Cannabis Is More Potent Than Ever — Here’s Why That Can Be Risky

Although humans have been using cannabis for at least 5,000 years, today’s cannabis is very different from ancient varieties. A key difference is THC, marijuana’s main mind-altering chemical. The amount of THC in cannabis has steadily increased over the last few decades.

But more THC isn’t always a good thing. Stronger cannabis products carry more health risks — and few benefits.

What is high-potency weed?

High-potency weed is cannabis that contains more than 20% THC or 10 mg or more of THC per serving. And the amount of THC in a cannabis product is typically how the product’s strength (or potency) is described.

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Must be 21 years or older to purchase. Cannabis is not recommended for women who are pregnant or nursing or those who are suffering from bipolar disorder or schizophrenia. Cannabis use may increase risk of falls. Always consult with your doctor before beginning any new medical treatment.

Keep in mind, there’s a wide range for what’s considered "high-potency" cannabis. Some cannabis products can have a potency of 95% THC or more. These are generally referred to as cannabis concentrates — and their use is increasing.

Why has the potency of marijuana increased over the years? 

Across the globe, the potency of cannabis has risen over the last several decades. From 1995 to 2017, cannabis flower potency increased from about 4% THC to about 17% THC.

Part of this is simply a side effect of prohibition. When a substance is illegal, people prefer strong drugs over weaker ones. Economists call this the potency effect of prohibition. 

High-potency THC products also tend to sell for more money. This gives growers and manufacturers a financial incentive to make more potent products. 

Unfortunately, cannabis testing labs can also make more money by reporting high THC values. This kind of fraud, called potency inflation, may have artificially increased the data on weed strength in recent years. Several states are trying to address this issue by creating new laws for cannabis testing labs.

High potency isn’t the same as high quality

Studies show that cannabis consumers are willing to pay more money for what they perceive as “high-quality” cannabis products. But there’s no scientific evidence to support the idea that high potency is the same as high quality.

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Most high-potency cannabis products increase the amounts of THC at the expense of other active ingredients. As THC goes up, levels of other cannabinoids (like CBD) and terpenes (essential oils found in cannabis) go down. This is especially true for concentrates. 

But why does this matter? Because these other active ingredients also have effects on the body. They contribute to the overall effect of cannabis — known as the entourage effect. CBD, in particular, may help reduce some of the negative side effects of THC. So consuming high doses of THC without CBD increases the risk of these side effects.

Also, consuming more THC doesn’t mean you’ll feel more “high.” A clinical study showed that people who took high-potency cannabis felt the same effect as people who took low-potency cannabis. Even though the blood levels of THC in the high-potency group were higher, they didn’t feel more intoxicated.

Health risks of high-potency cannabis

In addition to missing out on some of the entourage benefits of lower-potency cannabis, there are some very real health risks that come with consuming high-potency cannabis.

Addiction and dependency-related risks

When you consume high doses of THC, the brain and body develop tolerance. This means you’ll need to use more cannabis to achieve the desired effect. And consuming high amounts of THC regularly can also make you numb to its effects. Using lower-potency products, or taking regular cannabis breaks for at least 2 days, can help prevent this.

Increased use can lead to physical dependence. This occurs when a person has withdrawal symptoms after they stop using cannabis. Cannabis withdrawal is like caffeine withdrawal, with symptoms such as:

• Irritability and negative mood

• Difficulty sleeping

• Headaches

• Cannabis cravings

Tolerance and withdrawal symptoms are both red flags that a person may be developing Cannabis Use Disorder (CUD). Symptoms of CUD include:

• Difficulty controlling cannabis use

• Continued use, despite negative consequences in one’s life

• Continued use, despite negative health consequences

• Using cannabis in risky situations, such as driving

• Spending an excessive amount of time acquiring, using, and recovering from cannabis use

Using high-potency cannabis may increase the chances of experiencing these symptoms.

