Acute p-synephrine ingestion increases fat oxidation rate during exercise

source extracted confidence: high 2026-04-09
#adipose-tissue #adolescent #adult #dietary-supplements #double-blind-method

Acute p-synephrine ingestion increases fat oxidation rate during exercise

Gutiérrez-Hellín et al., 2016 | Br J Clin Pharmacol | Rct

Citation

Gutiérrez-Hellín Jorge, Del Coso Juan. Acute p-synephrine ingestion increases fat oxidation rate during exercise. Br J Clin Pharmacol. 2016-Aug;82(2):362-8. doi:10.1111/bcp.12952

Abstract

AIMS: p-Synephrine is a protoalkaloid widely used in dietary supplements for weight management because of its purported thermogenic effects. However, there is a lack of scientific information about its effectiveness to increase fat metabolism during exercise. The purpose of this investigation was to determine the effects of an acute ingestion of p-synephrine on fat oxidation at rest and during exercise. METHODS: In a double-blind, randomized and counterbalanced experimental design, 18 healthy subjects performed two acute experimental trials after the ingestion of p-synephrine (3 mg kg(-1) ) or after the ingestion of a placebo (cellulose). Energy expenditure and fat oxidation rates were measured by indirect calorimetry at rest and during a cycle ergometer ramp exercise test (increases of 25 W every 3 min) until volitional fatigue. RESULTS: In comparison with the placebo, the ingestion of p-synephrine did not change energy consumption (1.6 ± 0.3 vs. 1.6 ± 0.3 kcal min(-1) ; P = 0.69) or fat oxidation rate at rest (0.08 ± 0.02 vs. 0.10 ± 0.04 g min(-1) ; P = 0.15). However, the intake of p-synephrine moved the fat oxidation-exercise intensity curve upwards during the incremental exercise (P < 0.05) without affecting energy expenditure. Moreover, p-synephrine increased maximal fat oxidation rate (0.29 ± 0.15 vs. 0.40 ± 0.18 g min(-1) ; P = 0.01) during exercise although it did not affect the intensity at which maximal fat oxidation was achieved (55.8 ± 7.7 vs. 56.7 ± 8.2% VO2peak ; P = 0.51). CONCLUSIONS: The acute ingestion of p-synephrine increased the fat oxidation rate while it reduced the carbohydrate oxidation rate when exercising at low-to-moderate exercise intensities.

Key Findings

In comparison with the placebo, the ingestion of p-synephrine did not change energy consumption (1.6 ± 0.3 vs. 1.6 ± 0.3 kcal min(-1) ; P = 0.69) or fat oxidation rate at rest (0.08 ± 0.02 vs. 0.10 ± 0.04 g min(-1) ; P = 0.15). However, the intake of p-synephrine moved the fat oxidation-exercise intensity curve upwards during the incremental exercise (P < 0.05) without affecting energy expenditure. Moreover, p-synephrine increased maximal fat oxidation rate (0.29 ± 0.15 vs. 0.40 ± 0.18 g min(-1)

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size See abstract
Age Range See abstract
Condition See abstract

MeSH Terms

  • Adipose Tissue
  • Adolescent
  • Adult
  • Dietary Supplements
  • Double-Blind Method
  • Energy Metabolism
  • Exercise
  • Exercise Test
  • Humans
  • Oxidation-Reduction
  • Synephrine
  • Young Adult

Evidence Classification

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

Provenance

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