Does Wegovy make you feel tired?

Jump to: Why Wegovy causes fatigue | Low calorie intake and energy | Effects on sleep cycle | How to manage Wegovy fatigue | When to be concerned | Frequently asked questions | Take home message

Wegovy commonly causes tiredness and fatigue, particularly during the first 4-8 weeks of treatment.

Recent research from Second Nature found that 44% of people reported feeling more tired than usual after 4 weeks on Wegovy, dropping to 22% by week 8.

Fatigue is listed as a recognised side effect of Wegovy, alongside nausea and constipation. The good news is that for most people, this tiredness improves significantly as your body adjusts to the medication.

Understanding why Wegovy affects your energy levels can help you manage this side effect more effectively while still achieving your weight loss goals.

Why does Wegovy make you feel tired?

Researchers haven’t fully established exactly why Wegovy causes fatigue, as this specific side effect hasn’t been extensively studied yet.

However, clinical evidence and patient experiences point to two main mechanisms that likely contribute to feeling more tired than usual while taking Wegovy:

Fatigue Mechanism	How it Works	Signs You’re Experiencing This
Very low calorie intake	Wegovy significantly reduces appetite, potentially leading to insufficient energy intake to maintain normal activity levels	Feeling weak, lightheaded, having difficulty concentrating, or noticing increased tiredness after minimal activity
Effects on brain’s sleep/wake cycle	Semaglutide interacts with the hypothalamus, which controls both appetite and our internal body clock	Feeling tired despite adequate sleep, changes in sleep patterns, or difficulty waking up in the morning

“What many patients don’t realise is that the dramatic appetite reduction from Wegovy can lead to consuming fewer calories than their body needs for normal energy levels. In our experience, we often see energy levels improve when patients focus on nutritional quality rather than just eating less.”

– Dr. Rachel Hall, Principal Doctor at Second Nature

Our research at Second Nature shows that fatigue typically follows a predictable pattern:

• Weeks 1-4: Nearly half of patients (44%) report increased tiredness
• Weeks 5-8: Fatigue significantly improves, with only 22% still reporting tiredness
• Beyond week 12: Most patients return to normal energy levels as the body adapts

For some patients, tiredness can persist longer, particularly if they’re not consuming adequate nutrition or have underlying issues like poor sleep habits or nutrient deficiencies.

How low calorie intake leads to fatigue on Wegovy

The most common reason for feeling tired on Wegovy is simply not eating enough. Semaglutide (the drug in Wegovy) can dramatically reduce hunger, sometimes to the point where you have almost no desire to eat.

When your calorie intake drops too low, your body responds by conserving energy. This survival mechanism prioritises essential functions like heart and brain activity while reducing energy available for physical activity and alertness.

Signs you might not be eating enough on Wegovy:

• Feeling dizzy or lightheaded when standing up
• Difficulty concentrating or brain fog
• Feeling cold more often than usual
• Extreme fatigue after minimal activity
• Mood changes including irritability
• Hair loss or brittle nails

Practical strategies to ensure adequate nutrition:

1. Prioritise protein at every meal

Protein requires less volume than other nutrients while providing essential amino acids your body needs for energy and muscle maintenance.

• Aim for 20-30g protein per meal (roughly the size of your palm or 25% of your plate)
• Good options: Greek yoghurt, eggs, chicken, fish, tofu, lean red meat
• Consider protein smoothies if you’re struggling to eat enough protein in your main meals

2. Eat by the clock, not by hunger

Because Wegovy can lower hunger, relying on appetite to guide eating can lead to inadequate intake.

• Schedule three consistent meals daily
• Set alarms if you tend to forget eating
• Eat something even when not hungry
• Consider more frequent, smaller meals if that’s easier
• Eat protein-rich snacks, like 2 boiled eggs, between meals

3. Focus on nutrient-dense foods

When eating less volume, the nutritional quality of what you do eat becomes even more important.

