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Taking Medications on Intermittent Fasting: Do Medications Break a Fast?

If you’re practicing intermittent fasting for weight management and blood sugar control, you probably know that calories from foods and drinks disrupt fasting. But do medications break a fast, too? This article will focus on the effects of different medications on fasting to help you plan your fasting routine more effectively.

Taking Medications on Intermittent Fasting: Do Medications Break a Fast?
  • Antibiotics and painkillers like Paracetamol and NSAIDs can usually be taken while fasting, but antibiotics may cause digestive discomfort on an empty stomach.
  • Some medicines like chewable medications and fat-soluble vitamins can break your fast.
  • Medicines to treat diabetes and blood pressure don’t break a fast but can cause side effects like dizziness.
  • Supplements like electrolytes and water-soluble vitamins can generally be taken during fasting.
  • You can take specific medications like thyroid and heart treatments while fasting after consulting your physicians.


The information provided in this article is based on the recent academic research, but not a substitute for medical consultation by any means. Please consult a healthcare professional if you have any medical problems.

What Can Break a Fast?

Fasting is taking breaks from consuming calories to improve health, regulate blood sugar levels, lose weight, and so on. 

When we speak of consuming calories, we certainly think of calories coming from foods or even drinks. But calories do not just come from foods and drinks. Sometimes medications can also contain calories, or other content that can break a fast.

So, let's take a closer look, and find answers to the question, “Do medications break a fast?”.

Learn More: Can You Chew Gum While Fasting? 10 Best Gums for Fasting

Dr. Jason Fung:

"If you are taking medication, especially for blood pressure or diabetes, you need to be cautious with intermittent fasting and ideally do it under medical supervision. Fasting can alter how your body metabolizes these medications."

Do Medications Break a Fast?

The answer is both yes and no, as the connection between medications and intermittent fasting is complex. Intermittent fasting requires careful consideration when it comes to medication intake [1].

The impact of medications on fasting largely depends on the type of fasting and the medicines you want to take. Some medications need to be taken with food, which could break a fast.

Learn More: 48-Hour Fast: Benefits and Results: Is It Safe?


It's necessary to consult a healthcare professional if you’re on specific medications, like insulin, Corticosteroids, and heart and blood pressure medicines, to ensure fasting is safe for you.

Medications That Break Your Fast

Some medications can break your fast for various reasons. Knowing which medicines they are and how they can break your fast helps you modify your approach to make the most of your fasting experience.

The following table summarizes the common medications that can break a fast [2]:

Medications that break the fastRemarks
Fat-soluble vitamins (e.g., vitamins A and D) Should be taken with food
Gummy multivitamins (e.g., Vitafusion omega-3 gummy vitamins Break a fast as they contain sugar
Herbal supplements (e,g., Echinacea and Ginkgo) Often contain enough calories to break the fast

Let’s get into the details and learn more about these medications.

  • Chewable, Liquid, and Gummy Medications: These medications and other similar drugs often contain small amounts of sugar, which can trigger an insulin response and break your fast [3].
  • Fat-Soluble Vitamins: Vitamins like A, D, E, and K are some of the most common medications that are best absorbed with fatty foods. Taking these vitamins on an empty stomach may not only lower their effectiveness but could also break the fast [4].
  • Herbal Supplements and Tonic Syrups: Some liquid herbal extracts or tonic syrups have caloric content enough to break a fast.
  • Cough Drops: Many throat lozenges and cough drops contain sugar or honey, which can end a fasting state [5].

Apart from these medications that can break a fast, there are some medicines that don’t disrupt your fasting but can cause side effects when you’re in the fasting state.

Learn More: The 96-Hour Fast Benefits and Results: Is It Safe?

Some Medications Don't Break a Fast but Cause Side Effects in Fasting State

While some medications don't break a fast, they can cause discomfort or pose risks if taken while fasting. The following table shows some common medications that don’t break a fast but can cause side effects if taken on fasting [6]:

Medications that don't break a fast but cause side effects if taken while fastingRemarks
Corticosteroids (e,g., Prednisone) May cause stomach upset if taken while fasting
Heart medications (e.g., Warfarin) Align your diet with your fasting routine when using these medications to minimize side effects
Blood pressure pills (e,g, Lisinopril) Fasting might affect their effectiveness
Diabetes medications (e,g., Metformin) Risks of hypoglycemia

Diabetes Medications

Diabetic individuals need to be careful with medications like insulin or oral hypoglycemics. Fasting can affect blood sugar levels, and taking these medications without eating food may lead to dangerously low blood sugar (hypoglycemia). This can show itself with symptoms like dizziness, fatigue, and even serious issues like seizures and loss of consciousness. It’s essential to adjust your intermittent fasting schedule and consult with healthcare professionals if you're on diabetes medications​​​​ [7].

Blood Pressure Medications

These medications, including beta-blockers or diuretics, are often taken to manage high blood pressure. Taking these medications during a fast might lead to adverse effects, such as a drop in blood pressure and dizziness [8].

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Medications like Ibuprofen and Aspirin, common for pain relief, are best taken with food to avoid gastrointestinal discomfort and potential damage to the stomach lining [9]​​​​.

