Home Ingredients Rauwolscine (Alpha-Yohimbine)

Rauwolscine (Alpha-Yohimbine)

Evidence Level
Preliminary
7 Clinical Trials
4 Documented Benefits
1/5 Evidence Score

No human trial of oral rauwolscine has been published, so its effects and safety at supplement doses are unknown; the US military's Operation Supplement Safety program calls products listing it possibly unsafe. Rauwolscine, also sold as alpha-yohimbine, is a plant alkaloid and stereoisomer of yohimbine found in Rauvolfia plants and yohimbe bark, and it can also be made in a laboratory. It blocks alpha-2 adrenergic receptors, a stimulant action, and appears in pre-workout and fat-burner products, often alongside other stimulants. Its close relative yohimbine has been linked to irregular heartbeat, blood pressure problems and seizures; these risks have not been measured for rauwolscine, and in animal tissue tests the two differed in receptor selectivity. Human studies have only placed it into the skin. Health Canada seized pre-workout products labeled with rauwolscine in 2023 as unauthorized.

Studied Dose No oral dose has been studied in people. Human research has only placed it into the skin by iontophoresis. Animal studies used weight-based doses (0.5 mg/kg plus 0.1 mg/kg per hour in anesthetized rabbits; 2.24 mg/kg by intravenous infusion in rats) that do not translate into a supplement amount.
Active Compound Rauwolscine (alpha-yohimbine), an indole alkaloid and diastereoisomer of yohimbine and corynanthine. Products may list it alone or as a Rauvolfia (for example Rauwolfia vomitoria) extract, which can contain other plant alkaloids.

Benefits

Alpha-2 receptor blockade in human skin

In the latest of several small human studies that placed rauwolscine into the skin by iontophoresis (a small electric current), it was delivered into the forearm skin of 30 young adults; none was swallowed. It did not change sweating during 30 minutes of cycling in the heat in women or men. In a separate follow-up test it abolished skin blood vessel narrowing caused by the alpha-2 drug clonidine.

Supported by Trial 1

Food intake in a mouse study

In laboratory mice given limited daily access to food, rauwolscine and yohimbine both significantly reduced food intake over 3 and 6 hours, in genetically obese and in lean mice. This is animal work; no study has tested whether rauwolscine affects appetite or body weight in people.

Supported by Trial 5

Noradrenaline release in a rabbit study

In anesthetized rabbits, rauwolscine raised resting blood noradrenaline without raising nerve firing, meaning more noradrenaline was released per nerve signal. It also strengthened the heart rate response when blood pressure was lowered with a drug. This stimulant action has not been measured in people taking it by mouth.

Supported by Trial 6

Behavior in a rat anxiety test after intravenous dosing

In rats given rauwolscine intravenously (2.24 mg/kg), behavior in a lick and shock conflict test changed in the same direction as with the anti-anxiety drug diazepam, while yohimbine had no such effect. The study authors note yohimbine causes anxiety in animals and people. This single rat study cannot predict how rauwolscine capsules affect mood.

Supported by Trial 7

Mechanism of action

1

Alpha-2 adrenergic receptor blockade

Like yohimbine, rauwolscine blocks alpha-2 adrenergic receptors, which normally act as a brake on noradrenaline release from nerve endings. Blocking them raised noradrenaline release in rabbits and reversed the effects of the alpha-2 drug clonidine in dogs and rats.

2

Selectivity that differs from yohimbine

In anesthetized dogs, rauwolscine and yohimbine were about equally potent alpha-2 blockers and about 30 times more potent at alpha-2 than alpha-1 receptors. In rat tissue tests, however, rauwolscine was only about 3 times more selective for alpha-2 receptors, against about 45 times for yohimbine, and was the stronger alpha-1 blocker. These are animal findings.

3

Serotonin receptor activity

In cell studies, rauwolscine acted as a partial activator of the human serotonin 5-HT1A receptor and bound tightly to the human 5-HT2B receptor. What these lab findings mean for people taking it by mouth is unknown.

Clinical trials

1
Rauwolscine Delivered Through the Skin and Exercise Sweating: Human Study (not oral)
PubMed

Human study in which rauwolscine (an alpha-2 blocker), terazosin (an alpha-1 blocker) or saline was delivered into small forearm skin sites by transdermal iontophoresis before exercise; no rauwolscine was swallowed. (Meng et al. 2025, Skin Pharmacol Physiol)

30 healthy young adults (15 women, 15 men) cycling for 30 minutes at 50% of peak oxygen uptake at 32°C.

