Red eyes can be a telltale sign that someone has been smoking cannabis. Even if they completely cover up the smell of cannabis, red glassy eyes are a dead giveaway. 

They’re pretty obvious, and some people who want to be discreet attempt to hide the fact that their eyes are red with eye drops or sunglasses. 

Using CBD isn’t the same thing as using cannabis. 

CBD comes from hemp. Although hemp and “traditional” cannabis have a lot in common, their differences eliminate the possibility of many side effects. Can CBD make your eyes red if it comes from hemp?

What Are Cannabinoids?

Cannabinoids are compounds that naturally occur in plants, people, and animals. Although cannabis and hemp are commonly referred to as the source of cannabinoids, there are cannabinoids in many places. For example, clove, echinacea, broccoli, carrot, and ginseng plants naturally produce cannabinoids. 

There are well over 100 unique cannabinoids. They each serve a different purpose in keeping plants healthy and helping them thrive. Many cannabinoids in plants can work with the cannabinoid receptors in the human body.

Each cannabinoid is capable of producing or inspiring different effects. Some cannabinoids have a broad reach, some cannabinoids have a narrow reach, and some cannabinoids don’t seem to affect humans at all.

How Do Cannabinoids Work in the Body?

Almost every living creature has something called an endocannabinoid system. The endocannabinoid system isn’t like the cardiovascular system or the respiratory system. It isn’t an organ, doesn’t have one function, and doesn’t exist in a single place.

The endocannabinoid system is a massive network of cannabinoid receptors throughout your body. Almost every part of your body can receive cannabinoids. 

You have receptors in your brain, skin, organs, immune cells, digestive system, and even your eyeballs. Your cannabinoid receptors are everywhere

In addition to cannabinoid receptors, your body also has a wealth of other receptors susceptible to cannabinoid influence. That’s why people use CBD as a holistic wellness tool. 

Some cannabinoids, like THC, bind to your receptors and change how they work. Other cannabinoids, like CBD, interact with these receptors without binding to them. Non-binding cannabinoids float by, say hello, and metabolize out of your body. 

What Is the Difference Between Hemp and Cannabis?

Hemp and cannabis look and smell the same. That’s because they’re the same plant. Hemp is cannabis. The term “hemp” is a special designation for cannabis plants bred to produce far less THC than other varieties of cannabis.

Most of the crops we use are bred to favor specific traits. For example, you probably want to grow a tomato plant bred to strengthen its yield. 

Hemp plants are the opposite. They produce a lot of CBD and a little THC, which is the inverse of conventional cannabis plants. It’s a little tweak of nature. 

The hemp designation makes hemp production legal on a federal level. While many people think of cannabis as a drug, the plant is far more valuable. 

It’s an excellent source of plant-based protein. Its seed oil is rich in brain-healthy omega fats and works as an excellent moisturizer for the skin. Hemp fibers can even make paper, rope, clothing, and textiles. 

The United States legalized agricultural hemp production so that we could enjoy the countless uses for the plant. A hemp plant is any cannabis plant that produces 0.3 percent THC or less by its dry weight, a minuscule amount that won’t cause psychoactive effects. 

Why Does Cannabis Make Your Eyes Red?

Red eyes are a common side effect of using conventional cannabis. You’ve probably seen this effect firsthand or in a cannabis comedy movie. You might have even experienced it yourself. 

This side effect comes from THC, the plant's psychoactive compound. To understand how cannabis makes your eyes red, let’s look at how THC works.

What Is THC?

THC, also known as delta 9 tetrahydrocannabinol, is a psychoactive cannabinoid. It’s the one people refer to when they say they’re high. 

Cannabis plants cultivated for medical and recreational use usually contain about 20 percent THC by their weight but can contain upwards of 30 percent THC — a stark contrast to hemp’s 0.3 percent maximum (i.e. a fraction of a percent!).

How Does THC Work?

THC binds to the cannabinoid receptors in your brain and body. It changes how your body sends and receives signals when it latches on, leading to an altered perception of reality, changing the way sensations feel, and compromising your motor functions. 

