Do GLP-1 Injections Make You Feel Tired?

GLP-1 receptor agonists are a class of medication which have become widely used within the UK under brand names such as Mounjaro and Wegovy. They were originally developed for management of type 2 diabetes, but have since become a common treatment for weight management within the UK. These medications have gained increasing popularity and are either prescribed through the NHS, or most commonly through the private sector. But as popularity has increased, more questions are being asked about the side effects these medications are causing. One particular question is whether these injections can make you feel more tired or fatigued.

Why Do Some People Feel Tired When Using GLP-1s?

1. Reduced calorie intake and energy deficit

When trying to determine how GLP-1s could cause tiredness, it’s important to first understand how they work. One of their effects is suppressing appetite and reducing hunger. Because of this, many patients will naturally eat less. While this can help with weight loss as patients are shifting to a lower calorie intake, for some people this calorie deficit can also cause fatigue. This is more noticeable while the body is first adjusting to the lower-energy intake.

2. Metabolic and hormonal adaptation

Starting a GLP-1 treatment can cause a shift in how the body regulates appetite, how it digests food, and can affect  blood sugar levels and metabolism. All these changes, particularly in the first few weeks of treatment or in the early days of dose adjustment, can leave the body feeling drained while the body adapts.

3. Digestive side effects, dehydration and nutrient absorption

Other common GLP-1 side effects can include gastrointestinal effects such as nausea, vomiting, diarrhoea, or constipation. These effects can lead to dehydration, electrolyte imbalances, or reduced nutrient absorption; all of which can then lead to feelings of tiredness or low energy.

All of these overlapping factors, caused by GLP-1s and their side effects, can make it a little difficult to say whether the fatigue which patients can feel is directly due to the medication or perhaps just an effect of the changes the body is undergoing as it adapts to this change in food intake and metabolism.

What Can You Do If You Feel Tired?

If you’re using a GLP-1 medication such as Mounjaro, Wegovy, or Nevolat, and find yourself feeling more tired than usual, then here are some tips and tricks to getting back to feeling like yourself.

• Eat nutrient-dense meals. Aim for balanced nutrition even if you’re eating less overall. Make sure you’re getting enough protein, iron, B-vitamins, and healthy fats to help energy levels. Supplements can help for those struggling to find balance in the food they are eating.
• Stay hydrated. Dehydration due to reduces food intake or due to side effects such as vomiting or diarrhoea can worsen tiredness. Drinking water (with added electrolytes if needed) is key to maintaining hydration.
• Allow time for your body to adjust. It’s common that feelings of fatigue and tiredness will reduce after a week or two once the body adapts to the reduced calorie intake and change in metabolism.
• Don’t escalate your dose too quickly. If you feel more tired after a dose increase this is normal, but if tiredness is beginning to interfere with your daily routine, then it might be worth reducing your dose again.
• Speak to a healthcare professional. Persistent fatigue that interferes with your daily life should be discussed with your healthcare advisor. Either a GP or clinician can advise on the best course of action.

Go steady with your treatment, rushing the process can make you feel worse and exacerbate side effects.

The Bottom Line

GLP-1 injections such as Mounjaro and Wegovy can make you feel tired, often as a side effect of reduced appetite, lower calorie intake, and digestive side effects. For many people this is mild and temporary,  and they feel like their usual selves within a couple of weeks. However, if nutrition, and hydration haven’t been changed to accommodate for the medication, then this can make symptoms worse and more persistent.

With The Family Chemist, we believe that you should have all the facts. If you’re considering using a GLP-1 medication you should understand the realistic side effects. Not just the benefits (weight loss, improved blood sugar).