• Choose foods rich in vitamins and minerals, like red meat, green leafy vegetables, eggs, fish, and dairy
• Include healthy fats like olive oil, nuts, and avocado
• Ensure adequate iron intake through red meat, leafy greens, or supplements if recommended by your doctor

How Wegovy affects your sleep/wake cycle

The second way Wegovy may cause fatigue involves its effects on your brain’s internal clock. Semaglutide works by targeting the hypothalamus; the same brain region that regulates your sleep/wake cycle.

Recent research suggests GLP-1 medications like Wegovy may unintentionally disrupt your circadian rhythm, the 24-hour biological cycle that determines when you feel alert or sleepy.

A study in rats found that liraglutide (a similar GLP-1 medication) reduced wakefulness and altered sleep patterns. While human studies are limited, many patients report changes in their sleep quality and patterns when starting Wegovy.

Common sleep changes reported on Wegovy:

• Difficulty falling asleep despite feeling tired
• Waking during the night
• Vivid dreams or nightmares
• Morning grogginess that’s difficult to shake off
• Changes in preferred sleep timing (going to bed earlier/later than usual)

Evidence-based strategies to improve sleep on Wegovy:

1. Regulate your light exposure

Light is the primary signal that regulates your internal clock.

• Get bright light exposure within 30-60 minutes of waking
• Spend at least 10-15 minutes outdoors in morning daylight
• Reduce bright and blue light exposure 2-3 hours before bed
• Use night mode on devices and consider blue-light blocking glasses in the evening

2. Maintain consistent sleep/wake times

Regularity reinforces your body’s natural rhythm.

• Go to bed and wake up at the same time daily, even weekends
• Aim for 7-9 hours of sleep (individual needs vary)
• Avoid compensating for fatigue with excessive time in bed

3. Create an optimal sleep environment

Your sleeping space significantly impacts sleep quality.

• Keep your bedroom cool (16-18°C is ideal)
• Ensure the room is as dark as possible
• Reduce noise or use white noise if needed
• Reserve your bed for sleep and intimacy only

4. Monitor caffeine and timing of meals

• Avoid caffeine after 12pm
• Try to finish eating 2-3 hours before bedtime
• Consider a small protein-rich snack before bed if hunger disrupts sleep

Other ways of managing Wegovy fatigue

Beyond addressing nutrition and sleep, several additional approaches can help manage fatigue while your body adjusts to Wegovy.

Movement and exercise

While it may seem counterintuitive to exercise when tired, appropriate physical activity can actually boost energy levels.

• Start with gentle movement: Walking, stretching, or light yoga
• Time activity: Exercise when your energy naturally peaks
• Build gradually: Start with 5-10 minutes and increase slowly
• Consider strength training: Even brief sessions help maintain muscle mass during weight loss
• Avoid high-intensity exercise during periods of extreme fatigue

Hydration

Dehydration can worsen fatigue, and Wegovy may affect your fluid and electrolyte balance.

• Aim for at least 2 litres of water daily
• Include electrolyte-rich foods like bananas, yoghurt, nuts, seeds, and leafy greens
• Reduce alcohol consumption, which can worsen dehydration and fatigue

Stress management

Chronic stress depletes energy and can compound medication-related fatigue.

• Practice brief relaxation techniques (even 2-3 minutes can help)
• Try box breathing: inhale for 4 counts, hold for 4, exhale for 4, hold for 4
• Consider a mindfulness app or practice
• Reduce commitments temporarily if possible
• Communicate with family/colleagues about your temporary energy limitations

Timing your Wegovy injection

Some patients find that when they administer their injection affects their energy patterns.

• If fatigue is worse in the days immediately following injection, consider Friday evening administration so the lowest energy days fall on weekends
• Track your energy levels daily to identify patterns
• Discuss with your healthcare provider before changing your injection schedule

When to be concerned about fatigue on Wegovy

While tiredness is common and typically improves with time, certain symptoms warrant medical attention.

