Why Does Weed Make You Horny?

Have you ever lit up a joint and found yourself aroused afterwards? Don’t worry, you’re not weird for it or anything. It’s actually more common than you might think. In an article published in the Journal of Sex Research in 1974, investigators found that 48.5% of the people surveyed reported an increase in sexual desire after consuming marijuana. Due to its prevalence, the fact that weed can make you horny has not slipped away from scientists, and they’ve been trying to figure out why exactly cannabis has this effect.

I took a deep dive into a bunch of academic papers so you don’t have to, and if you’ve read any of my other articles, you know that I love being thorough, technical and accessible. So first, let’s take a look at the way your body regulates and experiences sexual arousal before we get into the ways marijuana can affect it. This article will not cover any psychological factors that might play into sexual arousal, but will focus on it from a biological point of view of why does weed makes you horny.

The way that sexual desire is mediated is still not fully understood, since the regulation is made up of complex interactions between different parts of the nervous system, the endocrine system and genetic factors. It’s just a lot, and scientists are still trying to figure out the way all of these pieces come together. And though the visible results of the sexual arousal depend on the person’s biological sex, we know that the neural mechanisms of desire, arousal and orgasm are the same regardless of it. 

If anyone needs a high school biology refresher, the nervous system can basically be divided into different parts depending on location— the central nervous system (CNS) which is made up of the brain and spinal cord, and the peripheral nervous system (PNS) that is basically the rest of the nerves in our bodies. The PNS can be further divided into the autonomic nervous system, which takes care of the bodily functions we have no control over, and the somatic nervous system, which includes our sensory neurons and the motor neurons.

Now, sexual desire pretty much involves all of the nervous system, complexly integrating both autonomic and voluntary responses, and it flows through the central and peripheral nervous systems. However, most of the work is done by the brain itself, especially when it comes to sexual motivation, with dopamine being a key player here. There are other molecules that are involved in sexual arousal, such as serotonin, oxytocin, androgens, and more, but for the sake of simplicity, we will focus on dopamine’s role. Mostly because it happens to be the one that seems to be most affected by the consumption of cannabis. That we know of so far, at least.

Dopamine is a type of neurotransmitter and hormone. It’s produced by our cells so that the neurons can communicate with each other, and it is very important in regulating our bodies’ movements, mood, motivation, and reward systems. It’s sometimes called the “happy hormone” or the “pleasure hormone”. The neurons that are activated by this neurotransmitter are called “dopaminergic”, and they play a major role in sexual drive and pleasure. The experience of it depends mainly on dopaminergic neurons in the midbrain, in structures such as the ventral tegmental area, hippocampus, amygdala, and hypothalamus.

Since now that we know which are the neurons that affect sexual desire, and which neurotransmitter is involved in it, we can finally explore exactly how cannabis interacts with this complex system. Generally, marijuana has been anecdotal linked to an increase in sexual desire, enhanced pleasure and lowered inhibitions. That's why many people love getting their favorite pipe and a good grinder before getting into action.

In an article published by the journal “Proceedings of the National Academy of Sciences of the United States of America”, scientists postulate two models for us to understand how the chief psychoactive component of marijuana, delta-9-tetrahidrocannabinol (also known as THC), can make you horny. This ingredient interacts with dopaminergic neurons and, in turn, influences sexual behavior. These neurons are located in the hypothalamus and other parts of the midbrain, which exhibit cannabinoid receptors. They say that there is a cross-talk between THC, dopamine and progesterone, which together influence sexual behavior, especially the motivation to engage in it.

THC enters neurons via a receptor that is called CB1. These receptors can be on the main body of the cell (also called the soma), and on the axon of the neuron. In the first model, when THC enters the soma of dopaminergic cells, it activates an intracellular signaling pathway called MAPK. When dopamine receptors are activated, they also trigger the same MAPK pathway inside the cell, which basically lets the cell know it’s time to be activated (get horny). 

In the second model, the scientists said that THC works on CB1 receptors that are located on the dopaminergic axons. So, on these neuron terminals, when THC binds to CB1, it triggers the release of dopamine into the space between the neurons that the biologists call the synaptic cleft. After the dopamine vacuoles are emptied out, receptors on the next neuron catch the neurotransmitter and subsequently activate the cAMP intracellular communication pathway that ends in a similar activation (getting horny). 

There are CB1 receptors in other parts of our bodies outside of the central nervous system, such as the spleen, white blood cells, endocrine glands and parts of the reproductive, gastrointestinal and urinary tracts. We can assume that the cannabinoid receptors in our reproductive organs might also be affected when consuming cannabis. However, we don’t know to what extent these receptors are activated during sexual behavior, or the way that they influence it. 

The fact that weed affects sexual arousal is interesting because it hints that the endocannabinoid system is most likely involved in some of the phases of sexual arousal, which has motivated scientists to research it. We still don’t know much of the exact role the endocannabinoid system plays in the sexual pleasure cycle, but hopefully, new research will become available to us soon.

Edited by Kite