Rauwolscine is a plant-based molecule that some use to boost fat loss & physical performance. It might also improve sexual function, but none of its uses are backed up by clinical evidence. This article explores the science behind the uses, potential benefits, and side effects of rauwolscine.
What Is Rauwolscine?
Rauwolscine is a molecule mainly found in two groups of plants: Rauwolfia and Pausinystalia. Sometimes it is called alpha yohimbine or isoyohimbine. Structurally, rauwolscine is very similar to yohimbine [1, 2].
Both rauwolscine and yohimbine are alkaloids found in the yohimbe plant (Pausinystalia johimbe), used traditionally as a stimulant and aphrodisiac. Rauwolscine appears to have similar effects as yohimbine but may be more potent and may have additional perks [2, 3, 4].
Like yohimbine, rauwolscine is primarily taken for boosting fat loss, improving physical performance, and enhancing libido and sexual function. Both are ingredients in various pre-workout supplements.
While animal and cell-based studies back some of these benefits, human trials are lacking to confirm them.
- May boost fat burning
- May reduce appetite
- More potent than yohimbine
- May support sexual function
- Mixed effects on anxiety and heart health
- Interacts with blood pressure meds
- Not studied in humans
- Unknown safety profile
How It Works
To start with, norepinephrine and epinephrine (adrenaline) play key roles in the fight-or-flight (sympathetic) nervous system. Their activity is called adrenergic. It mostly opposes cholinergic activity of the rest-and-digest (parasympathetic) nervous system .
Rauwolscine blocks alpha-2 adrenergic receptors (α2 receptors), binding to them more selectively than yohimbine [6, 3, 7].
Alpha-2 receptors are found in the brain and throughout the body. Mildly activated, they counter the stress response; they calm the heart and brain. That’s why rauwolscine may raise heart rate and act as a stimulant; this also explains its potential to trigger anxiety [8, 9, 10].
When strongly activated, alpha-2 receptors can promote the stress response and raise blood pressure. That’s why rauwolscine may also counter the effects of high stress and anxiety [8, 9, 10].
As another drawback, alpha-2 activation prevents insulin release and fat burning. Rauwolscine’s blockage may rev fat burning and raise insulin [8, 9, 10].
And by blocking alpha-2 receptors, rauwolscine increases norepinephrine, epinephrine, and dopamine levels and decreases serotonin levels. This chemical shift adds to the stimulant effect [11, 12, 13, 14, 15].
Rauwolscine also weakly activates certain serotonin (5-HT1A and 5-HT1D) receptors and blocks others (5-HT1B, 5-HT2A, 5-HT2B, 5-HT2C). As a result, it may reduce appetite and offer antianxiety and antidepressant effects [16, 17, 18, 19, 20, 21].
Still, the above effects are based on animal and cellular research and thus shouldn’t be taken for granted.
Potential Health Benefits & Effects of Rauwolscine
Animal and Cellular Research (Lacking Evidence)
No clinical evidence supports the use of Rauwolscine for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based studies; they should guide further investigational efforts but should not be interpreted as supportive of any health benefit.
Even though rauwolscine increases levels of hormones involved in the stress response, it may paradoxically help with anxiety, based on preliminary research [12, 13].
Rauwolscine reduced anxiety in rats to the same degree as the anti-anxiety drug diazepam (Valium). Yohimbine had no effect on anxiety in this study. What’s more, yohimbine might block the release of GABA, which helps soothe anxiety [7, 22].
Rauwolscine is a double-edged sword when it comes to anxiety as it might also amplify stress response.
2) Fat Burning and Appetite Reduction
Like yohimbine, rauwolscine may increase fat burning by blocking alpha-2 receptors. Both probably work by activating the fight-or-flight system, which mobilizes fats from stores and uses them for energy [14, 23, 24, 25].
Obese and lean mice given rauwolscine consumed up to 33% less food than mice who didn’t receive it. Rauwolscine achieved the same effect as yohimbine at one-third the dose. By reducing appetite, it might support fat loss .
Yohimbine increased fat loss in clinical trials. Rauwolscine might do the same, but studies have yet to determine this [23, 24].
3) Sexual Function
Yohimbine improved erectile dysfunction in a couple of clinical trials, which led researchers to examine the same for rauwolscine [27, 28].
In low doses, rauwolscine increased ejaculate volume and erectile response to stimulation in dogs. But high doses had the opposite effect: blocking erection and sexual behavior .
The available research doesn’t allow for any conclusions.
4) Anti-Cancer Potential
Extract of the Rauwolfia vomitoria plant, a source of rauwolscine, has been used in traditional medicine in Africa as an anti-cancer remedy .
