments appear to be adaptive [a physiologic response to weight loss maintaining or minimally affecting muscle health or function].”

The fact is, the vast majority (if not all) of studies don’t know how much muscle mass each participant had before they lost weight using a GLP-1 drug. Therefore, we do not know if any participant did not have the muscle mass to begin with, and, instead, many likely have genetic skinny fat tissue where they genetically should have muscle mass. If they do, indeed, have genetic skinny fat tissue where they should genetically have default muscle/mass tissue, then they never had the default genetic muscle tissue to start.

Weight Loss & Unique Genetic Body Composition

Did 27-year-old Research Participant 1053’s (28) weight loss cause them to lose muscle mass? Or is their unique genetic body composition the reason why they did not have the genetic muscle/mass tissue from the beginning?

They started at an obese BMI of 32.1. The widespread skinny fat tissue — thin fat and cellulite — is clear and obvious. So is the lack of genetic default muscle tissue.

They safely lost 34 pounds to get down to an overweight BMI of 26.3. The abundant skinny fat tissue and lack of muscle tissue remain clear and obvious in all the same places. They have 8 pounds to lose to get to within safe BMI (18.5 to 24.99). But they have obvious skinny fat tissue where they should have genetic default muscle mass, as per the Standard Body Type One (BT1)(29, 30, 31).

All 600+ of those supposed genetically developed muscles are not going to magically appear/exist on 1053’s body when they lose those remaining 8 pounds, or 20 pounds, or even all the way down to 18.5 BMI. Genetics, i.e. their unique genetic body composition matters.

Real Skinny Fat Tissue

Here is 23-year-old Research Participant 1170 (32). They started within safe BMI at 24.6. The skinny fat tissue  — cellulite and thin fat — is obvious and clear, as is the normal weight obesity and lack of genetic default muscle/mass. They safely lost even more regular fat weight and dropped deeper within safe BMi to 21.3, yet, the genetic skinny fat tissue relative to a lack of default genetic muscle tissue clearly and obviously remain, in all the same places. Genetics.

They are not a Standard Body Type One (BT1) — they are a Body Type Three (BT3)(33) due to their unique genetic body composition.

Here is Joe Rogan when he was fat-shamed on social media:

He is an obvious and clear Standard Body Type One (BT1) with all 600+ muscles developed. Even when he is fat (too much regular white/yellow body fat) you can clearly see his abdominal muscles et al, just like the Standard BT1 image above.

Science and Technology – How Skinny Fat Affects GLP-1 (Ozempic) Weight Loss & Muscle Mass

Human science and technology are young and evolving. Until skinny fat science reaches the mainstream, and healthcare, medical professionals, and people, in general, better understand unique genetic body composition as a whole, the inaccuracy and confusion will continue. As skinny fat science — science overall —  improves, technologies will adapt to accurately account for, measure, and determine the full spectrum of body composition variables including skinny fat tissue. And no less than how GLP-1’s like Ozempic effect weight loss and muscle mass will become more clear.

The Scientific Health Quizzes (34) are the first step in this evolution. The Science Body Type Quiz (17) is the debut technology to determine skinny fat tissue — with an AI version coming soon. It is complemented by the Scientific Metabolism Quiz (35), Scientific Diet Quiz (36), Scientific Exercise Quiz (37), Scientific Lifestyle Quiz (38), and Scientific Total Health Quiz (39). They all use the very latest comprehensive science in proprietary algorithms to accurately calculate each person’s unique metrics safely, securely, and privately.

No personal information is required; you can use a Pen Name and no face is used in the images. The only thing required is a valid email to sign up for a free account.

