Medically Reviewed by
Jason Crawford

Article Last Updated on January 12, 2023

The THC content in weed is often a subject of curiosity among weed enthusiasts, especially those who enjoy high-THC strains. With dispensary-sold edibles, you have the percentage or the milligrams printed on the package to give you some guidance, but it’s a bit trickier when it comes to smoking or vaping.

You may have been using marijuana for a long time and learned intuitively what works for you and what doesn’t in terms of effective dosing, without knowing the concrete details. Or you may be an occasional enthusiast looking to find out more about the theory behind what makes weed potent.

Whichever the case, below we’ll talk all about estimating the average THC percentage in weed, what factors influence it, the difference between the consumption methods of weed, and dosing. Let’s get into it!

About THC in Cannabis

Cannabinoids CBD and THC are the main magical ingredients that make weed so unique. While CBD is the star of many medical marijuana strains, THC is the key ingredient that gives you “the high”. It’s simple – no THC, no “high”.

THC (delta-9-tetrahydrocannabinol) is a psychoactive chemical secreted by the glands of the cannabis plant. It’s found in the highest doses in the resins of the buds and cannabis flowers of the female plant during the harvesting stage.

Its primary purpose may surprise you, but, the role of THC in the natural world is to protect the plant from predators, parasites, bacteria, and viruses, but its effect on humans is different. For humans, usually, CBD offers anti-inflammatory and antioxidative properties (Atalay et al, 2019). Therefore, we can say that nature offers cannabinoid content options for both worlds – the natural and the human.

THC in the Body

This cannabinoid has a specific molecular structure that quickly and effectively binds to the endocannabinoid receptors naturally present in the human body, particularly the CB1 receptors. These receptors are primarily located in the different parts of the brain responsible for functions like thinking, memory, concentration, coordination, movement, and time perception.

THC attaches to the neurotransmitters (chemical messengers through which neurons communicate) in the brain and mimics the neurotransmitter anandamide, a so-called “mood enhancer”. In this way, THC stimulates the body’s dopamine release, making you feel good in the process. THC also makes you feel relaxed, euphoric, and elated, but higher doses may bring on side effects, like dizziness, anxiety, and paranoia. It’s important to note that the effects are different for everyone.

Factors that Influence THC Content

It could be said that the THC content varies for different cannabis strains. Some contain as low as 0.3 to 4%, while others, usually hybrid strains, are much stronger, with a THC content of up to 25%. Some factors can influence the percentage of THC that will end up in the marijuana plant:

  • Growing conditions, including climate and necessary nutrients – this is essential for any plant, including cannabis. If the crops are not provided with the optimal growing conditions, like an ideal temperature and a rich soil, they will probably be less potent;
  • Genetics – this factor is highly variable, especially when you take hybrids into account. But, generally, Sativa strains naturally have higher THC content, and some hybrids are purposefully created to be high in THC;
  • Harvesting and processing – proper handling of the plant after it flowers is also an important part of the process. It needs to be dried and cured properly so that the THCA converts to its active form THC. Improper processing may hinder this process and create a less potent strain, which is why two farmers’ harvest of the same crop may be different;
  • Hasty growers – sometimes growers want to make a bigger profit and produce more weed in a certain amount of time which may result in premature harvesting before the plant is completely ready to be harvested.

How THC Becomes Active

To understand the potency of weed, it’s helpful to look into the amount of THC present in the cannabis plant from the beginning. You may have heard of “active” and “inactive” forms of THC, so let us clear that up.

The marijuana plant itself doesn’t produce THC, it produces THCA (tetrahydrocannabinolic acid), a non-intoxicating precursor to THC, or what you would call the “inactive” form of THC. This compound gets converted into THC in the presence of heat via a process called decarboxylation.

Simply put, decarboxylation is the chemical reaction that happens when weed is exposed to heat, thereby converting the THCA content into its psychoactive form of THC. This is what would happen when you light a joint or vape, while for edibles, weed needs to be decarboxylated first before being infused into food.

Methods of Consumption

Getting the right amount of THC for your needs can be a case of trial and error, especially if it’s your first time. If you take too little, it’ll be basically useless, and if you take too much, you’ll probably have an unpleasant experience. Even when you’ve built a routine with your cannabis use, a new strain or a new method of consumption might catch you by surprise.

That’s because THC behaves a little differently depending on how you ingest it. Add to this all the different strains, and other factors, like body physiology, and it might get confusing how much you’ll be ingesting approximately.

There are a lot of ways to get your THC dose, so let’s outline the differences between the three most common ways of taking weed, and hopefully, we’ll make it easier for you to choose your desired dose next time.


Estimating the average amount of THC in a joint may be the trickiest. There have been attempts to calculate the approximate weight of a joint, the most recent one being a 2016 study by the University of Pennsylvania where it was estimated that the average joint contains between 0.30-0.35 grams of marijuana. Bigger joints may even contain 1 gr, which is more suitable for heavy smokers or larger groups of people.

The good thing with joints when it comes to dosing is that the THC enters your bloodstream quite quickly, so it won’t take long for you to know if you need more, though beginners will usually do with one hit at first.


Similarly, with vaporizers, you can’t exactly gauge how many mg of THC you will ingest. It’s important to remember that the THC liquid in vaporizers is more concentrated than the weed in a joint, so you’ll definitely need fewer tokes to feel the effects.

The upside of vaporizers is that you don’t need to use up the whole thing right away. You can take one hit, see how you feel, and take another if you need to. When you’ve found your sweet spot, take note of it for next time.


You have the most control of how much you’ll be ingesting with edibles because the percentage and milligrams of THC are usually printed on the package. These cannabis products are the most straightforward when it comes to dosing, but, only if you’re informed about their potency.

We’ve previously talked about this, but for those of you who may not know, it bears repeating – edibles take a lot longer to kick in, and their effects are a lot more intense and long-lasting than your usual joint or vape.

For edibles, we always recommend you start as low as 10 mg (0.1 g), or even 5 mg if it’s your first time or you’re sensitive to THC. Once you take your dose, wait for at least 90 minutes to 2 hours to start feeling the effects before you decide to grab another piece. When in doubt, give it more time.

The same applies to homemade edibles, like brownies or weed butter, you should always take the lowest dose. Being patient with homemade edibles is even more important because you can never be sure of the THC dosage as there’s no way to measure it. Therefore, be mindful and don’t forget to enjoy it.


THC is the psychoactive cannabinoid in the marijuana plant that induces the characteristic “high”. It attaches to the cannabinoid receptors in the human body and influences the production of dopamine, thereby causing feelings of elation.

In the marijuana plant, THC is present in its inactive form THCA which activates under a source of heat. Many factors influence the total THC percentage in weed, including growing conditions, genetics, and processing.

Finally, different methods of consumption influence the levels of THC that will end up being absorbed, with edibles as the easiest to dose and smoking and vaping the hardest.

Additional Sources
Atalay S, Jarocka-Karpowicz I, Skrzydlewska E. Antioxidative and Anti-Inflammatory Properties of Cannabidiol. Antioxidants (Basel). 2019;9(1):21. Published 2019 Dec 25. DOI:10.3390/antiox9010021

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


The information presented on this page is provided as a public service to aid in education and is derived from sources believed to be reliable. Readers are responsible for making their own assessment of the topics discussed here. In no event shall Leaf Nation be held reliable for any injury, loss or damage that could happen if using or abusing drugs.