Yohimbine Information and research studies
Do pills work for impotence or erectile dysfunction?

Yohimbine is a potent and relatively nonselective alpha(2)-adrenergic receptor antagonist. It has been available as a prescription medication for several decades and was popular until Viagra, Levitra, and Cialis became available in 1998. These three prescription medications took over as effective treatments for impotence and since then the popularity of yohimbine pills dropped dramatically.
   Yohimbine is found in over the counter yohimbe bark extract which is effective for erectile dysfunction, particularly when used with other sexual enhancing herbs such as tribulus terrestris, Horny-Goat-Weed and tongkat ali. But use yohimbe bark extract containing yohimbine in low dosages since it is easy to get side effects from it. Yohimbe bark has a number of ingredients, including a small percentage of the alkaloid yohimbine. Various extract potencies are available for yohimbe, including yohimbine 2 percent, 4 percent, 8 percent, and up to 20 percent.
   In April 2009 we searched Medline for new human studies with yohimbine, but the latest one we could find was the study from May 2007 that evaluated this substance as a treatment for orgasmic dysfunction.

Users say Passion Rx with Yohimbe bark extract:
Supports healthy sensation and stamina
Supports healthy libido and sexual thoughts
Supports healthy erectile function
Supports healthy orgasms and climaxes
Passion Rx supports and maintains many aspects of the human sexual experience.

Click here to buy Yohimbe herb product or Passion Rx with Yohimbe. This product is very popular and effective as a sexual enhancer. It has a small amount of yohimbine in order to minimize side effects.

Yohimbine helpful for sexual dysfunction
Yohimbine in the treatment of orgasmic dysfunction.
Asian J Androl. 2007 May. Adeniyi AA, Brindley GS, Pryor JP, Ralph DJ. Institute of Urology and Nephrology, London W1P 7EY, UK.
To study the effect of yohimbine in the treatment of men with orgasmic dysfunction. A 20-mg dose of yohimbine was first given to 29 men with orgasmic dysfunction of different etiology in the clinic. Of the 29 patients who completed the treatment, 16 managed to reach orgasm and were able to ejaculate either during masturbation or sexual intercourse. A further three achieved orgasm, but only with the additional stimulation of a vibrator. A history of preceding nocturnal emissions was present in 69% of the men in whom orgasm was induced but only 50% who failed treatment. Of the patients, two have subsequently fathered children (one set of twins) and another 3 men were also cured. Side effects were not sufficient to cause the men to cease treatment. Yohimbine is a useful treatment option in orgasmic dysfunction.

Yohimbine side effects, caution, danger, and safety issues
Common side effects include increased body temperature, dizziness, headache, nausea, blurred vision (due to dilation of the pupil), flushing, tightness in the chest, rapid heartbeat, anxiety or panic attacks, restlessness, and sweating, especially in the armpits. These side effects are dose dependent, meaning the lower the dosage you use, the less likely you will have these adverse effects. Do not take yohimbine if you have a heart condition.

Yohimbine physiological effects
Effects of glucagon-like peptide-1, yohimbine, and nitrergic modulation on sympathetic and parasympathetic activity in humans.
Am J Physiol Regul Integr Comp Physiol. 2008 Sepember. Bharucha AE, Charkoudian N, Andrews CN, Camilleri M, Sletten D, Zinsmeister AR, Low PA. Bharucha AE, Charkoudian N, Andrews CN, Camilleri M, Sletten D, Zinsmeister AR, Low PA. Clinical Enteric Neuroscience Translational and Epidemiological Research Program, Mayo Clinic, 200 First St. S.W., Rochester, MN 55905, USA.
Glucagon-like peptide-1 (GLP-1), an incretin, which is used to treat diabetes mellitus in humans, inhibited vagal activity and activated nitrergic pathways. In rats, GLP-1 also increased sympathetic activity, heart rate, and blood pressure (BP). However, the effects of GLP-1 on sympathetic activity in humans are unknown. Our aims were to assess the effects of a GLP-1 agonist with or without alpha(2)-adrenergic or -nitrergic blockade on autonomic nervous functions in humans. In this double-blind study, 48 healthy volunteers were randomized to GLP-1-(7-36) amide, the nitric oxide synthase (NOS) inhibitor N(G)-monomethyl-l-arginine acetate (l-NMMA), the alpha(2)-adrenergic antagonist yohimbine, or placebo (i.e., saline), alone or in combination. Hemodynamic parameters, plasma catecholamines, and cardiac sympathetic and parasympathetic modulation were measured by spectral analysis of heart rate. GLP-1 increased (P = 0.02) MSNA but did not affect cardiac sympathetic or parasympathetic indices, as assessed by spectral analysis. Yohimbine increased plasma catecholamines and the low-frequency component of heart rate power spectrum, suggesting increased cardiac sympathetic activity.

