What is yohimbine?

In one line

Yohimbine is a substance in the bark of the African yohimbe tree that puts the body into a tense, excited state, raising blood pressure and making the heart beat faster.

What is yohimbine?
A name on fat-burning and workout supplements
On the labels of supplements that claim to help you lose fat or get energy for training, you may see the name 'yohimbine' or 'yohimbe'. This post explains where yohimbine comes from, what it does in the body, and what risks have been reported.
In short
A substance from tree bark that excites the body
Yohimbine is a substance found in the bark of the yohimbe tree, which grows in Africa. It puts the body into a tense, excited state, raising blood pressure and making the heart beat faster. It has also been used as an ingredient in prescription medicine for erectile dysfunction.
The yohimbe tree
In the same plant family as the coffee plant
Yohimbe is an evergreen tree that grows in central and western Africa. It belongs to the madder family (Rubiaceae), the same plant family as the coffee plant. The bark has long been used to boost sexual desire, and yohimbine is the most active substance in it.
Sympathetic nerves and noradrenaline
The signal that gets the body ready to fight
When you are startled or in danger, your heart races and your body tenses up. That is the work of the 'sympathetic nerves'. The ends of these nerves release a signal substance called 'noradrenaline' (norepinephrine), which passes the signal to cells in places like the heart and blood vessels. Yohimbine acts on exactly this signal.
What it does
It releases the 'brake' on noradrenaline
Cells have spots that only a specific substance fits, called 'receptors'. The 'alpha-2 receptors' at nerve endings act as a brake that keeps too much noradrenaline from being released. Yohimbine blocks these receptors and releases the brake, so more noradrenaline comes out.
The result
Blood pressure rises and the mind gets excited
When people were given yohimbine, the noradrenaline in their blood rose two- to threefold and their blood pressure went up. Their mood also shifted from calm toward excited. Because it causes anxiety, researchers have used yohimbine in experiments that study anxiety and panic attacks.
Yohimbine in supplements
The amount varied widely from product to product
When yohimbe and yohimbine supplements sold in the US were analyzed, the yohimbine in one serving ranged from none at all to about 12 mg. Only about one in five products listed how much yohimbine they contained. Even among those, most did not contain the amount on the label.
Reported risks (1)
Calls to a poison control center
In yohimbine-related calls to the California poison control system, the common symptoms were stomach upset, a fast heartbeat, anxiety or agitation, and high blood pressure. Compared with calls about other substances, severe outcomes were far more common, and more people needed care at a hospital or clinic.
Reported risks (2)
Irregular heartbeat, seizures and death
Yohimbine has been linked in reports to irregular heartbeat, heart attacks and seizures. In a case of severe yohimbine poisoning, a death also occurred. The harms were mostly reported when people took large amounts or combined it with other stimulants such as caffeine, and because the real amount in supplements often differs from the label, people can hardly tell how much they are taking.
Limits around the world
The EU banned it from food
Because of inaccurate labels and serious side effects, many countries have restricted or banned yohimbe supplements. Since 2019, the European Union has banned yohimbe bark and products made from it from use in food. No one had submitted scientific data showing it was safe within the set deadline.
A common misconception
It comes from tree bark, so is it mild?
No. Almost all of the yohimbine calls to the California poison control system came from supplements. Coming from natural tree bark does not mean it is mild. Raising blood pressure and speeding up the heart is the nature of yohimbine itself.
Summary
A strong stimulant from tree bark
Yohimbine is a substance in yohimbe tree bark that blocks the alpha-2 receptors at nerve endings so more noradrenaline comes out, and puts the body into a tense, excited state. Being natural does not make it mild, and many people were reported to poison control with heartbeat and blood pressure problems after taking supplements. Related terms: sympathetic nerves, noradrenaline, receptor.