Neither rauwolscine nor terazosin changed sweating during exercise compared with control sites, in women or men. In a follow-up study, rauwolscine abolished clonidine-induced narrowing of skin blood vessels, confirming that it reached and blocked alpha-2 receptors in the skin. The study tested a skin research tool, not an oral supplement.

2
Rauwolscine and Other Alkaloids in 49 US Yohimbe Supplements: Product Analysis
PubMed

Laboratory analysis of 49 brands of supplements labeled as containing yohimbe or yohimbine, bought from seven major US retailers, measuring three yohimbe alkaloids: yohimbine, rauwolscine and corynanthine. (Cohen et al. 2016, Drug Test Anal)

49 supplement brands; no people were studied.

Yohimbine per serving ranged from none detected to 12.1 mg. Rauwolscine and corynanthine were absent from 39% of products (19 of 49), which the authors read as a sign that the yohimbine came from a highly processed extract or was synthetic. Only 11 brands listed a yohimbine amount, and most were inaccurate. The abstract does not report rauwolscine amounts.

3
Yohimbine, Rauwolscine and Corynanthine Receptor Selectivity in Anesthetized Dogs
PubMed

Animal pharmacology study comparing the alpha-2 (presynaptic) and alpha-1 (postsynaptic) blocking potency of yohimbine and its two diastereoisomers. (Shepperson et al. 1981, J Pharmacol Exp Ther)

Anesthetized dogs; no people.

Yohimbine and rauwolscine were equally potent at blocking clonidine's alpha-2 effect on heart rate and about 100 times more potent than corynanthine. All three were equally potent alpha-1 blockers, so yohimbine and rauwolscine were about 30 times more potent at alpha-2 than at alpha-1 receptors.

4
Idazoxan, Yohimbine, Rauwolscine and Corynanthine Compared in Rat Tissues
PubMed

Animal pharmacology study of alpha-2 and alpha-1 blocking potency in isolated rat tissues, rat brain receptor binding and pithed rats given the drugs intravenously. (Doxey et al. 1984, Naunyn Schmiedebergs Arch Pharmacol)

Rat tissues and pithed rats; no people.

Alpha-2 to alpha-1 selectivity was 245 for idazoxan, 45 for yohimbine, 3 for rauwolscine and 0.03 for corynanthine; rauwolscine was the most potent alpha-1 blocker of the four. Intravenous rauwolscine fully reversed clonidine's effect in pithed rats. These results differ from the dog study, a reminder that rauwolscine and yohimbine are not interchangeable.

5
Rauwolscine and Yohimbine Reduce Food Intake in Obese and Lean Mice
PubMed

Animal study of the alpha-2 blockers yohimbine and rauwolscine on food intake. (Callahan et al. 1984, Pharmacol Biochem Behav)

Genetically obese (obob) and lean mice with 6 hours of food access a day; no people.

Both drugs significantly reduced food intake over 3 and 6 hours in obese and lean mice, and obese mice were more sensitive. Effective yohimbine doses did not change water intake. No human appetite or body weight data exist for rauwolscine.

6
Rauwolscine and Noradrenaline Release in Anesthetized Rabbits
PubMed

Animal study measuring blood pressure, sympathetic nerve firing, blood noradrenaline and heart rate after clonidine, yohimbine (1 mg/kg plus 0.1 mg/kg per hour) or rauwolscine (0.5 mg/kg plus 0.1 mg/kg per hour). (Szabo et al. 1989, Naunyn Schmiedebergs Arch Pharmacol)

Anesthetized rabbits; no people.

Rauwolscine and yohimbine raised resting blood noradrenaline without raising sympathetic nerve firing, meaning more noradrenaline was released per nerve impulse. When blood pressure was lowered with nitroprusside, the drop was smaller and the heart rate rise was larger. Clonidine reduced resting blood pressure, nerve firing and heart rate.

7
Intravenous Rauwolscine in a Rat Conflict Test
PubMed

Animal behavior study of alpha-2 blockers and other adrenergic drugs given intravenously in the Vogel lick and shock conflict test. (La Marca et al. 1994, Life Sci)

Rats; no people.

Rauwolscine (2.24 mg/kg) and idazoxan increased punished drinking, like clonidine and diazepam, a pattern read as anti-anxiety. Yohimbine and piperoxan had no such effect. It is a single animal test with intravenous dosing and does not show any mood effect of oral rauwolscine in people.

