The right cannabis dose is the smallest amount of THC that gives you the effect you want, and for most new or occasional users that means starting at about 5 milligrams of THC or less, then waiting before taking more. Edibles can take hours to peak while smoked or vaped cannabis peaks within minutes, so the method matters as much as the milligrams.
Dosing cannabis used to be guesswork. Today every legal product in Washington and Oregon carries a lab-tested THC number on the label, which makes it possible to measure a dose the way you would measure a drink. This guide explains how to read those numbers, how fast each method works, why tolerance changes everything, and what to do if you take too much. It is general information, not medical advice.
Cannabis Dosing at a Glance
| Question | Short answer | Source |
|---|---|---|
| What unit measures a dose? | Milligrams (mg) of THC. Researchers have proposed 5 mg as a “standard THC unit” for all products | Freeman and Lorenzetti, Addiction, 2020 |
| Largest edible serving sold in Washington | 10 mg THC per serving, 100 mg per package | WAC 314-55-095 |
| How fast does smoking or vaping peak? | Blood THC peaks in about 2 to 10 minutes | National Cancer Institute |
| How fast do edibles peak? | Blood THC peaks 1 to 6 hours after eating | National Cancer Institute |
| How strong is today’s flower? | Seized cannabis averaged 16% THC in 2022; dispensary flower and concentrates can exceed 40% | NIDA |
| Can you fatally overdose on THC? | No lethal overdoses have been documented, but too much can still send people to the emergency room | NCI, NIDA |
How Cannabis Dose Is Measured
Alcohol has the standard drink. Cannabis is catching up. In 2020, researchers writing in the journal Addiction proposed a “standard THC unit” of 5 mg that would apply to every product, from joints to gummies to vape pens. Their argument is simple: grams of flower and number of puffs tell you little, because THC concentration varies so widely. Milligrams of THC are what your body responds to.
That variation is real. The National Institute on Drug Abuse (NIDA) reports that the THC in cannabis seized by law enforcement rose from 3.96% in 1995 to 16.14% in 2022, and that dispensary flower and concentrates can exceed 40%. A dose that felt mild decades ago can be a large one today.
Reading a label
- Edibles and drinks: the label lists THC in mg per serving and per package. In Washington, a single serving cannot exceed 10 mg of THC and a package cannot exceed 100 mg. Oregon also caps THC per serving and per package; check the label before you eat a whole bar or bottle.
- Flower: the label gives a percentage. Multiply grams by the percentage to get the THC the material contains. One gram of 20% flower holds about 200 mg of THC. Only part of that reaches your bloodstream when smoked, and the share varies with how you inhale, so treat flower doses as approximate.
- Vapes and concentrates: usually far more concentrated than flower, so a single inhalation can deliver a large dose. Start with one small puff.
Starting Doses by Method
There is no official dosing chart for adult-use cannabis, and individual responses vary with body chemistry, tolerance and setting. The general principle used by researchers and clinicians is “start low, go slow.” In practice that looks like this:
- Edibles: a first dose at or below one standard unit (5 mg), which is half of a typical 10 mg serving. Wait at least two hours before taking more, because effects can keep building for hours.
- Smoking or vaping flower: one or two small inhalations, then wait 10 to 15 minutes to judge the effect before taking another.
- Concentrates and dabs: not a good starting point. NIDA notes that dabbing can deliver large amounts of THC very quickly.
- Tinctures under the tongue: use the dropper markings to measure milligrams and treat them like edibles if swallowed.
Why Edibles Hit Differently
When you inhale cannabis, THC moves from the lungs into the blood almost immediately. The National Cancer Institute’s review of cannabis pharmacology says inhaled THC peaks in 2 to 10 minutes and falls off over about 30 minutes.
Swallowed THC takes a slower route. It is absorbed through the gut and processed by the liver, which turns some of it into 11-hydroxy-THC, a potent psychoactive compound. NCI puts oral bioavailability at only 6% to 20%, with peak blood levels 1 to 6 hours after eating. That delay is the main reason people overdo edibles: they feel nothing after 45 minutes, take a second piece, and then both doses arrive at once. NIDA warns that because edibles take longer to show effects, people may take more, which raises the risk of a bad reaction.
