Chilean Protein Shakes High in L-Leucine: Study Analysis

Key Findings

This descriptive study found that protein shakes in the Chilean market (Santiago) consistently contain elevated levels of L-Leucine, a key branched-chain amino acid (BCAA). Among 80 assessed products, the median protein content per serving was 32 g (range: 25–52 g), with a median energy value of 390 kcal (range: 312–514 kcal). Per 100 g of product, median protein was 75 g (range: 42.5–97.2 g). While the combined median concentration of all measured amino acids was 4,749.75 mg, L-Leucine was specifically highlighted as one of the most prevalent amino acids alongside L-Glutamine (median 17,336 mg). L-Tryptophan had the lowest median concentration (1,591.50 mg). Animal-derived protein sources dominated the market.

Study Design

This was a descriptive cross-sectional study analyzing commercially available protein shakes in Santiago, Chile. Researchers extracted macronutrient and amino acid profile ("aminogram") data directly from product nutritional labels. The analysis evaluated content both per standard serving and per 100 g of product. No human participants were involved; the sample consisted of 80 distinct protein shake products purchased from the Chilean market. No study duration or intervention period applies, as it was a compositional analysis of existing products.

Dosage & Administration

The study did not investigate administered doses in a trial context. It reported the median protein dose per serving as 32 g (range: 25–52 g), as declared by manufacturers on product labels. L-Leucine levels were not reported as a specific median value but were identified as being present in "elevated levels" compared to other amino acids within the products analyzed. Administration details (e.g., timing, with/without food) were not applicable, as the research focused solely on product composition.

Results & Efficacy

The study measured compositional data only and did not assess efficacy, health outcomes, or performance effects of L-Leucine or the protein shakes. Key quantitative results include: median protein per serving = 32 g; median energy per serving = 390 kcal; median protein per 100 g = 75 g; combined median amino acid concentration = 4,749.75 mg. L-Glutamine had the highest median concentration (17,336 mg), while L-Tryptophan was the lowest (1,591.50 mg). L-Leucine was explicitly noted as having elevated concentrations, though an exact median value was not provided in the summary. No statistical significance testing (p-values, CIs) for efficacy outcomes was performed or reported, as the study design was descriptive.

Limitations

Major limitations include: reliance solely on manufacturer-reported label data without independent laboratory verification of amino acid content; no assessment of actual bioavailability or physiological effects of the nutrients; focus limited to the Santiago, Chile market, limiting generalizability; no human data on consumption patterns, safety, or efficacy; and the descriptive nature precluding causal inferences. The study did not quantify L-Leucine levels with specific median values or ranges beyond stating they were "elevated." Future research should include independent lab testing and clinical trials to link composition to outcomes.

Clinical Relevance

For supplement users, this study indicates that protein shakes commonly available in Chile typically provide high per-serving protein doses (median 32 g) and are rich sources of L-Leucine, a critical amino acid for muscle protein synthesis. Consumers seeking L-Leucine can expect it to be abundant in these animal-based products. However, users should note that label accuracy wasn't verified, and high L-Leucine content alone doesn't guarantee enhanced muscle growth or performance—actual benefits depend on total protein intake, training status, and overall diet. Athletes should prioritize total daily protein needs over isolated amino acid content from shakes.