General information, not medical advice
This page is educational and does not replace guidance from your licensed provider or pharmacist. Do not start, stop, or change any medication or supplement without talking to them first.
Why it can happen
GLP-1 medications can reduce appetite. When intake falls below what the body needs — particularly protein and fluids — energy can drop. Changes in eating patterns, sleep, and activity during treatment can add to that.
Fatigue that persists despite adequate intake, or that comes with other symptoms, is a reason to speak with your provider so other causes can be considered.
Everyday measures
General habits that many people find helpful. Your provider or a dietitian can give guidance specific to you.
Protein at each meal
Eggs, poultry, fish, dairy, legumes, or a protein shake when appetite is low. Regular protein intake supports muscle when you’re eating less.
Regular, smaller meals
Several small meals rather than one or two large ones, with complex carbohydrates such as oats or sweet potato for steadier energy.
Fluids
Dehydration is a common and easily missed contributor to tiredness.
Sleep and activity
Seven to nine hours of sleep, light daily activity such as a walk, rest days when needed, and limiting caffeine late in the day.
Keep track for a week or two
Many people eat less than they realise once appetite falls.
- Note meals, approximate protein, and fluids for one to two weeks.
- Bring the notes to your provider if fatigue continues; they help identify whether intake is the issue.
What to ask your provider about
If fatigue persists despite adequate intake, sleep, and activity, your provider can consider other causes.
- Lab work, for example for anaemia, thyroid function, or vitamin levels.
- Whether another medication you take could contribute.
- Whether your GLP-1 dose or schedule should change. Do not change it on your own.
When to contact your provider
Contact your provider if you have:
- Fatigue severe enough to prevent daily activities.
- Fatigue with dizziness, fainting, or shortness of breath on minimal exertion.
- Persistent tiredness despite adequate food, fluids, and sleep.
- Low mood or significant mood changes.
- Signs of dehydration: dark urine, dry mouth, or confusion.
For severe abdominal pain, chest pain, trouble breathing, signs of an allergic reaction, or confusion, call 911 or go to the nearest emergency department.
References
- Tardy AL, Pouteau E, Marquez D, Yilmaz C, Scholey A. Vitamins and minerals for energy, fatigue and cognition: a narrative review of the biochemical and clinical evidence. Nutrients. 2020;12(1):228. https://pubmed.ncbi.nlm.nih.gov/31963141/
- Pasiakos SM, et al. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J. 2013;27(9):3837-3847. https://pubmed.ncbi.nlm.nih.gov/23739654/
- FDA-approved prescribing information for semaglutide injection products, via DailyMed (U.S. National Library of Medicine). Compounded versions were not studied in these trials. https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=semaglutide