Relationship of cytochrome P450 pharmacogenetics to the effects of yohimbine on gastrointestinal transit and catecholamines in healthy subjects.
Neurogastroenterol Motil. 2008 August. Bharucha AE, Skaar T, Andrews CN, Camilleri M, Philips S, Seide B, Burton D, Baxter K, Zinsmeister AR. Clinical and Enteric Neuroscience Translational and Epidemiological Research Program (C.E.N.T.E.R.), Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Alpha-2 adrenergic receptors tonically inhibit colonic motility and the alpha(2)-adrenergic antagonist yohimbine, given intravenously, increased colonic tone in humans. However, the effect of yohimbine on colonic transit in humans is unknown. In this study, 30 healthy volunteers were randomized to yohimbine 16 mg p.o. t.i.d. or identical placebo for 7 days. We evaluated gastric emptying, small intestinal, and colonic transit by scinitigraphy, bowel habits, haemodynamics and plasma catecholamines. As cytochrome P450 enzymes metabolize yohimbine, P450 genotypes (CYP2D6 and CYP3A4) were determined in 25 of 30 subjects who consented to genetic studies. Compared to placebo, yohimbine increased diastolic blood pressure, plasma noradrenaline concentrations and maximum tolerated volume during the satiation test. However, yohimbine did not affect gastrointestinal transit. Based on CYP2D6 and CYP3A4 alleles, seven and 18 subjects were, respectively, extensive (EM) and poor (PM) metabolizers of yohimbine. Compared to EM, PM of yohimbine had a greater increase in plasma noradrenaline, lower maximum tolerated volumes, and faster colonic transit. These data suggest that CYP2D6 and CYP3A4 genotypes which determine the metabolism of yohimbine may influence its sympathetic and gastrointestinal effects.

Yohimbine attenuates baroreflex-mediated bradycardia in humans.
Hypertension. 2007 November. Franz Volhard Clinical Research Center, Medical Faculty of the Charité and HELIOS Klinikum, Berlin, Germany. Tank J, Heusser K, Diedrich A, Brychta RJ, Luft FC, Jordan J. Franz Volhard Clinical Research Center, Medical Faculty of the Charité and HELIOS Klinikum, Berlin, Germany.
Alpha-2 adrenoreceptor stimulation profoundly augments baroreflex-mediated bradycardia presumably through parasympathetic activation. We tested the hypothesis that endogenous alpha-2 adrenergic tone mediates a similar response. In 10 healthy men, we determined baroreflex control of heart rate and sympathetic traffic after ingestion of the selective alpha-2 adrenoceptor antagonist yohimbine (20 mg) or placebo. We measured heart rate, brachial and finger blood pressure, and muscle sympathetic nerve activity. Plasma norepinephrine increased with yohimbine and was unchanged with placebo. Blood pressure increased with yohimbine. Heart rate increased 5+/-1 beats per minute with yohimbine but did not change with placebo. Ninety minutes after yohimbine ingestion, resting muscle sympathetic nerve activity was similar with yohimbine and with placebo. Baroreflex control of heart rate was decreased with yohimbine (6 ms/mm Hg versus 10 ms/mm Hg) and reset to higher blood pressure and heart rate values. In contrast, yohimbine did not alter the sympathetic baroreflex curve. Yohimbine selectively attenuates baroreflex heart rate control in normotensive young men possibly through parasympathetic mechanisms.

Yohimbine, exercise performance, and weight loss
Yohimbine: the effects on body composition and exercise performance in soccer players.
Res Sports Med. 2006 Oct-Dec. Ostojic SM. Institute of Sports Medicine, Sports Academy, Belgrade, Serbia and Montenegro.
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. There were no statistically significant changes in body mass and muscle mass within or between trials after the supplementation protocol. Percentage of body fat significantly decreased in the yohimbine group after the supplementation protocol. Furthermore, fat mass was significantly lower in the yohimbine versus placebo trial at postsupplementation assessment. There were no changes in exercise performance indicators. No subject reported any side effects from yohimbine. The results of the current study indicate that supplementation with yohimbine combined with resistance training does not significantly alter the body mass, muscle mass, or performance indicators in professional soccer players. Nonetheless, yohimbine supplementation appears to be suitable as a fat loss strategy in elite athletes.
   Comments by us: We believe there are safer natural supplements for exercise performance enhancement and appetite suppression, for instance creatine supplements and Diet Rx, respectively.