Iron Supplements

While iron is best absorbed on an empty stomach, these supplements can cause stomach cramps, nausea, and other digestive issues. Taking them with a small amount of food is often recommended to mitigate these side effects [10]​​​​.

Dr. Valter Longo:

"It's crucial to consult with a healthcare professional before starting intermittent fasting if you are on medication. Certain medications may need to be adjusted to avoid adverse effects."

Some Psychiatric Medications

Certain psychiatric medications like Fluoxetine should be taken with food to reduce side effects, such as gastrointestinal discomfort [11].

Certain Osteoporosis Medications

Food intake is necessary for the proper absorption of these medications and for minimizing their side effects [12].


Used for treating conditions like asthma and autoimmune diseases, Corticosteroids can upset the stomach lining if taken without food, potentially leading to internal bleeding​​ [13].

Heart Medications

Some medications for heart-related conditions, including blood thinners like Warfarin, should be consumed with a certain  diet, i.e., a small change in the diet (avoiding food) can alter the effect of the drug or cause adverse effects. Such medications often require food intake when fasting​​, and you need to monitor your body's situation and changes in metabolism [14]. Of course, some heart medications are safe while fasting, which we’ll discuss below.

As you've seen, certain medications aren't safe to take during fasting. However, you can freely take some other medicines during intermittent fasting, as they won’t disrupt fasting or pose significant risks.

Learn More: How To Flush Oxalates From the Body? What is Oxalate Dumping?

Medications You Can Take During the Fasting Window

Certain medications are considered safe to take during the fasting window as they are unlikely to break your fast or cause significant discomfort. Here's a table including medications that you can take while fasting [15]:

Medications that don't break a fastRemarks
Water-soluble vitamins (e.g., vitamins B and C) Are best to be taken on an empty stomach May cause minor side effects
Thyroid medications (e.g., Levothyroxine) Are recommended to be taken on an empty stomach
Heart medications (e.g., Digoxin) Can be taken with or without food Must be taken on time
Allergy medications (e.g., Antihistamines) Can be taken during fasting because they do not contain calories

Thyroid Medications (e.g., Levothyroxine)

These medications are used for treating hypothyroidism, are usually taken on an empty stomach, so are safe during fasting. Avoid eating or drinking immediately after taking them [16]​​.

Certain Heart Medications (e.g., Digoxin)

Digoxin, used for treating various heart conditions, can be taken with or without food. You need to take such medications on time as prescribed by your physician [17]​​.

Certain Allergy Medications (e.g., Antihistamines)

Many antihistamines do not contain calories and are considered safe to take during fasting. However, it's important to check the specific medication as formulas and effects might differ [18].


This non-essential amino acid, beneficial for brain function and stress regulation, can be taken on an empty stomach. It is advisable to avoid food about 30 minutes after taking L-tyrosine [19]​​.

Water-Soluble Vitamins (e.g., Vitamins B and C)

These vitamins are flushed out by the body and are usually okay to be taken on an empty stomach. They're quickly metabolized by the body [20] and won’t affect your fasting state. 

Learn More: How to Get Vitamin C on a Carnivore Diet?

Another group of medicines commonly used, like vitamins, is supplements. Can we take them during fasting?

Dr. Krista Varady:

"When intermittent fasting, medications that require food for absorption or those that irritate the stomach lining should be taken with meals during the eating window to prevent gastrointestinal issues."

Can You Take Supplements while Fasting?

You can generally take supplements during fasting, but we need to know the different types of supplements and how they affect fasting [21]:

  • Electrolyte Supplements: Supplements like potassium, sodium, and calcium don't contain sweeteners or calories and are fine to take during fasting.
  • Fat-Soluble Vitamins: Fat-soluble vitamins, such as vitamins D and E, as well as multivitamins with fat-soluble ingredients, should be taken with a meal as they don't dissolve in water. It's always a good idea to check the label for specific directions.

Another group of medications that we may commonly use in our everyday lives is painkillers. Can we take them while we're fasting?

Learn More: [Expert Guide] 20-Hour Fast Results, Side Effects, and How to

Do Painkillers Break a Fast?

Painkillers are among the most common medications, and many of them do not break a fast.

  • Paracetamol: This painkiller can be taken with or without food, making it suitable for use during fasting without breaking it [22].
  • NSAID Painkillers (e.g., Ibuprofen): While commonly recommended with food to prevent stomach upset, scientific evidence suggests that taking some NSAIDs like Ibuprofen with food might slightly reduce their effectiveness. To maintain fasting, you should wait a few hours between meals and taking NSAID medications​​ [23].
  • Opioids (e.g., Morphine, Codeine, Oxycodone, Hydrocodone): These strong painkillers do not contain sugar or significant calories, so they're unlikely to break a fast. However, they can cause gastrointestinal side effects, which might be more noticeable during fasting [24].

How about antibiotics? We usually need to take them several times a day. Will they break intermittent fasting?

Intermittent Fasting Can Help Reduce Blood Pressure

A study published in "Hypertension Research" found that intermittent fasting can significantly lower blood pressure in hypertensive patients, which may necessitate adjustments in medication dosages.

