Acute p-synephrine ingestion increases whole-body fat oxidation during 1-h of cycling at Fatmax

Gutiérrez-Hellín, Jorge; Ruíz-Moreno, Carlos; Coso, Juan Del

doi:10.1007/s00394-019-02101-6

Cited by 14 publications

(48 citation statements)

References 15 publications

(27 reference statements)

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“…As a result, it seems safe to indicate that p-synephrine is effective to enhance fat utilization during exercise of low to moderate intensity. In fact, it has been recently found that 3 mg/kg of body mass of p-synephrine increased the amount of fat oxidized during 1 h of exercise at Fatmax, equivalent to~57% VO 2max from 33.6 to 37.3 ± 9.8 g [32]. Interestingly, the co-ingestion of p-synephrine and caffeine does not produce a synergistic effect on fat oxidation during exercise over the benefit of these substances when they are ingested isolatedly [33].…”

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 97%

“…In all the abovementioned investigations, the increases in fat oxidation rate with p-synephrine were accompanied by a concomitant reduction in carbohydrate oxidation rates [28,[30][31][32]. This is because p-synephrine does not modify energy expenditure rates at any exercise intensity, which contradicts its potential thermogenic effect, at least during exercise.…”

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 97%

“…Interestingly, the co-ingestion of p-synephrine and caffeine does not produce a synergistic effect on fat oxidation during exercise over the benefit of these substances when they are ingested isolatedly [33]. In addition, it has been found that the magnitude of the effect of p-synephrine on fat oxidation during exercise of increasing intensity [33] and during steady-state exercise is similar to caffeine when both substances are ingested in a dose of 3 mg/kg of body mass [32,34]. Collectively, this evidence supports the benefit of acute p-synephrine intake to increase the rate of fat oxidation during low-to moderate-intensity exercise.…”

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 98%

“…This is because p-synephrine does not modify energy expenditure rates at any exercise intensity, which contradicts its potential thermogenic effect, at least during exercise. Hence, it seems that p-synephrine produces a shifting in substrate oxidation during exercise without affecting the energy expended with exercise [32]. The reduction of carbohydrate oxidation is evident during exercise of increasing intensity [28] and during steady-state exercise [32], and it may help individuals to spare muscle and liver glycogen during exercise.…”

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 99%

“…Hence, it seems that p-synephrine produces a shifting in substrate oxidation during exercise without affecting the energy expended with exercise [32]. The reduction of carbohydrate oxidation is evident during exercise of increasing intensity [28] and during steady-state exercise [32], and it may help individuals to spare muscle and liver glycogen during exercise. Glycogen sparing through feeding or training with low carbohydrate availability has been found effective to increase some forms of aerobic exercise performance [35].…”

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 99%

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Effects of p-Synephrine during Exercise: A Brief Narrative Review

et al. 2021

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The p-synephrine is the principal phytochemical found in bitter orange (Citrus aurantium). This substance is widely included in dietary supplements for weight loss/body fat reduction due to its potential benefits of increasing fat oxidation. For years, p-synephrine-containing dietary supplements have been marketed without proper knowledge of their true effectiveness to enhance fat utilization, especially when combined with exercise. However, the effects of p-synephrine on fat oxidation during exercise have been investigated in the last few years. The aim of the current discussion is to summarize the evidence on the effects of p-synephrine intake on fat oxidation and performance during exercise. Previous investigations have demonstrated that the acute intake of p-synephrine does not modify running sprint performance, jumping capacity, or aerobic capacity. However, the acute intake of p-synephrine, in a dose of 2–3 mg/kg of body mass, has been effective to enhance the rate of fat oxidation during incremental and continuous exercise. This effect has been observed in a range of exercise workloads between 30% and 80% of peak oxygen uptake (VO2peak). The p-synephrine has the ability to increase the maximal rate of fat oxidation during exercise of increasing intensity without affecting the workload at which maximal fat oxidation is obtained (Fatmax). The effect of p-synephrine on fat oxidation is normally accompanied by a concomitant reduction of carbohydrate utilization during exercise, without modifying the energy expended during exercise. The shifting in substrate oxidation is obtained without any effect on heart rate during exercise and the prevalence of adverse effects is negligible. Thus, the acute use of p-synephrine, or p-synephrine-containing products, might offer some benefits for those individuals seeking higher fat utilization during exercise at low to moderate intensities. However, more research is still necessary to determine if the effect of p-synephrine on fat oxidation during exercise is maintained with chronic ingestion, in order to ascertain the utility of this substance in conjunction with exercise programs to produce an effective body fat/weight loss reduction.