Side effects and drug interactions

Common Potential side effects

No clinical study of the safety of rauwolscine has been reported, so its side effects at supplement doses are unknown. The US military's Operation Supplement Safety program describes products listing rauwolscine as possibly unsafe.
Rauwolscine shares yohimbine's main action. According to NCCIH, yohimbine has been linked to irregular heartbeat, blood pressure problems, heart attacks and seizures. These risks have not been measured for rauwolscine, but the shared action is a reason for caution.
Health Canada lists these possible effects of yohimbine: higher blood pressure and heart rate, anxiety, dizziness, tremors, headache, nausea and sleep problems. Its 2023 advisory described rauwolscine as also known as yohimbine, but these effects have not been measured for rauwolscine itself.
According to Operation Supplement Safety, weight-loss and pre-workout products containing rauwolscine have been found to contain other, sometimes hidden, stimulants, and their combined effects can be dangerous.
According to Operation Supplement Safety, products labeled as a Rauvolfia extract may also contain other Rauvolfia compounds such as reserpine. Rauvolfia might lower blood pressure, causing dizziness, tiredness, irregular heartbeat and breathlessness, and might cause or worsen depression; children and pregnant or nursing women should avoid it.
Health Canada advises against yohimbine during pregnancy or breastfeeding and for people with high blood pressure, heart, kidney or liver disease, or psychiatric conditions. Rauwolscine has not been studied in these groups.

Important Drug interactions

MAO inhibitors and tricyclic antidepressants: do not combine. These are listed as interactions for yohimbe; rauwolscine has not been tested, but it blocks the same receptors.
Clonidine and other alpha-2 agonists: rauwolscine reversed clonidine's effects in animal studies and blocked clonidine's effect in human skin, so it may work against these medicines.
Blood pressure medicines: yohimbine is linked to higher blood pressure and heart rate, and rauwolscine's effect has not been measured, so it may work against them.
Caffeine and other stimulants: pre-workout products often combine rauwolscine with several stimulants, and combined stimulant effects can be dangerous.
If you take any medicine, talk with your health care provider before using rauwolscine.

Explore Other Ingredients

Antioxidant
Milk Thistle
Milk thistle (Silybum marianum) supplies silymarin, a mix of plant compounds called flavon…
Antioxidant
NAC (N-Acetylcysteine)
N-acetylcysteine (NAC) is a modified form of the amino acid cysteine. The body uses cystei…
Dandelion Root
Dandelion root is the root of the common dandelion (Taraxacum officinale), a plant used as…

Frequently asked questions about Rauwolscine (Alpha-Yohimbine)

Is rauwolscine safe, and does it have side effects?

Its safety is unknown. No clinical safety study of rauwolscine has been reported, and the US military's Operation Supplement Safety program calls products listing it possibly unsafe. It shares yohimbine's main action. According to NCCIH, yohimbine has been linked to irregular heartbeat, blood pressure problems, heart attacks and seizures, and Health Canada lists higher blood pressure and heart rate, anxiety, dizziness, tremors, headache, nausea and sleep problems for yohimbine. These effects have not been measured for rauwolscine itself. Products containing it often add other stimulants. Do not combine it with MAO inhibitors, tricyclic antidepressants, clonidine or blood pressure medicines, and talk to a doctor first.

What is rauwolscine?

Rauwolscine, also labeled alpha-yohimbine, is a stimulant alkaloid found in Rauvolfia plants and in yohimbe bark, and it can also be made in a laboratory. It blocks alpha-2 adrenergic receptors and is sold mainly in pre-workout and fat-burner products. It has not been tested in human trials as an oral supplement.

Is rauwolscine the same as yohimbine?

No. It is a stereoisomer of yohimbine, meaning the same atoms arranged differently. Both block alpha-2 receptors, but in rat tissue studies rauwolscine was far less selective for those receptors than yohimbine, so yohimbine research cannot simply be applied to it. Some labels and regulators still treat the two as the same.

What is the recommended dosage of rauwolscine?

There is no recommended or studied oral dose. No human trial has tested rauwolscine taken by mouth, so the amounts on pre-workout and fat-burner labels are not based on human research. Animal studies used weight-based doses, some given intravenously, that do not translate into a supplement amount.

What is rauwolscine used for?

It is sold mainly in pre-workout and fat-burner products for its stimulant action, but no human trial supports these uses. Research on it consists of animal and lab pharmacology plus small studies that placed it into human skin to study blood vessel and sweating responses.

Does rauwolscine help with fat loss?

