BCAAs | Benefits? Side Effects? When To Take? Dosage?

Branched-chain amino acids (BCAAs) are very popular within the fitness industry. They’re often taken as a standalone powder or tablet, and they’re a key ingredient in many pre-workout formulas.

BCAAs are considered the perfect supplement for people looking to build muscle mass, and also for people that are looking to reduce their body fat whilst maintaining as much muscle as possible.

You’ll find in this article:

How Do BCAAs Work?

When you’re cutting calories, your body will be in a catabolic state. This means that your body will be breaking down tissue (fat, some muscle etc.) rather than making it (which is known as being in an anabolic state).

As well as fat loss, muscle loss is likely to occur when you’re reducing your calorie-intake, as the body uses muscle protein (which is made up of amino acids) as an energy source.

To build muscle, your body’s rate of protein synthesis must be greater than the rate of protein breakdown. When it’s the opposite way around, muscle loss occurs, and when the rates are equal, your muscle mass is likely to remain the same.

Why Take BCAAs?

Three of the nine essential amino acids are called branched-chain amino acids (BCAAs). These are leucine, isoleucine and valine. They account for approximately 35% of essential amino acids in muscle proteins.

BCAAs can be oxidised in skeletal muscle, whereas other essential amino acids are catabolised (broken down) mainly in the liver.

Exercise greatly increases energy expenditure and promotes oxidation of BCAAs in the muscles, therefore supplementation can be helpful for those who wish to maintain or increase muscle mass.

The branched-chain amino acid, leucine, is particularly special as it has been shown that when taken orally, it promotes muscle protein-synthesis (creation of muscle protein).

What Are The Other Benefits Of BCAAs?

BCAAs also have several other benefits:

? BCAA supplements can help to reduce tiredness, which can significantly boost your workout. This is one of the key reasons why they are recommended to take before your workout.

They do this by inhibiting the production of serotonin, which often rises during exercise. Serotonin increases the perception of fatigue. BCAAs will prevent this from occurring, giving you more energy. Therefore you can work out for longer, push harder and lift even more weight.

? Furthermore, they have been shown to reduce muscle soreness, which means you can push even harder the days following intense exercise.

Are They Suitable For Me?

BCAAs are great for those looking to increase mass, as well as those looking to lose fat. Anyone can take BCAAs, and they will benefit you in different ways.

As people age, creating the optimum muscle-building environment within your body can be harder to accomplish. BCAAs are a great way for those over the age of 35 to boost the amount of muscle they can build. Even younger lifters who want that extra edge would benefit from these amino acids, especially leucine, as studies have shown that it can increase muscle-protein synthesis by up to 145%.

BCAAs are also excellent for people following specific diets, or eating schedules such as Intermittent Fasting. For example, BCAAs are incredibly beneficial to take pre-workout during a fast, in order to fuel your muscles, giving you energy and encouraging them to grow whilst you burn fat.

Other Supplements

Many people have argued that you can get the same benefits that BCAAs offer from other sources, such as whey protein. Whilst whey is an excellent source of fast-absorbing protein, BCAAs offer a concentrated source of the three essential amino acids that are oxidised the most during exercise.

Side Effects/Safety Precautions

If you fall into one of the following categories, you should use BCAAs with caution, and if you do, always consult your doctor beforehand.

Pregnant or breastfeeding – if you’re pregnant or breastfeeding, it’s not recommended that you take BCAAs, as there has not been enough reliable evidence to suggest it is safe to do so.

Before surgery – BCAAs have been shown to affect blood sugar levels, so it’s not recommended that you take them directly before you undergo surgery.

BCAA Dosage

BCAA powder can be taken in 5g dosages, 2-4 times daily, whenever needed. Consume pre-workout, during training (the powdered form is available as flavoured or unflavoured), post-workout, or during the day to help with delayed-onset muscle soreness (DOMS).

Take Home Message

When utilised correctly, BCAAs are an extremely powerful supplement. They can help to increase your muscle mass by increasing the rate of protein-synthesis, in addition to preventing muscle loss when cutting.

They deliver a good source of amino acids intra-workout, and are great to take before a workout, especially when training fasted.


Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

Lauren Dawes

Lauren Dawes

Writer and expert

Lauren is an English Literature graduate originally from the South. She’s always loved swimming, has discovered the power of weight training over the past few years, and has lots of room for improvement in her weekly hot yoga class. On the weekends she’s usually cooking or eating some kind of brunch, and she enjoys trying out new recipes with her housemates – especially since shaking off student habits, like mainly surviving off pasta. Above all, she’s a firm believer in keeping a balance between the gym and gin. Find out more about Lauren’s experience here: