The Best Supplements to Take While Fasting (And What to Avoid)

Fasting has many health benefits, from weight loss to better digestion and mental clarity. But as your body adjusts, you may need extra support to stay energized and avoid nutrient deficiencies. That’s where supplements come in.

Did you know you can fast without feeling exhausted or lethargic? The correct nutrients can help you stay hydrated, have energy, and feel good while maintaining your fast. However, making an informed choice is crucial because some supplements may unintentionally disrupt your fast.

If you’ve ever wondered what supplements I can take while fasting, this article has the answers. We’ll discuss which supplements are best, why they work, and which ones to avoid.

These pointers will guarantee you get the most out of your fasting regimen without experiencing any unintended side effects, regardless of whether you’re fasting for weight loss, a faster metabolism, or overall wellness.

READ MORE: Intermittent Fasting Can Improve Your Skin

What Supplements Are Safe During Fasting?

Fasting has many health advantages, such as improved energy, better digestion, and weight loss. However, your body might require additional assistance as it adapts to stay hydrated, preserve vital nutrients, and prevent weariness. Although not all vitamins are safe to use when fasting, they can be helpful in this situation.

Best Supplements for Fasting

When fasting, the key is to choose fasting-safe supplements that support your body without breaking your fast. Here are some of the best supplements for fasting:

• Electrolytes (Sodium, Potassium, Magnesium) — These minerals help prevent dehydration, muscle cramps, and fatigue. You can take them in water without added sugars or flavors.
• Creatine — It supports muscle strength and endurance and does not affect fasting.
• Omega-3 Fatty Acids (Fish Oil) — These help reduce inflammation and support brain health. Choose a version with no added sugars or fillers.
• Probiotics — They promote gut health without disrupting fasting benefits.
• Vitamin D and B Vitamins — These support energy levels and immune health, especially if taken in non-caloric forms.

Some supplements, like protein powders, gummy vitamins, or anything with added sugars, can break your fast. Always check labels and, if unsure, take supplements during your eating window.

By choosing fasting-safe supplements, you can support your body’s needs while maintaining the benefits of fasting. Making the right choices will help you stay energized and feel your best throughout your fasting journey.

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Essential Supplements That Won’t Break Your Fast

Fasting can improve metabolism, support weight loss, and boost overall health. However, long hours without food may lead to dehydration or nutrient deficiencies.

The right supplements can help you stay energized and healthy while keeping your fast intact. Below are some supplements that don’t break a fast and can support your body during fasting.

Electrolytes

Electrolytes are minerals that help regulate hydration, muscle function, and nerve signals. Since fasting reduces your intake of food and fluids, your electrolyte levels can drop, leading to fatigue, dizziness, and muscle cramps. Some fasting-safe electrolytes include:

• Sodium – Maintains fluid balance and prevents dehydration. A pinch of salt in your water may help.
• Potassium – Supports muscle and heart health. You can take it as a supplement or through potassium-rich fasting drinks.
• Magnesium – Helps with muscle relaxation, sleep, and energy production. Choose a supplement without added sugars.

Minerals

Minerals play a crucial role in body functions; fasting can deplete them. Some essential supplements that don’t break a fast include:

• Zinc – Boosts immunity and supports cell repair.
• Iron – Helps transport oxygen in the blood, which is especially important for women.
• Calcium – Supports bone and muscle health and is best taken in a non-caloric form.

Vitamins

Some vitamins are water-soluble, meaning they can be taken while fasting, while others should be consumed with food. By choosing the right vitamins during fasting, you can maintain energy levels, support overall well-being, and make your fasting journey smoother.

The best supplements for fasting in this category include:

• Vitamin D – Supports bone health and immunity. Choose a liquid or capsule without added oils.
• B Vitamins – Help with energy production and brain function, making them great for fasting.
• Vitamin C – Supports the immune system and overall health.

Which Supplements Should You Avoid While Fasting?

Not all supplements are fasting-friendly. While some help maintain energy and hydration, others can break your fast by triggering digestion, spiking insulin levels, or containing hidden calories. Knowing which supplements to avoid is essential to get the full benefits of fasting.

Supplements That Contain Calories

Fasting means avoiding anything that causes an insulin response or digestion. Some supplements contain oils, sweeteners, or proteins that can break your fast, such as:

• Gummy Vitamins – These often contain sugar, gelatin, and other ingredients that provide calories, disrupting fasting benefits.
• Protein Powders and amino Acids—Although amino acids help with muscle recovery, they trigger an insulin response and should be taken during eating windows.
• Fish Oil & Other Fat-Based Supplements – Omega-3 and MCT oil provide essential fatty acids but contain calories that may interfere with fat burning during fasting.