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Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 97%

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 97%

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 98%

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 99%

Section: Effect Of P-synephrine To Shifting Substrate Oxidation During Exercisementioning

confidence: 99%

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Effects of p-Synephrine during Exercise: A Brief Narrative Review

et al. 2021

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Caffeine increases whole-body fat oxidation during 1 h of cycling at Fatmax

et al. 2020

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PurposeThe ergogenic effect of caffeine on exercise of maximum intensity has been well established. However, there is controversy regarding the effect of caffeine on shifting substrate oxidation at submaximal exercise. The aim of this study was to investigate the effect of acute caffeine ingestion on whole-body substrate oxidation during 1 h of cycling at the intensity that elicits maximal fat oxidation (Fatmax). Methods In a double-blind, randomized, and counterbalanced experiment, 12 healthy participants (VO2max = 50.7 ± 12.1 mL/ kg/min) performed two acute experimental trials after ingesting either caffeine (3 mg/kg) or a placebo (cellulose). The trials consisted of 1 h of continuous cycling at Fatmax. Energy expenditure, fat oxidation rate, and carbohydrate oxidation rate were continuously measured by indirect calorimetry. Results In comparison to the placebo, caffeine increased the amount of fat oxidized during the trial (19.4 ± 7.7 vs 24.7 ± 9.6 g, respectively; P = 0.04) and decreased the amount of carbohydrate oxidized (94.6 ± 30.9 vs 73.8 ± 32.4 g; P = 0.01) and the mean self-perception of fatigue (Borg scale= 11 ± 2 vs 10 ± 2 arbitrary units; P = 0.05). In contrast, caffeine did not modify total energy expenditure (placebo = 543 ± 175; caffeine = 559 ± 170 kcal; P = 0.60) or mean heart rate (125 ± 13 and 127 ± 9 beats/min; P = 0.30) during exercise. Before exercise, caffeine increased systolic and diastolic blood pressure whilst it increased the feelings of nervousness and vigour after exercise (P < 0.05). Conclusion These results suggest that a moderate dose of caffeine (3 mg/kg) increases the amount of fat oxidized during 1 h of cycling at Fatmax. Thus, caffeine might be used as an effective strategy to enhance body fat utilization during submaximal exercise. The occurrence of several side effects should be taken into account when using caffeine to reduce body fat in populations with hypertension or high sensitivity to caffeine.

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Review of Case Reports on Adverse Events Related to Pre-workout Supplements Containing Synephrine

et al. 2023

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The use of pre-workout supplements has become increasingly popular, including the use of supplements containing synephrine. Synephrine might stimulate weight loss and improve sports performance by its proposed adrenergic properties. However, with its increasing popularity, numerous cases of adverse events related to synephrine use have been reported. This study provides a comprehensive overview and analysis of current case reports related to the supplemental use of synephrine. The scientific literature on cases of adverse events related to synephrine intake was collected through August 2021 using Pubmed and Google Scholar and subsequently reviewed and analysed. We obtained 30 case reports describing a total of 35 patients who suffered from medical complaints following use of synephrine-containing supplements. The patients most often presented with chest pain, palpitations, syncope and dizziness. Commonly raised diagnoses were ischaemic heart disease, cardiac arrhythmias and cerebrovascular disease. Five patients were left disabled or remained on medication at last follow-up. We here show an association between the use of pre-workout supplements containing synephrine and adverse events, mainly related to the cardiovascular system. However, we cannot exclude a role of possible confounding factors such as caffeine. Thus, the use of pre-workout supplements containing synephrine may lead to serious adverse health events, and therefore, caution is needed.

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Acute p-synephrine ingestion increases whole-body fat oxidation during 1-h of cycling at Fatmax

Cited by 14 publications

References 15 publications

Effects of p-Synephrine during Exercise: A Brief Narrative Review

Effects of p-Synephrine during Exercise: A Brief Narrative Review

Caffeine increases whole-body fat oxidation during 1 h of cycling at Fatmax

Review of Case Reports on Adverse Events Related to Pre-workout Supplements Containing Synephrine

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