Tolerance and Personal Factors
The same 10 mg can feel very different to two people. The biggest factor is tolerance. NCI notes that the brain develops tolerance to cannabinoids. A controlled NIDA study found that after smoking the same 6.8% THC cigarette, occasional smokers showed more psychomotor impairment than frequent smokers, though both groups were affected. Tolerance is not permanent: a PET imaging study found that cannabinoid receptors reduced in daily smokers returned to normal after about four weeks of abstinence. After a break, your old dose may hit much harder.
Other factors that change how a dose feels:
- Food in the stomach, which can change how fast an edible kicks in
- Alcohol, which adds to cannabis impairment
- Other medications, including sedatives and some antidepressants
- Anxiety, fatigue and setting
- CBD content: researchers note that CBD may partly offset some effects of THC, though the evidence is still limited
Strain names are not a reliable guide to dose. Two jars of Blue Dream from different growers can test at very different THC levels, so read the number, not the name. Our strain guides cover typical effects and potency ranges.
Risks and Side Effects of Taking Too Much
Too much THC is unpleasant and sometimes dangerous, even though it is not fatal the way an opioid overdose can be. NCI explains that cannabinoid receptors are not located in the brainstem areas that control breathing, which is why lethal overdoses do not occur. Common effects of overconsumption include:
- Anxiety, panic or paranoia
- Rapid heart rate and dizziness, especially on standing
- Nausea and vomiting
- Impaired thinking, memory, time perception and body movement, which NIDA lists among short-term effects
Children are at particular risk. NIDA reports that children who eat edibles by accident can end up hospitalized. Store products locked and out of reach.
Heavy, long-term use carries its own risks, including cannabis use disorder and cannabinoid hyperemesis syndrome, a cycle of severe vomiting that NIDA says only resolves when a person stops using cannabis completely. See our guide to marijuana addiction for warning signs.
What to do if you took too much
- Stop taking more. Remind yourself the effects are temporary.
- Sit or lie down somewhere safe and quiet, and drink water.
- Do not drive. Washington treats 5 ng/mL of active THC in the blood as a per se DUI; see our Washington marijuana laws guide.
- For questions, call Poison Control at 1-800-222-1222. For chest pain, trouble breathing, fainting or a child who ate cannabis, call 911.
Medical Dosing: Talk to Your Doctor
If you are using cannabis for a health condition, dose with a clinician, not a budtender. The FDA has approved specific cannabinoid drugs with set doses, such as dronabinol for chemotherapy nausea, but has not approved the cannabis plant for any condition. Tell your doctor about any cannabis use, especially if you take blood thinners, sedatives, seizure medicines or psychiatric medicines, are pregnant, or have heart disease or a history of psychosis.
Cannabis Dosage FAQ
How many milligrams of THC should a beginner take?
Start at about 5 mg or less, which is half of a standard 10 mg edible serving. Researchers have proposed 5 mg as a standard THC unit. Wait at least two hours before taking more of an edible.
How long does it take for an edible to kick in?
Often 30 minutes to 2 hours, and blood THC can peak anywhere from 1 to 6 hours after eating, according to the National Cancer Institute. Do not redose early.
Is 10 mg of THC a lot?
For a new or occasional user, 10 mg in an edible is a strong dose. It is the maximum single serving allowed in Washington. Regular users with tolerance may find it moderate.
How much THC is in a joint?
It depends on weight and potency. A half-gram joint of 20% flower contains about 100 mg of THC, but only part of it reaches your bloodstream, and you rarely smoke it all at once.
Can you overdose on cannabis?
Not fatally, as far as research shows, because cannabinoid receptors are absent from the brainstem areas that control breathing. But too much THC can cause panic, vomiting and a racing heart, and accidental ingestion by children can require hospital care.
Does tolerance go away if I take a break?
Yes, largely. Brain imaging research found that cannabinoid receptors reduced by daily smoking returned to normal levels after about four weeks without cannabis. Start low again after any break.
Buying in Washington or Oregon? Every store in our Washington and Oregon dispensary directories is state licensed, and staff can point you to low-dose products. For more basics, see Cannabis 101.
For adults 21+ in legal states. General information, not medical advice. Talk to a doctor before using cannabis for a health condition.