What the product information records
A reaction reaches a US label’s main table only when at least 2% of people on the medicine reported it and it was more frequent than on placebo. Muscle pain and joint pain do not meet that bar in the Zepbound®, Wegovy® or Mounjaro® tables, and the EU product information for Mounjaro® does not list them either [1][2][3][6]. The nearest entries are fatigue and, for Wegovy®, a group of skin-sensation changes.
- The Wegovy® label adds that dysesthesia became more common as the dose and blood levels rose, and that most people whose dose was paused, lowered or stopped recovered [2].
- The Canadian Trulicity® monograph lists muscle strain, a raised muscle enzyme (creatine phosphokinase) and low potassium among less common trial reactions, without rates [5].
| Document and trial pool | Entry | Medicine | Comparison |
|---|---|---|---|
| Zepbound®, US label, weight-reduction trials [1] | Fatigue (includes asthenia, lethargy, malaise) | 5% (5 mg), 6% (10 mg), 7% (15 mg) | Placebo 3% |
| Wegovy®, US label, adults on 2.4 mg [2] | Fatigue (includes asthenia) | 11% | Placebo 5% |
| Wegovy®, US label, 7.2 mg trials [2] | Dysesthesia (burning skin, skin pain, sensitive skin) | 22% (7.2 mg), 6% (2.4 mg) | Placebo 0.3% |
| Mounjaro®, US label, cardiovascular outcomes trial [3] | Dysesthesia; fatigue | 0.7%; 10% | Active-comparator trial; comparator rates not given |
| Victoza®, US label, type 2 diabetes trials [4] | Back pain | 4% (1.2 mg), 5% (1.8 mg) | Placebo 3% |
| Trulicity®, Canadian monograph, placebo-controlled pool [5] | Joint pain (arthralgia) | 3.1% (0.75 mg), 2.6% (1.5 mg) | Placebo 3.0% |
| Trulicity®, Canadian monograph, all trials up to 104 weeks [5] | Back pain; pain in a limb | 4.7% and 3.9%; 3.4% and 3.0% | Other diabetes medicines 4.7%; 3.0% |
What studies report
An analysis of FDA adverse event reports from 2004 to mid-2024 examined about 15,000 musculoskeletal reports linked to diabetes medicines that act on the incretin system. Across the whole musculoskeletal category there was no signal. For individual terms, GLP-1 medicines were linked to back pain and muscle pain, and tirzepatide to muscle wasting, with a median onset within the first 30 days [7]. Reporting studies count reports, not patients, so they cannot give a rate or prove cause.
A large US Veterans Affairs cohort compared people with diabetes starting a GLP-1 medicine with those on usual care across 175 outcomes. It found a higher risk of arthritic disorders, alongside lower risks of many other conditions [8]. Observational data like these can be skewed by who gets prescribed what.
Trial evidence points the other way for one kind of joint pain. In STEP 9, 407 adults with obesity and knee osteoarthritis were given semaglutide 2.4 mg or placebo for 68 weeks. Knee pain scores fell by 41.7 points on semaglutide and 27.5 on placebo, on a 0 to 100 scale [9].
Rare, serious muscle breakdown has been described in single case reports. One describes a 35-year-old woman on tirzepatide who developed rhabdomyolysis needing hospital care and recovered after stopping it [12]. A single case cannot show how often this happens.
Gout and uric acid
Gout is a type of arthritis caused by uric acid building up over time; flares usually hit one joint, often the big toe, with sudden intense pain, swelling, redness and warmth [15]. Obesity, alcohol, some diuretics and diets rich in purines raise the risk [15].
In a post hoc analysis of SURMOUNT-1, uric acid fell on all three tirzepatide doses compared with placebo over 72 weeks, and the authors estimated that weight loss explained most of that fall [10]. A network meta-analysis of 22 outcome trials found that GLP-1 medicines neither raised nor lowered the risk of gout compared with placebo [11]. Neither study answers whether a flare is more likely in the early weeks of rapid change, so a new hot, swollen joint should be checked rather than assumed to be gout or a side effect.
How a GLP-1 medicine might lead to aches
- Supported by the labels: vomiting, diarrhea and nausea can lead to dehydration, and dehydration has been linked to kidney injury on these medicines [1][2]. Dehydration and low sodium, potassium or calcium also make muscle cramps more likely [14].
- Supported by the labels: fatigue, weakness and malaise are more common than on placebo, and people often describe these as feeling achy [1][2].
- Proposed but not measured: eating much less can change how much protein and minerals you take in, and fast weight loss includes some loss of lean tissue. Whether this causes pain has not been studied directly.
- General: new or more intense exercise, a change in posture as weight shifts, and stretching muscles that have been used less are ordinary causes of soreness [13].
Other causes of muscle and joint pain
MedlinePlus lists the usual suspects for muscle aches: overuse, injury, tension and stress. It also names infections such as the flu, low potassium or calcium, autoimmune conditions like lupus or polymyalgia rheumatica, fibromyalgia and certain medicines, including statins for cholesterol and ACE inhibitors for blood pressure [13]. Many people starting a GLP-1 medicine also take one of these.
Cramps can follow heavy exercise without enough fluid, and are also linked to an underactive thyroid, kidney failure, alcohol use, pregnancy and some medicines [14]. A short list of what you take, including supplements, makes the conversation with your clinician much quicker.
What may help
For aches from overuse, MedlinePlus describes rest, ice for the first one to three days, then heat, gentle stretching and a gradual return to activity, with acetaminophen or ibuprofen as over-the-counter options [13]. Ask your pharmacist before adding a pain reliever, particularly if you have kidney problems or take other medicines.
For cramps, the same source suggests stretching and massaging the muscle and getting enough fluids, noting that water alone does not always help when minerals are low [14]. Because GLP-1 medicines already raise the chance of fluid loss when stomach side effects are active, keeping up fluids is one of the few steps that the labels and general sources point to together [1][14].
Do not change your GLP-1 dose or stop it because of aches without talking to your prescriber. If a statin or another medicine might be involved, that also needs their input.
Ozempic®, Wegovy® and Victoza® are registered trademarks of Novo Nordisk A/S. Mounjaro®, Zepbound® and Trulicity® are registered trademarks of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Novo Nordisk or Eli Lilly and Company.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| Muscle weakness or being unable to move part of the body | Emergency services (112/911) | Emergency | MedlinePlus, muscle aches [13] |
| Muscle pain with passing much less urine, or sudden swelling and weight gain | Emergency services (112/911) | Emergency | MedlinePlus [13]; Zepbound® label, section 5.3 [1] |
| Muscle pain with vomiting, a very stiff neck or high fever | Emergency services (112/911) | Emergency | MedlinePlus [13] |
| A suddenly hot, red, swollen and very painful joint | Your clinician | Today | MedlinePlus, gout [15] |
| Severe or unexplained pain, or pain that began after starting or changing a medicine such as a statin | Your clinician | Today | MedlinePlus [13] |
| Aches lasting more than three days, or cramps that keep returning | Your prescriber or primary care clinician | At your next appointment | MedlinePlus [13][14] |
