Why Does Weed Make Your Eyes Red?

Whether you’re a fan of weed or you’ve never smoked it in your life, you probably are wondering, why does weed make your eyes red?


Maybe you have at least some understanding of how weed works. The chemical THC (tetrahydrocannabinol) moves through your bloodstream and interacts with your brain to cause you to feel “high” or “stoned”. These effects vary depending on the strain of marijuana and how much or often you use it. A big hit of a high-THC strain will affect you very differently than a small bite of a pot cookie.


In this article, we answer the question regarding why weed makes your eyes red as a result of smoking or consuming marijuana.


Why Weed Makes Your Eyes Red

Weed causes blood vessels across the body to dilate, which makes your blood pressure drop. This is most noticeable in the eyes. As your blood pressure falls, they look red, and your pupils can become dilated. This is what gives weed users the bloodshot appearance in the eyes after using cannabis. At the same time, breathing passages relax and open up, which adds to the feeling of relaxation and calm that some people feel when they’re high.


Most people may think that it is the inhalation of the smoke itself that causes eyes to get red. However, this phenomenon doesn’t happen when people smoke other compounds such as tobacco for example, so it leaves more evidence towards the prior argument.


Other Factors: Body Fluids Dry Up

Weed can temporarily dry up mucus membranes throughout the body, including in the vagina. Other mucus membranes in your body include your eyes and mouth, so you may find that dryness affects you in your eyes as well, depending on the strain of weed and your reaction to it. Some people may find that genetically, their eyes do not get as affected as other peoples’.


Other Affects of Cannabis

Besides your eyes getting red from smoking marijuana, there are also some other affects that are worth mentioning. Below you can learn more about how weed affects the brain and body. Most people are unaware that these things are even occurring when they are consuming marijuana.


Dopamine Floods Your Brain

Like most drugs, the high from cannabis comes from the neurotransmitter dopamine, which is part of our brain’s reward system. Dopamine is responsible for several things, including pleasure, memory, thinking, concentration, movement, coordination, and sensory and time perception


THC acts through cannabinoid receptors in the brain and body.  THC stimulates the release of dopamine in large amounts, causing you to feel euphoric. This is what makes you feel high when you use weed. It’s not only dopamine that is affected by weed. It also alters other receptors for neurotransmitters like GABA and serotonin, which change your mood. The high that happens depends on which neurotransmitters are affected.


Your Senses Get More Intense

You might find that as well as the effects of a slower heart rate and the widening of your breathing passages, your senses can feel more acute. You might be able to notice different smells, touches, or other sensations that you might not normally notice, or experience them to a more intense level.


This is because, as well as triggering the release of dopamine, THC binds to brain receptors that are associated with your senses of smell and taste, which heightens their sensitivity. Along with the side effect of pupil dilation, a lot of your senses can become heightened for a short while. This is why THC affects your cognition and coordination when you’re very high, and why driving while high is a dangerous idea. It helps to buy from a legitimate weed store so you know what to expect from your high. 


Your Heart Rate Increases

Despite the fact that weed is used by lots of people to relax, what you might not know is that smoking weed is known to speed up your heart rate for up to three hours after you get high.  Your dilated blood vessels cause the muscles in your heart to work harder to pump blood. THC can make you more likely to experience anxiety and panic attacks, which make the heart beat rapidly. Although a quick heart rate is usually harmless, a racing heart rate can increase your chances of having a heart attack, especially when combined with the drop in blood pressure.


Your Sense Of Hunger Is Distorted

Even if you don’t smoke, you probably know about the munchies. Researchers and weed users have known for a long time that cannabis increases the appetite, and recently, science has begun to look into the reason. THC is responsible for most of the psychoactive effects associated with cannabis use including the high as well as increased appetite, known as the munchies. THC interacts with the neurons that are responsible for telling your body to stop eating. When you get high, these neurons start to signal that you’re actually really hungry. 



The main reason that weed makes your eyes red is because the different cannabinoid compounds in the cannabis are actually causing the dilation of blood vessels in your head. This in turn causes more blood to flow to your eyes, which are proportionately affected due to normally being white. The increase in blood actually makes the vessels become more red and protrude into the white pupil.

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