Effect of p-Synephrine on Fat Oxidation Rate during Exercise of Increasing Intensity in Healthy Active Women

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#female #humans #carbohydrates #cellulose #citrus

Effect of p-Synephrine on Fat Oxidation Rate during Exercise of Increasing Intensity in Healthy Active Women

Gutiérrez-Hellín et al., 2022 | Nutrients | Rct

Citation

Gutiérrez-Hellín Jorge, Aguilar-Navarro Millán, ... Varillas-Delgado David. Effect of p-Synephrine on Fat Oxidation Rate during Exercise of Increasing Intensity in Healthy Active Women. Nutrients. 2022-Oct-17;14(20). doi:10.3390/nu14204352

Abstract

p-Synephrine is the principal alkaloid of bitter orange (Citrus aurantium). Several recent investigations have found that the intake of 2-3 mg/kg of p-synephrine raises fat oxidation rate during exercise of low-to-moderate intensity. However, these investigations have been carried out only with samples of male participants or mixed men/women samples. Therefore, the aim of this investigation was to study the effect of p-synephrine intake on fat oxidation during exercise of increasing intensity in healthy women. Using a double-blind, randomized experiment, 18 healthy recreationally active women performed two identical exercise trials after the ingestion of (a) 3 mg/kg of p-synephrine and (b) 3 mg/kg of a placebo (cellulose). The exercise trials consisted of a ramp test (from 30 to 80% of maximal oxygen uptake; VO2max) on a cycle ergometer while substrate oxidation rates were measured at each workload by indirect calorimetry. In comparison to the placebo, the intake of p-synephrine increased resting tympanic temperature (36.1 ± 0.5 vs. 36.4 ± 0.4 °C p = 0.033, d = 0.87) with no effect on resting heart rate (p = 0.111) and systolic (p = 0.994) and diastolic blood pressure (p = 0.751). During exercise, there was no significant effect of p-synephrine on fat oxidation rate (F = 0.517; p = 0.484), carbohydrate oxidation rate (F = 0.730; p = 0.795), energy expenditure rate (F = 0.480; p = 0.833), heart rate (F = 4.269; p = 0.068) and participant's perceived exertion (F = 0.337; p = 0.580). The maximal rate of fat oxidation with placebo was 0.26 ± 0.10 g/min and it was similar with p-synephrine (0.28 ± 0.08 g/min, p = 0.449, d = 0.21). An acute intake of 3 mg/kg of p-synephrine before exercise did not modify energy expenditure and substrate oxidation during submaximal aerobic exercise in healthy active women. It is likely that the increase in resting tympanic temperature induced by p-synephrine hindered the effect of this substance on fat utilization during exercise in healthy active women.

Key Findings

It is likely that the increase in resting tympanic temperature induced by p-synephrine hindered the effect of this substance on fat utilization during exercise in healthy active women.

Outcomes Measured

  • blood pressure
  • systolic blood pressure
  • diastolic blood pressure

Population

Field Value
Population healthy women
Sample Size See abstract
Age Range See abstract
Condition blood pressure

MeSH Terms

  • Female
  • Humans
  • Carbohydrates
  • Cellulose
  • Citrus
  • Dietary Supplements
  • Energy Metabolism
  • Exercise
  • Oxidation-Reduction
  • Oxygen
  • Oxygen Consumption
  • Plant Extracts
  • Synephrine
  • Double-Blind Method

Evidence Classification

  • Level: Rct
  • Publication Types: Randomized Controlled Trial, Journal Article
  • Vertical: bitter-orange

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09