Cannabis is used by smoking, vaping, eating, applying it to the skin, or placing drops under the tongue. Each method delivers cannabinoids to the body differently, with wide variation in how quickly effects begin, how long they last, and how much of the active compounds actually reach your bloodstream. The method you choose shapes the entire experience.
How Cannabis Works in the Body
Your body has a built-in network of receptors that respond to cannabinoids, the active compounds in cannabis. These receptors fall into two main types. The first type is concentrated in the brain, particularly in areas that control movement, memory, cognition, and pain perception. These receptors sit at the ends of nerve cells, where they regulate the release of chemical messengers. They’re also found at lower levels throughout the body in organs like the heart, lungs, liver, and reproductive system.
The second type of receptor is concentrated in immune tissue: the spleen, tonsils, thymus, and white blood cells. These receptors play a role in regulating inflammation and immune responses. When THC and other cannabinoids enter your system, they bind to these receptors and alter normal signaling, which produces the range of effects cannabis is known for, from pain relief and relaxation to euphoria and altered perception.
One important detail: raw cannabis doesn’t produce a high. The plant contains an inactive precursor that must be converted into THC through heat, a process called decarboxylation. When you smoke or vape, this happens instantly. When making edibles, the cannabis needs to be heated first, typically at around 131°C (268°F) for about 65 minutes, or at a higher temperature of 137°C (279°F) for roughly 57 minutes.
Smoking and Vaping
Inhaling cannabis, whether by smoking a joint, using a pipe, or vaping, is the fastest way to feel its effects. Cannabinoids pass through the lungs and enter the bloodstream almost immediately, making this the go-to method when rapid onset matters.
The tradeoff is efficiency. When cannabis is burned, roughly 23% to 30% of the THC is destroyed by the heat itself, and another 40% to 50% drifts away in smoke that isn’t inhaled. Only about 20% to 37% makes it into the smoke you actually breathe in, resulting in a maximum of 25% of the THC reaching your system. Vaping is somewhat comparable, with bioavailability ranging from 10% to 35% depending on how you inhale: the number of puffs, how long you hold each breath, and how deeply you draw.
Effects from inhalation are short-lived compared to other methods, which can be an advantage when you want more control over the experience. If the effects are too strong, they’ll fade relatively quickly. This is why inhaled cannabis is sometimes recommended for medical patients dealing with sudden flare-ups of pain.
Edibles
Edibles include any food or drink infused with cannabis: gummies, chocolates, baked goods, beverages, and capsules. The experience is fundamentally different from smoking. Effects can begin as early as 30 minutes after eating, but they typically build over one to three hours. This slow ramp-up is the main reason people accidentally take too much. They eat a dose, feel nothing after an hour, take more, and then both doses hit at once.
Your body absorbs far less THC through digestion than through the lungs. Oral bioavailability is only about 4% to 12%, meaning the vast majority of the THC you swallow never makes it into your bloodstream. However, the liver converts THC into a different compound during digestion that is actually more potent and longer-lasting, which is why edible highs feel stronger and can persist for several hours.
Dosing for edibles is measured in milligrams of THC. For someone trying cannabis for the first time, 1 to 2.5 mg is the standard starting range. Recreational users with some experience typically use around 5 mg, which is also common for people using cannabis for sleep or persistent symptoms. At 10 mg, newer users may experience unpleasant side effects like impaired coordination or anxiety. Experienced users with high tolerance may use 20 mg or more, and patients with cancer or serious inflammatory conditions sometimes use 50 to 100 mg, though those doses would overwhelm most people.
Sublingual Products
Tinctures and oils placed under the tongue offer a middle ground between inhaling and eating. The cannabinoids absorb through the thin tissue beneath the tongue and enter the bloodstream more directly than swallowed edibles. Sublingual bioavailability is estimated at around 13%, slightly higher than oral ingestion’s 4% to 12% range. The onset is generally faster than edibles, though not as immediate as smoking. This method appeals to people who want to avoid inhaling anything but still want reasonably quick, controllable effects.
Topicals and Transdermals
Cannabis-infused creams, balms, and lotions are applied directly to the skin, usually over sore muscles or inflamed joints. Cannabinoids generally have low skin penetration. They tend to accumulate in the outermost layer of skin and were long thought not to reach the bloodstream at all. This means standard topicals provide localized effects without producing a high.
Transdermal patches are a different technology. They’re designed to push cannabinoids through the skin and into systemic circulation. Recent research has confirmed that specially formulated transdermal systems can deliver both THC and CBD into the bloodstream. Even so, the concentrations reaching the brain appear too low to produce psychoactive effects. In one study, 100% of participants reported feeling no “high” at any point after using a transdermal patch.
Microdosing
Microdosing involves taking very small amounts of cannabis, often well below 1 mg of THC, to achieve subtle therapeutic effects without intoxication. The goal is to stay below the threshold where you’d notice impairment while still getting benefits like improved mood, better sleep, or reduced anxiety. In one documented medical case, a patient with early-stage Alzheimer’s disease was treated with roughly 500 micrograms (0.5 mg) of THC per day, a tiny fraction of a standard recreational dose. Over the course of treatment, the patient reported feeling more alert, sleeping better, and showing improvements in mood stability.
Medical Uses With Strong Evidence
Cannabis is used medically across dozens of conditions, but the strength of evidence varies enormously. Three areas stand out with the most robust clinical support.
For chronic pain in adults, a major review by the National Academies of Sciences found “substantial evidence” that cannabis is effective. Pooled data from clinical trials showed that plant-derived cannabinoids increased the odds of meaningful pain improvement by about 40% compared to placebo.
For nausea and vomiting caused by chemotherapy, the evidence is even stronger. The same review classified it as “conclusive evidence,” the highest tier. Patients using oral cannabinoids were nearly four times more likely to achieve complete relief from nausea and vomiting than those on placebo.
For muscle spasticity in multiple sclerosis, oral cannabinoids produced a statistically significant improvement in patient-reported symptoms, reducing spasticity scores by about 0.76 points on a 10-point scale compared to placebo. That may sound modest, but for patients dealing with constant muscle tightness, it translates to a noticeable improvement in daily comfort. Patients were also 44% more likely to report overall improvement on a global assessment.
FDA-Approved Cannabinoid Medications
The FDA has not approved the cannabis plant itself as a medicine for any condition. It has, however, approved four cannabinoid-based pharmaceutical products. One is derived directly from the cannabis plant: a purified CBD medication approved for treating seizures in patients two years and older with certain severe forms of epilepsy. The other three are synthetic versions of THC, approved for chemotherapy-related nausea and for appetite loss and weight loss in AIDS patients. These are prescription medications dispensed through pharmacies, distinct from the cannabis products sold in dispensaries.