Dose-Response Absorption Kinetics of Oral L-Beta-Aminoisobutyric Acid (L-BAIBA) Supplementation in Healthy Men and Women

L-Beta-amino isobutyric acid (L-BAIBA) is a myokine produced in skeletal muscle during exercise and has been shown to impact carbohydrate and fat metabolism in both animals and humans. This study was designed to determine the rate and extent to which L-BAIBA appeared in human plasma after oral ingestion. In a randomized, double-blind, placebo-controlled, crossover fashion, six males and 6 females (N = 12; 24 ± 5 yrs; 173.6 ± 12.0 cm; 72.3 ± 11.3 kg; 21.0 ± 7.0 body fat %) completed a single-dose supplementation protocol of placebo (PLA), L-BAIBA at 250 mg (B250), 500 mg (B500), 1,500mg (B1500), and 1,500mg of valine (V1500). Participants fasted overnight (8-10 h) and consumed their dose with 8-12 fluid ounces of cold water. Venous blood samples were collected 0, 30, 60, 90, 120, 180, 240 and 300 min after ingestion and analyzed for L-BAIBA. Complete blood counts and comprehensive metabolic panels were analyzed 0 and 300 min after ingestion. Peak concentration (C_Max) and area under the curve (AUC) were calculated for all variables. Baseline L-BAIBA levels were not different between conditions (p = 0.46). The observed AUC for B1500 (30,513 ± 9190 µM•300 min) was significantly higher than B500 (11,087 ± 3378 µM•300 min, p < 0.001), B250 (7081 ± 2535 µM•300 min, p < 0.001), V1500 (2837 ± 2107 µM•300 min, p < 0.001), and PLA (2836 ± 2061 µM•300 min, p < 0.001). Similarly, L-BAIBA C_Max for B1500 (278.1 ± 52.1 µM) was significantly higher than all other supplement conditions: B500 (95.4 ± 33.5 µM, p < 0.001), B250 (63.3 ± 61.1 µM, p < 0.001), V1500 (10.1 ± 7.2 µM, p < 0.001), PLA (11.0 ± 7.1 µM, p = 0.001). AUC and C_Max for B500 was significantly higher than B250 (p < 0.001), V1500 (p < 0.001), and PLA (p < 0.001). BAIBA AUC for B250 was significantly higher than V1500 (p < 0.001) and PLA (p < 0.001). No clinically significant changes in blood-based markers of health or adverse events were observed across the study protocol. L-BAIBA doses of 250 mg, 500 mg, and 1500 mg produced significantly greater concentrations of plasma L-BAIBA across a five-hour measurement window when compared to a 1500 mg dose of valine or a placebo. Follow-up efficacy studies on resting and exercise metabolism should be completed to assess the impact of L-BAIBA supplementation in normal weight and overweight individuals. Retrospectively registered on April 22, 2022 at ClinicalTrials.gov as NCT05328271.