Yohimbine and orgasmic dysfunction
Yohimbine in the treatment of orgasmic dysfunction.
Asian J Androl. 2007 May. Adeniyi AA, Brindley GS, Pryor JP, Ralph DJ. Institute of Urology and Nephrology, London W1P 7EY, UK.
To study the effect of yohimbine in the treatment of men with orgasmic dysfunction. A 20-mg dose of yohimbine was first given to 29 men with orgasmic dysfunction. Patients were then allowed to increase the dose at home (titration) under more favourable circumstances. The patients were classified into three groups of orgasmic dysfunction: primary complete (13), primary incomplete (8) and secondary (8). Nocturnal emissions were present in 75%, 40% and 50% of patients in the above groups, respectively (overall average 62%). The men presented because of fertility problems (52%) or because they wanted to experience the pleasure of orgasm (48%). Of the 29 patients who completed the treatment, 16 managed to reach orgasm and were able to ejaculate either during masturbation or sexual intercourse. A further three achieved orgasm, but only with the additional stimulation of a vibrator. A history of preceding nocturnal emissions was present in 69% of the men in whom orgasm was induced but only 50% who failed treatment. Of the patients, two have subsequently fathered children (one set of twins) and another 3 men were also cured. Side effects were not sufficient to cause the men to cease treatment. Yohimbine is a useful treatment option in orgasmic dysfunction.

Yohimbine, behavior and impulsivity
Acute yohimbine increases laboratory-measured impulsivity in normal subjects.
Biol Psychiatry. 2005 May 15. Swann AC, Birnbaum D, Jagar AA, Dougherty DM, Moeller FG.
Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston, Texas 77030, USA. State-dependent changes in impulsivity may be related to norepinephrine. To examine possible relationships between norepinephrine and acute changes in impulsivity, we measured effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on laboratory-measured impulsivity in healthy subjects without psychiatric or substance-use disorders. Yohimbine was associated with a dose-related increase in impulsive behavior. Our results are consistent with increased impulsivity in normal subjects given yohimbine, possibly related to increased norepinephrine.

Yohimbine and Food
Role of food type in yohimbine- and pellet-priming-induced reinstatement of food seeking.
Physiol Behav. 2006 Jul 30;88(4-5):559-66. Epub 2006 Jun 27. Behavioral Neuroscience Branch, National Institutes of Health, Baltimore, MD 21224,
The anxiogenic drug yohimbine reinstates palatable food seeking in a rat relapse model: a role of CRF(1) receptors. Neuropsychopharmacology [in press]]. We found that the anxiogenic drug yohimbine, as well as pellet-priming, reinstate food seeking in food restricted rats previously trained to lever press for palatable food pellets (25% fat, 48% carbohydrate). Here, we studied the generality of the effect of yohimbine and pellet priming on reinstatement of food seeking by using three distinct pellet types: non-sucrose carbohydrate (NSC) (5.5% fat, 60% carbohydrate, 4.5% fiber), fiber (0% fat, 0% carbohydrate, 91% fiber) and sucrose (0% fat, 91% carbohydrate, 4% fiber). Rats were placed on a restricted diet (75-80% of daily standard food) and for 9-12 intermittent training days (9 h/day, every other day) lever-pressed for the food pellets under a fixed ratio-1 (20-s timeout) reinforcement schedule. Subsequently, the rats were given 9-10 daily extinction sessions during which lever-presses were not reinforced, and were then injected with yohimbine (0, 0.5, 1.0, 2.0 mg/kg, i.p.) or given a single food pellet to induce reinstatement of food seeking. Yohimbine reinstated food seeking previously reinforced by NSC and sucrose pellets, but had a minimal effect on food seeking in rats previously trained to lever press for fiber pellets. Pellet priming produced a greater degree of reinstatement of lever pressing in rats previously trained on NSC pellets than in rats trained on fiber or sucrose pellets. Results suggest that the magnitude of the effect of yohimbine and pellet priming on reinstatement of food seeking depends in part on the composition of the food pellets used during training.

