21 Best Fasting Supplements (Intermittent and Extended)

Fasting means not eating for hours or even days, which means your body will receive less macronutrients and micronutrients. If you’re new to fasting and wonder if you can take supplements to boost overall health while fasting, you’re on the right page.

From the cellular energy powerhouse creatine to the intricacies of amino acids, omega-3 fatty acids, and the stress-reducing potential of CBD oil, this article covers the scientific data behind the 21 best fasting supplements you can take while fasting.

Table of Contents:

What Are the Best Fasting Supplements?

Creatine, electrolytes, l-tyrosine powder, and water-soluble vitamins are the best fasting supplements.

They alone will not break the fast and will hardly influence autophagy during fasting.

Before diving into the scientific data behind each supplement, it’s important to note that it’s vital to read the ingredients on the specific supplements you take when fasting.

Ensure they don’t contain sweeteners or calories that may alter your fasting results.


Creatine is a well-researched and highly effective supplement known for its role in cellular energy production. This naturally occurring compound, composed of amino acids, is primarily stored in muscles and the brain.

When glucose availability is reduced, the body turns to alternative energy sources during fasting. Creatine phosphate, generated from creatine, plays a crucial role in the rapid regeneration of adenosine triphosphate (ATP),1 the cellular energy currency. Moreover, creatine is an excellent supplement for maintaining and gaining muscle mass.2

Research suggests that a daily dosage of 0.03 g/kg day is sufficient to maintain muscle mass, but you can also take 0.3 g/kg per day for seven days as a loading dose.


Electrolyte imbalance3 is a common concern during fasting, leading to symptoms such as fatigue and muscle cramps. Sodium, potassium, and magnesium are essential electrolytes that play pivotal roles in maintaining cellular balance.

Most fasting electrolyte supplements contain sodium chloride, magnesium citrate, and potassium chloride.

Research indicates that fasting can increase the excretion of electrolytes through urine. Supplementing with electrolytes helps prevent imbalances, supporting muscle function, nerve transmission, and overall cellular homeostasis.

However, it’s important not to overdo your electrolyte supplementation to avoid side effects like muscle spasms, arrhythmia, and numbness.

L-Tyrosine Powder

L-tyrosine is a non-essential amino acid precursor to neurotransmitters such as dopamine, norepinephrine, and epinephrine. During fasting, the body may experience stress, impacting cognitive function. L-tyrosine supplementation has been linked to  improved cognitive performance and mood,4 particularly in stressful conditions, and better exercise performance.

Experts suggest that a dosage ranging from 100 to 150 mg/kg per day can be effective.

Water-Soluble Vitamins

Experts have long established the importance of water-soluble vitamins5 in one’s overall health. The B-complex vitamins, encompassing thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate, and cobalamin, play diverse roles in energy metabolism, DNA synthesis, and neurological function.

Vitamin C, a potent antioxidant, also contributes to immune function and collagen synthesis. The strategic incorporation of these water-soluble vitamins supports energy production and overall health, fortifying the body against potential nutrient deficiencies during intermittent fasting.

fasting supplements

Intermittent Fasting Supplements When Eating

The following supplements should not be taken during the fasting period.

Fat-soluble vitamins

Vitamins A, D, E, and K are fat-soluble and play vital roles in metabolic processes, including bone health, immune function, and antioxidant defense.6 These vitamins are crucial during intermittent fasting, as they are absorbed more efficiently with dietary fat.

While meeting daily recommended values through a balanced diet is ideal, supplementation may be necessary for individuals with deficiencies and those who are fasting. Note that these vitamins need fat, so this works best for those in a keto diet.

Amino Acids

Essential amino acids, especially branched-chain amino acids (BCAAs), are vital for muscle protein synthesis.

They are crucial if you want to use the increased growth hormone release during intermittent fasting to build muscle mass.

Taking amino acids may break a fast since they may trigger an increase in insulin,7 so it’s best to take this in between meals as a post-workout supplement.

Omega-3 Fatty Acids

Omega-3 fatty acids, primarily found in fish oil, have potent anti-inflammatory properties8 and are crucial for brain health.9 Intermittent fasting combined with omega-3 supplementation may support cognitive function and overall well-being.

Omega-3 is among the supplements that you need to take with food to maximize its absorption. The National Institute of Health recommends a maximum of 4g of omega-3 per day for adults.


Medium-chain triglycerides (MCTs) are quickly metabolized into energy, making them a valuable supplement during intermittent fasting.10 They also support fat metabolism and may enhance satiety. Studies also report MCT’s positive effects on cognition and is a good supplement to induce ketosis.11

The same study advised that healthy adults can take 20g of MCT/day by starting with small amounts and gradually increasing them. For better absorption, MCT can be taken on an empty stomach or with low-carbohydrate food.


Cannabidiol (CBD) has recently gained attention for its anti-inflammatory12 and stress-reducing properties.13 During intermittent fasting, CBD oil may complement the physiological stress response.

Research on optimal CBD dosage is ongoing, but studies suggest starting with a low dose of 300-400 mg14 and adjusting based on individual response.


Magnesium is a crucial mineral involved in over 300 biochemical reactions15 within the body, playing a pivotal role in muscle and nerve function, energy production, and bone health. Magnesium becomes even more critical during intermittent fasting as fasting periods may limit dietary intake.

Experts recommend 400-420 mg/day for men and 310-320 mg/day for women.


Calcium is renowned for its role in bone health, but it also participates in various body functions,16 including blood clotting, cholesterol and blood pressure management, nerve transmission, and muscle function. Intermittent fasting may limit calcium intake, making supplementation pivotal, especially if you plan on doing any fasting long-term.