There are many cannabinoid receptors inside your eyes, and THC can also bind to those. This is something to keep in mind while we’re working out the science of THC and red eyes. Put a pin in this fact because we’re coming back to it.

Medical cannabis patients use cannabis products with THC because these changes in perception improve the way they feel. Recreational cannabis users simply like the way it makes them feel. 

THC causes many effects that change the way the body works.THC acts as a vasodilator, which means it causes blood vessels to expand. This effect is the reason why THC may make your eyes red. 

What Is a Vasodilator?

Vasodilators are things that cause blood vessels to dilate. Cannabinoids like THC can change the circulation in your body. When your blood vessels dilate, they expand in diameter, allowing them to carry more blood throughout your body. 

The many blood vessels in your eyes are very small. Vasodilators like THC can cause them to expand. THC also binds to your cannabinoid receptors, some of which are in your eyes.

Most of your eye is white and full of liquid and gel-type material. It’s very soft. When blood vessels in your eye expand, they become very noticeable. They’re easy to see clearly, and when they’re full of blood, they leave a red or pink hue to your eyes.

This effect is temporary and goes away after the vasodilator has worn off. Depending on your metabolism and the amount of THC you use, the effect can linger from anywhere between four and 12 hours. People highly sensitive to THC may experience red eyes for 12 hours, even on a small dose of THC. 

How Does CBD Work?

CBD works by circulating throughout your body and stimulating your cannabinoid receptors. Unlike THC, CBD doesn’t bind to your receptors. 

It interacts with them and supports them in performing their natural functions. CBD won’t make you feel high. Its benefits are subtle and supportive. 

Does CBD Make Your Eyes Red?

CBD is also a vasodilator, but its effects don’t seem as extreme or noticeable as THC. In traditional cannabis, the vasodilating effects of CBD and THC combine. 

In hemp-derived CBD products, the amount of THC is insignificant, and the two don’t stack. Although it’s theoretically possible, there’s no hard evidence that CBD alone or hemp-derived CBD products will make your eyes red. 

Some people who use CBD insist that it makes their eyes red, but it all depends on the products that they’re using. In states with legal recreational cannabis, some dispensaries carry cannabis-derived CBD. 

Cannabis-derived CBD naturally has a lot more THC than hemp-derived CBD products. Cannabis-derived CBD usually contains anywhere between five percent and 15 percent THC. 

This can be as much as 50 times more than the maximum amount of THC in CBD products. It wouldn’t be unexpected for that much THC to make your eyes red. 

Can the Small Amount of THC in Federally Legal CBD Make My Eyes Red?

CBD products created from whole hemp are called full-spectrum CBD. The small amount of THC in full-spectrum CBD products probably isn’t enough to make your eyes red. You would need to be extremely sensitive to the effects of THC for your body to know it's there. 

You can still avoid THC if you have concerns about ingesting it. You can avoid THC entirely by using broad-spectrum CBD products. Broad-spectrum CBD products are hemp extract products without any detectable levels of THC. 

Broad-spectrum CBD products are a great solution for people who cannot use THC products (like athletes who receive drug tests) and people who are simply uncomfortable with the idea. You should feel good about the products you choose for your wellness, and if eliminating THC from the equation feels like the right choice, that’s what you should do.

Find Relief With Pure Relief

Pure Relief’s CBD gummies are broad spectrum. They’ve had all detectable levels of THC removed. If you’re worried about the effects of THC or concerned that it may make your eyes red, Pure Relief has your back.

Our vegan gummies contain 25 mg of CBD per piece. Our daytime blend contains ingredients to support healthy energy levels to help you start your day on the right foot. Our nighttime blend contains soothing ingredients to help you snuggle up and relax at the end of a long day. Find relief with a single bite.

Sources:

A Systematic Review of the Complex Effects of Cannabinoids on Cerebral and Peripheral Circulation in Animal Models | Frontiers in Physiology

Blood vessels and nerves of the eye: Anatomy | Kenhub

Cardiovascular Pharmacology of Cannabinoids | National Institutes of Health

August 24, 2022