Yohimbine and salivation
Salivary alpha-amylase levels following yohimbine challenge in healthy men.
J Clin Endocrinol Metab. 2006 Sep 12; Department of Clinical Psychology and Psychotherapy, University of Zurich, Zurich, Switzerland.
Standardized psychosocial stress significantly increases salivary alpha-amylase (sAA) but it remains unclear whether sAA reflects autonomic nervous system activation. The aim of this study was to assess cardiovascular effects, sAA and catecholamine secretion following i.v. injection of yohimbine. 13 healthy males (aged 20-28 yr) were examined. Intervention: i.v. injection of yohimbine (0.4 microg/kg) or placebo (0.9% NaCl). Eight saliva and blood samples were taken before and after injection for the assessment of salivary flow rate, sAA, and catecholamine concentrations. In addition, blood pressure, mood, and anxiety were assessed repeatedly. Results: Yohimbine induced increases of sAA activity and output in comparison to placebo, salivary flow rate, and catecholamines were also significantly increased. No significant correlations between alpha-amylase parameters and catecholamines were observed. Conclusions: The results indicate that yohimbine administration activates not only autonomic parameters but also sAA via adrenergic mechanisms, suggesting that sAA might be an indirect indicator of the central sympathetic system.

Yohimbine acts as a putative in vivo alpha2A/D-antagonist in the rat prefrontal cortex.
Neurosci Lett. 2006 Jul 24;402(3):253-8. Epub 2006 May 11. Department of Experimental Zoology and Neurobiology, University of Pecs, 6. Ifjusag str., H-7624 Pecs, Hungary.
Yohimbine has been widely used as alpha2-adrenergic receptor antagonist in neurophysiological research and in clinical therapy. In this study, we provide in vivo electrophysiological evidence, that microiontophoretic application of yohimbine inhibits spontaneous activity of prefrontal neurons of the rat.

The adrenergic alpha2 receptor and sexual incentive motivation in male rats.
Pharmacol Biochem Behav. 2006 Mar;83(3):360-9. Nonclinical R&D, Orion Pharma, Turku, Finland.
The purpose of the present series of experiments was to determine whether drugs acting at the alpha2-adrenoceptor modify unconditioned sexual incentive motivation in the male rat. To that end a highly specific agonist, dexmedetomidine, a corresponding antagonist, atipamezole, and a less specific antagonist, yohimbine, were administered to groups of sexually inexperienced male rats. The subjects were tested in a large rectangular arena, where a sexually receptive female and an intact male were employed as incentives. The incentive animals were confined behind a wire mesh in opposite corners of the arena. The animals could see, hear and smell each other, but no sexual interaction was possible. Approach to the incentives constituted the measure of incentive motivation. In addition, the test provided data on ambulatory activity and general arousal. Dexmedetomidine, at a dose of 8 microg/kg, produced a slight reduction of sexual incentive motivation. Ambulatory activity and general arousal were also inhibited. Atipamezole enhanced the positive incentive properties of the receptive female. Yohimbine had a slight stimulatory effect on sexual incentive motivation at a dose (4 mg/kg) that also reduced ambulatory activity and general arousal. It is concluded that blockade of the adrenergic alpha2 receptor stimulates sexual incentive motivation in the male rat whereas stimulation of it has the opposite effect.

Long-lasting effects of yohimbine on the ejaculatory function in male dogs.
Biomed Res. 2005 Oct;26(5):201-6. Department of Physiology and Anatomy, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai, Japan.
Previous studies have demonstrated that systemic administration of a low dose of the alpha2-adrenoceptor antagonists stimulates the ejaculatory response of male dogs, when this function is analyzed using the amount of ejaculated semen in response to genital stimulation. The present study was designed to further examine the features of the stimulatory effects of the alpha2-adrenoceptor antagonists on ejaculation, especially the duration of action. Treatment with yohimbine (0.1 mg/ kg, i.p.) to male dogs, at 0.5, 1, 3, or 5 h before the testing, produced a significant stimulatory effects on the ejaculatory response elicited by manual penile stimulation; the amount of ejaculated semen was increased and the onset of ejaculation was shortened following each treatment. However, such effects were not observed in the treatment with yohimbine at 8 and 24 h before the testing, indicating that the ejaculatory stimulation induced by yohimbine lasted for a relative long period. By contrast, the stimulatory effects of RX821002, a selective alpha2-adrenoceptor antagonist, on ejaculation were observed only for 1 h after administration. To determine the contribution of the alpha2-adrenoceptor blockade for the long-lasting effect of yohimbine, we tested whether yohimbine can prevent the ejaculatory inhibition induced by clonidine, an alpha2-adrenoceptor agonist. The ejaculatory inhibition (a decrease in the amount of ejaculated semen and a delay onset of ejaculation) elicited by clonidine 1 h before testing was completely blocked by pretreatment with yohimbine at 1 or 5 h before the testing, whereas the pretreatment with the drug at 24 h before the testing did not affect the clonidine-induced ejaculatory inhibition. These results indicate that yohimbine-induced ejaculatory stimulation is continued for a relative long period (at least 5 h after administration), and this long-lasting effects may be related to the alpha2-adrenoceptor blocking property of the drug.