Supplements That Affect Metabolism & Autophagy

Some vitamins and minerals don’t contain calories but may still influence fasting by altering metabolic processes:

• Multivitamins with Fillers – Some multivitamins include sugar, artificial flavors, or coatings that activate digestion.
• Antioxidant Supplements (Vitamin E, CoQ10, etc.) can interfere with fasting benefits like autophagy, the body’s natural cell-repair process. Many people ask, do supplements break autophagy? The answer depends on the type of supplement—those with potent antioxidants may reduce autophagy’s effectiveness.
• Certain Herbal Supplements – Adaptogens like ashwagandha and ginseng can impact blood sugar and insulin levels.

To maximize fasting benefits, focus on fasting-safe options like electrolytes while fasting, unflavored vitamins, and water-soluble nutrients. If unsure, take supplements during your eating window to avoid breaking your fast.

READ MORE: Common Mistakes of Intermittent Fasting

Best Times to Take Supplements During Your Fasting Window

Taking supplements while fasting requires careful planning. Some are safe to take on an empty stomach, while others need food for proper absorption. Understanding fasting supplement timing can help you get the most benefits without breaking your fast.

Supplements to Take During Fasting

Certain supplements don’t contain calories or trigger digestion, making them safe to take during fasting:

• Electrolytes (Sodium, Potassium, Magnesium) – Help maintain hydration, prevent muscle cramps, and support nerve function. Take them with water throughout your fasting window.
• Water-soluble vitamins (Vitamin C, B) Absorb quickly and work well on an empty stomach. They can be taken in the morning or any time while fasting.
• Probiotics support gut health and digestion. They are best taken first thing in the morning on an empty stomach.

Supplements to Take with Food

Some supplements require food for better absorption or to prevent stomach discomfort:

• Fat-Soluble Vitamins (A, D, E, K) – Dietary fat is necessary for optimal absorption. Take them with a meal.
• Iron – Can cause nausea if taken without food. It absorbs most effectively when combined with vitamin C.
• Multivitamins often contain both water-soluble and fat-soluble vitamins, which are best taken with a balanced meal.

Timing Based on Fasting Protocols

Your fasting schedule affects when to take supplements. Dr. Rodolfo Perez-Gallardo, MD, said, “Your body can’t fully absorb vitamins unless you know the best time to take them.”

Following the right fasting supplement timing can maximize benefits without breaking your fast.

• 16:8 Fasting – Take fasting-safe supplements in the morning; food-dependent ones during the eating window.
• OMAD (One Meal a Day) – Take all food-dependent supplements with your meal.
• Extended Fasting – Prioritize electrolytes while fasting to avoid deficiencies.

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Supplements for Different Types of Fasting

Different fasting methods impact your body’s nutritional needs. Whether you’re following Intermittent Fasting (IF), the 16:8 method, or extended fasting, the right supplements can help maintain energy levels, prevent deficiencies, and support overall health.

Supplements for Intermittent Fasting (IF)

Intermittent fasting involves cycles of eating and fasting. Since food intake is limited for several hours, supplements can help fill nutritional gaps.

• Electrolytes (Sodium, Potassium, Magnesium) are essential minerals during intermittent fasting to prevent dehydration, headaches, and muscle cramps.
• B Vitamins – Help support energy levels and metabolism, especially if you feel sluggish during fasting.
• Green Tea Extract – May enhance fat burning and aid weight management.

A 2023 review in Nutrients suggests that intermittent fasting may reduce fatigue, enhance quality of life, and diminish IGF-1, an agent that speeds up tumor growth and spread.

Supplements for 16:8 Fasting

In the 16:8 method, you fast for 16 hours and eat within an 8-hour window. Since food is consumed daily, most supplements can be taken with meals, but fasting-safe options provide extra support:

• Creatine – Helps maintain muscle strength and endurance without breaking a fast.
• Collagen Peptides support skin, hair, and joint health. Some prefer to take them during their eating window.
• Apple Cider Vinegar – Helps regulate blood sugar and curb cravings.

Supplements for 5:2 Fasting

The 5:2 fasting method involves eating normally for five days and significantly reducing calorie intake (around 500–600 calories) on two non-consecutive days. Since you’re still consuming some food, supplement needs differ from complete fasting but remain essential for energy and well-being.

• Electrolytes While Fasting – Even with a small calorie intake, sodium, potassium, and magnesium help prevent dehydration, fatigue, and headaches.
• Omega-3 Fatty Acids – Support brain function, reduce inflammation, and promote heart health.
• Fiber Supplements – Help maintain digestion and curb hunger during low-calorie days.
• Multivitamins – Ensure essential nutrients are met on fasting days when food intake is limited.
• Protein Supplements (Whey or Plant-Based) – Aid muscle preservation and prevent excessive muscle loss while maintaining satiety.

