What Happens When THC Enters the Body and How Long It Stays

Have you ever wondered how THC gets you high? Did you ever consider the differences between smoking a joint and eating a cannabis-infused edible with regard to the duration and intensity of the effects? For anyone who has ever been curious about what THC enters the body, you’re in the perfect place to find all the answers you seek.

First, we’ll discuss how THC is absorbed via all the popular delivery methods. Second, you’ll discover what effects you can expect from the THC circulating your bloodstream. Finally, a look at THC excretion will help us learn all about how long THC stays inside your body.

Consuming and Absorbing THC

THC can be absorbed into the body through different delivery methods. Ultimately, the goal is to get as many THC compounds to reach your brain and body to produce psychoactive and medicinal effects. We’ll review each of the standard modes of delivery before turning to the effects of all these THC compounds circulating within you.

Smoking and Vaporizing cannabis involve inhalation of THC and absorption through the lungs and into the bloodstream. The smoke or vapour reaches the tiny air sacs at the tips of your lung airway tubes before crossing over into the bloodstream. This process is identical to how we humans absorb oxygen and release carbon dioxide.

The absorption efficiency is relatively high and occurs nearly instantaneously. There is no need to hold your cannabis smoke, as it won’t enhance the high. Smoking or vaping cannabis can produce a rapid onset of effects, but it can take 10-30 minutes to feel the full impact. The results of inhaling THC generally persist up to 6 hours, but residual effects can be felt for up to 24 hours.

Orally consumed cannabis products involve the absorption of cannabinoids inside the intestines and colon. First, these cannabinoids must pass from your mouth through the stomach and into the intestines. Once here, absorption occurs into the bloodstream, passing through the liver before travelling throughout the body. Often described as the first-pass effect, THC is processed by the liver before dispersing around the body. This first-pass metabolism can reduce the efficiency of the edibles we consume.

All of this processing also takes time, which is why edibles take longer to produce a high. In general, it can take 20 to 120 minutes to begin to feel effects. That said, it can take up to 4 hours to feel the full impact. Keep this delay in mind, so you can be cautious and avoid double-dosing before reaching your peak high. New cannabis users should be especially thoughtful in deciding what dosage to consume, with a suggested first dose of 2.5mg of THC or less. The effects of eating an edible can last up to 12 hours. Residual effects can persist even longer, up to 24 hours after use.

Topical products lead to absorption through the skin, although it appears that cannabinoids do not reach the bloodstream. This depth of absorption can occur with transdermal topical products, which use a carrier compound to assist with cannabinoid transportation. Ultimately, topical creams and lotions are best used for local administration and targeted relief.

Once inside your body and circulating your bloodstream, THC rapidly disperse throughout the body. Since THC is a lipid, it can quickly permeate just about everywhere. THC is known to spread into your muscle and fat cells, even reaching your lymphatic system. But that is not all, as THC goes where your blood goes. This includes heavy concentrations of THC inside your organs and central nervous system.

Our natural endocannabinoid system mediates the effects of THC. THC concentrates at the various sites of action to produce effects. Generally, the highest concentrations of THC can be found in the heart and adipose tissue (fat cells). Furthermore, THC can cross the blood-brain-barrier, but this transportation is somewhat more limited.

Research has shown us that THC interacts with our cannabinoid receptors and other physiological targets. It is the activation of CB1 receptors inside our nervous system that produces many familiar cannabis symptoms. THC also interacts with CB1 receptors all over our body, including our muscles, fat cells, bones, and other tissues.

Smoking, vaping and eating cannabis each have pros and cons that you should consider. Once you decide how you want to consume your cannabis, the next thing to know is what to expect. For example, after you got your Mandarin Cookie rolled into a joint, what happens next? Let’s explore the effects of THC on the human body and mind.

The Body and Mind Effects of THC

The acute or rapid effects of consuming THC include euphoria production, the most familiar symptom of the cannabis high. The acute effects include changes to our cardiovascular system (heart and blood vessels), eyes, and central nervous system (brain and spinal cord). Moreover, THC has noticeable effects on our musculoskeletal, gastrointestinal, and respiratory systems.


Consuming cannabis leads to a more rapid heartbeat, called tachycardia. Furthermore, THC leads to increased cardiac output and heart palpitations. THC has been shown to induce vasodilation, which is the widening of blood vessels. One of the most famous cases of this vasodilation is the stereotypical baked ‘red eyes.’ The eye also happens to be our next topic.

The Eye

You may be amazed to hear it, but yes THC compounds reach the blood vessels of your eyes. Once here, THC appears to decrease the intraocular pressure, which is the eye’s internal liquid pressure. This ability led to the treatment of certain eye disorders with medical cannabis. This intervention was one of the first medically recognized uses of cannabis in Canada.

Musculoskeletal System

While more research is needed, there is evidence that THC can help individuals who have rheumatoid arthritis (RA) and fibromyalgia (FM). Unfortunately, THC may have some adverse effects on bone healing. Conversely, cannabis can potentially decrease spasticity (muscle stiffening and tightening that restrict fluid movement) in those with multiple sclerosis (MS) and spinal cord injury.

Gastrointestinal System

Cannabis is a common remedy for individuals suffering from gastrointestinal (GI) distress. There is some limited evidence showing benefits for inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). The research shows that THC can reduce intestinal motility (food movement through the GI tract) and decrease gastric secretions. The overindulgence of THC can induce adverse events like abdominal pain, nausea, vomiting, and diarrhea.

Respiratory System

The acute administration of THC produces bronchodilation, of the widening of your lung airways. Low levels of THC can stimulate the lungs, while heavy smoking can lead to decreased lung function. Chronic smoking can also lead to coughing, wheezing, and increased phlegm production.

The Central Nervous System

As we already mentioned, once THC reaches the brain, a slew of psychological effects occur. These symptoms include euphoria, drowsiness, mental clouding, and memory impairment. Pain-relief and nausea-reductions are other areas being explored in research, with some optimistic findings. Moreover, THC also impacts our perceptions, including heightened sensory perception, distortion of space and time, and hallucinations.

Too much THC may cause dysphoria (unease and unrest), anxiety, and depersonalization (dream-like detachment from life). THC can also stimulate appetite (the munchies), although this effect appears to reduce over a period of time with tolerance buildup. Other cannabis effects, including euphoria, also appear to decrease in intensity as tolerance develops.

There is also a collection of muscle and motor function changes from THC presence in the central nervous system. You should avoid driving while high because THC can cause incoordination, weakness, and muscle impairment. There is limited evidence on the medical cannabis side to suggest potential benefits for dystonia (involuntary muscle contractions), Huntington’s disease, Tourette’s syndrome, and Parkinson’s disease.

How Long Does THC Stick Around?

Now that we understand how THC enters the body and what effects it has, it is time to find out how long it takes to be excreted. After inhaling THC, the levels of THC in your blood quickly decrease. After 30 minutes, THC levels can fall to 20% of their earlier peak. After this rapid initial drop, it has been estimated that it takes at least four days for half of the remaining THC to be degraded or excreted.

THC is excreted in both your urine and feces. Low levels of THC metabolites have been detected in urine and feces up to five weeks after cannabis consumption. As odd as it may seem, the THC you inhale leaves you via the bathroom.

We learned how THC is a lipid that rapidly disperses into adipose tissue. Research has shown that our body stores THC compounds within these fat cells. This storage can lead to the delayed release of THC back into the bloodstream. THC has been detected in the blood of individuals over a month after the cessation of cannabis consumption. While there is little evidence to show that the levels can be high enough to cause a high, they can reach detectable drug test levels and possibly cause motor impairment.