Jaquish Biomedical
January 9, 2023

The Supplements to Take While Fasting

Intermittent fasting can help you burn fat, lose weight, boost energy, heighten immunity, and improve mental clarity. The latest research says fasting is most beneficial if we abstain from food for 18 hours or more. But a long term fast puts you more at risk for nutritional deficiencies and energy loss. If you’re fasting for 24 hours or more, you might want some fasting support. The best fasting supplements will help you get the most from your fasted workouts.

Intermittent Fasting

clock in front of man eating

The benefits of intermittent fasting have been well-researched. Intermittent fasting for 18 hours or more triggers ketosis, the prioritization of fat-burning for energy. Those who fast for 24 hours or more also benefit from enhanced autophagy, the process of cell repair and turnover. Long term fasting also boosts immunity, human growth hormone, and insulin sensitivity.

Working out in a fasted state promotes fat over carbohydrate metabolism, for greater fat loss.1 But what if you’re trying to build muscle? If you’re doing a fast of less than 18 hours, your strength workouts will be just as effective. Studies of bodybuilders fasting during daylight hours found no difference between those who did their workouts on an empty stomach, versus those who waited until after they broke their fast.2 So, does long-term fasting make a difference? It’s likely that even during a 72 hour fast, you won’t lose muscle if you keep your strength training protocol.3 The question is, how much will you gain? To get the most out of your fasted resistance workouts, you might want to supplement.4

Why Take Fasting Supplements?

mixing protein powder in glasses for the best supplements for fasting

When fasting for 18-48 hours, it’s not likely you’ll become malnourished. Assuming your diet is healthy while you’re eating, the body has a remarkable ability to go without food.5 That doesn’t necessarily mean you’ll be able to perform with as much energy as you’re used to, nor build as much muscle.

Those who are new to fasting or eat a high-carb diet will find it challenging to make the metabolic switch from carbs to fats. This can present as fatigue, making workouts hard to complete. If you’re strength training after a long fasting period you might find you just don’t have the energy to lift as much as you’re used to. This will certainly slow your gains.

In addition, if the body has been deprived of protein for several days, there’s less building material available for muscle. You won’t necessarily lose lean body mass, but you might be limiting your gains.

Supplementing while fasting can help boost your energy for stronger workouts and can give your body the nutrients it needs to keep building muscle. The question is, can you supplement without breaking a fast?

What Breaks a Fast

an athlete eats a protein bar

Hardliners will say any number of calories consumed during an intermittent fasting period will break your fast, no matter how few. Others set a boundary of 50 calories or less. For most people, what matters is if the calories come from carbs, meaning do they spike your blood sugar?

A spike in blood sugar will kick you out of ketosis, intermittent fasting’s primary fat-loss benefit. Research indicates you can maintain ketosis as long as carbohydrate consumption is limited to fewer than 20-50 grams per day.6

The research is mixed regarding the effect of a small amount of calories on fasting’s additional benefits, such as autophagy. Some studies say even minor supplementation will put the brakes on autophagy, while other studies show that non-caloric supplements are ok.7

What will certainly break your fast are supplements that induce a spike in blood sugar. These include whey or soy-based protein powders, and supplements that deliver BCAAs in the wrong ratios.8 Of course, supplements delivered in gummy or pill format containing fillers such as pectin, cane sugar, fruit juice concentrate, or maltodextrin will also break your fast.

There are, however, beneficial fasting supplements that won’t kick you out of ketosis.

Best Supplements For Fasting

Fortagen protein supplement

The best supplements for fasting let your body remain in a fasted state, but give you the energy you need to keep lifting heavy, and the protein you need to keep building muscle.


Unlike most BCAA supplements, Fortagen provides the body with the essential amino acids it needs to build muscle, in exactly the ratio it needs them. So, you won’t be left with excess circulating BCAAs to spike your blood glucose.9

Fortagen supplies the body with the building blocks needed to build and repair muscle tissue. At just 4 calories, it won’t stimulate your appetite or break a fast like other protein shakes do.

Fortagen is a vegan, sugar-free, gluten-free supplement that is nearly 10 times more efficient than other vegan supplements, and five times more efficient than whey protein powders. Because the essential amino acids in Fortagen are in the exact ratios your body uses, they’re nearly 100% usable.

