Page last checked 2026-09-07

Does Ozempic cause muscle loss?

Lean mass can fall during weight loss with semaglutide. That does not mean all the lost tissue is muscle, and a semaglutide weight-loss study does not give an Ozempic-specific muscle-loss rate.

What the STEP 1 body scans found

An exploratory study used DXA body scans in 140 adults with overweight or obesity and no diabetes. It compared weekly semaglutide 2.4 mg with placebo over 68 weeks, alongside lifestyle support.

In the semaglutide group, lean mass fell 9.7% from its starting amount and fat mass fell 19.3%. Lean mass therefore made up a larger share of the remaining body weight. These are changes from baseline, not percentages of the weight lost.

The cited conference poster reports a small substudy. It does not establish an Ozempic-specific rate of skeletal muscle loss or prove a loss of strength.

Read the body-composition study

Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewer

Information checked 2026-09-07

How these findings apply

The useful evidence comes from body-composition scans, not just side-effect lists. The study below measures fat and lean mass. The wider table shows what our reaction summaries contain.

Ozempic and Wegovy contain semaglutide. Their approved uses and doses differ, so a weight-loss study must keep its own dose and population attached.

Exploratory DXA substudy; conference poster

Compound summary coverage

Compounds that list it

0 of 42

Only in a combined category

No reaction list in this guide

Best available source

FDA label

Which compound summaries list muscle loss

These rows search reaction summaries for muscle-related terms. They do not contain body-scan measurements. An empty row cannot establish that lean mass stayed the same.

◆ Muscle loss across 42 compoundsguide or source for every row

Every compound covered on this site, showing whether it lists muscle loss and at what frequency its own cited source states.
Compound	How it appears	Frequency reported	Source type
TirzepatideZepbound, Mounjaro	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	FDA label
SemaglutideWegovy, Ozempic, Rybelsus	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	FDA label
LiraglutideVictoza, Saxenda	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	FDA label
Retatrutide	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
Cagrilintide	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
Survodutide	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
BPC-157	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
TesamorelinEgrifta SV, Egrifta WR	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	FDA label
PT-141Vyleesi	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	FDA label
CJC-1295	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
Ipamorelin	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
TB-500	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
GHK-Cu	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
Sermorelin	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
MOTS-c	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
AOD-9604	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
NAD+	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
Epitalon	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
Kisspeptin-10	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
DSIP	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
Hexarelin	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
IGF-1 LR3	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
PEG-MGF	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
LL-37	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
KPV	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
Thymosin alpha-1	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
SS-31Forzinity	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	FDA label
Semax	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
Selank	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
Melanotan II	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
Mazdutide	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
Pinealon	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	limited human data
AHK-Cu	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
VK2735	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
Zenagamtide	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
Pemvidutide	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
Brenipatide	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
Eloralintide	Not listed in this summaryThis short reaction list does not include the symptom. Check the full product label or study for more detail.	—	Human trial
Enicepatide	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
Macupatide	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
MariTide	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work
Petrelintide	No reaction list in this guideThis guide has no reaction entries. That does not establish that no human safety evidence exists.	—	no human dose shown to work

These tables summarize selected reaction entries. A missing entry does not mean the full label or all published studies omit it. A summary does not replace the full prescribing information. A pharmacist or clinician can review the complete label alongside the rest of a person’s medicines.

2Read deeperWhy it happens and what the evidence shows

Lean mass is not the same as muscle

A body-composition scan separates fat from lean tissue and bone. Lean tissue includes more than skeletal muscle. A change in lean mass should not be relabeled as the same percentage of muscle lost.

Body weight, body composition and strength answer different questions. A scale alone cannot show which tissue changed. A side-effect count cannot measure that change either.

Describe changes in eating as well as weight

Decreased appetite is also listed for Tirzepatide (common (1–10%)), Liraglutide (reported in Victoza trials (≥5%)), Retatrutide (reported in trials) and Cagrilintide (reported in trials). Each result links to its original source.

Reduced appetite appears in several reaction summaries. If eating has changed, describe it to your care team alongside weight, activity and strength. A reaction list cannot determine your nutrition needs.

How to read a muscle-loss claim

Check what was measured before interpreting a percentage.

How to read a muscle-loss claim
The claim	What the evidence shows
Lean mass and muscle mass mean the same thing.	They are different measurements. Use the study’s own term instead of replacing it with “muscle.”
A fall in lean mass tells us how much strength was lost.	A scan and a strength test measure different outcomes. One cannot substitute for the other.
An empty side-effect row rules out a body-composition change.	The row only describes the reaction summary. Body-scan results need their own source.
One result describes every semaglutide product and patient.	Keep the dose, study group and follow-up period attached to a result. Those details limit where it applies.

New weakness needs its own assessment

Do not assume new weakness is muscle loss. Low blood sugar and dehydration are among the concerns described in the product warnings below.

Acute kidney injury from dehydration

Prompt

Signs: Vomiting or diarrhea bad enough that you cannot keep fluids down, passing much less urine than usual, dizziness when you stand up, or unusual weakness.

The label links the risk to dehydration, so ongoing fluid loss is worth reporting early. A clinician can check kidney function.

Hypoglycemia when combined with insulin or a sulfonylurea

Prompt

Signs: Shakiness, sweating, confusion, sudden hunger, a racing heart, blurred vision or trouble concentrating — especially in someone also taking insulin or a sulfonylurea.

