Why You Might Feel Tired on Semaglutide—And What to Do About It
Semaglutide has become one of the most talked-about weight loss and diabetes medications in recent years. Mimicking the GLP-1 hormone helps regulate blood sugar levels, slows down digestion, reduces appetite, and can lead to significant weight loss.
But for some patients, there’s an unexpected side effect: feeling unusually tired or run-down. If you’ve started taking semaglutide and noticed a dip in your energy, you’re not alone. Fatigue is a fairly common complaint—especially in the first weeks or months of treatment.
In this article, we’ll explore why semaglutide fatigue occurs, what’s happening in your body, and how strategies such as B-vitamin injections, nutrient optimization, and adaptogens can help you regain your energy.
Understanding Semaglutide and GLP-1’s Role in the Body
Semaglutide is a GLP-1 receptor agonist—a class of medications originally designed to treat type 2 diabetes but now also widely used for weight loss. GLP-1 stands for glucagon-like peptide-1, a hormone that:
- Increases insulin secretion after eating
- Slows gastric emptying (making you feel full longer)
- Signals the brain to reduce appetite
- Helps regulate blood sugar
These effects are beneficial for weight loss, but they also change how your body processes energy. This shift can sometimes trigger fatigue, especially if your body isn’t yet adapted to the new metabolic rhythm.
Why You Might Feel Tired on Semaglutide
Fatigue while taking semaglutide can stem from several overlapping factors. Let’s break them down:
1. Caloric and Carbohydrate Reduction
One of semaglutide’s main benefits—reduced appetite—can also contribute to lower energy if your calorie intake drops too far, too quickly.
- Rapid calorie cuts mean there is less fuel available for your muscles and brain.
- If carbohydrates are drastically reduced, your body may temporarily lack quick-access energy sources.
- Low-carb diets can cause initial fatigue while your body adjusts to burning more fat for fuel (a state called ketosis).
Tip: Even on semaglutide, your body still needs adequate nutrition. A calorie deficit should be moderate, not extreme.
2. Blood Sugar Fluctuations
Semaglutide helps stabilize blood sugar, but if your eating schedule is irregular or you skip meals entirely, your glucose can dip too low.
- Hypoglycemia (low blood sugar) can cause weakness, dizziness, and tiredness.
- People new to semaglutide may eat less without realizing they’re under-fueling, which increases the risk of fatigue.
Tip: Include protein- and fiber-rich carbohydrates at meals to maintain steady energy levels.
3. Metabolic Slowdown
When calorie intake drops significantly, your body adapts by slowing metabolism—a survival mechanism.
- Thyroid hormone production may decrease temporarily.
- Fewer calories burned means less energy available.
While semaglutide helps preserve lean muscle better than crash dieting, it can still trigger a mild metabolic slowdown if nutrition and strength training aren’t part of your plan.
4. Nutritional Gaps
Eating less can mean taking in fewer vitamins and minerals. Over time, deficiencies—especially in B-vitamins, iron, and magnesium—can leave you feeling drained.
- B12 deficiency in particular is linked to fatigue and brain fog.
- Low iron reduces oxygen delivery to tissues, making even simple activities feel exhausting.
5. Dehydration and Electrolyte Imbalance
GLP-1 medications can cause mild nausea, reduced thirst, or increased urination, all of which can lead to dehydration.
- Even mild fluid loss impacts energy, mood, and focus.
- Electrolytes like potassium and magnesium help your cells generate energy efficiently—without them, fatigue sets in fast.
6. Sleep Disruption
Some people experience changes in sleep patterns when starting semaglutide. This might be due to:
- Changes in blood sugar stability at night
- Mild digestive discomfort affecting rest
- Hormonal shifts alter circadian rhythm
Poor sleep quality compounds fatigue, even if total hours slept remain the same.
How to Combat Semaglutide Fatigue
The good news is that semaglutide-related tiredness often improves over time—and you can take steps to accelerate this process.
1. Prioritize Balanced Nutrition
Even if your appetite is reduced, aim for nutrient-dense meals. Focus on:
- Lean proteins (chicken, fish, eggs, tofu) to support muscle and metabolism
- Healthy fats (avocado, olive oil, nuts) for hormone health
- Complex carbs (sweet potatoes, quinoa, oats) for steady energy
- Colorful vegetables for micronutrients and antioxidants
Small, frequent meals may help prevent dips in blood sugar and energy.
2. Consider B-Vitamin Injections
B-vitamins—especially B12—play a crucial role in energy production and nerve health. Injections can:
- Bypass digestive absorption issues (common if appetite or intake is low)
- Provide an immediate energy boost for those who are deficient
- Support red blood cell production and oxygen delivery
For many patients, adding a regular B12 or B-complex injection dramatically improves stamina within days.
3. Use Adaptogens for Stress and Energy
Adaptogens are herbs that help the body adapt to physical and mental stress. Some may counteract fatigue:
- Rhodiola rosea: Enhances mental performance and reduces tiredness
- Ashwagandha: Balances cortisol and supports resilience
- Panax ginseng: Boosts energy and endurance
Always consult your provider before starting herbal supplements, especially while on prescription medication.
4. Stay Hydrated—with Electrolytes
Make hydration intentional:
- Aim for at least half your body weight in ounces of water daily
- Add electrolyte packets or mineral-rich foods (bananas, leafy greens, nuts)
- Watch for signs of dehydration: dry mouth, dark urine, headache
5. Support Metabolism Through Movement
While you may feel too tired for intense workouts, gentle activity can actually increase energy:
- Light strength training helps preserve lean mass and metabolic rate
- Walking or stretching boosts circulation and oxygen delivery
- Gradually increase activity as your energy improves
6. Address Sleep Quality
If fatigue persists, evaluate your sleep habits:
- Keep a consistent bedtime and wake time
- Avoid heavy meals or screens right before bed
- Consider magnesium glycinate or calming herbal teas (like chamomile) to promote deeper rest
When to Call Your Provider
Fatigue can be a normal adjustment period, but sometimes it signals a deeper issue:
- Persistent low energy beyond the first few months
- Dizziness, fainting, or severe weakness
- Signs of nutrient deficiency (hair loss, brittle nails, pale skin)
- Rapid or extreme weight loss
Your provider can determine whether dosage adjustments, laboratory testing, or supplemental therapies are necessary.
Key Takeaways
- Feeling tired on GLP-1 medications, such as semaglutide, is common but often temporary.
- Causes include reduced calorie intake, changes in blood sugar levels, nutrient deficiencies, and a mild metabolic slowdown.
- Targeted solutions—like balanced nutrition, B-vitamin injections, adaptogens, hydration, and sleep optimization—can help restore energy.
- Your healthcare provider should evaluate persistent or severe fatigue.
If you’re experiencing semaglutide fatigue, you don’t have to push through it. At Anuli Med Spa, we create individualized weight loss programs that support your metabolism, optimize your nutrition, and utilize targeted therapies, such as B-vitamin injections, to help maintain high energy levels while you lose weight.
Visit Anuli Med Spa to book your consultation and take the next step toward feeling your best—inside and out.
Nneka “Adaeze” Anyanwu, MSN, FNP-C, blends board-certified clinical mastery with a passion for luxury wellness at Anuli Aesthetics & Weightloss. Trained in pharmacology and cosmetic science and fellowship-certified in aesthetic medicine, she designs evidence-based weight-loss and body-sculpting programs for high-achieving women who demand results.