Yohimbine is one of the most popular supplements for weight loss.
But popular doesn’t always mean effective.
My goal in this article is to take a step back and look at the evidence from a pharmacists point of view.
Before I get into the actual facts it’s important that you understand one critical factor that relates to Yohimbine.
Fat Cells Have Alpha-2 Receptors
Your fat cells have a lot of different receptors on them. Which means they can receive messages and act in certain ways based off the signal they’re getting.
One of the receptors that should be of interest to you is called the alpha-2 receptor.
In short, when those alpha-2 receptors are activated they actually feed back to your body and tell it to stop releasing norepinhephrine (noradrenaline). When this happens lipolysis (fat burning) is shut down.
Based of what we know right now some fat cells have more alpha-2 receptors than others. This is one theory behind why men have ‘stubborn’ fat in their lower belly and women have stubborn saddlebags around their hips.
Because we know that you can’t ‘spot reduce’ fat away through training the idea of using supplements to target stubborn areas of fat has become pretty popular.
Now that we’ve laid the groundwork let’s look at Yohimbine.
Yohimbine Is An Alpha-2 Blocker
Yohimbine blocks alpha-2 receptors in your body. So when it hits a fat cell and ‘binds’ that alpha-2 receptor it blocks the signal to shut down fat burning. In theory, it at least keeps the option of fat burning still open.
Now I say in theory because while Yohimbine is an alpha-2 blocker it’s not a selective alpha-2 blocker just for fat cells. That means it blocks ALL alpha-2 receptors in your body.
You have a lot of alpha-2 receptors in your brain, spinal cord and arteries which explains why you can get a lot of side effects – especially at higher doses.
Looking At The Evidence At Yohimbine For Fat Loss
So far Yohimbine has some promise but lets look at any actual evidence to date.
The Sax Study. In this study the researcher (Sax) looked at 47 men over a six month time period. The average age was 42 and the men were broken up into two groups: placebo (sugar pill) and Yohimbine (43 mg/day as a peak dose).
At the end of the six months they wanted to see if there was any difference between bodyweight, body mass index, total and HDL cholesterol, body fat and body fat distribution measured by waist-to-hip ratio and CT scan.
The outcome? Treatment with Yohimbine and no effects on any of these.
The Polish Study. This is a much older study (1985) that looked at lower dose Yohimbine supplementation (15mg). The researchers found that energy expenditure (while resting and exercising) increased 8% in both lean and obese women.
Interestingly, they showed a big 1.5 pound greater average weekly weight loss. I’m not sure how much weight to put into this because most of the weight loss happened in the first week with things slowing down after that. Now I’m not sure what caused this discrepancy. Some people have suggested water loss.
This is a tough one because a lot of yohimbine users complain of bloating and water retention while some studies show yohimbine can act as a diuretic.
Judgement? There’s potential
The Infamous ‘Soccer Player’ Study. This is one of the most referenced studies about yohimbine. Bottom line is that this study showed soccer players who took yohimbine 20mg daily for 21 days did show a decrease in body fat.
But there’s a couple of big problems with this study:
- They didn’t control for the athletes diets during the study. Meaning their body fat loss could have been a direct results of simply eating less.
- They measured body fat percentage with skin fold calipers. This is widely considered one of the most unreliable ways to measure body fat.
My take: this study is a wash.
The Israeli Study. They took 20 obese female patients. They were started on a diet of 1,000 calories/day for 3 weeks. Then they were assigned to receive yohimbine or a sugar pill in addition to continuing the low calorie diet.
At the end of the study they looked at resting and exercise energy expenditure, serum noradrenaline concentration and finally serum glycerol concentration – which is a sign of how much fat burning was occurring.
Yohimbine did significantly increase weight loss but no significant effect on lipolysis (fat burning was seen). So either the weight loss was coming from muscle (which is pretty unlikely in obese women) or it was simply water weight – which is more likely in my opinion.
The outcome: Yohimbine did NOT appear to help fat loss.
The French Study. Very similiar to the Israeli Study above. This study took 19 obese volunteers and gave them all a low calorie (1000 calories/day) diet then gave half of them 18mg of yohimbine daily or a sugar tablet. At the end of 8 weeks there were no changes in glycerol levels (a sign of fat burning). There’s was also no difference in their body weights.
Again, Yohimbine did NOT help with fat or weight loss.
Another study in healthy male volunteers found that giving yohimbine orally at 0.2mg/kg of bodyweight DID increase blood glycerol and fatty acid levels in healthy subjects who were fasting. Yohimbine did not cause a significant increase in heart rate or blood pressure.
But was the apparent fat burning effects from fasting or the yohimbine? This study can’t really answer that.
This final study (also in healthy male volunteers) looked at giving yohimbine not only to look at the effects on fat mobilization (which did improve) but also to find out if yohimbine could have long lasting effects on fat loss (it did not). Basically they found that after 15 days of treatment the effect on fat mobilization decreased.
Based off the studies we have so far it looks like 0.2mg/kg of bodyweight is a good daily dose. To work out that math take your bodyweight in pounds and divide it by 2.2 to get your weight in kilograms. So if you’re 180 pounds that is 81kg. Now multiply that by 0.2mg and you have a daily dose of 16.2mg per day of yohimbine.
Like I mentioned above I would cycle this dose and not take it anymore than 2 weeks at a time. I would probably shoot for 2 weeks on and 2-4 weeks off.
Would I Recommend Yohimbine?
As a pharmacist I would NOT recommend Yohimbine for fat loss. I simply haven’t seen enough to show that it’s that helpful.
If you’re looking to lose weight focus on the few activities that are going to give you the biggest bang for your buck:
- Eat in a caloric deficit
- Lift weights three to four times weekly with a sprint session once a week if you like
- Get enough good quality sleep
If you insist on taking it and have cleared it with your doctor – I’d recommend ‘cycling’ it – meaning maybe take it for a week or two. Take a break. Then start up again. It appears that our bodies do become ‘resistant’ or adapt to the effects of yohimbine after a couple of weeks.
I would also only take yohimbine while fasting. Food shuts down any positive effects that you might get.
Yohimbine also comes with a number of possible side effects. Namely:
- Abnormal heart rhythms
- Heart failure
- Blood pressure changes
Obviously you need to talk with your doctor before you start taking yohimbine but if you have any sort of seizure disorder, anxiety, heart problems or are being treated for any mental health disease I would not take yohimbine.