Learn More: The Best Multivitamin on Carnivore Diet

Do Antibiotics Break a Fast?

Antibiotics are generally okay to be consumed while fasting, but there are two important factors to keep in mind if you plan to take them [25]:

  • Caloric Value and Blood Sugar Levels: Most antibiotics don't have caloric value and don't affect blood sugar levels. This means they generally won't break your fast.
  • Stomach Upset and Gut Bacteria: Taking antibiotics on an empty stomach may cause stomach upset. This occurs because antibiotics can also impact the good bacteria in your gut. Some antibiotics like Amoxicillin might be better taken with food to avoid these issues, even though they don't break a fast in terms of calories or blood sugar levels​​.

Managing your medication while practicing intermittent fasting can be tricky, especially when it comes to weight loss drugs. Can you use them effectively with your fasting plan, or are there complications you need to be aware of?

Can You Take Weight Loss Medication while Fasting?

Weight loss medications work in diverse ways, from suppressing appetite to altering how your body processes calories. However, their effects can vary when taken during fasting.

Factors like an empty stomach and altered metabolic processes may influence the efficacy of weight loss medications [26].

Also, fasting can affect the absorption and distribution of weight loss medications in your body. Understanding these shifts is crucial to ensure you get the desired results from your medication while maintaining your fasting goals [27].

The following weight loss medications won’t break a fast.

Intermittent Fasting Can Help Diabetic Patients

Research in "Diabetes Care" indicated that intermittent fasting can improve insulin sensitivity and glycemic control in people with type 2 diabetes, potentially reducing the need for diabetes medications.

Weight Loss Medications That Don’t Break a Fast

These drugs help with appetite control and weight loss.

  • Liraglutide (Saxenda): This drug helps you feel less hungry by decreasing your appetite. It's not known to have ingredients that would interrupt your fast, but it's always best to consult your physician for personalized guidance [28].
  • Semaglutide (Wegovy, Ozempic): It's used for managing blood sugar in diabetes and helping weight loss. When you're fasting, Semaglutide can make you feel less hungry and more satisfied, which can streamline fasting. Plus, it helps you lose weight without disrupting your fast [29].
  • Tirzepatide (Mounjaro): It is a newer medication primarily used for type 2 diabetes. It controls your blood sugar and makes you feel full quicker. Although it's mainly for diabetes, scientists have found it helpful for weight loss. It can be particularly beneficial for people who are fasting, as it helps manage hunger while also helping weight loss [30].

Now, let's take a quick look at the other side of the equation: how can fasting  affect your medications?

Learn More: The Mounjaro Diet: Side Effects, Meal Plan, and Food List

How Can Fasting Affect Your Medication Regimen?

Fasting can influence how your body absorbs and processes medications. This interaction is important as it can affect the therapeutic outcomes of the medications you take. Here are the key factors to consider [31]:

  • Stomach Emptying: When you fast, particularly for extended periods, the excretion process can slow down. This delay can affect the rate at which medications are released into your digestive system, postponing their effects.
  • Gastric pH: Fasting can change the pH level of your stomach. This shift can influence the solubility and absorption of certain medications, making them less effective or unpredictable in their action.
  • Food Interactions: Some medications are designed to be taken with food. Food can increase their absorption and reduce the risk of stomach upset. When fasting, as your stomach is almost empty, some medications may not be absorbed completely, which can decrease the effectiveness of the drugs.
  • Metabolic Changes: When you fast, your metabolism undergoes changes, for example, your liver produces enzymes more or less than before, or your blood flow to the digestive organs decreases or increases (depending on the effect of the medicine). These metabolic changes can impact how drugs are metabolized, which can affect the effectiveness of the medications.

So, let’s finish by focusing on tips for taking medicines during intermittent fasting.

Learn More: Can I Lose Weight on a Carnivore Diet? How Much? How Fast?

Patients Must Try Fasting Under Supervision

A study in the "Journal of Translational Medicine" found that patients practicing intermittent fasting need to be carefully monitored to ensure proper medication adherence and avoid potential side effects due to changes in eating patterns.

Tips for Taking Medications During Fasting

Taking medications during fasting requires careful consideration. The following tips can help you with this.

  • Take your medications during fasting as recommended by your doctor.
  • Consult a healthcare expert before changing your medication dosage for fasting.
  • Drink enough water to stay hydrated and increase the effectiveness of the medications.
  • Control your blood sugar regularly if you have diabetes or take blood-sugar meds.
  • Break your fast and seek medical help if you experience extreme reactions.


All in all, most medications, such as antibiotics and Paracetamol, won't usually break a fast because they don't have calories or harmful content that can disrupt fasting.

However, some drugs, like NSAIDs, require a time gap between taking them and eating to reduce possible side effects.

Please consult your healthcare professional before trying intermittent fasting if you are on certain medications to ensure you can fast without negative health impacts.


The information provided in this article is based on the recent academic research, but not a substitute for medical consultation by any means. Please consult a healthcare professional if you have any medical problems.

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