What Is Rauwolscine?
Rauwolscine is a molecule mainly found in two groups (genera) 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 has anti-cancer potential [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.
How It Works
To understand how rauwolscine works, we can’t escape diving into physiology a bit. Here we’ll zoom into the effects of rauwolscine on a cellular level.
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 .
This sounds simple enough, but the receptors rauwolscine acts on are less straightforward. 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 may be why rauwolscine’s blockage may also counter the effects of high stress and anxiety [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].
Snapshot of Rauwolscine
- May boost fat burning
- May reduce appetite
- May relieve anxiety
- Anti-cancer potential
- Much lower dosage needed than for yohimbine
- Potential to cause anxiety
- Interacts with medications
- Not studied in humans
Health Benefits & Effects of Rauwolscine
1) May Reduce Anxiety
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. Despite this, yohimbine helped reduce social anxiety in one clinical study [7, 22, 23].
Rauwolscine is a double-edged sword when it comes to anxiety: it may help you feel less anxious, but it might also amplify your stress response. Carefully monitor your reaction and avoid high doses.
2) May Increase Fat Burning and Reduce Appetite
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, 24, 25, 26].
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 may support fat loss .
3) May Improve Sexual Function
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 .
Rauwolscine appears to improve sexual function within a narrow range of lower doses. When it comes to rauwolscine, more is not better.
4) Mixed Effects on the Heart
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. However, it had the opposite effect in conscious rats: it increased their heart rate [9, 15].
Rauwolscine also prevented the narrowing of blood vessels and an increase in blood pressure caused by stress .
Rauwolfia, a plant that contains rauwolscine and after which this compound got its name, is traditionally used to lower high blood pressure. Interestingly enough, its effects stem from another compound called reserpine. Reserpine lowers the levels and release of norepinephrine from neurons, reducing fight-or-flight activity–somewhat countering the effects of rauwolscine .
Unlike rauwolfia, rauwolscine has mixed effects on the heart and stress response; it could even be dangerous in people with heart disease. Even if your heart is healthy, pay attention to the changes in your heart rate and blood pressure when supplementing with rauwolscine.
5) Anti-Cancer Potential
Extracts of the Rauwolfia vomitoria plant, in which rauwolscine is found, have been used in traditional medicine in Africa as an anti-cancer remedy .
Norepinephrine and epinephrine stimulate growth and division in breast cancer cells by activating alpha-2 receptors. Rauwolscine injections prevented breast cancer cells from multiplying in mice, shrinking their tumors. Yohimbine had no effect on tumor growth [34, 35, 4].
Rauwolscine may help reduce the growth of certain cancers by making alpha-2 receptors less functional, which sets it apart from yohimbine.
- Excessive sweating
- Increased heart rate
- Frequent urination
- Increased blood pressure
Dosage & Forms
The optimal dosage can’t be established as there are no studies in humans.
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 is probably more effective for fat loss when taken in a fasted state as a pre-workout [25, 25, 38].
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
For increasing fat loss and sexual function, opt for pure rauwolscine HCL. Extracts will 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 .
Propranolol (Inderal) is a beta-blocker used to treat high blood pressure, chest pain, and irregular heartbeat. Rauwolscine counteracts the blood pressure-lowering effect of propranolol .
Clonidine (Catapres) is a drug used to treat high blood pressure. Rauwolscine reduces the effectiveness of clonidine by preventing it from binding to alpha-2 receptors .
Rilmenidine (Albarel, Hyperium) is a drug used to reduce high blood pressure. It may also help with glaucoma by decreasing pressure in the fluids of the eye. Rauwolscine prevented rilmenidine from reducing fluid pressure in the eye .
Rauwolscine may enhance the effects of the antidepressant desipramine (Norpramin) .
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.
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 is similar to yohimbine. Their effects on revving fat loss, reducing anxiety, and improving sexual function overlap. But unlike yohimbine, rauwolscine has some anticancer potential.
Its effects in humans are unknown, the current research is limited to animal studies.
Rauwolscine may also interact with drugs commonly used to reduce blood pressure.
If you are prone to anxiety or high blood pressure, avoid this supplement.