Cannabis for medical purposes: Using a cannabis product
On this page
- Ways to take cannabis
- Choosing how to take your cannabis product
- Finding the right dose
- Recommended instructions
- Decreasing your risk
- Monitoring your treatment
- Storing your cannabis products
Ways to take cannabis
The most common ways to take cannabis are:
- smoking
- eating or drinking
- dissolving under the tongue
- vaping (inhaling aerosols and vapour)
- applying topically (to skin, hair or nails)
For a summary on how to reduce and manage the risks of using cannabis for medical purposes, refer to:
Choosing how to take your cannabis product
How you choose to use cannabis depends on:
- your personal preferences
- how long you want the effects to last
- how quickly you want to feel the effects
- what your health care provider recommends
Note: You may still feel some of the effects of cannabis, including impairment, up to 24 hours after smoking, vaping, eating, drinking, or using cannabis under your tongue.
Smoking
Smoking is not recommended as a way to use cannabis for medical purposes because cannabis smoke contains the same harmful and cancer-causing chemicals found in tobacco smoke.
When smoking cannabis, you:
- use dried cannabis or cannabis extracts, such as hash or infused pre-rolls
- start to feel the effects within seconds or minutes
- could feel the strongest effects after 10 to 30 minutes
- could feel effects for 2 to 4 hours
Smoking may be used for symptoms or diseases that require rapid onset of effects.
Vaping
Vaping lets you avoid inhaling smoke, but it has other risks. It can expose you to substances that may cause potential long-term lung damage.
When vaping cannabis, you:
- use dried cannabis or cannabis extracts such as vaping liquids, wax, shatter or dabs (high THC or CBD products)
- start to feel the effects within seconds or minutes
- could feel the strongest effects after 10 to 30 minutes
- could feel effects for 2 to 4 hours
Vaping may be used for symptoms or diseases that require rapid onset of effects.
Dissolving under the tongue
Products applied under the tongue, such as oral sprays, may sting or burn. They may also have other unpleasant effects, which you should discuss with your health care provider.
When you dissolve cannabis under your tongue, you:
- use lozenges, sprays, buccal strips, oil or tinctures (extracts made using alcohol, oils or glycerin)
- start to feel the effects within 15 to 40 minutes
- could feel the strongest effects after 1.5 to 4 hours
- could feel effects for 12 hours
Dissolving under the tongue may be used for symptoms or diseases that require:
- faster onset of effects than eating or drinking
- longer duration of action than vaping or smoking
Eating or drinking
It takes longer to feel the effects of eating or drinking cannabis compared to other methods. The short-term effects can also be more unpredictable. The short-term risks of eating or drinking cannabis include accidentally taking too much, and poisoning.
When you eat or drink cannabis, you:
- use oils (in droppers or capsules), edibles (such as gummies, chocolates or drinks) or tinctures (extracts made using alcohol, oils or glycerin)
- start to feel the effects within 30 minutes to 2 hours
- could feel the strongest effects after 2 to 4 hours
- could feel effects for 4 to 8 hours
The timing and duration of effects depend on various factors, including:
- the format of the product
- any other medications taken orally
- the amount or type of food in your stomach
Eating or drinking may be used for symptoms or diseases that require longer duration of action.
Topical application (applying to skin, hair or nails)
Topical use may cause localized allergic reactions, such as rashes and itching.
When you apply cannabis topically, you:
- use ointments, creams, lotions, oils, balms, salves, patches, gels or similar products
Topical application may be used for local relief of symptoms, but this is not well understood.
We don’t yet have enough information about the timing and duration of effects, or the specific risks of topical use.
Nasal application (applying through the nose)
When you use cannabis nasally, you:
- use sprays, drops or foams
We don’t yet have enough information about the timing and duration of effects, or the risks of using cannabis nasally.
Vaginal application (applying in the vagina)
When you use cannabis vaginally, you:
- use gels, sprays, suppositories, capsules, tablets or foams
We don’t yet have enough information about the timing and duration of effects, or the risks of using cannabis vaginally.
Rectal application (applying in the rectum)
When you use cannabis rectally, you:
- use suppositories, capsules, tablets or gels
- could feel the strongest effects after 6 to 8 hours, depending on the product
We don’t yet have enough information about the exact timing and duration of effects, or the risks of using cannabis rectally.
Finding the right dose
The dose is the amount of cannabis that you take. The dosage is the dose of cannabis and how often you take it.