The anxiogenic drug yohimbine activates central viscerosensory circuits in rats.
J Comp Neurol. 2005 Nov 28;492(4):426-41. Myers EA, Banihashemi L, Rinaman L. Department of Neuroscience, University of Pittsburgh, PA 15260, USA.
Systemic administration of the alpha(2)-adrenoceptor antagonist yohimbine activates the HPA stress axis and promotes anxiety in humans and experimental animals. We propose that visceral malaise contributes to the stressful and anxiogenic effects of systemic yohimbine and that yohimbine recruits brainstem noradrenergic (NA) and peptidergic neurons that relay viscerosensory signals to the hypothalamus and limbic forebrain. To begin testing these hypotheses, the present study explored dose-related effects of yohimbine on food intake, conditioned flavor avoidance (CFA), and Fos immunolabeling in rats. Systemic yohimbine (5.0 mg/kg BW, i.p.) inhibited food intake, supported CFA, and increased Fos immunolabeling in identified NA neurons in the ventrolateral medulla, nucleus of the solitary tract, and locus coeruleus. Yohimbine also increased Fos in the majority of corticotropin releasing hormone-positive neurons in the paraventricular nucleus of the hypothalamus. Yohimbine administered at 1.0 mg/kg BW did not inhibit food intake, did not support CFA, and did not increase Fos immunolabeling. Retrograde neural tracing demonstrated that neurons activated by yohimbine at 5.0 mg/kg BW included medullary and pontine neurons that project to the central nucleus of the amygdala and to the lateral bed nucleus of the stria terminalis, the latter region receiving comparatively greater input by Fos-positive neurons. We conclude that yohimbine produces anorexigenic and aversive effects that correlate with activation of brainstem viscerosensory inputs to the limbic forebrain. These findings invite continued investigation of how central viscerosensory signaling pathways interact with hypothalamic and limbic regions to influence interrelated physiological and behavioral components of anxiety, stress, and visceral malaise.

Yohimbine pill questions
Q. Thank you for your great research. Please clear up some confusion. I have taken a product containing Yohimbe. I have stopped taking anything with Yohimbe because it makes me a little dizzy and flush. I also stopped because I have read that the FDA warns against taking it, and that it should not be taken with cheese and red wine. I eat cheese and drink red wine. I also have read that Yohimbine is ok. What is the difference and how do you get just Yohimbine instead of the Yohimbe. I took Passion Rx to help with erectile dysfunction. It helped, but I prefer Levitra because it doesn't cause the discomforting side effects.
   A. Yohimbine is an extract found in yohimbe bark. Yohimbine pill, by itself, is available by prescription from a doctor. The benefit of Passion Rx with yohimbe can be obtained with less side effects by taking a lower dose. A capsule can be opened and one can take half or 2/3 or 3/4 of a capsule every other day or 2 days on, 2 or more days off. Cheese does not interfere with yohimbe or yohimbine, alcohol is not a good idea to have the same day as a yohimbe product.

Q. As for the Yohimbe experiment, I repeated the experiment using pure yohimbine HCl in the amount of 6 mg per day spread out in 3 doses in the morning. For a few days I got both the blood pressure raising effect and the blood pressure lowering effect when the displaced norepinephrine cleared the body. No narcolepsy benefit noted. Also the blood pressure rise was less. After a week the blood pressure stayed up and did not get beck to normal until I was off the yohimbine for 3 days. End of experiment. I will next try the yohimbe bark extract. According to the literature yohimbine is supposed to do nice things in the male department including making the penis hang about a cm longer due to the vasodilation effect. I observed no such effects whatsoever.

Q. I am taking 8 mg yohimbine pill per day for erectile function and want to know how much is in Passion Rx so I can adjust the amount accordingly.
   A. We would suggest not taking the yohimbine pill the same day as Passion Rx. They can be alternated every day with a day or two off each week if your doctor approves.

Q. Where can I buy yohimbine pills over the counter?
   A. Yohimbine pills are only available by prescription but you can buy yohimbe bark extract which will have yohimbine in it depending on the extract concentration.

Q. Is it okay to take a yohimbine pill along with tongkat ali herb?
   A. Only in low dosages since the combination of yohimbine and Tongkat-Ali  could speed heart rate and increase body temperature and cause other side effects.