However, note that taking too much calcium may increase the risk of kidney stones. Stick to the 1,000-1,200 mg RDA daily, depending on age. Taking more than 2,000 mg daily is unnecessary.


When you fast, your body’s metabolic processes change to conserve energy and extract it from other sources, often leading to frequent urination and potassium loss, making supplementation necessary.

Low potassium levels17 often cause muscle cramps, weakness, and headache, all common complaints during fasting.

However, too much potassium also has side effects, so staying within the recommended daily intake of 2,600 for females and 3,400 for males is crucial.


Iodine is a trace element vital for thyroid function, as it is a critical component of thyroid hormones that regulate metabolism. Older and newer studies suggest a decrease in T3, T4, and TSH,18 which may cause slow metabolism and affect how your body burns fat.

The RDA for iodine is around 150 mcg for adults. Supplementation, preferably taken with meals, ensures optimal absorption.

Chromium and Vanadium

Chromium and vanadium are minerals that help regulate insulin sensitivity and blood sugar regulation.19 Supplementing with these minerals may support stable energy levels during intermittent fasting. Moreover, chromium showed positive mood effects,20 which may help with irritability and cravings during extended fasting periods.

Zinc and Copper

Zinc supplementation significantly improves health benefits, particularly in shedding extra kilos.21

It reduces oxidative stress, improves lipid profile, and reduces insulin resistance in obese patients—furthermore, zinc supplementation aids in bone density and tissue production.

You should stick to RDA, 11 mg of zinc and 1 mg of copper per day, to avoid side effects, such as digestive issues and liver damage.

Protein Powder

Protein powder is a crucial building block for building muscles and reducing waist circumference. It contains various proteins like whey, soy, casein, hemp, and pea. Compared with restrictive dietary interventions, it improves blood glucose levels, fat, and body weight indicators, reducing cardiovascular disease risk in obese individuals.22


Curcumin, an efficient antioxidant and anti-inflammatory substance from turmeric, has been shown to reduce weight and fats in obese and diabetic individuals.23 It interacts with adipose tissues, inhibiting fat cell differentiation. Curcumin prevents weight regain after caloric restrictions are halted, allowing weight maintenance even after stopping the fasting diet.

In controlled studies, daily administration of 1500 mg curcumin positively reduces fasting blood glucose and weight in patients with type 2 diabetes.

Probiotics and Prebiotics

Both probiotics and prebiotics are good fasting supplements that improve gut health by promoting the growth of beneficial bacteria.24 Probiotics, beneficial bacteria in the gut, can strengthen the immune system, alleviate lactose intolerance symptoms, and reduce the risk of chronic ailments.

Consuming probiotics during fasting can improve mental health and mood, while prebiotics, which are safe for consumption during fasting, can also enhance immune and nervous system performance.

collagen, turmeric, and ginger supplements for fasting

Can You Take Supplements While Fasting?

In general, water-soluble vitamins and minerals, such as B-complex vitamins, vitamin C, magnesium, and electrolytes, can be taken during fasting periods without significantly impacting the fasting state.

These supplements are unlikely to stimulate an insulin response, an essential aspect of fasting, and their absorption is typically not hindered by the absence of food.

Strategically incorporating these supplements can help address nutrient gaps during caloric restriction, supporting energy metabolism, immune function, and overall well-being.

On the other hand, fat-soluble vitamins and supplements with calories, such as those containing proteins or carbohydrates, may disrupt the fasting state due to their potential to stimulate insulin release, so you should take them with a meal after your fasting period.

Moreover, the choice of supplements during fasting should be guided by the specific goals of the fast, whether it’s for metabolic benefits, autophagy, or other health objectives.

When to Take Supplements: Eating Vs. Fasting

While most supplements should be taken with food for improved absorption and reduced likelihood of stomach upset, the timing can vary depending on the supplement type, especially when planning on committing to long-term intermittent fasting or any fasting regimen.

Generally, you can take creatine, electrolytes, tyrosine, and water-soluble vitamins on your fasting days as they get easily absorbed with only water and do not affect your fasting state. However, as mentioned above, you can also take them with meals for better absorption.

Supplements containing fat-soluble ingredients and those that could alter your insulin levels should go with food. Taking them on an empty stomach may decrease their absorption, defeating the purpose.

Moreover, supplements like BCAA and protein powder probably break a fast, so you should take them when you are not fasting.

When taking supplements in a fasting state, make sure that the one you take does not contain any sweetener that could alter your glucose and insulin levels.

Do You Need Supplements on Intermittent Fasting?

You can take fasting supplements if you have nutritional deficiencies or feel your diet lacks nutrients. It depends on your dietary habits.

You will not need supplements on intermittent fasting if you get enough macro and micronutrients through food.


Fasting can have minimal side effects, and supplements help you manage them.

They are no necessity if you feel great.

However, it would help if you considered these supplements’ timing and dosage to prevent any side effects and reap the expected benefits.

Frequently Asked Questions

Do I need supplements for 3 day fast?

While a well-balanced diet can meet your nutritional needs, supplementing with electrolytes, vitamins, and minerals can support your body during an extended fast.

What supplements will not break a fast?

Water-soluble vitamins, electrolytes, and amino acids are generally safe and won’t break the fast. Just make sure that they do not contain any sweetener.

What supplements should I take for a 48-hour fast?

Consider a comprehensive approach tailored to your health needs, including electrolytes, amino acids, and vitamins. You can also add BCAA and protein powder to prevent muscle loss when working out.


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Mag. Stephan Lederer, MSc.

Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.

Stephan is a true man of science, having earned multiple diplomas and master's degrees in various fields. He has made it his mission to bridge the gap between conventional wisdom and scientific knowledge. He precisely reviews the content and sources of this blog for currency and accuracy.

Click on the links above to visit his author and about me pages.

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