Health effects of cannabis on adults over 55

Health effects of cannabis on adults over 55 - [Version PDF format - 234 KB]

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This page outlines some important facts to consider for adults over 55, when deciding whether to use cannabis. If you choose to use cannabis, you should always buy it from the legal market because cannabis products from the illegal market are not subject to the same quality controls. It may therefore expose consumers to unnecessary health risks.

Because cannabis products are much stronger today and come in a greater variety of forms and ways to consume, regardless of your previous experience, you should "start low, go slow".

All legal cannabis products are clearly labelled with their THC and CBD levels. Refer to How to read and understand a cannabis product label for more information.

If you experience any of the following serious side effects right after using cannabis, stop using cannabis and contact your health care professional:

Report any adverse reactions to cannabis or submit a report on cannabis for concerns about the quality of cannabis products.

Why using cannabis can be riskier for adults over 55

Your body's ability to process drugs and substances changes as you age. Adults over 55 may be more sensitive to cannabis and have a higher risk of having side effects. This is especially true when they have certain medical conditions.Footnote 1 For example, you shouldn't use cannabis if you have serious:

Using cannabis while taking prescription or non-prescription health products can increase the risks of side effects. Such products include:

Talk to your health care professional first if you're thinking of using cannabis for medical or non-medical purposes.

How to help minimize your risk

Below are important factors to consider to help minimize your risk of experiencing side effects from cannabis.

Choose cannabis products with lower amounts of THC and equal or higher amounts of CBD.Footnote 2

THC causes the intoxicating effects of cannabis. CBD isn't intoxicating and may reduce some of the effects of THC. However, CBD does have effects on your brain and body.

Choose legal products with lower THC amounts:

Wait to see how your body reacts before using more

Avoid mixing cannabis with other substances

Avoid using cannabis with tobacco, alcohol or other substances. Using them together can increase the risk of side effects.

Learn more about Common interactions with other substances.

Cannabis has gotten stronger over time

Cannabis products are stronger today than they were decades ago.Footnote 3Footnote 4

Your response to cannabis can vary

If you're over 55, cannabis can have added health risks, even if you're an experienced consumer or using for medical purposes. Side effects may depend on many factors like:

Both THC and CBD can have side effects. It's important to understand the amounts of THC and CBD in your product to help avoid or reduce the risk of side effects.

Health effects

Below are some of the more well-known effects of cannabis on the body and brain. Adults over 55 may feel some of these more strongly because of:

Visit Health effects of cannabis to learn more about the general effects of cannabis.


THC can cause these effects on your brain:


THC can increase your heart rate shortly after use. The higher the THC content, the higher the potential increase. An increased heart rate can:

In some people with cardiovascular or cerebrovascular disease, cannabis may increase the risk of having a heart attack or stroke.

Blood pressure

Cannabis can lower your blood pressure, especially when you change positions from lying down or sitting to standing up. Symptoms of low blood pressure include:

These symptoms may increase the risk of falls and injuries by causing dizziness or problems with coordination and balance. The risk of falls or injuries can increase if you use cannabis with other health products or alcohol.


The kidneys play a role in removing THC and CBD from the body.
It's unknown how having kidney disease impacts the effects of cannabis.


The liver helps eliminate drugs or substances from the body. Age can cause some changes in liver function and adults over 55 are more likely to be taking multiple medications. This means that cannabis and medications can stay longer in the body and increase their risk of interaction which can result in side effects. Long-term oral use of cannabis containing higher amounts of CBD (more than 240 mg a day) may also lead to liver problems. As well, using cannabis daily can increase the severity and the progression of fatty liver disease and liver fibrosis for people with chronic hepatitis C.

Contact your health care professional if you experience these side effects right after using cannabis as they may be serious:


While further research is needed to better understand the effects of THC and CBD on the eyes, limited evidence suggests CBD may cause increased pressure inside the eyes. This effect could damage the eyes with repeated use over time. If you have glaucoma, be cautious when using cannabis products, especially those containing CBD.

Blood sugar and diabetes

If you have type 1 diabetes and use cannabis, you may have an increased risk of developing side effects, including diabetic ketoacidosis. This can be fatal if untreated.

Contact your health care professional right away if:

Common interactions with other substances

Using prescription, non-prescription or natural health products with cannabis may increase the risks of interactions between these drugs/substances and the risks of side effects. Adults over 55 should be aware that cannabis may interact with:

Additional resources

Other materials in the cannabis resource series:


For more information about health effects of cannabis on adults over 55, consult the references below.



Blood pressure




Blood sugar and diabetes



Abramovici, H., Lamour, S., Mammen, G. (2018). Information for health care professionals: Cannabis (marihuana, marijuana) and the cannabinoids. Health Canada.

Return to footnote 1 referrer


Freeman, A. M., Petrilli, K., Lees, R., Hindocha, C., Mokrysz, C., Curran, H. V.,... & Freeman, T. P. (2019). How does cannabidiol (CBD) influence the acute effects of delta-9-tetrahydrocannabinol (THC) in humans? A systematic review. Neuroscience & Biobehavioral Reviews, 107, 696-712.

Return to footnote 2 referrer


Miller, S., Daily, L., Leishman, E., Bradshaw, H., & Straiker, A. (2018). Δ9-Tetrahydrocannabinol and cannabidiol differentially regulate intraocular pressure. Investigative ophthalmology & visual science, 59(15), 5904-5911.

Return to footnote 3 referrer


Kinney, G. L., Akturk, H. K., Taylor, D. D., Foster, N. C., & Shah, V. N. (2020). Cannabis use is associated with increased risk for diabetic ketoacidosis in adults with type 1 diabetes: findings from the T1D exchange clinic registry. Diabetes Care, 43(1), 247-249.

Return to footnote 4 referrer


Cash, M. C., Cunnane, K., Fan, C., & Romero-Sandoval, E. A. (2020). Mapping cannabis potency in medical and recreational programs in the United States. PloS one, 15(3), e0230167.

Return to footnote 5 referrer


Sholler, D. J., Strickland, J. C., Spindle, T. R., Weerts, E. M., & Vandrey, R. (2020). Sex differences in the acute effects of oral and vaporized cannabis among healthy adults. Addiction biology, e12968.

Return to footnote 6 referrer


Calakos, K. C., Bhatt, S., Foster, D. W., & Cosgrove, K. P. (2017). Mechanisms underlying sex differences in cannabis use. Current addiction reports, 4(4), 439-453.

Return to footnote 7 referrer

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