Skinny Fat Body Type Science

References

1. NIH, National Library of Medicine: Compare and Contrast the Glucagon-Like Peptide-1 Receptor Agonists (GLP1RAs), February 25, 2024, Wafa Latif; Katerina J. Lambrinos; Preeti Patel; and Rolando Rodriguez. https://www.ncbi.nlm.nih.gov/books/NBK572151/
2. Mayo Clinic: GLP-1 agonists: Diabetes drugs and weight loss, June 29, 2022, M. Regina Castro, M.D. https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/expert-answers/byetta/faq-20057955
3. Cleveland Clinic: GLP-1 Antagonists, July 3, 2023. https://my.clevelandclinic.org/health/treatments/13901-glp-1-agonists
4. NIH, National Library of Medicine: Glucagon-Like Peptide-1 Receptor Agonists, February 29, 2024, Logan Collins and Ryan A. Costello. https://www.ncbi.nlm.nih.gov/books/NBK551568/
5. NBC’s The Today Show: What is ‘Ozempic face’? Significant weight loss on the drug can change your face, doctors say, January 27, 2023. Maura Hohman. https://www.today.com/health/ozempic-face-rcna67737
6. Wikipedia: Lean body mass, https://en.wikipedia.org/wiki/Lean_body_mass
7. ScienceDirect: Lean Body Mass, https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/lean-body-mass
8. NIH, National Library of Medicine: Lean body mass: the development and validation of prediction equations in healthy adults, October 14, 2013, Solomon Yu, Thavarajah Visvanathan, John Field, Leigh C Ward, Ian Chapman, Robert Adams, Gary Wittert, and Renuka Visvanathan. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3833312/
9. Healthline: How Much Muscle Mass Should I Have, and How Do I Measure It?, March 10, 2023, Kirsten Nunez (Medically reviewed by Gregory Minnis, DPT, Physical Therapy). https://www.healthline.com/health/muscle-mass-percentage
10. NIH, National Library of Medicine: Relationship between body mass, lean mass, fat mass, and limb bone cross‐sectional geometry: Implications for estimating body mass and physique from the skeleton, January 18, 2018, Emma Pomeroy, Alison Macintosh, Jonathan C.K. Wells, Tim J. Cole, and Jay T. Stock. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178563/
11. Skinny Fat Science: Are Regular Fat and Skinny Fat the Same Thing?, August 28, 2024. https://skinnyfat.fellowone.com/are-regular-fat-and-skinny-fat-the-same-thing/
12. Healthline: The 10 Best Ways to Measure Your Body Fat Percentage, May 18, 2023, The 10 Best Ways to Measure Your Body Fat Percentage. https://www.healthline.com/nutrition/ways-to-measure-body-fat
13. VeryWell Fit: How to Calculate Body Fat Percentage, May 2, 2024, Malia Frey, M.A., ACE-CHC, CPT (Medically reviewed by Tyra Tennyson Francis, MD). https://www.verywellfit.com/how-to-use-body-fat-percentage-calculator-3858855
14. WebMD: What Is Waist to Hip Ratio?, July 21, 2023, WebMD Editorial Contributor (Medically reviewed by Tyler Wheeler, MD). https://www.webmd.com/fitness-exercise/what-is-waist-to-hip-ratio
15. NASM: Body fat calculator, https://www.nasm.org/resources/body-fat-calculator
16. Skinny Fat Science: What Is Skinny Fat?, July 26, 2024. https://skinnyfat.fellowone.com/what-is-skinny-fat/
17. Fellow One Research: Scientific Body Type Quiz (Official). https://scientificbodytypequiz.fellowone.com/product/scientific-body-type-quiz-official/
18. NIH, National Library of Medicine: Pitfalls in the measurement of muscle mass: a need for a reference standard, January 18, 2019, Fanny Buckinx, Francesco Landi, Matteo Cesari, Roger A. Fielding, Marjolein Visser, Klaus Engelke, Stefania Maggi, Elaine Dennison, Nasser M. Al‐Daghri, Sophie Allepaerts, Jurgen Bauer, Ivan Bautmans, Maria Luisa Brandi, Olivier Bruyère, Tommy Cederholm, Francesca Cerreta, Antonio Cherubini, Cyrus Cooper, Alphonso Cruz‐Jentoft, Eugene McCloskey, Bess Dawson‐Hughes, Jean‐Marc Kaufman, Andrea Laslop, Jean Petermans, Jean‐Yves Reginster, René Rizzoli, Sian Robinson, Yves Rolland, Ricardo Rueda, Bruno Vellas, and John A. Kanis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5879987/
19. MedicalNewsToday: How and why to calculate muscle mass percentage, September 2, 2024, Aaron Kandola (Medically reviewed by Megan Soliman, MD). https://www.medicalnewstoday.com/articles/muscle-mass-percentage#calculation
