BCAA While Bulking: Is There Any Point
During the mass-gaining phase, an athlete eats more calories and protein than usual. So a logical question arises: is there any point in spending money on BCAA if the body already receives an excess of amino acids from food? The editorial team analyzed the study data and explains why during bulking BCAA are usually the least useful supplement in a sports diet.
How mass gain works
Muscle gain is the result of a prolonged predominance of muscle protein synthesis over its breakdown. This balance shifts in the positive direction thanks to two main stimuli: mechanical load during strength training and the intake of amino acids from food. A calorie surplus creates a favorable energy background in which the body more willingly «builds» new tissue.
The ISSN position (Jäger et al., 2017) recommends 1.4–2.0 g of protein per kilogram of body weight per day for physically active people, distributed over several meals of 20–40 g. The meta-analysis by Morton and co-authors (2018) showed that the gain of lean mass from additional protein reaches a plateau at about the level of 1.6 g/kg per day.
During bulking, most athletes already consume this or a larger amount of protein. Each meal with meat, eggs, fish, or dairy products contains several grams of leucine and all the other essential amino acids.
In such a situation, additional BCAA mean that a little more leucine, isoleucine, and valine is added to an already sufficient pool of amino acids. The question is whether this is able to change anything.
What studies say about BCAA with sufficient protein
Controlled studies in which participants received enough protein did not reveal convincing benefits of BCAA for muscle growth. For example, Spillane and co-authors (2012), over eight weeks of strength training, saw no difference in body composition and strength indicators between the BCAA group and the placebo group.
The review by Plotkin and co-authors (2021), devoted to isolated leucine and BCAA, concluded: provided there is sufficient protein intake, these supplements do not give an additional gain in strength or hypertrophy. Possible exceptions concern situations with insufficient protein in the diet.
A mechanistic explanation is provided by the review by Wolfe (2017). BCAA only amplify the signal for protein synthesis, but they do not provide the rest of the essential amino acids. When the diet is rich in protein, this signal is already strong enough, and there is enough raw material — an additional serving of BCAA changes nothing substantial.
A comparison with a complete protein is also not in favor of BCAA. Jackman and co-authors (2017) showed that 5.6 g of BCAA after training increased myofibrillar protein synthesis by about 22% compared with placebo, but this response was about half of what was observed in other studies after a serving of whey protein with a similar amount of BCAA.
Why the «leucine threshold» is not an argument during bulking
The concept of the leucine threshold states that for maximum stimulation of muscle protein synthesis in one meal, a certain amount of leucine is needed — in young people about 2–3 g is usually mentioned. Hence the popular advice to «add BCAA to every meal».
However, during bulking most meals already exceed this threshold. A serving of meat, fish, or cheese with 30–40 g of protein contains more leucine than is needed for the maximum signal. Additional leucine above this level does not increase protein synthesis proportionally.
Another idea is to take BCAA between meals in order to «stimulate synthesis more often». However, studies with frequent «feeding» of amino acids showed that muscles have the so-called «muscle full» effect: after the peak, synthesis decreases even with a high level of amino acids in the blood, and new stimulation is not possible right away.
Thus, during the mass-gaining phase, the theoretical arguments in favor of BCAA mostly do not work: the diet already provides both the signal and the raw material.
When BCAA during bulking can still make sense
There are several scenarios in which amino acids may be appropriate even during the gaining phase:
- a vegetarian or vegan diet with a low leucine content in individual meals;
- very long workouts (over 90 minutes) with a large interval after the previous meal;
- appetite problems, when it is hard to eat enough protein food;
- situations when protein is poorly tolerated, for example with lactose intolerance.
Even in these cases, the editorial team advises first considering alternatives. Plant protein blends, a lactose-free whey isolate, or an EAA complex solve the same problems more completely.
We also note that during bulking an important factor is cost. A gram of BCAA usually costs significantly more than a gram of complete protein, while giving only part of its benefit.
Finally, BCAA do not protect against gaining excess fat. If the surplus is too large, the gain of fat mass will be significant regardless of supplements.
Rational alternatives during the gaining phase
| Supplement | Evidence base for mass gain | Editorial comment |
|---|---|---|
| Creatine monohydrate | High | One of the most studied supplements for strength and mass |
| Whey protein | High (as a protein source) | A convenient way to make up protein |
| Gainer | Depends on the diet | Useful with low appetite, but contains a lot of carbohydrates |
| EAA | Moderate | A better choice than BCAA if amino acids are needed |
| BCAA | Low with sufficient protein | The least priority supplement during bulking |
The meta-analysis by Morton and co-authors (2018) emphasizes that the effect of any protein supplement depends on training. Without a progressive load, no supplements will provide a significant gain in muscle.
If the budget is limited, the editorial team advises investing first of all in quality food, then in protein and creatine, and only lastly in amino acid complexes.
People with diseases of the kidneys, liver, or metabolic disorders should discuss a high-protein diet and any supplements with a doctor.
Editorial conclusions
During bulking, when the diet provides enough protein and calories, BCAA do not give a proven additional gain in muscle mass or strength.
The leucine signal and the raw material for protein synthesis are already present in every complete meal. Adding isolated amino acids changes little.
BCAA can be justified only in individual situations — with low protein, poor appetite, dietary features — and even then better alternatives are protein or EAA.
Also read «BCAA While Cutting: Does It Help», «Creatine Monohydrate: The Evidence Base», and «BCAA or Leucine: What Is the Difference».
References
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
- Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384.
- Spillane M, Emerson C, Willoughby DS. The effects of 8 weeks of heavy resistance training and branched-chain amino acid supplementation on body composition and muscle performance. Nutr Health. 2012;21(4):263–273.
- Plotkin DL, Delcastillo K, Van Every DW, Tipton KD, Aragon AA, Schoenfeld BJ. Isolated leucine and branched-chain amino acid supplementation for enhancing muscular strength and hypertrophy: a narrative review. Int J Sport Nutr Exerc Metab. 2021;31(3):292–301.
- Wolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017;14:30.
- Jackman SR, Witard OC, Philp A, et al. Branched-chain amino acid ingestion stimulates muscle myofibrillar protein synthesis following resistance exercise in humans. Front Physiol. 2017;8:390.
- Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15:38.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
