BCAA is short for branched-chain amino acid. The BCAAs, leucine, isoleucine and valine, are essential amino acids because your body can’t synthesize them. Therefore, you need to include them in your diet.
Gym-goers usually take BCAA powders to improve their exercise performance and to optimise their muscle growth. They can also help reduce post-gym tiredness and even help you lose weight.
BCAAs make up about 35–40% of your total amino acids and 14–18% of amino acids in your muscle tissue.
They are mainly broken down in your muscles, rather than your liver and experts believe that they help you produce energy during exercise. And, like most amino acids, your body can use BCAAs to synthesise protein and muscle.
Additionally, they can help to induce cells to use your blood sugar, enabling you to preserve the glucose stores in your liver and muscles.
By inhibiting your brain’s production of serotonin, BCAAs may also help you feel less tired when you’re working out.
Reported Effects of BCAA Powders
They Can Reduce Fatigue
BCAAs can make you 15% less tired from physical exertion, clinical studies have shown.
In one study, a group of participants that took BCAAs were able to work out for 17% longer before they became exhausted, compared to a group that took a placebo.
In another trial, subjects consumed a drink containing either BCAAs or a placebo, and then undertook a cycling test under heat stressed conditions. The group that took the BCAAs were able to exercise for 12% longer than those who took the placebo.
Correspondingly, BCAAs may be more beneficial at curtailing fatigue in relatively sedentary individuals, than those that exercise regularly. (1)
They Can Reduce Muscle Soreness
BCAAs may also help you avoid post-gym soreness. Experts believe they do this by decreasing levels of the muscle-damaging enzymes, lactate dehydrogenase and creatine kinase. This helps to safeguard your muscles and even help your recovery.
One study found that when participants took BCAA supplements they experienced 33% less muscle soreness than participants that took a placebo.
Another study determined that participants who consumed BCAAs achieved up to 20% better results in strength tests when they repeated them 24-48 hours later. (2)
They Can Increase Muscle Mass
Many gym-goers take BCAA supplements to increase their muscle mass. Scientific studies have indeed demonstrated that BCAAs help activate your muscle-building enzymes.
Research has also shown that BCAA supplements help to increase your muscle mass. This is particularly true if they contain a higher ratio of leucine to isoleucine and valine.
There’s little evidence, though, showing that BCAAs provide any more muscle-building benefit than whey supplements or various protein-rich foods. (3)
They Can Help You Lose Weight
BCAAs may help you prevent weight gain and even help you lose fat.
In one clinical trial, participants that took 15 grams of BCAAs every day can have 30% less risk of obesity compared to people consuming only 12 grams every day.
A 19-day study showed that wrestlers taking BCAAS to supplement their high-protein, low calorie diet shed about 1.6 kg more weight than wrestlers taking soya protein supplements. The BCAA group also lost 0.6% more body fat.
In eight weeks, a group of weightlifters taking 14 grams per day of BCAAs lost 1% more of their body fat than a similar group consuming 28 grams of whey protein daily. The BCAA group also increased their muscle mass by about 2kg.
However, more conclusive research is needed into the composition of the BCAA supplements and participants’ diets. (4)
Common Ingredients Found in BCAA Powders
Leucine is sometimes called the ‘main’ amino acid because it’s mostly responsible for the muscle-building properties of BCAAs. It’s the most efficient at activating mTOR, a protein which induces muscle protein synthesis.
Leucine has undergone more extensive research than either isoleucine or valine, the other two BCAAs.
Research has mostly focused on muscle protein synthesis when leucine is added to the diet. Studies showed that leucine can consistently improve muscle protein synthesis, but it’s not known whether this causes a consistent increase in lean mass.
Leucine seems to be better at helping people gain muscle if they have a low protein diet. It also benefits the elderly because they tend to be less efficient at synthesising muscle protein.
Leucine can release insulin from the pancreas, reducing blood sugar, and it can help cells take up glucose. Conversely, leucine can also suppress insulin-stimulated glucose uptake.
Isoleucine isn’t as strong as leucine at inducing muscle protein synthesis, but it’s stronger than valine. It can also considerably increase the uptake and use of glucose when you exercise.
Additionally, isoleucine can improve your muscle cells’ consumption of glucose. More clinical research is required to verify this, but isoleucine is the best of the BCAAs at using glucose and converting it into energy. Experts believe that this enables isoleucine to enhance your gym performance and even to act as a hypoglycaemic, helping to lower your blood sugar.
Valine is not as efficient as either leucine or isoleucine at enabling muscle synthesis, or at utilizing glucose, experts believe. This may be down to insufficient evidence, as the metabolic properties of valine don’t appear to have been researched extensively.
Valine appears to be more similar to leucine than isoleucine. It doesn’t induce insulin resistance as rapidly as leucine, though. Additionally, as mentioned above, its muscle-building effects are less pronounced than both leucine and isoleucine.
Side-Effects of Using BCAA Powder
BCAAs are typically free of side-effects.
However, sufferers of amyotrophic lateral sclerosis (ALS), a nervous system disorder also known as Lou Gehrig’s disease, are advised not to take BCAA supplements. (5)
Also, those suffering from maple syrup urine disease, a rare condition, should be careful when taking BCAAs because they can’t break them down properly. (6)
BCAA Powder Dosage
BCAA dose should be approximately 144mg per kg of body weight daily. Women should consume at least 9 grams of BCAAs, and men should take at least 12 grams per day.
You can take BCAAs before or after your workout or you can do both. You may also want to take them in the morning and in the evening if you want to build muscle.
However, as yet, there’s been little research as to whether exactly when you take them has a significant effect.
- Effect of BCAA intake during endurance exercises on fatigue substances, muscle damage substances, and energy metabolism substances. Dong-Hee Kim, Seok-Hwan Kim, Woo-Seok Jeong, Ha-Yan Lee. Affiliations expand PMID: 25566428 PMCID: PMC4241904 DOI: 10.5717/jenb.2013.17.4.169
- Effect of branched-Chain Amino Acid Supplementation on Muscle Soreness following Exercise: A Meta-Analysis. Michael V Fedewa, Steven O Spencer, Tyler D Williams, Zachery E Becker, Collin A Fuqua. Affiliations expand PMID: 30938579 DOI: 10.1024/0300-9831/a000543
- Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? Robert R. Wolfe
- The Weight Loss Effects of Branched Chain Amino Acids and Vitamin B6: A Randomized Controlled Trial on Obese and Overweight Women. Zahra Shakibay Novin, Saeed Ghavamzadeh, Alireza Mehdizadeh. Affiliations expand PMID: 30841823 DOI: 10.1024/0300-9831/a000511
- Stronger is not always better: could a bodybuilding dietary supplement lead to ALS? Marin Manuela, and C. J. Heckman
- Maple Syrup Urine Disease. Kevin A Strauss, Erik G Puffenberger, Vincent J Carson, Margaret P Adam, Holly H Ardinger, Roberta A Pagon, Stephanie E Wallace, Lora JH Bean, Karen Stephens, Anne Amemiya.