Why Does Weed Make Your Eyes Red?

Why does weed make your eyes red? The short answer is that cannabis contains a chemical called tetrahydrocannabinol, which is also known as THC.

The solution? In many cases, it's as simple as using eye drops to ease those bloodshot eyes.

THC binds to receptors and turns your eyes red because of the blood vessels underneath. This is usually a dead giveaway showing a person consumed cannabis.

But what does this mean for bloodshot eyes? And how does this impact your blood vessels and blood pressure?

This article will talk about why it happens, what other effects cannabis has on our body, and why marijuana makes some people's eyes turn red while others don't experience this side effect at all. We'll also explore how long this reaction typically lasts for individuals who use marijuana regularly or have just consumed a small amount of weed in one sitting.

The Blood Vessels & Red Eyes

The smoke from your joint isn't the direct reason for your eyes turning red.

A low THC strain or high THC strain can cause weed eyes. The red eyes come from the amount of THC you consume. So if you smoke more cannabis low in THC, you'll likely still have red eyes.

A 1978 study revealed marijuana can impact glare recovery, citing this is “dose-related” after studying how tetrahydrocannabinol impacts intense light exposure recovery time. 

Eye drops can help. But it's important to know that capillary dilation isn't a sign of shoddy overall health. In fact, it's perfectly normal for capillaries to dilate if you smoke or eat cannabis. This is the natural reaction of your body with the cannabinoids present in your cannabis.

Why Does Weed Make Your Eyes Red?

Whether you smoke or eat cannabis, your body is going to react the same way. The main thing that causes red eyes is the cannabinoids present in your marijuana.

THC Causes Capillaries to Dilate

Dilated capillaries and increased pressure happen for the same reason: it's a universal reaction to the way these cannabinoids bind to our cannabinoid receptors. This causes blood vessels to dilate, which results in an overall decrease in blood pressure as the capillaries dilate.

Does CBD Cause Red Eyes?

High-THC edibles and oils cause red eyes. But CBD doesn't offer the same eye reddening effects.

While CBD consumers can experience eye watering from the smoke, the CBD itself doesn't cause eyes to turn red. CBD can contain some THC in trace amounts. But for your eyes to change, you'll need a higher concentration of THC – or you'll have to consume a lot of the CBD product.

CBD has a comparable chemical structure to THC. However, since CBD has more hydrogen and oxygen, it doesn't disrupt cognitive processes in the same way as THC.

Does Cannabis Ingestion Increase Blood Flow?

THC binds to your cannabinoid receptors when you're smoking cannabis. The resulting dilation or expansion of blood vessels and capillaries causes red eyes, as well.

This isn't an allergic reaction. Instead, these small blood vessels are encouraging blood to flow to the area, which makes your eyes red. The fluctuation in inner eye pressure encourages red eyes, which eases pressure on the retinal nerve.

Even eating or vaping other cannabis products makes your eyes red. This is because regardless of the consumption method, cannabis makes the ocular capillaries dilate. Thus, red eyes result, and while cannabis can make your eyes red, you might avoid vision loss if you're using it for your glaucoma treatment.

Will Increased Blood Flow from Cannabis Raise or Lower My Blood Pressure?

According to Harvard Health Publishing, regardless of whether you're consuming flower, edibles, concentrates, or something else, marijuana in some people can increase heart rate and blood pressure. This happens because of the cannabinoids in cannabis.

These chemical compounds provide therapeutic and medical benefits. But consuming marijuana also raises blood pressure and heart rate similar to physical activities.

So, what happens?

Within five to ten minutes, your heart rate will stabilize and your blood pressure will start to drop. While the blood pressure lowers, the blood vessels and capillaries start to dilate. This includes the ocular capillaries. The dilation of your ocular capillaries results in more blood to flow to the eyes, which gives users one of the most telltale signs of cannabis consumption: red eyes.

Eye redness comes from the dilation of the ocular capillaries. When the ocular capillaries dilate, intraocular pressure is reduced.

Cannabis reduces intraocular pressure in the eyes, which makes it a potentially effective option for treating glaucoma. Glaucoma, a group of eye disorders that damage optic nerves and can cause blindness, might be treatable with medical marijuana.

But smoking cannabis is the simplest explanation of this treatment. While it causes eye redness for a few hours, THC can lower intraocular pressure (IOP). While some studies don't support the idea that smoking marijuana benefits glaucoma patients, we still need more research to determine the efficacy of smoking weed for treating glaucoma patients.

Do Redder Eyes Mean Better Results?

Your bloodshot eyes is one of the varying effects of medical marijuana. But how red eyes get depends on the THC consumed. More marijuana use means more THC, which means more THC enters your bloodstream.

While eye drops can help with your red eyes, it's important to know you can get the same effect in other ways. Reduce eye redness with cold water over your face and eyelids, stay hydrated, and switch to low THC strains.

Staying hydrated ensures the blood vessels in your eyes don't get too constricted, which aids in the relief of intraocular pressure.

Solving the Red Eye Dilemma

Most people don't like shouting from the rooftops that they've just consumed cannabis. But sometimes, eye drops aren't enough.

So how can you deal with eye redness from smoking marijuana or eating an edible?

Sunglasses can be effective for shielding red eyes from the masses.  The right hat could also reduce your eye redness visibility by offering some shade to bloodshot eyes.

Long story short, if your eyes turning red troubles you, this is only a minor side effect of THC consumption. Of course, consult your doctor if you feel dizzy or woozy from your medicine.

Keep this information in mind as you consume your medical cannabis. And remember, if you have red eyes, you're probably doing something right!