Rauwolscine injections prevented breast cancer cells from multiplying in mice, thus shrinking their tumors. Yohimbine, on the other hand, had no effect on tumor growth [31, 32, 4].
Still, it’s too early to talk about any real anticancer effects based on the available evidence.
Effects on the Heart and Blood Pressure
In rats, rauwolscine reduced heart rate by 22% and blood pressure by 39%. In another study on rats under anesthesia, rauwolscine injections lowered blood pressure. It prevented the narrowing of blood vessels in response to epinephrine .
Rauwolscine also prevented the narrowing of blood vessels and an increase in blood pressure caused by stress in rats .
However, it had the opposite effect in another study on rats: it increased their heart rate .
Rauwolfia, a plant that contains rauwolscine, is traditionally used to lower high blood pressure. However, its effects stem from another compound called reserpine. Reserpine lowers the levels and release of norepinephrine from neurons, reducing fight-or-flight activity .
Mixed effects of rauwolscine on heart health require further investigation.
Limitations and Caveats
While rauwolscine is similar to yohimbine, it is yet to be tested in humans so its exact effects are unknown. Clinical trials are needed to confirm the benefits seen in animal and cell research and to determine the safety, absorption, and appropriate dosage of rauwolscine.
Rauwolscine Side Effects
Keep in mind that the safety profile of rauwolscine is relatively unknown, given the lack of well-designed clinical studies. The list of side effects below is not a definite one, and you should consult your doctor about other potential side effects, based on your health condition and possible drug or supplement interactions.
Due to its similarity in effects, side effects of rauwolscine may resemble those of yohimbine, including [35, 36]:
- Excessive sweating
- Increased heart rate
- Frequent urination
- Increased blood pressure
Caution is warranted until we know more about its safety. Pregnant women and children should avoid it.
Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let them know about all drugs and supplements you are using or considering.
Propranolol (Inderal) is a beta-blocker used to treat high blood pressure, chest pain, and irregular heartbeat. Rauwolscine may counteract the blood pressure-lowering effect of propranolol .
Clonidine (Catapres) is a blood pressure-lowering drug. Rauwolscine reduces the effectiveness of clonidine by preventing it from binding to alpha-2 receptors .
Rilmenidine (Albarel, Hyperium) is used for high blood pressure and glaucoma. In rabbits, rauwolscine prevented rilmenidine from reducing fluid pressure in the eye .
Based on preclinical research, rauwolscine may enhance the effects of the antidepressant desipramine (Norpramin) .
Rauwolscine Dosage & Supplement Forms
Since rauwolscine is not approved by the FDA for any condition, there is no official dose. Users and supplement manufacturers have established unofficial doses based on trial and error. Discuss with your doctor if rauwolscine may be useful as a complementary approach in your case and which dose you should take.
Because it is more potent in activating alpha-2 receptors, the rauwolscine content in supplements is lower (0.5 mg – 2 mg/serving) than of yohimbine (2.5 mg – 5 mg/serving). Like yohimbine, it might be more effective for fat loss when taken in a fasted state as a pre-workout [24, 24, 40].
Supplementing with agmatine may reduce the effectiveness of rauwolscine. Rauwolscine may also interfere with the effectiveness of forskolin [41, 17].
Rauwolfia vs. Rauwolscine HCl
Rauwolscine supplements will usually come in the form of either:
- An extract of Rauwolfia vomitoria or Rauwolfia serpentina standardized to contain 90% rauwolscine (10% other compounds)
- Pure (> 99%) rauwolscine HCl
Extracts are a more natural option, but they contain other active compounds that may cause unwanted effects .
Yohimbe bark extracts often contain small quantities of rauwolscine.
However, many of the popular extracts on the market were incredibly inaccurate in how much yohimbine their product actually contained (ranging from 23% to 147% of the label content). Take the information on the product label with a grain of salt, as the stated rauwolscine content may be equally inaccurate .
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Rauwolscine users generally report increased fat loss, especially in stubborn areas around the chest and abs. Increases in energy and motivation are also noted.
Heachaches and anxiety have been reported by some users, though to a lesser extent than with yohimbine.
Some people that can’t tolerate yohimbine find that they can tolerate rauwolscine.
Rauwolscine blocks alpha-2 adrenergic receptors, which may support sexual function but have mixed effects on heart health and anxiety. It is similar to yohimbine; their potential effects on revving fat loss and improving sexual function might overlap.
Still, its effects in humans are unknown, as the current research is limited to animals. Rauwolscine may interact with drugs commonly used to reduce blood pressure.
You may want to avoid taking it until clinical trials verify its safety and efficacy.