Physical health risks

The following unwanted side effects are much more likely to happen when using high-potency cannabis:

• Poor body coordination

• Difficulty thinking or concentrating

• Rapid heart beat

• Anxiety, fear, or panic

• Confusion or disturbing thoughts

Cannabinoid Hyperemesis Syndrome (CHS) is another possible side effect of high-potency cannabis use. We need more research to draw a clear link between high-potency cannabis and CHS. But it’s clear that too much THC can lead to the uncontrollable nausea and vomiting associated with this disorder.

High-potency cannabis may also cause seizures. People who use cannabis concentrates appear to be the most at risk for seizures, even if they are otherwise healthy. 

Cannabis-related deaths are very rare, and most deaths are due to fatal accidents. However, there are several case reports of people who had fatal heart complications after using cannabis. THC has also been linked with other heart problems, including heart attacks.

Mental health risks

High-potency cannabis products are also linked with poor mental health outcomes. A high dose of THC may cause psychotic-like symptoms in an estimated 35% to 50% of people. And regular use of high-potency cannabis makes people five times more likely to develop psychosis. 

Psychosis is a potentially life-threatening mental health emergency where a person experiences:

• Hallucinations — seeing, hearing, or perceiving things that aren’t there

• Delusions — unusual beliefs that do not match shared reality

• Confused or disturbed thoughts

In some cases, a high dose of THC can trigger a specific condition called Cannabis-Induced Psychotic Disorder. This condition is very different from simply consuming excess THC. Some of these differences include:

• Psychotic symptoms are more severe.

• People believe their hallucinations are real. 

• Symptoms last much longer than the normal duration of THC’s effects — sometimes still being experienced days or even weeks after cannabis exposure.

Benefits of high-potency cannabis

There are a couple possible benefits to opting for high-potency cannabis, including:

1. High-potency cannabis may allow you to save money. While high-potency products are often more expensive, you don’t need to use as much of them to get an effect. So they may last longer and be more cost-effective in the long run. 

2. High-potency cannabis may be a better choice for certain people. Some people metabolize cannabis very rapidly. They need very high doses to feel its effects. Also, some people with severe pain may need high doses of THC to treat their symptoms. For these people, high-potency cannabis may be the only kind that provides the effect they need.

How to consume THC responsibly

One best practice is to limit how much THC you consume in order to avoid the increased risks associated with high-potency cannabis.

Mindful cannabis use

There are several ways to minimize the risk of negative effects from cannabis, such as: 

• Choosing a high-CBD formulation. CBD does not cause people to feel high, is not habit-forming, and may have several medical benefits. It may also help prevent some of the negative effects of THC when they’re used together.

• Starting with a small dose of THC and increasing your dose slowly over time. The goal here is to find the lowest effective dose for your needs. Increasing your dose slowly over time allows your body to adjust to small changes. This reduces the risk of side effects.

Buy cannabis from regulated sources

Unlike illicit market cannabis, most legalized cannabis markets require lab testing and labeling. Purchasing from a legal state retailer ensures you’ll know exactly how much THC is in each product. Buying cannabis from a licensed retailer is safer than informal sources. Many states also permit people to grow their own cannabis and get it tested at state-licensed laboratories. 

It can be challenging to find dispensary products that are low in THC. This can be frustrating for people who prefer low-potency products. 

Some things to look for when shopping for low-potency products include:

• Flower with less than 10% THC 

• “Balanced” products with a 1 to 1 ratio of THC to CBD

• CBD-dominant flower, edibles, or tinctures

• Products marketed as a “microdose” of THC

If your dispensary doesn’t carry many low-THC options, it might be helpful to have a conversation with dispensary management. Consumer demand is a powerful force — cannabis retailers will generally only carry products they know will sell. 

Why trust our experts?

Written by:

Adie Rae, PhD

Adie Rae, PhD, is a neuroscientist known for her extensive expertise on cannabis. She has been conducting peer-reviewed research about cannabis since 2004.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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If you or someone you know struggles with substance use, help is available. Call SAMHSA’s National Helpline at 1-800-662-HELP (4357) to learn about resources in your area.

Keep in mind that cannabis is legal in some states for recreational and/or medicinal use, but not in others. Cannabis is still illegal under federal law. Before you use cannabis products, find out the laws in your state.