Creatine vs. BCAAs: Which Actually Has Evidence?

Branched-chain amino acids (BCAAs) and creatine monohydrate are both marketed as muscle-building supplements, both come in powder form, and both occupy premium shelf space in every supplement store. The similarities end there. One of these supplements has an evidence base spanning hundreds of randomized controlled trials, multiple consensus position statements, and universal recommendation from sports nutrition researchers. The other has been called into serious question by the very researchers who once championed amino acid supplementation.

This comparison examines what each supplement actually does, what the evidence says, and whether either deserves your money.

What BCAAs Are and How They Supposedly Work

The branched-chain amino acids are leucine, isoleucine, and valine. They are three of the nine essential amino acids (EAAs), meaning the body cannot synthesize them and they must be obtained through diet. Leucine in particular is a potent activator of the mTOR signaling pathway, the primary molecular switch that initiates muscle protein synthesis.

The theoretical case for BCAA supplementation rests on several premises. First, that leucine's role as an MPS trigger means consuming it in isolation should stimulate muscle growth. Second, that BCAAs may reduce exercise-induced muscle damage and soreness. Third, that BCAAs consumed during training could reduce perceived exertion through modulation of central serotonin pathways (the "central fatigue hypothesis").

These premises are not entirely wrong in isolation. Leucine does activate mTOR. The problem, as subsequent research has made clear, is that activating the trigger for protein synthesis is not the same as completing the process. Building muscle protein requires all 20 amino acids, not just three.

What Creatine Does

Creatine monohydrate increases intramuscular phosphocreatine stores, enhancing the capacity of the phosphocreatine energy system to regenerate ATP during high-intensity exercise. This is a distinct, well-characterized physiological mechanism that operates independently of protein synthesis pathways. The result is measurably greater work capacity during repeated bouts of high-intensity effort, which over time translates to greater training adaptations.

Creatine also increases intracellular water retention (cell volumization), which may itself serve as an anabolic signal. Additionally, creatine has been shown to enhance satellite cell activity and myogenic regulatory factor expression, suggesting direct effects on muscle growth beyond simply enabling more training volume.

The Evidence for BCAAs: A Critical Examination

The BCAA supplement market is worth billions of dollars. The evidence supporting BCAA supplementation for individuals consuming adequate total protein is, to put it directly, remarkably weak.

Robert Wolfe, a leading amino acid metabolism researcher, published a pointed critique in 2017 in the Journal of the International Society of Sports Nutrition examining whether BCAAs could stimulate muscle protein synthesis in humans. His conclusion was unambiguous: there is no credible evidence that dietary supplementation with BCAAs alone results in a physiologically significant stimulation of muscle protein synthesis.

Wolfe's reasoning centers on a fundamental biochemical limitation. Muscle protein synthesis requires all essential amino acids. When BCAAs are consumed in isolation, the other essential amino acids needed to actually build muscle protein must come from the only available source: the breakdown of existing muscle protein. This means BCAA supplementation could theoretically increase both protein synthesis and protein breakdown simultaneously, resulting in no net anabolic effect or potentially a net catabolic state.

Empirical data supports this analysis. Studies examining BCAAs in the context of adequate protein intake consistently find no additional benefit for muscle growth, recovery, or performance. The studies that do show benefits often compare BCAA supplementation to inadequate protein intake or caloric restriction, conditions where any amino acid source would show a benefit.

What About Soreness and Recovery?

Several studies have reported that BCAA supplementation reduces delayed-onset muscle soreness (DOMS). However, systematic reviews note significant heterogeneity in study designs, outcomes, and quality. A review by Fouré and Bendahan (2017) found that while some studies showed reductions in markers of muscle damage, the clinical significance was questionable and the effects were inconsistent. When BCAAs are compared to an equivalent amount of complete protein, the purported recovery benefits largely disappear.

The Evidence for Creatine

The contrast in evidence quality is stark. The ISSN position stand on creatine (Kreider et al., 2017) reviewed over 500 studies and concluded that creatine monohydrate is the most effective ergogenic nutritional supplement currently available for increasing high-intensity exercise capacity and lean body mass. This conclusion has been reaffirmed by every major sports nutrition body that has evaluated the evidence.

Meta-analyses consistently show that creatine supplementation combined with resistance training produces greater gains in lean body mass (approximately 1 to 2 kg additional gain over 4 to 12 weeks), greater increases in maximal strength (5 to 10% improvement), and enhanced work capacity during high-intensity exercise (10 to 20% more total work performed).

The safety data is equally robust. Long-term studies extending to five years have found no adverse effects on renal function, hepatic function, or hydration status in healthy individuals.

Side-by-Side Evidence Comparison

When Each Might Be Appropriate

Creatine Is Appropriate For

Anyone engaged in resistance training, high-intensity interval training, team sports, or any activity involving repeated bouts of maximal effort. It is also increasingly studied for cognitive performance and may have particular benefits for older adults and vegetarians, whose baseline creatine levels tend to be lower.

BCAAs May Have a Narrow Use Case

If an individual is training in a fasted state and cannot tolerate whole protein before or during training, BCAAs may provide some benefit over consuming nothing. However, even in this scenario, essential amino acid (EAA) supplements would be a more rational choice, as they provide all nine essential amino acids rather than just three. In virtually all other scenarios, BCAAs are redundant if protein intake is adequate.

Should You Stack Them?

There is no evidence that adding BCAAs to a diet already containing adequate protein and creatine provides any additional benefit. The money spent on BCAAs would be better allocated to food-based protein sources or, if a supplement is desired, a complete protein powder.

Verdict

This is not a close comparison. Creatine has one of the strongest evidence bases of any supplement in any category. BCAAs, when evaluated against the standard of adequate protein intake, have failed to demonstrate meaningful benefits for muscle growth, performance, or recovery in the peer-reviewed literature. Leading researchers in amino acid metabolism have explicitly stated that the theoretical basis for BCAA supplementation is flawed.

If you are consuming adequate daily protein (1.6 g/kg/day or more), BCAAs are providing nothing your diet does not already supply. Creatine, by contrast, is providing a physiological effect that your diet almost certainly does not match. At roughly half the cost of most BCAA products, creatine is the clear choice by every metric that matters: evidence quality, evidence quantity, mechanism uniqueness, cost, and expert consensus.