Normal fatigue on Wegovy	Concerning fatigue symptoms
Gradual onset of tiredness	Sudden, severe fatigue that doesn’t improve with rest
Improved energy after eating or resting	Extreme weakness or inability to perform daily activities
Tiredness that improves over time	Progressively worsening fatigue beyond 8-12 weeks
Mild dizziness when standing quickly	Fainting or severe dizziness
Some difficulty concentrating	Confusion, disorientation, or memory problems
Manageable tiredness during the day	Fatigue accompanied by yellowing skin, dark urine, or right upper abdominal pain

Potential medical causes of excessive fatigue:

• Thyroid dysfunction: Wegovy may rarely affect thyroid function
• Anaemia: Reduced food intake may lead to iron or B12 deficiency
• Dehydration: Particularly if experiencing diarrhoea or vomiting
• Hypoglycaemia: Low blood sugar, more common if taking diabetes medications
• Medication interactions: Wegovy may interact with other medications

Frequently asked questions about Wegovy and tiredness

How long does Wegovy fatigue last?

Most people notice significant improvement in energy levels after 4-8 weeks. In our research, the percentage of patients reporting fatigue dropped from 44% at week 4 to 22% by week 8. For most people, energy levels return to normal or near-normal by 12 weeks as the body adjusts to the medication.

Is tiredness on Wegovy dangerous?

Typical Wegovy-related fatigue is not dangerous, though it can be uncomfortable and disruptive. However, extreme fatigue, especially when accompanied by other symptoms like severe dizziness, confusion, or jaundice, should be evaluated by a healthcare provider. Monitoring your symptoms and communicating with your healthcare team is important.

What can I take for energy while on Wegovy?
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ather than turning to supplements, focus on nutrition, hydration, and sleep quality first. Ensure adequate protein intake, stay well-hydrated, and maintain consistent sleep patterns.

If fatigue persists, speak with your healthcare provider about testing for deficiencies in iron, vitamin B12, or vitamin D, which can be supplemented if levels are low. Caffeine can help temporarily but may disrupt sleep if consumed later in the day.

Does everyone get tired on Wegovy?

No, not everyone experiences fatigue. Our research shows about 44% of patients report increased tiredness in the first month, meaning more than half don’t experience this side effect significantly. Individual responses vary based on factors like starting weight, dose, dietary habits, and overall health status.

Can I exercise if I’m tired on Wegovy?

Yes, but it’s important to adjust your expectations and approach. Light to moderate activity like walking, gentle yoga, or brief strength training can actually improve energy levels, while intense exercise might temporarily worsen fatigue.

Listen to your body, start with short sessions (5-10 minutes), and gradually increase as your energy improves.

Will fatigue affect my ability to work while on Wegovy?

Most people can continue working normally while adjusting to Wegovy, though you might need to make temporary accommodations.

Consider scheduling your injection on Friday so initial side effects occur over the weekend, prioritise rest during off-hours, and implement the energy management strategies discussed in this article.

If fatigue significantly impacts your work, discuss dose adjustments with your healthcare provider.

Take home message

Feeling tired is a common side effect of Wegovy, affecting nearly half of patients in the first month of treatment. The good news is that this fatigue typically improves significantly by week 8 as your body adjusts to the medication.

Two main mechanisms likely cause Wegovy-related tiredness: dramatically reduced calorie intake and effects on the brain areas controlling both appetite and sleep cycles. Understanding these mechanisms helps you take effective steps to manage fatigue.

Key strategies for combating Wegovy fatigue include maintaining adequate nutrition despite reduced appetite, optimising your sleep environment and schedule, staying properly hydrated, and incorporating gentle physical activity into your routine.

Remember that while tiredness is expected, severe or worsening fatigue should prompt a conversation with your healthcare provider, as it may indicate an underlying issue that needs addressing.

By implementing the practical approaches outlined in this article, most people can effectively manage energy levels while still benefiting from Wegovy’s powerful weight loss effects.