Yohimbine is a potent herbal alkaloid that has been used to treat erectile dysfunction for years before Viagra was put on the market. It works through the central nervous system to block adrenergic receptors, dilate blood vessels and mess with blood pressure. It may even burn fat, improve diabetes, help to create new memories, and more… but it can come with some nasty side effects.
What is Yohimbine?
The Yohimbe tree is an evergreen that thrives in the lowland forests of West and Central Africa. The bitter-tasting bark is rich in an alkaloid phytochemical called yohimbine, extracted by local tribes for use as a herbal tonic and aphrodisiac.
Yohimbine has been shown to work as an alpha-2 (α2) antagonist. α2-adrenergic receptors located throughout the body control the effects of the sympathetic nervous system. Their signals promote a “fight or flight” response characterized by a tightening of the blood vessels, constricting smooth muscles and veins, inhibiting insulin release, and stopping the breakdown of glycogen.
Yohimbine could reverse these effects by antagonizing (or “blocking”) these receptors and boosting the conversion of adrenaline into noradrenaline. This creates greater blood flow, relaxes smooth muscles, improved blood sugar utilization, energy production, and fat mobilization. While other α2 antagonists generally lower blood pressure, yohimbine has the opposite effect.
The combination of increased blood pressure, heart rate, and vasodilation create a huge rush of oxygenated blood flowing to peripheral tissues – we’re talking areas of dense microcirculation that commonly suffer from poor blood flow: the brain, fat storage, and genitalia.
The Benefits of Yohimbine
Yohimbine has many benefits to it. Here are the most prominent:
Treats Erectile Dysfunction
Yohimbine has been used as a treatment for erectile dysfunction since the 1980s – in fact, it’s been around longer than Viagra or Cialis, but there is a dearth of large and in-depth studies on its effects and safety. A systematic review and meta-analysis of all available research in the late ’90s found that despite the potential for serious side-effects, the effectiveness of yohimbine to treat erectile dysfunction is worth the risk.
Erectile dysfunction is commonly caused by a narrowing of the small arteries in the penis. Yohimbine works to counteract this by dilating these vessels while also boosting blood pressure – this causes an influx of greater blood flow to the small vessels in the penis, resulting in easier and firmer erections.
One double-blind, placebo-controlled crossover study showed that men who took 30mg of yohimbine per day experienced improved self-assessed erectile response during masturbation – but not during intercourse. This may be due to psychological factors, or it may highlight the need to combine yohimbine with other ED therapies.
Aids in Social Anxiety
Yohimbine has a stimulating effect on mood and cognition, increases heart rate, and can cause panic attacks – not the usual cocktail for treating anxiety, right? But it also improves emotional memory which can help to rewire the nervous system to react differently to various stimulus. Yohimbine has been shown to improve the outcomes of clinical interventions for social anxiety disorder, such as exposure therapy.
This type of therapy gently and repeatedly exposes people to fearful situations in a safe, controlled environment. With repetition, this can kind of “re-program” the brain to experience previously fear-inducing situations and now see them as safe and comfortable. By blocking α2 receptors and increasing the activity of noradrenaline in the central nervous system, yohimbine promotes the retention of these safe emotional memories.
With the stronger retention of the new emotional response, fear and social anxiety symptoms could improve more rapidly and fewer total therapy sessions may be needed.
A randomized controlled trial with 40 participants found that taking a 10.8mg dose of yohimbine an hour before exposure therapy sessions resulted in a faster and better total improvement in symptoms and severity of social anxiety disorder, especially when compared to a placebo.
Treats Type 2 Diabetes
Early type 2 diabetes (T2DM) involves insulin resistance in tissues throughout the body, which prohibits glucose from leaving the blood and entering cells. In later stages, T2DM is characterized by a dangerous combination of this resistance along with insufficient insulin release from the pancreas.
A study of 50 type 2 diabetics found that 20mg of yohimbine corrected the insulin response – it stimulated the pancreas to release the correct amount of insulin required by current levels of blood sugar. This increased secretion from the pancreas resulted in normalized blood glucose levels.
There was no improvement in measurements of insulin sensitivity, but the increased total insulin release may be enough to correct blood glucose dysfunction in some cases of T2DM.
The study also found that the participants who took yohimbine showed biochemical markers of increased fat breakdown, which may help to protect against diabetes-related metabolic syndrome.