The source ties this risk to that combination specifically, which makes your full medicine list worth going through with whoever prescribes for you. Severe confusion, a seizure or passing out is an emergency call.

These warnings can help you recognize a concern. A clinician can assess your symptoms alongside your health history and other medicines.

EmergencySome symptoms should not wait for an appointment. Call emergency services (911 in the US) if they are severe, getting worse fast, or involve trouble breathing, chest pain, fainting or confusion.

Common questions

Is muscle loss listed on the Ozempic or Wegovy label record?

The local semaglutide reaction summary does not measure body composition. Read scan findings separately from the label’s reaction table.

Is muscle loss on these compounds different from any other weight loss?

Separating a drug effect from the effect of weight loss needs a study designed for that comparison. The reaction summaries below do not provide one.

Why do other sites give a percentage for muscle loss?

Some percentages come from body-composition studies. Check whether the number means a change from the starting amount or a share of weight lost.

Also check whether the authors measured lean mass, skeletal muscle or strength. Those terms should not be swapped.

Does decreased appetite explain it?

An appetite change alone cannot establish the cause of a measured tissue change. Your care team can review food intake, activity and other factors.

Should I take protein supplements or lift weights while taking it?

Ask your clinician or dietitian about your nutrition and activity needs, particularly if eating or strength has changed. A scan result alone cannot select a supplement or exercise plan.

Is feeling weak the same as losing muscle?

No. Feeling weak does not measure muscle mass. Sudden or worsening weakness needs assessment on its own, rather than being assumed to be part of weight loss.

The warning signs above cover low blood sugar and kidney concerns. They are not a complete list of possible causes.

How is this different from the hair-loss question?

Hair loss appears as a reported reaction in the Wegovy and Zepbound labels. This question also needs body-composition measurements. The two outcomes use different evidence.

Want the full picture for one compound? Open its guide for uses, dosage information, side effects and serious warnings.

Tirzepatide reactions in full, including muscle loss

Information from an approved label behind tirzepatide, apart from muscle loss.

Every semaglutide reaction, not only muscle loss

9 common and 6 serious semaglutide reactions, in full past muscle loss.

Constipation across every page, as with muscle loss

Which sources name constipation, under what wording and at what frequency, beyond muscle loss.

Nausea read the same way as muscle loss

13 of 42 pages carry nausea, counted class-wide rather than within muscle loss.

Explore compound guides related to muscle loss

Find individual compound guides to help you understand muscle loss.

Separate lean and fat mass after reading about muscle loss

The calculator keeps measurement uncertainty beside the result, with muscle loss as context

Reading muscle loss for a length nobody published

Three different questions hide inside this one, and each needs a different study, including muscle loss

The protein ledger that keeps muscle loss claims separate

Muscle loss included only as context: the planner makes no prevention or treatment claim.

Vial, water and draw for the muscle loss compounds

U-100, U-50 and U-40 barrels each read differently, including muscle loss

Every symptom in this section is listed on the symptom questions index.

Questions readers ask

How do I stop losing muscle on Ozempic?

The study discussed here did not test a plan to prevent muscle loss on Ozempic.

The STEP 1 body scans measured lean tissue during weight loss with semaglutide. Lean tissue includes more than muscle. A clinician or dietitian can assess strength, food intake and changes in body composition.

Why am I losing muscle instead of fat?

Weight change alone cannot show whether you are losing muscle instead of fat.

The STEP 1 scans found decreases in both fat and lean tissue. They cannot establish what happened to you. A lean-mass result also cannot be read as an equal amount of muscle loss.

What are the signs that I'm losing muscle?

The sources on this page do not provide a symptom checklist that diagnoses muscle loss.

A drop in strength or new weakness needs assessment rather than a conclusion from the scale. The body-scan study measured tissue changes, not a test for the cause of someone’s weakness.

Can you still build muscle on Ozempic?

The study here does not answer whether a muscle-building program works while taking Ozempic.

STEP 1 measured body composition during weight loss. It did not test a strength-training program or report a muscle-growth outcome. That leaves this question open; it does not show that building muscle is impossible.

8primary sources, each with the day we read it — open the documents used on this page

Zepbound (tirzepatide) — FDA-approved Prescribing Informationretrieved 2026-09-19FDA label
Wegovy (semaglutide) — FDA-approved Prescribing Information (DailyMed)retrieved 2026-08-20FDA label
Saxenda (liraglutide) injection — FDA-approved Prescribing Information (DailyMed)retrieved 2026-09-19FDA label
Peters B, Hadimeri H, Wahlberg R, Afghahi H. Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN Case Rep. 2020;9(3):219-222retrieved 2026-08-13limited human data
Victoza (liraglutide) injection — FDA-approved Prescribing Information (DailyMed)retrieved 2026-09-19FDA label
Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med 2023;389:514-26 (PMID 37366315)retrieved 2026-08-12Human trial
Lau DCW et al. Once-weekly cagrilintide for weight management: dose-finding phase 2 trial. Lancet 2021;398:2160-72 (PMID 34798060)retrieved 2026-08-17Human trial
Impact of Semaglutide on Body Composition in Adults with Overweight or Obesity: Exploratory Analysis of the STEP 1 Studyretrieved 2026-09-13Exploratory DXA substudy; conference poster