Yohimbine

Summary (The Good, The Bad, and all other Essential Benefits/Effects/Facts Information)

Yohimbe and its subset Yohimbine are fat-burning compounds that work in the body by increasing adrenaline levels in the body and inhibiting a regulatory process found on fat cells that is normally suppressive of fat burning, thus leading to an increase fat burning potential.

Yohimbines effects seem to be partially negated with food intake, making yohimbine a great supplement to take during short term fasts or for prolonged periods between meals.

Although its main usage is for fat burning yohimbine is also known to be an aphrodisiac and aid to erectile dysfunction, as well as a general stimulant.

Also Known As

Yohimbe, Corynanthe Yohimbe, Yohimbe Bark

Is a Form of

• Fat-Burner

Goes Well With

• Adrenaline increasing compounds (L-Tyrosine, Caffeine)

Does Not Go Well With

• large insulin spikes and food intake.

How to Take (recommended dosage, active amounts, other details)

Dosages of 0.2mg/kg bodyweight have been used with success to increase fat burning without significant implications on cardiovascular parameters (heart rate, blood pressure, etc.)

This equates to 13.6mg for a 150lb individual and 18.2mg for a 200lb individual.

This dosage level has been shown as safe and efficacious for yohimbine in isolation.

Things to Note

Yohimbe is highly stimulatory.

Caution Notice (just some FYI - if needed)

Yohimbine can act as a Monoamine Oxidase inhibitor and can elevate levels of adrenaline, serotonin, and dopamine (amongst other monoamines). Caution should be taken when taking other compounds which may also act as MAO inhibitors or with compounds that increase levels of monoamines.

Yohimbine can cause extreme anxiety in individuals predisposed to anxiety. Yohimbine may trigger manic psychosis or suicidal episodes in Bipolars.

Detailed Summary

1. Yohimbine as an aphrodisiac
2. Actions on the Adipocyte
3. Ketogenesis and Lipolysis
4. Actions in the Nervous and Endocrine System
5. A note on In Vivo Studies
6. In Vivo Studies
7. Safety Profile

Edit1. Yohimbine as an aphrodisiac

Yohimbine is known as an aphrodisiac able to induce sexual behavior and ejaculatory response in lab animals.^[1][2] These results have been somewhat validated in human anecdotes.

It is also a treatment for erectile dysfunction.^[3]

Edit2. Actions on the Adipocyte

Yohimbine acts upon the adrenergic receptor system of fat cells, which regulate thermogenesis. The beta-subunits of the adrenergic receptors can be seen as stimulatory for fat loss as they increase the enzyme Adenyl Cyclate activity and cAMP levels (mainly via the b1 and b2 subunits) whereas the alpha-subunits are more suppressive of fat metabolism, in which their agonism reduces activity of Adenyl Cyclate and reduces cAMP levels (specifically alpha-2).

Yohimbine is a selective alpha-2 adrenergic receptor antagonist, upon the antagonism of the inhibitory receptor, yohimbine supplementation can lead to increased thermogenesis and synaptic noradrenaline levels via increase Adenyl Cyclate activity, cAMP, and other reactions downstream from the two such as modulating the actions of hormone sensitive lipase towards a fat-burning state.^[4]

Yohimbine seems to show high affinity for the alpha-2A subtype in particular.

Edit3. Ketogenesis and Lipolysis

Ketogenesis, or the production of ketone bodies, is enhanced under the presence of noradrenaline under normal conditions. Blocking the alpha adrenergic receptors, via the blocking of the alpha-2 adrenergic receptor, augments the ketogenic and lipolytic effects of noradrenaline. ^[5]

The expected increase in plasma free fatty acids with yohimbine supplementation was not seen when said yohimbine was taken with a meal, as yohimbine appears to augment insulin release when taken concomitantly with food.

Edit4. Actions in the Nervous and Endocrine System

Yohimbine in isolation (at 30mg) does not seem to increase cortisol nor related stress hormone levels in vivo^[6], although increases were noted at this level when injected^[7] and when paired with caffeine at 10mg/kg BW.^[8]

Interestingly, A2-adrenergic receptors are found on both adrenergic and cholinergic nerve terminals, where they serve as negative feedback regulators of neurotransmitter release.