So far, we don’t have precise and standardized dosages for legal cannabis products. Each person must find their own dosage. You and your health care provider can work together to find the dosage that gives you the most benefits with the least side effects. The process of finding the right dosage is called dose titration.
Talk to your health care provider about how to use your cannabis products properly, including dosage. This is especially important if you:
- are older
- use other medications
- have health conditions
- may be more vulnerable to side effects (for example, younger people)
Most people using cannabis for medical purposes use between 1 and 3 grams daily of dried cannabis or its equivalent. Some people need more but they’re an exception. It’s highly unusual to consume more than 10 grams or its equivalent per day.
Always start with the lowest dose and go slow. Gradually adjust the dose to achieve the best results and reduce side effects. Some patients begin cannabis therapy with CBD products before trying any with THC. Work with your health care provider to choose the products and dosage that work best for you.
Vaping or smoking (dried cannabis or cannabis extracts)
Start with only 1 or 2 inhalations per day. Total daily amounts can vary but tend to range from 1 to 3 grams of dried cannabis or its equivalent. Beneficial effects have been reported with even less than 1 gram per day.
Eating, drinking or dissolving under the tongue
THC
Start with a low dose of 2.5 milligrams (mg) THC once per day. Consider a lower starting dose of 1.25 mg THC if you:
- are over the age of 55
- have specific health conditions
- are taking medications that may interact with THC and CBD
We don’t know what the maximum recommended dose of THC is for any health condition. The higher the dose of THC you take, the more likely you are to have side effects.
CBD
Start with a low dose of 25 mg CBD per day. This can be divided into:
- 2 doses of 12.5 mg CBD
- 3 doses of about 8.3 mg CBD
We don’t know what the maximum recommended dose of CBD is for any health condition. The higher the dose of CBD you take, the more likely you are to have side effects.
CBD products can contain some THC. Read the label to make sure you know how much THC you’re consuming with each dose of CBD.
Topical, nasal, vaginal or rectal administration
There is currently no information on what dosage you should use for topical, nasal, vaginal or rectal administration of cannabis. Talk to your health care provider to choose a starting dosage.
Recommended instructions
Vaping or smoking
Start with only 1 or 2 vaping or smoking sessions per day. A vaping or smoking session can be defined as a period when you vape or smoke 1 or more times in a row. Only vape or smoke as much as you need to relieve your symptoms.
Only use cannabis more than once or twice per day if:
- you don’t feel any side effects
- you need a higher dose to relieve your symptoms
Stop when you feel side effects.
Eating, drinking or dissolving under the tongue
- If the product is in the form of an oil, start with 1 drop.
- If the product is sprayed into the mouth, start with 1 spray.
- If the product comes with a measured syringe, start with the lowest unit of the graduated marking on the syringe.
Only increase your dose if needed to relieve your symptoms.
Increase your dose by 1 oil drop, 1 spray, or the smallest unit of measurement on a syringe at a time.
Decreasing your risks
When beginning to take cannabis or when switching to a different cannabis product:
- take it in a safe environment
- start low (lowest dose) and go slow (don’t take too much at once)
- take it in the evening so it doesn’t interfere with your daytime activities
- take it in the presence of someone you trust in case you experience a side effect and need medical attention
- take it around the same time every day and under the same conditions (for example with or without food) for more consistent effects
Cannabis can cause drowsiness and can impair your ability to concentrate and make quick decisions. Don’t drive or operate machinery after taking cannabis.
Monitoring your treatment
Monitor the effects of cannabis on your symptoms and share this information with your health care provider. It can help determine if the product, dosage and the way you use it is right for you.
To monitor the effects, record:
- the amount or dose, type and brand name of the product you take
- how you take it (for example vaping or eating)
- the symptoms you’re treating and their intensity before and after taking cannabis
- any side effects you experience and when they occur
- what times of day you take it
- which foods or drinks you take it with
- meals eaten during the day
- any changes in:
- appetite
- daily activities
- quantity and quality of sleep
- overall energy level and how you feel and function
- how others perceive the impact of cannabis on your function, energy level, and well-being
- any prescription medications, over-the-counter medications or natural health products taken at the same time and their doses or amounts
- anything else you think might affect the relief of your symptoms, such as:
- drinking alcohol
- smoking tobacco or vaping nicotine
There are some mobile apps and web tools that can help you track this information.
Storing your cannabis products
Store cannabis securely. Keep it out of reach and out of sight of children, teenagers, and pets. Cannabis can be poisonous to children and pets.
Always store cannabis products in their original child-resistant plain packaging.
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