Dietary berberine supplementation improves select physiological and psychological responses during exertional heat stress: A pilot study in young adults.

2026-05
Physiological reports 14(10)
- Dante A Van Arman
- Jacob C Saunders
- Yaw O Korankyi
- Emerson P Heckler
- Ben J Lee
- Trevor L Gillum
- Matthew R Kuennen

PubMed: 42204774
DOI: 10.14814/phy2.70937

Study Design

Type: Randomized Controlled Trial (RCT)
Population: Eight participants (6 men/2 women; Age: 23±3 years, Stature: 1.75±0.03 m, Mass: 71.8±2.7 kg, VO2max: 57.5±2.1 mL/kg lbm/min-1)
Methods: ingested 1.5 g of Berberine or Placebo for 7d prior to a 1 h treadmill run (60% VO2max) in hot (35°C), moderately humid (39% RH) conditions
Blinding: Double-blind
Duration: 7d
Funding: Unclear

Berberine has been shown to lower core temperature and heart rate during passive heat stress in animal models. This study evaluated the effect of dietary berberine supplementation on physiological and perceptual responses to exercise-heat stress in humans. Eight participants (6 men/2 women; Age: 23 ± 3 years, Stature: 1.75 ± 0.03 m, Mass: 71.8 ± 2.7 kg, VO_2max: 57.5 ± 2.1 mL/kg lbm/min^-1) ingested 1.5 g of Berberine or Placebo for 7d prior to a 1 h treadmill run (60% VO_2max) in hot (35°C), moderately humid (39% RH) conditions. Mean body temperature (T_b), heart rate (HR), expired gasses (VO₂, VCO₂, RER), minute ventilation, respiratory rate (R_R), tidal volume, and perceptual responses (thermal sensation, perceived discomfort, and perceived exertion) were measured throughout exercise. Data are reported as average ± standard deviation over the 60 min exercise trial. T_b was lower (p = 0.030) in Berberine (37.69 ± 0.53°C) than Placebo (37.84 ± 0.38°C). Heart rate was lower (p = 0.025) in Berberine (163 ± 28 bpm) than Placebo (166 ± 30 bpm). R_R was lower (p = 0.045) in Berberine (38.8 ± 11.2 bpm) than Placebo (41.4 ± 10.6 bpm). Thermal sensation was lower (p = 0.002) in Berberine (9.5 ± 4.2) than Placebo (12.3 ± 5.0). Generalized discomfort was lower (p = 0.044) in Berberine (9.3 ± 5.1) than Placebo (12.1 ± 5.6). Perceived exertion was lower (p < 0.001) in Berberine (11.4 ± 3.4) than Placebo (13.1 ± 4.0). Dietary berberine supplementation improved mean body temperature, heart rate, respiratory rate, and perceptual responses during exertional heat stress. Many of these changes were of small magnitude, calling into question the potential utility of dietary berberine supplementation for work or exercise in hot ambient conditions.

Research Insights

Berberine→Reduced Body Temperature
Tb was lower (p = 0.030) in Berberine (37.69 ± 0.53°C) than Placebo (37.84 ± 0.38°C).
Effect
Beneficial
Effect size
Small
Dose
1.5 g/day for 7 days
Berberine→Reduced Discomfort
Generalized discomfort was lower (p = 0.044) in Berberine (9.3 ± 5.1) than Placebo (12.1 ± 5.6).
Effect
Beneficial
Effect size
Small
Dose
1.5 g
Berberine→Reduced General Discomfort
Generalized discomfort was lower (p = 0.044) in Berberine (9.3 ± 5.1) than Placebo (12.1 ± 5.6).
Effect
Beneficial
Effect size
Small
Dose
1.5 g/day for 7 days
Berberine→Reduced Heart Rate
Heart rate was lower (p = 0.025) in Berberine (163 ± 28 bpm) than Placebo (166 ± 30 bpm).
Effect
Beneficial
Effect size
Small
Dose
1.5 g/day for 7 days
Berberine→Reduced Perceived Exertion
Perceived exertion was lower (p < 0.001) in Berberine (11.4 ± 3.4) than Placebo (13.1 ± 4.0).
Effect
Beneficial
Effect size
Small
Dose
1.5 g/day for 7 days
Berberine→Reduced Respiratory Rate
RR was lower (p = 0.045) in Berberine (38.8 ± 11.2 bpm) than Placebo (41.4 ± 10.6 bpm).
Effect
Beneficial
Effect size
Small
Dose
1.5 g/day for 7 days
Berberine→Reduced Thermal Sensation
Thermal sensation was lower (p = 0.002) in Berberine (9.5 ± 4.2) than Placebo (12.3 ± 5.0).
Effect
Beneficial
Effect size
Small
Dose
1.5 g/day for 7 days