What the research found

A 2026 systematic review examined seven studies tracking physical activity in people taking GLP-1 receptor agonists. Accelerometer data from 924 participants (468 on GLP-1s) showed a consistent pattern: unplanned movement—what exercise physiologists call NEAT (non-exercise activity thermogenesis)—declined in five of the seven studies. However, only one trial reached statistical significance in isolation, and when researchers combined the randomized controlled trials, the difference disappeared. The one statistically significant finding involved roughly 1,100 fewer daily steps in a small liraglutide group.

The reduction in unplanned movement appears distinct from scheduled exercise. The patient in question maintained her three weekly training sessions perfectly but lost motivation for informal activity like walking or general movement outside the gym. In caloric terms, 1,100 fewer steps amounts to approximately 30–50 calories daily—modest compared to the 240–290 calorie reduction in food intake that GLP-1s typically produce.

Why it matters for you

If you're using liraglutide, tirzepatide, or semaglutide while tracking activity or managing body composition, this distinction matters. Your formal workouts—the structured sessions you log—appear largely unaffected by the drug. The slump occurs in the "background" movement that fills the rest of your day: walking between tasks, fidgeting, taking stairs instead of lifts, parking farther away. This is the largest component of daily energy expenditure for most people, and it's also the most invisible on paper.

The clinical implication: appetite suppression is still doing the heavy lifting for weight loss. A reduction in incidental movement may slow fat loss or contribute to plateaus over time, especially as appetite suppression itself wanes after several months. MyKine users tracking steps, daily movement, or resting metabolic rate should expect this pattern and adjust expectations accordingly—it doesn't mean the medication is failing, but it does mean the calculus for energy balance changes.

The bigger question your prescriber should answer: is the loss of movement drive purely a side effect of eating less, or is the drug itself dampening your brain's motivation to move? The evidence leans toward the former, but the text hints that thyroid hormone changes, sleep quality, and reward-circuit signaling remain under investigation.

Caveats

• Small sample size: The one study reaching significance involved roughly 20 people on liraglutide—too few to anchor firm conclusions
• Heterogeneous measurement: Pooling seven different studies, some randomized and some not, weakens confidence in the combined signal
• Mechanism unclear: Animal models (mice unable to receive GLP-1 signals) do not support the "low blood sugar = low energy" hypothesis, but no human studies have isolated whether the drug itself suppresses movement motivation independent of calorie restriction
• Incomplete picture: The source does not address thyroid hormone changes, sleep architecture, menopause-related effects, or reward-circuit signalling—factors the author flags as possible culprits still under investigation