There is no human evidence that it does. The only related finding is that it reduced short-term food intake in mice. No trial has tested rauwolscine for appetite, fat loss or body weight in people.

Is rauwolscine legal?

It is sold in US supplements, which the FDA does not approve before sale. It is not prohibited for US service members. In 2023 Health Canada seized pre-workout products labeled with rauwolscine as unauthorized, treating it as yohimbine, which is a prescription drug in Canada.

Does Rauwolscine interact with any medications?

Possible interactions include: MAO inhibitors and tricyclic antidepressants: do not combine. These are listed as interactions for yohimbe; rauwolscine has not been tested, but it blocks the same receptors. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Rauwolscine?

NutraSmarts rates the evidence for Rauwolscine as Preliminary (1 out of 5). It is backed by 7 study summaries and 14 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(14 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Meng L, Wang H, Otsuka J, Okamoto Y, Yokoyama S, Oshima S, Kato H, Lei TH, Amano T. Do Transdermal Administration of α(1)- and α(2)-Adrenergic Receptor Antagonists Modulate Sweating in Exercising Young Females in the Heat? Skin Pharmacol Physiol. 2025;38(4):149-158. doi: 10.1159/000546961.PubMedUsed to support: Human study in 30 young adults (15 women): rauwolscine delivered into forearm skin by transdermal iontophoresis did not change sweating during 30 minutes of cycling in the heat, but abolished clonidine-induced skin vasoconstriction in a follow-up study. Skin delivery, not oral.
  2. Cohen PA, Wang YH, Maller G, DeSouza R, Khan IA. Pharmaceutical quantities of yohimbine found in dietary supplements in the USA. Drug Test Anal. 2016;8(3-4):357-69. doi: 10.1002/dta.1849.PubMedUsed to support: Analysis of 49 US yohimbe or yohimbine supplements for three Pausinystalia johimbe alkaloids (yohimbine, rauwolscine, corynanthine): yohimbine per serving ranged from none to 12.1 mg; 39% of products contained no rauwolscine or corynanthine; most labels that stated an amount were inaccurate.
  3. Shepperson NB, Duval N, Massingham R, Langer SZ. Pre- and postsynaptic alpha adrenoceptor selectivity studies with yohimbine and its two diastereoisomers rauwolscine and corynanthine in the anesthetized dog. J Pharmacol Exp Ther. 1981;219(2):540-6..PubMedUsed to support: Anesthetized dog study: yohimbine and rauwolscine were equipotent alpha-2 blockers, about 100 times more potent than corynanthine, and about 30 times more potent at alpha-2 than alpha-1 receptors. Animal pharmacology.
  4. Doxey JC, Lane AC, Roach AG, Virdee NK. Comparison of the alpha-adrenoceptor antagonist profiles of idazoxan (RX 781094), yohimbine, rauwolscine and corynanthine. Naunyn Schmiedebergs Arch Pharmacol. 1984;325(2):136-44. doi: 10.1007/BF00506193.PubMedUsed to support: Rat tissue, binding and pithed rat study: alpha-2/alpha-1 selectivity was 45 for yohimbine and 3 for rauwolscine; rauwolscine was the most potent alpha-1 blocker of the four drugs; intravenous rauwolscine reversed clonidine's effect in pithed rats. Animal pharmacology.
  5. Callahan MF, Beales M, Oltmans GA. Yohimbine and rauwolscine reduce food intake of genetically obese (obob) and lean mice. Pharmacol Biochem Behav. 1984;20(4):591-9. doi: 10.1016/0091-3057(84)90309-5.PubMedUsed to support: Mouse study: yohimbine and rauwolscine significantly reduced 3- and 6-hour food intake in food-restricted obese (obob) and lean mice, with obese mice more sensitive. Animal work only.
  6. Szabo B, Hedler L, Starke K. Peripheral presynaptic and central effects of clonidine, yohimbine and rauwolscine on the sympathetic nervous system in rabbits. Naunyn Schmiedebergs Arch Pharmacol. 1989;340(6):648-57. doi: 10.1007/BF00717740.PubMedUsed to support: Anesthetized rabbit study: rauwolscine (0.5 mg/kg plus 0.1 mg/kg per hour) and yohimbine raised basal plasma noradrenaline without raising renal sympathetic nerve activity, and augmented the heart rate response to nitroprusside. Animal pharmacology.
