Yohimbine: The Effects on Body Composition and Exercise Performance in Soccer Players
The main aim of this study was to determine the effects of yohimbine supplementation on body composition and exercise performance in professional soccer players.
The athletes (20 top-level male soccer players) were allocated to two randomly assigned trials. Subjects in the yohimbine group orally ingested tablets that contains yohimbine at a dose of 20 milligrams per day in two equal doses for 21 days. Subjects in the placebo group ingested an equal number of identical-looking pills that contained cellulose.
Percentage of body fat significantly decreased in the yohimbine group after the supplementation protocol (9.3 ± 1.1 vs. 7.1 ± 2.2%; p < 0.05). Furthermore, fat mass was significantly lower in the yohimbine versus placebo trial at post supplementation assessment (7.1 ± 2.2 vs. 9.2 ± 1.9%; p < 0.05).
No subject reported any side effects from yohimbine. Yohimbine supplementation appears to be suitable as a fat loss strategy in elite athletes. [Source]
Pre-exercise administration of yohimbine may enhance the efficacy of exercise training as a fat loss strategy by boosting lipolysis
The natural alpha-2 antagonist yohimbine promotes sympathetic activity by central as well as peripheral mechanisms, and yet in moderate doses dose not usually raise heart rate, increase blood pressure, or induce anxiety (in contrast to sympathomimetic drugs such as ephedrine).
Administered prior to exercise, it boosts lipolysis and serum FFA levels both during and following exercise; blockade of adipocyte alpha-2 adrenoreceptors makes at least a modest contribution to this pro-lipolytic activity. These considerations suggest that pre-exercise administration of yohimbine will lower the respiratory quotient during and following exercise, thus promoting fat loss.
Since yohimbine can potentiate postprandial insulin secretion, its bariatric benefits should be greatest if administered on a schedule that minimizes postprandial yohimbine activity.
A possible synergism of yohimbine and caffeine should be explored. Pre-exercise yohimbine administration has the potential to down-regulate the lipoprotein lipase activity of visceral adipocytes, increase lipolysis in refractory gynoid fat depots, and improve the impaired lipolytic response to exercise in the elderly. [Source]
α2-Antagonist compounds and lipid mobilization: evidence for a lipid mobilizing effect of oral yohimbine in healthy male volunteers
Investigations were carried out to analyse the interactions of α2-antagonists (yohimbine, idazoxan, SK & F-86,466) with human fat cell α2-adrenoceptors. All the α2-antagonists enhanced the lipolytic potencies of epinephrine with an order of potency: yohimbine > idazoxan > SK & F-86,466; the same order was also found in 3H-yohimbine competition studies on human fat cell membranes.
The most potent agent, yohimbine, was administered orally in humans to define the conditions of appearance and the time-course of a putative lipid-mobilizing action. Oral yohimbine administration (0·2 mg kg-1) elevated plasma glycerol and non-esterified fatty acids in fasting healthy subjects without significant action on heart rate or blood pressure during the time-course of the experiment.
The lipid-mobilizing action of yohimbine was reinforced during physical exercise, completely suppressed after a meal and partially blocked by administration of propranolol (0·5 mg kg-1; 60 min before yohimbine). Plasma norepinephrine concentrations were increased (40–50%) after oral yohimbine administration.
The lipid-mobilizing effect of yohimbine could be attributable to: (i) the increase in synaptic norepinephrine with a resultant increment in lipolysis by β-adrenergic agonism; (ii) a decrease in α2-adrenoceptor stimulation of human fat cell α2-adrenoceptors; (iii) a blockade of presynaptic α2-adrenoceptors. The use of highly selective α2-antagonists will allow investigations into α2-adrenoceptors, which may represent a novel locus for pharmacological intervention in lipid-mobilization strategies. [Source]