BCAA: Benefits, Side Effects, Best Time to Take It & More

BCAA

(Branched Chain Amino Acids)

Evidence: High
Possible Benefits: Reasonable
Safety: High

What is BCAA?

Branched Chain Amino Acids are 3 essential amino acids used primarily for increasing exercise performance and muscle growth. They include leucine, isoleucine, and valine. While BCAA supplements are worth consideration if you prioritize muscle growth, they are often overhyped and not as effective as many people claim them to be. This article is about the main benefits of a BCAA supplement, its potential side effects, the best time to take it, and more.

What does BCAA do for the body?

There are three branched-chain amino acids (BCAAs), each of which has its unique effect.

Leucine is the main activator of protein synthesis.

Leucine also helps activate the SIRT1 gene. This effect may be associated with slowing down aging but more research is needed to prove this.

Isoleucine has strong anti-catabolic effects, which means it slows down the breakdown of muscle mass, amongst other things in the body.

Valine shares similar properties to those of isoleucine and leucine but to a lesser extent. Its effects are not as pronounced as those of leucine and isoleucine.

Possible benefits

It is important to note that all of the potential benefits mentioned below are dose-dependent. Generally, the higher the dose, the more pronounced the effects are. However, they do reach a plateau at a certain point. We will discuss the best dosing protocol later in this article.

Major benefits

Correcting a leucine, isoleucine, or valine deficiency – Since these 3 BCAAs are essential amino acids, the body needs at least some amount of them to survive and function properly. Not getting enough of them can lead to multiple health problems, such as weakening and wasting of muscles, tremors, decreased appetite, lethargy, poor growth, weight loss, skin rashes, and hair loss. Fortunately, a deficiency in these amino acids is rare and shouldn’t happen unless you consume very low amounts of protein.

Minor benefits

Reduced fatigue – BCAA supplements can reduce both mental and physical fatigue after a workout when taken at doses of 10+ grams. This benefit directly leads to other proven benefits, such as improved processing accuracy and reaction time.
Increased fat oxidation and weight loss – When combined with aerobic exercise (such as running, swimming, or riding a bike), BCAA can aid the fat-burning effect by preserving glucose and helping the body utilize fat as a fuel source.
Improved aerobic exercise – This effect mainly applies to untrained or lightly trained individuals. Whether or not BCAA can increase cardio and time to exhaustion in athletes is not yet clear.
Improved carbohydrate absorption – BCAAs promote insulin secretion from the pancreas and help the body utilize carbohydrates. Taking these amino acids before a carbohydrate-rich meal lowers the blood glucose spike from it.

Possible side effects

These side effects are dose-dependent. The risk for them increases (often linearly but sometimes exponentially) as you increase the dose. Some of the side effects only apply to very high doses.

Amino acid imbalance – All essential and non-essential amino acids need to be kept in balance as they act synergistically in many ways. Too much of one amino acid can sometimes cause side effects without enough of another amino acid. That is most notably the case for glycine and methionine, but the principle applies to other amino acids, such as lysine and arginine, and the BCAA trio. Using a single amino acid supplement may lead to a negative nitrogen balance, which can lessen how well your metabolism works. A protein powder is usually a better choice for getting enough amino acids unless you have a specific goal in mind targeted by a particular amino acid/s.
Toxicity – While acute toxicity has never been reported, taking high amounts of BCAA could lead to chronic toxicity and cause some health problems. For example, doses of leucine over 500 mg/kg/d have caused increases in serum ammonia and very high doses of isoleucine can increase levels of urea in the body. Valine isn’t proven to have significant adverse reactions in the body but that is likely because it is one of the least studied essential acids To prevent chronic toxicity, it is best to stay below 20 grams a day unless you have a great reason to take more.
Contamination – Contaminated supplements are uncommon in the USA and other well-regulated countries. However, if you wish to buy products from China, India, or other countries without strict regulations, beware that the supplements may be contaminated. Either way, you need to choose the brand you order from wisely. It is highly recommended to check the certificates or read through some reviews for the specific product before you buy it. The FDA (Food and Drug Administration) has the power to regulate dietary supplements but can only do so after they have been on the market for a while. That’s because supplement companies are not obligated to announce to the FDA when releasing a new product on the market. The FDA has to discover the product and test it for potential impurities, which can take a lot of time. During that time, the supplement can be sold on the market even if it’s impure. Also, supplement companies can change their manufacturers without announcing it to the FDA.

Who should not take BCAA?

You should probably avoid taking the supplement if you:

eat high amounts of protein from food (most whole foods contain at least some amount of each essential amino acid)
experience a severe adverse reaction after taking the supplement
are inactive

Who will benefit the most?

You should consider taking the supplement if you:

consume very little protein (less than 0.3 grams/pound of body weight)
are muscular and work out a lot
do lots of aerobic exercises
are an older person (older people need up to 2 times more BCAAs than young adults for similar activations of muscle protein synthesis and to reduce age-related catabolic effects)

How much BCAA should you take?

The RDA (recommended daily allowance) for leucine is 42 mg/kg/day for all adult men and most adult women. The RDA for isoleucine is 19 mg/kg/day and for valine, it is 24 mg/kg/day. These amounts are enough for the majority of people to prevent any symptoms of deficiency.

The RDAs increase by about 20-45% if you are pregnant or lactating.