20. NIH, National Library of Medicine: A Review of the Effects of Glucagon-Like Peptide-1 Receptor Agonists and Sodium-Glucose Cotransporter 2 Inhibitors on Lean Body Mass in Humans, September 26, 2019, Jack Alistair Sargeant, Joseph Henson, James Adam King, Thomas Yates, Kamlesh Khunti, and Melanie Jane Davies. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6769337/
21. Healthline: Ozempic Can Cause Major Loss of Muscle Mass and Reduce Bone Density, May 2, 2023, Cathy Cassata (Fact checked by Jill Seladi-Schulman, Ph.D.). https://www.healthline.com/health-news/ozempic-muscle-mass-loss
22. NIH, National Library of Medicine: Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies, June 27, 2024, Ian J Neeland, Jennifer Linge, and Andreas L Birkenfeld. https://pubmed.ncbi.nlm.nih.gov/38937282/
23. Medscape: Losing Muscle With GLP-1 RAs? There May Be a Drug for That, Miriam E. Tucker May 24, 2024. https://www.medscape.com/viewarticle/losing-muscle-glp-1-ras-there-may-be-drug-2024a10009v1?form=fpf
24. Wiley Journal of Diabetes Research (Diabetes, Obesity, and Metabolism): Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies, June 27, 2024, Ian J. Neeland MD, Jennifer Linge PhD, and Andreas L. Birkenfeld MD. https://dom-pubs.onlinelibrary.wiley.com/doi/10.1111/dom.15728?af=R
25. UCLA Health: Rapid weight loss can lead to loss of muscle mass, Ask the Doctors, Eve M. Glazier, MD Internal Medicine, Elizabeth Ko, MD, and Elizabeth Ko, MD Internal Medicine. https://www.uclahealth.org/news/article/rapid-weight-loss-can-lead-loss-muscle-mass
26. NIH, National Library of Medicine: Effects of Antidiabetic Drugs on Muscle Mass in Type 2 Diabetes Mellitus, 2021, Satoshi Ida, Ryutaro Kaneko, Kanako Imataka, Kaoru Okubo, Yoshitaka Shirakura, Kentaro Azuma, Ryoko Fujiwara, and Kazuya Murata. https://pubmed.ncbi.nlm.nih.gov/32628589/
27. American Heart Association Journals: Muscle Mass and Glucagon-Like Peptide-1 Receptor Agonists: Adaptive or Maladaptive Response to Weight Loss?, October 14, 2024, Volume 150, Number 16, Jennifer Linge, PhD, Andreas L. Birkenfeld, MD, and Ian J. Neeland, MD. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.124.067676
28. Fellow One Research: Body Type Test (Quiz) Results 1053 – Body Type Four (BT4) Female (Woman), Millennial (Generation Y), https://www.fellowone.com/fellow-one-research/the-four-body-types/body-type-quiz/body-type-test-quiz-results-1053-body-type-four-bt4-female-woman-millennial-generation-y/
29. Britannica: human muscle system, Shane W. Cummings and Robin Huw Crompton (Fact-checked by the Editors of Encyclopaedia Britannica. https://www.britannica.com/science/human-muscle-system
30. Wikipedia: Muscular system. https://en.wikipedia.org/wiki/Muscular_system
31. Cleveland Clinic: Muscles, January 23, 2024. https://my.clevelandclinic.org/health/body/21887-muscle
32. Fellow One Research: Body Type Test (Quiz) Results 1170 – Body Type Three (BT3) Female (Woman), Generation Z. https://www.fellowone.com/fellow-one-research/the-four-body-types/body-type-quiz/body-type-test-quiz-results-1170-body-type-three-bt3-female-woman-generation-z/
33. Fellow One Research: Body Type Science Research Data. https://www.fellowone.com/category/fellow-one-research/the-four-body-types/body-type-science/body-type-quiz/research-data/
34. Fellow One Research, Scientific Health Quizzes: Shop. https://scientificbodytypequiz.fellowone.com/shop/
35. Fellow One Research, Scientific Health Quizzes: Scientific Metabolism Quiz Health Score. https://scientificbodytypequiz.fellowone.com/product/scientific-metabolism-quiz-health-score/
36. Fellow One Research, Scientific Health Quizzes: Scientific Diet Quiz Health Score. https://scientificbodytypequiz.fellowone.com/product/scientific-diet-quiz-health-score/
37. Fellow One Research, Scientific Health Quizzes: Scientific Exercise Quiz Health Score. https://scientificbodytypequiz.fellowone.com/product/scientific-exercise-quiz-health-score/
38. Fellow One Research, Scientific Health Quizzes: Scientific Lifestyle Quiz Health Score. https://scientificbodytypequiz.fellowone.com/product/scientific-lifestyle-quiz-health-score/
39. Fellow One Research, Scientific Health Quizzes: Scientific Total Health Quiz Score: https://scientificbodytypequiz.fellowone.com/product/scientific-total-health-quiz-score/