Burns Fat and Aids in Weight Loss
Yohimbine is marketed as a fast fat burner and the science backs this up. By blocking α2 receptors, yohimbine can improve energy metabolism in two ways:
- Insulin. Yohimbine “potentiates” the amount of insulin required based on the number of carbohydrates in the digestive system. Basically, it makes sure there is exactly enough insulin to deal with the incoming glucose so that this sugar doesn’t get stored as fat.
- Fat release. Yohimbine has been shown to increase fatty acid flux after exercise. This means that it helps to release fat from within adipose tissue – in short, it burns fat… but only in some circumstances.
Two early studies (one from 1986, and another from 1991) showed accelerated weight loss in participants who took yohimbine, while two others reported no benefit at all. The studies with positive results looked at the effects of yohimbine for obese women – a group that typically has a greater expression of α2 receptors.
The others that reported no benefit were on overweight men, suggesting that yohimbine may be more effective in women, or in people with more weight to lose. These trials looked at the impact of yohimbine in combination with a calorie-controlled diet, but more recent research has suggested that its best use is for boosting fat burning during exercise.
A 2006 trial looked at the effects on yohimbine in a small cohort of 20 top-level soccer players. Baseline testing was performed and then the players were assigned to either a supplement group which took 20mg of yohimbine per day or to the placebo group which took identical-looking cellulose pills.
After 21 days, there were no significant changes to exercise performance but the yohimbine group showed a significant reduction in body fat percentage with no change in muscle mass, especially compared to the placebo group.
Decreases Blood Clotting
Blood clotting in the arteries is associated with angina, stroke, deep vein thrombosis, heart attack, and sudden cardiac death. Adrenaline stimulates clotting pathways in the blood, causing platelets to aggregate together and form solid clots, while noradrenaline reduces the rate of platelet aggregation – it stops platelets from clumping together and forming clots.
Yohimbine blocks clotting pathways by converting adrenaline into noradrenaline, as well as blocking key α2 receptors. Studies have shown that this anti-clotting action can occur in at doses as low as 4mg in healthy subjects at rest and during exercise.
CAUTION: Healthy blood clotting is essential for wound repair and recovery. Yohimbine may cause excessive and dangerous bleeding during medical procedures. Stop taking yohimbine at least two weeks before surgery.
Aids Kidney Protection
The kidneys are at high risk of damage in poorly controlled diabetes, and yohimbine may protect against this by improving the insulin response in type-2 diabetics. Unfortunately, research is lacking – only a few animal studies have looked at the effects of yohimbine on kidney function. The results have been positive, showing that yohimbine may prevent kidney damage, protect nerve signals, and suppress inflammation in the kidneys.
However, human studies have shown that the vasodilation and increased blood pressure may cause excessive blood flow to the kidneys – a situation that can actually cause damage particularly in people who have kidney disease or renal impairment. Case studies have reported adverse effects on the kidneys, including a 42-year-old man who experienced kidney failure after taking 15mg of yohimbine for erectile dysfunction.
Potential Benefits of Yohimbine
While there are many benefits to Yohimbine, there’s plenty of benefits that aren’t fully verified.
Memory Improvement
Yohimbine promotes memory retention by blocking α2 receptors and increasing the activity of noradrenaline in the central nervous system. This is particularly effective when it comes to emotional memories. A placebo-controlled study of 36 healthy young adults showed that taking 20mg of yohimbine improved memory retention and its recall one week later; another showed that a single 5mg dose improved the accuracy of immediate working memory recall.
People with depression may experience even greater positive effects from yohimbine. A 2013 study showed that a 5mg dose of yohimbine improved memory consolidation (measured through learning a word list) significantly more effective in people with the major depressive disorder than in neurotypical participants. There were no effects on working memory or memory recall in either group.
Potential to Improve Cognitive Performance
Changes to the levels of noradrenaline in the pre-frontal cortex significantly impact cognitive performance. A study on cognition in anxious students found that 15mg of yohimbine improved cognitive performance but also boosted the number of errors and sky-rocketed levels of anxiety. A dose may be a factor here – a small study of 20 participants showed that a single, smaller dose of 5mg of yohimbine can improve measurements of cognition, including psychomotor reaction time, with no reported side effects of anxiety.
May Help with Dry Mouth Syndrome
Dry mouth syndrome is characterized by a decreased rate of saliva production and is associated with low levels of acetylcholine. This neurotransmitter controls involuntary muscle movements and digestive secretions – including the release of saliva. Yohimbine has been shown to increase acetylcholine and boost saliva release in human studies.
