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Do BCAAs Break a Fast? Everything You Need to Know About Amino Acid Supplements

You learn that some things will and won’t break your fast when fasting intermittently. You know food is off-limits, but what about dietary supplements?

BCAA supplements (branched-chain amino acids) are popular in the fitness world. Many individuals use these essential amino acids to boost muscle growth, enhance physical performance, and relieve muscle soreness after exercise.

As BCAAs bring many perks, you’re probably wondering if you can continue to use supplementation in your fasting windows. In this article, you can find out whether BCAAs break intermittent fasting.

What Are BCAAs – or Amino Acids – and Why Should You Use Them?

BCAA supplements are branched-chain amino acids. BCAAs are three of nine essential amino acids – leucine, isoleucine, and valine. Amino acids combine to make proteins. Both amino acids and proteins are the building blocks of life.

People use BCAAs while exercising to improve performance. Taking BCAAs can aid muscle building, prevent muscle loss, and reduce exercise fatigue. BCAA supplements are especially trendy among athletes, bodybuilders, and weight lifters.

Taking BCAA supplements can support your intermittent fasting journey depending on your fitness goals. Restricting calories with intermittent fasting and regularly working out helps reduce body fat. Without enough protein, however, you can lose muscle tissue.

BCAAs can help you build muscle and preserve your muscle mass during a fasted workout if you want to lose fat, not muscle. Generally, you can take BCAAs up to three times a day, before, during, or after a workout.

For best results when fasting intermittently, you may benefit from taking your supplement only once a day before a workout. That way, you can enjoy the benefits of the extra protein without taking in too many calories and raising your blood sugar levels.

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Do BCAAs Break a Fast?

If you’re strictly fasting and following all intermittent fasting protocols, then yes – BCAAs break a fast. Introducing calories to your body in the fasted state officially ends fasting. As BCAAs supplements contain calories, taking them breaks your fast.

Many BCAA supplements have very few calories and carbs. When taken in mindful doses, they won’t trigger a significant insulin response and won’t eliminate your progress. Look out for low-calorie varieties without added ingredients and sugar.

Although BCAAs can break the fasting period, these supplements can improve overall athletic performance and results. For most people, the pros of supplementation outweigh the cons of technically breaking a fast. Their use should solely depend on the individual and their health goals.

3 Benefits of BCAAs

Sometimes the benefits of BCAAs outweigh the disadvantages of breaking a fast. BCAAs have many potential health benefits that can also support your DoFasting journey.

DoFasting – an easy-to-use intermittent fasting app – is specifically designed for all stages of fasting. It includes recipes, workouts, and essential tips to help you navigate your fasting journey. And if you supplement your intermittent fasting with BCAAs, you’ll further enhance your muscle-building efforts.

Below are 3 key health benefits of using a BCAA supplement in the fasting window.

1. Reduces muscle soreness

BCAAs are commonly used for improving muscle recovery after exercise-induced muscle damage. More research is required, but the effects may result from reduced levels of creatine kinase – a type of protein that indicates muscle damage.

Muscle soreness occurs following exercise, and BCAA supplementation may be particularly effective at reducing delayed onset muscle soreness (DOMS). So, BCAA supplements may speed up your recovery time if you’re sore following a fasted workout.

2. Reduces fatigue during workouts

The intake of a BCAA supplement may contribute to enhanced exercise performance by reducing fatigue substances, like serotonin – a chemical associated with fatigue, lethargy, and loss of motivation.

While your body is still adapting to your new eating pattern, you may have less energy than usual to work out. You may feel tired quicker and unable to perform as effectively. Reducing exercise fatigue can boost your ability to sustain your routine and burn fat.

3. Promotes muscle growth

Taking BCAAs helps build muscle as these three molecules play an important role in stimulating muscle protein synthesis – the process of muscle building. The amino acid leucine has a particularly potent effect on encouraging protein synthesis.

As the supplements also support muscle fatigue, you can exercise for a more extended period without getting tired. Longer and more effective training sessions allow you to build more muscle, burn more calories, and lose more fat.

Losing muscle can be a matter of concern while fasting intermittently. You no longer supply your body with enough protein to maintain lean muscle mass. Consuming BCAAs may help you lose fat and gain muscle while preventing muscle breakdown.

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Other Ways to Build Strength During Intermittent Fasting

Aside from taking BCAAs, there are other ways to enhance muscle gain without breaking your fasting efforts. For effective results, it’s worth considering a few other supplements to improve your athletic performance.

Here are 3 more supplements to consider for training purposes throughout your fasting journey.


Creatine is a substance naturally present in muscle cells. It provides a continuous energy supply to working muscles to fuel your workouts. Like branched-chain amino acid supplements, taking creatine supplements can enhance strength, build muscle, and improve sports performance.

Creatine supplements do not end your fast. They have no calorie content and do not create an insulin response or increase blood glucose levels. Taking creatine in the fasting window has many positive effects that can improve body composition.


MCT (medium-chain triglycerides) oil is a popular supplement made from a unique fat found in coconut and palm. The body absorbs medium-chain triglycerides quickly, and the liver breaks them down into ketones, promoting fat-burning.

MCT oil is highly beneficial for those following the keto diet and provides the same benefits to those practicing intermittent fasting. MCT oil boosts energy levels, enhances exercise endurance, and curbs hunger – all excellent perks to help you sustain a longer fast.

As MCT oil contains calories, it does technically end your fast. However, many dieters opt to take MCT oil regardless because it doesn’t mitigate the benefits of fasting. Instead, it helps you power through until your eating window arrives.

Since it is a high-calorie supplement, limiting your intake is imperative. Small amounts will keep hunger pangs at bay while fueling your body with energy for a fasted workout. As MCT oil promotes weight loss, coupling it with fasting may help you reach your goal weight sooner.


Pre-workout supplements usually come in powder form and are full of healthy ingredients that deliver essential nutrients straight to your muscles. Pre-workouts are very popular in the health and fitness industry for better performance and mental focus.

These dietary formulas are great for intermittent fasting because they boost energy. They typically contain BCAAs and therefore aid in muscle protein synthesis. You can use them to get the most out of your training sessions while fasting.

Many pre-workouts are calorie-free. However, lots of brands add sugar and sweeteners that will cause an insulin spike and break your fast. It is critical to check the caloric value and ingredients list before adding a pre-workout supplement to your fasting regime.

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So, taking BCAAs – yes or no?

BCAAs have little effect on insulin levels, especially compared with other protein supplements. As they have a caloric value, they will break your intermittent fast in technical terms. Whether you choose to take BCAAs depends on your personal goals.

If you want to improve body composition and get the most out of a fasted workout, BCAA supplements tick a lot of boxes. Intermittent fasting and BCAAs allow you to reduce body fat and build muscle to achieve your ideal body weight.


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This is an evidence-based article that includes scientific citations. DoFasting’s professional writers and editors prepared the content, which a team of medical experts verified to be accurate.

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