Cannabis 101

What is delta-9 THC?

Published on October 26, 2022 · Last updated November 14, 2022
pile of weed
(Matthew Benoit/AdobeStock)

THC is the active compound in cannabis that causes you to feel high. The compound is the main reason people consume cannabis, either for fun or for medical benefits. When you smoke, vape, eat an edible, or do a dab, you can thank THC for the high. 

THC’s scientific name is delta-9-tetrahydrocannabinol, or delta-9 for short. Delta-9 is a cannabinoid. The cannabis plant contains many cannabinoids and terpenes, plus other compounds. Cannabinoids in the plant (phytocannabinoids) interact with cannabinoids in the body (endocannabinoids) to cause effects and make you feel high.

Some other cannabinoids include (plus many more):

  • CBD
  • Delta-8
  • Delta-10
  • CBG
  • CBN
  • THCA

THC in cannabis is what makes the plant illegal federally, and the amount of THC is important. States that have legalized cannabis allow products with THC levels above 0.3% to be sold (most cannabis flower contains 15-25% THC). Cannabis products with less than 0.3% THC are considered hemp and are legal at the federal level, since 2018

Products containing minor cannabinoids delta-8 and delta-10 have become popular lately because they can skirt the law and be sold in states that do not have legal cannabis. They can do this because they’re derived from hemp, that is, plants with less than 0.3% THC. 

Further complicating the legal landscape is hemp delta-9, a newer product that can also get around the law because it is derived from hemp.

Learn all about delta-9 THC, its effects, and other minor cannabinoids below.

Does delta-9 THC get you high?

Absolutely. Delta-9 is just another name for THC, the main compound in cannabis that gets you high. It combines with terpenes and other compounds in the cannabis plant to elicit different effects in a person.

Shop highly rated dispensaries near you

Showing you dispensaries near
See all dispensaries

The potency, or strength, of a cannabis product is determined by the amount of THC in it. The higher the THC percentage, the stronger the weed.

The science of getting high: How does weed create effects?

What are the effects of delta-9 THC?

People consume cannabis for many reasons, whether recreationally or for relief from medical symptoms. Common recreational effects include feeling:

  • Euphoric
  • Uplifted
  • Relaxed
  • Sleepy
  • Energized
  • Creative
  • Sociable
  • Focused
  • Giggly

Explore cannabis strains and their effects on Leafly’s strain database.

What are the benefits of delta-9 THC?

Cannabis is also consumed to help with medical symptoms. It most commonly is used to help treat symptoms related to:

  • Cancer
  • Glaucoma
  • Cachexia (wasting syndrome)
  • Persistent muscle spasms
  • Seizures
  • Severe nausea
  • Severe pain
  • Post-traumatic stress disorder (PTSD)
  • Autism spectrum disorders

Is delta-9 THC safe?

Compared to other substances, cannabis is relatively safe. 

Despite the plant’s many benefits, it’s important to note that weed isn’t for some people. A common negative effect some report is feeling paranoia or anxiety after consuming weed—this can be especially true with edibles, which can be hard to dose (our motto is: “start low, go slow”). 

While you can’t die from weed, consuming too much can ruin your evening. If you have too much weed in your system, here are some ways to sober up if you’re too high. If you’ve been smoking too much in general, you can always take a tolerance break.

8 ways to sober up from being too high

Does delta-9 THC show up on a drug test?

Absolutely. Because the plant is still federally illegal, many employers can test for weed and you can lose your job if you test positive. However, as legalization increases across the country, some employers are not testing for weed—for example, online retail giant Amazon has said they won’t.

Learn how to detox from weed.

How long does delta-9 THC stay in your system?

Conventional wisdom says that THC will stay in your system for 30 days, but it really depends. Frequency of use is a big factor: THC will likely clear your system more quickly if you only smoke every once in a while, versus smoking every day for months on end. 

Additionally, different types of tests have different detection windows: a urine test can usually detect THC up to 30 days; blood, a day or two; hair, up to 90 days.

What’s the difference between delta-9 THC, delta-8, and delta-10?

THC, or delta-9, is the main compound in weed that gets you high. Delta-8 and delta-10 are separate cannabinoids that will also get you high, albeit less so. 

Chemically, all the deltas have a chain of carbon atoms with a double bond in their structure. The placement of the double bond defines each cannabinoid—delta-9 has it on the ninth carbon, delta-8 on the eighth, etc. The placement of that double bond is thought to make delta-9 THC more potent than the other two.

Are delta-8 and delta-10 stronger than delta-9 THC?

Delta-9 THC is much stronger than both delta-8 and delta-10. Both delta-8 and delta-10 are thought of as “diet weeds” because of their lesser effects. Anecdotally, some claim that delta-8 is more sedating, and delta-10 is more energizing. 

Does delta-8 stay in your system longer than delta-9 THC?

Delta-8 will typically stay in your body for the same amount of time as delta-9 THC. If you smoke or vape either, they will last about an hour or so; if you take some edibles, they will last a few hours.

What is delta-8?

THC is illegal at the federal level and is only legal in specific US states that have enacted laws to allow it, either for recreational or medical use. It is also legal in all of Canada and Uruguay. 

Check out Leafly’s Legalization guide for specific cannabis laws in each state, including possession, consumption, purchasing, growing, and more.

Where can I buy delta-9 THC?

As of Oct. 2022, weed is legal in 19 US states for adult use and 39 states for medical use. THC products can be purchased in adult-use states by anyone over the age of 21 with a valid ID. Requirements vary slightly in medical states, but typically, patients must be over 18 years of age, have a medical marijuana card, and a prescription from a doctor in order to buy cannabis.

Hemp-derived delta-9 exists in a legal gray area. It is technically legal in all US states because it is sourced from hemp, but laws can change quickly. For example, delta-8 is specifically outlawed in some states, and hemp delta-9 may have a similar fate.

Leafly’s guide to marijuana legalization

Does delta-9 THC have a possession limit?

Generally speaking, most states with adult-use cannabis allow the possession of up to one ounce, or 28 grams, of cannabis flower on your person. Some states have different possession limits for other products, such as edibles and concentrates. 

For example, in Oregon, adults can possess one ounce of flower, one ounce of concentrates, and 16 ounces of edibles, but other states may vary. Medical allowances are usually higher than recreational ones.

Can I ship delta-9 THC?

No. It is illegal to ship any cannabis product, that is, any product containing more than 0.3% THC. As cannabis is federally legal, it cannot be shipped through the USPS, which is run by the federal government. It is also a federal offense to move cannabis products across state lines, as it violates federal contraband law, even between two states that both have legal cannabis.

Hemp-derived delta-9, delta-8, or delta-10 products can be shipped to some states as they are sourced from hemp, plants with less than 0.3% THC, and not cannabis plants. However, some states have specifically outlawed these hemp substances. Be sure to check if it is legal to mail a certain hemp product in your state.


Shop highly rated dispensaries near you

Showing you dispensaries near
See all dispensaries
Pat Goggins
Pat Goggins
Pat Goggins is a former Leafly senior editor who handled the site's informational Cannabis 101 and Learn section content, as well as health and science, and growing articles. When not fixing typos or reading a book, you’ll probably find him on a boat or in the mountains.
View Pat Goggins's articles
Get good reads, local deals, and strain spotlights delivered right to your inbox.

By providing us with your email address, you agree to Leafly's Terms of Service and Privacy Policy.