A dose of 6mg of yohimbine taken three times a day has been shown to relieve dry mouth side effects in people taking tricyclic antidepressants and neuroleptic drugs. Another placebo-controlled trial found that a total dose of 14mg effectively increased saliva in healthy adults on no medication, too.
Could Help Treat Arthritis
Traditional uses for yohimbine include relief of pain and stiffness associated with arthritic joints. There are no human trials to date but a recent animal study suggested that yohimbine may help to reduce inflammation and immune dysfunction associated with rheumatoid arthritis. More research and studies on human participants are required before yohimbine could be considered an effective treatment for arthritis.
May Reduce Pain
A dose of yohimbine may block pain receptors for 15 – 30 minutes. A 2008 study found that an intravenous infusion of yohimbine effectively improved the pain threshold in participants who suffered from chronic back pain. Obviously, an IV of yohimbine isn’t a readily accessible painkiller but the study indicates that oral doses may also improve pain tolerance.
Can Potentially Treat Clonidine Overdose
Clonidine is a blood pressure medication that is also used to treat ADHD, anxiety disorders, tic disorders, migraines, diarrhea, and the symptoms of withdrawal from alcohol, opioids, and tobacco. It works in the opposite way to yohimbine – it stimulates α2 receptors, leading to decreased blood pressure. Clonidine and yohimbine are often used in trials to compare different effects of the α2 receptor pathways.
Like all drugs, an overdose of clonidine is possible – this is where yohimbine may help. In theory, giving yohimbine can switch “off” the α2 receptors that the clonidine is switching “on”, reserving the effects of the overdose. One case study demonstrated that a clonidine overdose was successfully treated with yohimbine, even after being non-responsive to conventional treatments.
The Potential Side Effects of Taking Yohimbine
Frequently reported side effects from yohimbine products to include:
- Anxiety for 1 – 5 hours
- Irritability
- Headaches
- Irregular heartbeat
- Nausea and vomiting
- Red face and hands
- Chest pain
- Chills and shivering
- Tremors
- Excessive saliva production and drooling
- High or very low blood pressure
- Fainting
- Changes to urination frequency
Dangers Posed by Yohimbine Supplements
People have reported serious adverse drug events from yohimbine products, including:
- Heart attack
- Atrial fibrillation
- Seizure
- Acute kidney failure
- Priapism (persistent and painful erection)
Based on studies and case reports, yohimbine is likely to be UNSAFE in:
- Bleeding conditions. Due to its anti-clotting actions, yohimbine can exacerbate bleeding conditions including heavy or frequent menstrual periods.
- Kidney disease.
- Heart disease. Yohimbine can contribute to heart damage.
- Hypertension or hypotension. Yohimbine can cause serious and unpredictable changes to blood pressure.
- Anxiety, PTSD, and panic attack disorders.
- Diabetes. Seek personalized advice from your doctor before you take yohimbine – it may negatively interact with your medication and other therapies.
- Surgery. Yohimbine increases bleeding risk. Tell your medical team that you have been taking yohimbine, and stop taking it at least two weeks before surgery.
The Recommended Yohimbine Dosage
Generally, yohimbine doses vary from 5mg – 30mg per day. Studies have used these doses of yohimbine to treat the following conditions:
- Erectile Dysfunction: 30mg per day for two weeks.
- Diabetes Management: 15mg per day, separated into three 5mg doses.
- Weight Loss: 10mg before exercise, twice a day.
- Decrease Blood Clotting: Doses as low as 4mg have been shown to decrease clotting.
- Exposure Therapy for Social Anxiety: Single dose of 10mg, taken one hour before exposure therapy session.
- Memory & Cognition: Doses between 4mg – 15mg have been shown to be effective.
- Dry Mouth Syndrome: 6mg per day.
Final Thoughts on Yohimbine
Yohimbine is a potent adrenergic modulator that deserves more research to explore its full potential. It has the power to pump up noradrenaline levels and block α2 receptors to uniquely boost blood pressure while causing blood vessels to relax. It holds promise as a powerful treatment for erectile dysfunction, obesity, memory issues and T2DM but until more research is done, the safety profile appears to be a little risky.
There are more reported side effects and serious reactions than we’d care to mess around with but lower doses may be useful for short periods of time. There’s no denying that this alkaloid has great potential and we’d love to see more clinical trials exploring its efficacy and safety.