Since the 5:2 approach includes some food intake, meal supplements can enhance absorption while ensuring your body gets the nutrients it needs on lower-calorie days.

Eat-Stop-Eat

This fasting method involves fasting for 24 hours once or twice a week while eating normally on other days. Hydration and nutrient balance are key since you go an entire day without food.

• Electrolytes (Sodium, Potassium, Magnesium) – Prevents fatigue, dizziness, and muscle cramps.
• Green Tea or Black Coffee – Helps manage hunger and supports metabolism without breaking the fast.
• Omega-3 fatty acids support brain function and reduce inflammation. They are best taken on eating days.

The Warrior Diet

This method involves fasting for 20 hours and eating within a 4-hour window, typically at night. Since meals are concentrated quickly, nutrient-dense foods and supplements can help optimize health.

• Digestive Enzymes – Supports digestion and nutrient absorption after long fasting periods.
• Protein Supplements – Helps maintain muscle mass, especially if training while fasting.
• Probiotics – Supports gut health and digestion and is best taken with meals.

Time-Restricted Fasting

This method involves fasting for a set number of hours daily, like 14:10 or 12:12. Since food is consumed daily, fasting-safe supplements can enhance benefits.

• B Vitamins – Supports energy levels and metabolism.
• Magnesium – Helps with muscle function, sleep, and relaxation.
• Collagen Peptides – Promotes skin, hair, and joint health, best taken during the eating window.

Supplements for Extended Fasting (24+ Hours)

More extended fasting periods require additional nutrients to sustain the body:

• Electrolytes While Fasting – Crucial for preventing dizziness, fatigue, and muscle weakness.
• Amino Acids (BCAAs) may help preserve muscle but could impact autophagy.
• Magnesium – Supports heart health, nerve function, and relaxation.

Which Supplements to Take and When

Your fasting length determines which supplements to prioritize. For shorter fasts, focus on hydration and energy-supporting vitamins. For extended fasts, minerals during intermittent fasting become even more essential to maintain overall well-being.

Dr. Mark Mattson notes that intermittent fasting prolongs the period when the body has burned through the calories consumed during the last meal and begins burning fat.

READ MORE: 15 Myths About Fasting 

Safety and Side Effects of Taking Supplements While Fasting

Understanding Potential Risks

While fasting, your body undergoes changes that can affect how supplements are absorbed and utilized. Some supplements may upset the stomach when taken on an empty stomach, leading to nausea or discomfort.

Additionally, skipping meals for extended periods may impact blood sugar levels, so certain supplements could interact differently than when taken with food.

Electrolyte Imbalance

One of the most common issues during fasting is electrolyte depletion. Since fasting reduces food intake, essential minerals like sodium, potassium, and magnesium can drop, leading to fatigue, headaches, and muscle cramps.

Supplementing electrolytes while fasting can help maintain balance, but always choose supplements without added sugars or artificial ingredients that could break your fast.

Fat-Soluble vs. Water-Soluble Vitamins

Water-soluble vitamins, such as vitamin C and B-complex, are generally safe to take while fasting. However, fat-soluble vitamins (A, D, E, and K) require dietary fat for proper absorption.

Taking these vitamins during a fasting window may reduce their effectiveness. It’s often recommended to consume them with meals during eating periods.

Medication and Medical Considerations

If you take prescription medications, fasting may alter their effectiveness. Some medicines need food for absorption, while others may cause side effects on an empty stomach.

Always consult a healthcare professional before changing your supplement or medication routine while fasting.

Heather Mangieri, MS, RD, CSSD, of Nutrition CheckUp, a nutrition consulting practice in Pittsburgh, says, “It’s the registered dietitian’s job to help clients understand that whether restricting food or not, it’s important to include a variety of healthful foods, including lean proteins, fruits, vegetables, a few servings of whole grains, low-fat dairy, and some healthful fats in their diets.”

Conclusion

It can be challenging to fast. Eating a healthy diet rich in high-energy foods, drinking plenty of water, and taking vitamin supplements that include particular nutrients can help maintain energy levels and protect your intake of vital vitamins and minerals.

By taking supplements during a fast, you can reduce your caloric intake while still providing yourself with the nutrients you need. It’s also much more straightforward to determine what you might need to supplement without significantly changing the items you eat during a diet.

By being mindful of these factors, you can take supplements safely while fasting and avoid unnecessary risks.