How Long Do Red Eyes Last From Weed?

Introduction

Cannabis consumption brings a variety of effects, and one of the most recognizable is red or bloodshot eyes. For those new to medical cannabis or even seasoned users, noticing red eyes in the mirror after use can be a common experience. But how long do these red eyes last? And why does cannabis cause such a reaction? 

Let’s explore the causes, duration, and remedies for cannabis-induced red eyes, so you can enjoy the effects without worry.

What Causes Red Eyes From Cannabis Use?

To understand the phenomenon of red eyes after cannabis use, it’s essential to dive into the relationship between THC (tetrahydrocannabinol)—the primary psychoactive component in cannabis—and the body’s blood vessels. THC affects the endocannabinoid system (ECS), which has receptors all over the body, including the eyes. The two main receptors involved are CB1 and CB2, and when THC binds to these receptors, it lowers blood pressure and causes blood vessels to expand.

The eye redness happens because THC induces vasodilation—an increase in blood flow and a subsequent drop in blood pressure, which dilates blood vessels throughout the body. This dilation is most noticeable in the eyes, where blood flow to the ocular capillaries causes that classic red-eye effect. Interestingly, this same effect is what makes cannabis a valuable treatment for glaucoma. For people with glaucoma, THC’s ability to reduce intraocular pressure (pressure in the eye) provides relief from eye strain and potential damage to the optic nerve.

How Long Do Red Eyes Last?

For most people, red eyes from cannabis use are temporary, typically lasting between one and two hours. However, the exact duration depends on several factors, including THC concentration, personal metabolism, and ingestion method. For some, the red-eye effect may last up to three or four hours.

1. THC Concentration: Higher THC levels in a strain tend to cause more intense and prolonged redness. Consuming high-THC strains can result in red eyes that last longer than lower-THC strains or strains that are rich in CBD or other cannabinoids.

2. Metabolism: Each person’s metabolism processes THC at a different rate, which means some individuals will experience red eyes for longer than others. Those with faster metabolisms may notice redness subsiding sooner, while slower metabolisms may extend the duration of red eyes.

3. Cannabis Consumption Method: Red eyes appear regardless of the method of cannabis ingestion, but timing varies. Smoking or vaping cannabis sends THC directly into the bloodstream, where it quickly affects the eyes. Consuming edibles, on the other hand, results in a slower onset since the THC must first pass through the liver, delaying both the onset and duration of red eyes.

Do Other Cannabinoids Cause Red Eyes?

The red-eye effect is specifically tied to THC consumption. Unlike THC, cannabinoids like CBD (cannabidiol), CBG (cannabigerol), and CBN (cannabinol) do not have the same vasodilating effects. In fact, CBD may even reduce blood pressure, eliminating the cardiovascular reaction that typically causes red eyes.

Over time, frequent THC consumers may develop a tolerance, leading to a lower likelihood of red eyes. Much like other aspects of cannabis tolerance, as users become accustomed to THC, their bodies may exhibit less capillary dilation in response to its effects. This can mean that regular users are less likely to experience red eyes than occasional users, or the redness may be less pronounced.

Related: CBD vs. CBN: What’s the Difference?

Remedies for Cannabis-Induced Red Eyes

Although red eyes are harmless, they can sometimes be inconvenient or unwanted in social or professional settings. Fortunately, there are a few methods for reducing or concealing red eyes:

1. Over-the-Counter Eye Drops: Eye drops are one of the most reliable ways to reduce redness. Designed to treat allergies or dryness, these drops often contain tetrahydrozoline, a vasoconstrictor that contracts blood vessels, limiting blood flow in the eye and reducing redness. Using eye drops a few minutes after consuming cannabis can quickly clear up bloodshot eyes, making them an easy go-to solution for many users.

2. Caffeine: Like tetrahydrozoline, caffeine is a vasoconstrictor, meaning it can help decrease blood flow and reduce redness. Drinking caffeinated beverages such as coffee, energy drinks, or tea after cannabis consumption may help reduce red eyes. Caffeine is readily available and can be particularly useful if eye drops aren’t accessible.

3. Cold Compress: Placing a cold compress over the eyes or splashing cold water on your face can reduce blood flow and cause blood vessels to constrict. This natural response to cold is a survival mechanism that reduces blood flow in peripheral areas like the eyes, helping to reduce redness. If you don’t have an ice pack, a cold washcloth can work just as well.

4. Wear Sunglasses: If red eyes are unavoidable and you need to conceal them, sunglasses provide a simple solution. While they won’t reduce the redness, they effectively hide it. Wearing sunglasses can be particularly helpful if you’re out in public or with others who may not understand your choice to consume cannabis.

5. Choose a Low-THC Strain: For those particularly sensitive to THC, choosing strains with lower THC levels may help avoid red eyes altogether. Since redness is directly linked to THC concentration, opting for a high-CBD or balanced strain can be a proactive way to prevent red eyes before they start. Although this won’t reverse redness once it appears, it can reduce the likelihood of its onset.

Does the Ingestion Method Matter?

The method of ingestion impacts the timing and intensity of the red-eye effect. Smoking or vaping cannabis typically results in a quicker onset of red eyes because the THC is rapidly absorbed into the bloodstream. As a result, users may notice red eyes within minutes of smoking or vaping.

Edibles, however, provide a slower onset of effects, including red eyes. When consumed orally, THC is absorbed through the digestive system and metabolized by the liver, resulting in a delayed but prolonged experience. Thus, people who use edibles may notice a delay before their eyes turn red, but the effect might last longer as THC is gradually metabolized.

You May Also Read: Do Edibles Cause Liver Damage?

Bottom Line: Why Red Eyes From Cannabis Are Nothing to Worry About

While red eyes can sometimes be a nuisance, they’re ultimately a minor and harmless side effect of cannabis use. The reddening occurs as a direct result of THC’s interaction with the endocannabinoid system, causing vasodilation and increased blood flow. Not only does this effect provide temporary relief for people with high intraocular pressure or conditions like glaucoma, but it’s also generally manageable with easy, accessible remedies.

The duration of red eyes from cannabis varies depending on THC concentration, individual metabolism, and consumption method. For most people, the redness will subside within one to two hours. However, those consuming high-THC products or edibles may experience red eyes for three to four hours. Solutions like eye drops, caffeine, cold compresses, and sunglasses can help reduce or conceal red eyes, offering peace of mind in various settings.

So, the next time you notice your eyes looking a little red after consuming cannabis, remember it’s a normal and temporary effect. With a few simple remedies and an understanding of how cannabis interacts with your body, you can enjoy the benefits of cannabis without worrying about red eyes.

FAQs

• Do other cannabinoids like CBD cause red eyes too?

  No, only THC is directly responsible for the red-eye effect. Other cannabinoids, such as CBD (cannabidiol), CBG (cannabigerol), and CBN (cannabinol), generally do not cause eye redness. In fact, these cannabinoids may even help reduce blood pressure and have a calming effect on the cardiovascular system, making red eyes less likely.

• How long do red eyes last after using cannabis?

  Red eyes typically last 1–2 hours, but for some users, they may persist for up to 3–4 hours. The exact duration depends on factors like THC concentration, individual metabolism, and the method of consumption. Smoking or vaping tends to cause quicker onset of red eyes, while edibles may have a delayed but longer-lasting effect.

• Are red eyes from cannabis use harmful?

  No, red eyes from cannabis are generally harmless and temporary. While they may be inconvenient in certain settings, red eyes are just a minor side effect of THC-induced vasodilation. The effect will wear off on its own within a few hours, and using eye drops or other remedies can help reduce the redness if needed.