Edit5. A note on In Vivo Studies

Yohimbine acts vicariously through the adrenergic system of fat cells, of which inter-species differences have been noted. The dog has been identified as the most likely representative animal model for alpha-adrenergic antagonism, although caution should still be taken in extrapolating animal studies to humans in this scenario.^[9]

Edit6. In Vivo Studies

Yohimbine supplementation at 0.2mg/kg bodywight in healthy men increased markers of fat burning (free plasma glycerol, non-esterified fatty acids) and was augmented with physical exercise under fasting conditions. These markers were wholly blunted upon feeding.^[10] No adverse cardiac reactions were reported.^[11] However, at least one study has noted opposite results, in that yohimbine did not decrease weight in healthy volunteers.^[12]

In obese women, adding yohimbine (5mg x 2) to a standard combination of Ephedrine (25mg x 2) and Caffeine (200mg x 2) increased the degree of cardiac work.^[13]

Edit7. Safety Profile

In doses of 0.2mg/kg bodyweight, as is the standard in human studies, no adverse effects are noted on parameters of heart health (heart rate, blood pressure) nor are adverse effects on blood glucose or insulin secretion rates noted when administered in isolation.

However, acute neurotoxicity has been reported in man in a dose of 5g (far above the recommended dosage of 0.2mg/kg) in an isolated case study^[14].

Yohimbine does not appear to adversely affect sleep quality.^[15]

Scientific Support & Reference Citations

Yohimbine review study

Adverse drug report summary, Reproductive cytotoxicity potential, and

HPLC analysis of yohimbine

References

1. Rodríguez-Manzo G, Fernández-Guasti A. Reversal of sexual exhaustion by serotonergic and noradrenergic agents. Behav Brain Res. (1994)
2. Yonezawa A, et al. Biphasic effects of yohimbine on the ejaculatory response in the dog. Life Sci. (1991)
3. Vitezic D, Pelcic JM. Erectile dysfunction: oral pharmacotherapy options. Int J Clin Pharmacol Ther. (2002)
4. Lafontan M, et al. Alpha-2 adrenoceptors in lipolysis: alpha 2 antagonists and lipid-mobilizing strategies. Am J Clin Nutr. (1992)
5. Keller U, Weiss M, Stauffacher W. Contribution of alpha- and beta-receptors to ketogenic and lipolytic effects of norepinephrine in humans. Diabetes. (1989)
6. Cuneo RC, et al. Effects of alpha-2 adrenoreceptor blockade by yohimbine on the hormonal response to hypoglycaemic stress in normal man. Horm Metab Res. (1989)
7. Krystal JH, et al. Serotonergic and noradrenergic dysregulation in alcoholism: m-chlorophenylpiperazine and yohimbine effects in recently detoxified alcoholics and healthy comparison subjects. Am J Psychiatry. (1996)
8. Mattila M, Seppala T, Mattila MJ. Anxiogenic effect of yohimbine in healthy subjects: comparison with caffeine and antagonism by clonidine and diazepam. Int Clin Psychopharmacol. (1988)
9. Taouis M, et al. Mechanism of the lipid-mobilizing effect of alpha-2 adrenergic antagonists in the dog. J Pharmacol Exp Ther. (1988)
10. Galitzky J, et al. Alpha 2-antagonist compounds and lipid mobilization: evidence for a lipid mobilizing effect of oral yohimbine in healthy male volunteers. Eur J Clin Invest. (1988)
11. Galitzky J, et al. Pharmacodynamic effects of chronic yohimbine treatment in healthy volunteers. Eur J Clin Pharmacol. (1990)
12. Sax L. Yohimbine does not affect fat distribution in men. Int J Obes. (1991)
13. Waluga M, et al. Cardiovascular effects of ephedrine, caffeine and yohimbine measured by thoracic electrical bioimpedance in obese women. Clin Physiol. (1998)
14. Giampreti A, et al. Acute neurotoxicity after yohimbine ingestion by a body builder. Clin Toxicol (Phila). (2009)
15. Gentili A, et al. Effect of clonidine and yohimbine on sleep in healthy men: a double-blind, randomized, controlled trial. Eur J Clin Pharmacol. (1996)

Last Updated: Jan 6, 2012 13:23:15