  7. La Marca S, Dunn RW. The alpha-2 antagonists idazoxan and rauwolscine but not yohimbine or piperoxan are anxiolytic in the Vogel lick-shock conflict paradigm following intravenous administration. Life Sci. 1994;54(10):PL179-84. doi: 10.1016/0024-3205(94)00556-7.PubMedUsed to support: Rat study: intravenous rauwolscine (2.24 mg/kg) disinhibited conflict responding like clonidine and diazepam, while yohimbine did not; the authors note yohimbine is anxiogenic in animals and man. Animal work only.
  8. Arthur JM, Casañas SJ, Raymond JR. Partial agonist properties of rauwolscine and yohimbine for the inhibition of adenylyl cyclase by recombinant human 5-HT1A receptors. Biochem Pharmacol. 1993;45(11):2337-41. doi: 10.1016/0006-2952(93)90208-e.PubMedUsed to support: Cell study: rauwolscine and yohimbine were partial agonists at the recombinant human 5-HT1A receptor (Ki 158 nM for rauwolscine, 690 nM for yohimbine). Lab work only.
  9. Wainscott DB, Sasso DA, Kursar JD, Baez M, Lucaites VL, Nelson DL. [3H]Rauwolscine: an antagonist radioligand for the cloned human 5-hydroxytryptamine2b (5-HT2B) receptor. Naunyn Schmiedebergs Arch Pharmacol. 1998;357(1):17-24. doi: 10.1007/pl00005133.PubMedUsed to support: Cell study: rauwolscine bound the cloned human 5-HT2B receptor with relatively high affinity (Ki 14.3 nM) and served as an antagonist radioligand for it. Lab work only.
  10. Operation Supplement Safety (OPSS). Rauwolscine and Rauwolfia: Read your label carefully. Operation Supplement Safety. 2020;Updated 3 November 2020..SourceUsed to support: Not PubMed-indexed. US military supplement-safety resource: rauwolscine (synonym alpha-yohimbine) occurs in Rauwolfia plants or can be made in a laboratory; it is not the same as yohimbine but very similar; no clinical studies on its safety or efficacy have been reported; products listing it are possibly unsafe and have been found to contain other, sometimes hidden, stimulants; Rauwolfia extracts might lower blood pressure, causing dizziness, tiredness, irregular heartbeat and breathlessness; not prohibited for service members.
  11. Health Canada. Unauthorized workout supplements may pose serious health risks. Health Canada Recalls and Safety Alerts. 2023;Public advisory RA-73367, original version published 22 March 2023 (archived revision; the advisory was later updated, last on 9 July 2025)..SourceUsed to support: Not PubMed-indexed. Health Canada seized five Killer Labz Stim Reaper products labeled to contain rauwolscine (Rauwolfia vomitoria extract), described in the advisory as also known as yohimbine; yohimbine is a prescription drug in Canada with possible effects including higher blood pressure and heart rate, anxiety, dizziness, tremors, headache, nausea and sleep disorders, and should not be used in pregnancy, breastfeeding, heart, kidney or liver disease or psychiatric conditions.
  12. National Center for Complementary and Integrative Health. Yohimbe. NCCIH Health Information. 2025;Last updated May 2025..SourceUsed to support: Not PubMed-indexed. US government fact sheet on yohimbe (not rauwolscine): yohimbine has been associated with cardiac arrhythmia, blood pressure problems, heart attacks and seizures; do not use yohimbe with MAO inhibitors or tricyclic antidepressants; it might be unsafe in pregnancy and breastfeeding; dietary supplements are not approved by the FDA before sale.
  13. Drummond PD. Prior iontophoresis of saline enhances vasoconstriction to phenylephrine and clonidine in the skin of the human forearm. Br J Clin Pharmacol. 2002;54(1):45-50. doi: 10.1046/j.1365-2125.2002.01597.x.PubMedUsed to support: Human study in 20 healthy participants: clonidine narrowed forearm skin blood vessels, and skin sites pretreated with rauwolscine by iontophoresis blocked this response. Skin delivery, not oral; one of several small human skin studies of rauwolscine.
  14. Ekenvall L, Lindblad LE, Norbeck O, Etzell BM. alpha-Adrenoceptors and cold-induced vasoconstriction in human finger skin. Am J Physiol. 1988;255(5 Pt 2):H1000-3. doi: 10.1152/ajpheart.1988.255.5.H1000.PubMedUsed to support: Human study: rauwolscine delivered into finger skin by iontophoresis abolished the narrowing of skin blood vessels caused by local cooling, while the alpha-1 blocker doxazosin did not. Skin delivery, not oral.