Just 1 serving of Fortagen equates to roughly 50 grams of protein, a much needed nutrient for accelerated lean muscle growth while fasting.


If working out while fasting has you feeling sluggish, IN-Perium is the pre-workout energy boost you need. This coffee alternative supports your fast by replenishing electrolytes, boosting metabolism and delivering jitter-free energy.

IN-Perium logs in at just 25 calories per serving, the majority of which come from fat. This fasting supplement primarily delivers medium-chain triglyceride (MCT) oil, so it won’t spike your insulin, allowing you to remain in ketosis. What’s more, MCT oil slows the absorption of caffeine, so the energy boost you’ll get from the coffee extract and L-Theanine will be long-lived and crash-free.

The benefits of MCT oil include appetite suppression and a boost to your metabolism. IN-Perium also includes beta-alanine, a special amino acid known to increase muscular performance.

Take IN-Perium before your next fasted strength workout and notice the difference.


IN-Perium contains electrolytes, but you can also take magnesium, potassium, calcium or sodium on their own. If fasting has made you fatigued, or if you’re experiencing headaches, muscle cramps or nausea, it’s possible you need more hydration and electrolytes during your fasting window.

These supplements are generally non-caloric and won’t break a fast. Just read the label carefully and beware of the added ingredients that make them palatable.


MCT oil is also found in IN-Perium, but you can take it on its own. Because it is fat, you’ll remain in ketosis. Many people add MCT oil to their coffee for a pick-me-up during a fast.

Keep your consumption to a minimum to avoid too many calories. As always, beware of added ingredients like maltodextrin that could kick you out of ketosis.

Omega 3’s

Omega 3 supplements such as fish oil are another means of getting added healthy fats even while fasting. Cod liver oil may also have added vitamin A and D. Because these oils are fat, they’ll keep you in ketosis and can help curb your appetite while offering some energy.

Read the label to ensure you’re ingesting pure fat, and understand how the dose relates to the number of calories consumed.


Most multivitamins won’t break a fast. Just don’t opt for the sugar-laden gummy kind. Water-soluble vitamins such as vitamin B and C can also be absorbed on an empty stomach. Some vitamin B derivatives can make you feel nauseous if taken without food, so note how you feel when you take them.

Fat-soluble vitamins such as A, D, E, and K won’t be effectively absorbed unless consumed alongside fat. Take these with your Omega 3’s, or just wait until you’re back within your eating window.


Creatine is a potential cellular hydration amplifier which some weightlifters are very attached to. However, extensive research has done little to prove that the benefits of creatine outweigh the risks. The supplement in its isolated form has been linked to bipolar disorder, kidney dysfunctions, and Parkinson’s disease.

That said, it has no effect on insulin secretion and won’t break your fast, assuming it isn’t loaded with added flavors and sugars.10


Probiotics, also known as good bacteria, are found naturally in fermented foods. Fermentation is one reason why the proteins in Fortagen are so easy to digest. Probiotics help contribute to a healthy gut and can reduce inflammation. If your bowel movements are abnormal or you’re feeling bloated, you might try probiotics. In supplement form, read the label to understand which are best taken on an empty stomach.


Iron deficiency is related to severe, long-term caloric restriction and is often the result of disordered eating.11 But intermittent fasting is not necessarily a caloric restriction. In fact, IF can help boost red blood cell function.12 Signs of iron deficiency include fatigue, lightheadedness, and elevated heart rate or pale skin.

If iron supplementation is something you need, it won’t break your fast. Iron is also best taken on an empty stomach, so if you do take iron, do it while fasting.

Keep in mind that iron, fish oils, and other vitamin or mineral supplements aren’t essential while fasting. If you’re eating a healthy, well-balanced diet during your eating window, fasting won’t lead to a deficiency of these essentials.

When fasting for long periods of time, however, you might consider fasting support as a means of maintaining energy and continuing to build muscle. Fortagen and IN-Perium in particular, can help provide you with the energy and essentials needed to keep training hard while fasting and reap the most benefit.

Why Is X3 More Powerful Than Weights?

  • More Resistance Where Your Body is Stronger
  • Less Risk of Injury Than Traditional Weights
  • Easier On the Joints, Harder on the Muscle
  • Complete Muscle Fatigue for Greater Muscle Gains

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