Since these amino acids are found in almost every food, you probably already get sufficient amounts from food alone. About 0.36 grams of protein/pound of body weight should be enough to prevent a deficiency.

If you plan to take BCAA as a supplement, 10 grams appears to be the best daily target for most people. This amount should provide most of the benefits without meaningful side effects.

Some people may benefit from doses higher than 10 grams. These include older people, bodybuilders, very physically active individuals, and those on a low-protein diet.

Valine and isoleucine do not have well-established safety limits. The upper safety limit for leucine is 500 mg/kg/d. However, even lower amounts can cause some health problems if you take the supplement for a prolonged period.

To stay on the safe side, don’t take more than 20 grams of BCAA daily unless you have a great reason to do so.

Food sources of BCAAs

All BCAAs (leucine, isoleucine, and valine) are found in all whole foods that contain dietary protein.

The amount of BCAA per gram of protein varies from food to food but a general rule of thumb is that the more protein you eat, the more BCAAs you are getting from food.

The easiest way to find out exactly how much leucine, isoleucine, valine, or other amino acids you are getting from food is with Cronometer.com. This free app allows you to track all vitamins, minerals, and more.

Best time to take BCAA

BCAAs are water-soluble, so you don’t have to take them with food to absorb them well. Taking the supplement with food is better if it causes stomach upset when you take it on an empty stomach.

To maximize the benefits, take BCAA before or after a workout.

Whether you take the supplement in the morning or the evening doesn’t matter. It should not interrupt your sleep in any way.

If you practice time-restricted eating, take BCAA during your eating window to guarantee it won’t break your fast.

Unless it feels too impractical, spread the daily dose into 2+ smaller doses throughout the day.

Interactions

Carbohydrates
BCAAs promote insulin secretion from the pancreas and help the body utilize glucose. Taking this amino acid before a carbohydrate-rich meal lowers the blood glucose spike from it and increases muscle protein synthesis.
Other amino acids
All essential and non-essential amino acids need to be kept in balance as they act synergistically in many ways. Too much of one amino acid can sometimes cause side effects without enough of another amino acid. That is most notably the case for glycine and methionine, but the principle applies to other amino acids, such as lysine and arginine, and the BCAA trio. Using a single amino acid supplement may lead to a negative nitrogen balance, which can lessen how well your metabolism works. A protein powder is usually a better choice for getting enough amino acids unless you have a specific goal in mind targeted by a particular amino acid/s.
Resveratrol
Both resveratrol and leucine can activate the SIRT1 gene and act synergistically in doing so when taken together. Whether or not this effect is of practical significance is not yet clear.

Where to buy BCAA

Amazon is the best option for ordering BCAA supplements in most countries. They offer some very affordable products backed by many positive reviews. Also, you can choose from a wide range of brands without having to search through other markets on the internet.

Beware some brands display the dosage per serving instead of per pill or capsule. Therefore, you may accidentally buy something less potent than you intended. Do not fall for this marketing trick.

FAQ

You can take the supplement daily and do not need to cycle it. However, it is certainly not a problem if you don’t take it daily. Not taking the supplement every once in a while could lead to better absorption. That is yet to be proven or disproven.

All of these options are fine. The two most important things to consider are the price and dosing. Powders are almost always the cheapest form. However, you may need a highly accurate scale to dose them correctly (preferably 0.001g). You can get one for as little as $20 from Amazon. Dosing the powders also takes some time that can add up over months or years. The disadvantage of capsules is that they often contain bovine gelatin, which rarely comes from an ethical source.

Yes. Most amino acids, including BCAAs, absorb and digest well if you take them before falling asleep. The supplement should not impact sleep quality in any significant way.

BCAA should not become harmful once it exceeds the expiration date but can lose potency over time.

Keep the supplement in a cold, dark, and dry place, and it should remain just as potent for many months or even years.

While toxicity is rare, too much BCAA in the system can cause some health problems, often related to causing an imbalance in other amino acids or being too anti-catabolic. It is best to stay below 20 grams a day to prevent these side effects.

You may need more of this amino acid if you:
– eat very little protein (less than 0.3 grams/pound of body weight)
– are muscular and work out a lot
– are an older person (older people need up to 2 times more BCAA than young adults for similar activations of muscle protein synthesis and the anti-catabolic effects)

The half-life of leucine in the body is about 45 minutes. For isoleucine, the half-life is 3-5 hours. Valine doesn’t have a well-established half-life.

If you take the supplement before a workout, you may notice a mild increase in power output. In the long term, you need to take the supplement for many months to begin noticing the benefits.

Amino acid supplements often come from animal products, but they do not have to be since all whole plant foods contain all essential amino acids. You can easily find vegan-friendly BCAA pills and powders but always check the label to be sure. If you buy BCAA in a capsulated form, beware that the capsules often contain animal-based gelatin. Instead, find a brand that puts its products into cellulose capsules.

BCAA is water-soluble, so you don’t have to take it with food to absorb it well.

While low doses may not break a fast, higher doses certainly can. If you practice time-restricted eating, take BCAA during your eating window so it doesn’t break your fast.

References

Most of the information provided in this guide is supported by scientific research that can be found and verified in the PubMed medical library. We highly encourage you to use the library to verify anything said in this article. We excluded from consideration studies that are either confounded or have a high conflict of interest.

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