How Long Does Weed (Marijuana) Stay in Your System?
It varies according to dose
Weed, also known as marijuana or cannabis, is usually detectable in bodily fluids for 1 to 30 days after last use. As with other drugs, it may be detectable in hair for several months.
Weed detection windows depend on how much you smoke or ingest, as well as how often. In general, higher doses and more frequent use are associated with longer detection times.
For daily users, cannabis may be detectable for several months after last use. The longest-reported detection times are more than 90 days.
Read on to find out the detection windows for cannabis in urine, blood, saliva, hair, and more.
Drug tests measure weed and its by-products, or metabolites. These metabolites remain in your system long after weed’s effects have worn off.
According to Mayo Clinic Proceedings, weed is detectable in urine for the following amounts of time after last use:
- Occasional users (up to three times a week): 3 days
- Moderate users (four times a week): 5 to 7 days
- Chronic users (daily): 10 to 15 days
- Chronic heavy users (multiple times a day): more than 30 days
Cannabis metabolites are fat-soluble, which means they bind to fat molecules in your body. As a result, it can take some time for them to leave your system.
According to an article in Therapeutic Drug Monitoring, weed is typically detectable in the blood for 1 to 2 days. However, in some cases, it’s been detected after 25 days. Chronic heavy use increases the length of time that it can be detected.
Weed is detectable in the bloodstream within seconds of inhalation. It’s distributed to the tissues. Some of it is reabsorbed in the blood and broken down. Its metabolites may remain in the bloodstream for days.
Blood testing may be used in laboratory settings or to indicate recent use of weed.
According to a 2014 review on cannabinoids in oral fluid, weed is detectable in saliva for the following amounts of time after last use:
- Occasional users: 1 to 3 days
- Chronic users: 1 to 29 days
Weed can enter the saliva through smoking and exposure to smoke. However, its metabolites are only present in saliva when weed has been smoked or ingested.
In jurisdictions where weed is legal, oral fluid may be used for roadside testing.
Hair follicle tests assess drug use for up to 90 days . After use, weed reaches the hair follicles via small blood vessels. Trace amounts may remain in the hair.
Since hair grows approximately 0.5 inches per month, a 1.5-inch hair segment taken close to the scalp can provide a window of weed use for the past three months.
The active ingredient in weed is a chemical substance called THC, which stands for delta-9-tetrahydrocannabinol. THC that enters your body is absorbed into the bloodstream.
Some THC is temporarily stored in organs and fatty tissues. In the kidneys, THC can be reabsorbed into the bloodstream.
THC is broken down in the liver. It has more than 80 metabolites, but the most significant ones are 11-OH-THC (11-hydroxy-delta-9-tetrahydrocannabinol) and THCCOOH (11-nor-9-carboxy-delta-9-tetrahydrocannabinol).
Drug tests look for these metabolites, which stay in your body longer than THC. Eventually, THC and its metabolites are excreted in urine and stool.
A number of factors affect how long weed stays in your system. Some of these factors, such as your age, gender, and body mass index (BMI), aren’t related to the drug itself, but to how your body processes and metabolizes the drug.
Other factors are related to weed and how you use it. This includes how much you take (dose) and how often (frequency). Higher doses and more frequent use tend to increase the amount of time it takes to eliminate weed from your system.
More potent weed, which is higher in THC, may also stay in your system for longer. Weed that’s ingested may also remain in your system slightly longer than weed that’s smoked.
There isn’t much you can do to speed up the amount of time it takes for weed to leave your system.
Once it’s entered your system, your body needs time to break it down. Exercising, eating healthy, and staying hydrated may help, but not drastically.
There are a number of weed detox remedies and kits available on the internet. Many require drinking a lot of water to dilute your urine, and then using herbal supplements such as creatinine or vitamin B-12 to mask the dilution.
These kits don’t work reliably.
Weed’s effects appear quickly, usually within 15 to 30 minutes after smoking. It can take one or two hours to feel weed’s effects when it’s ingested.
Weed’s active ingredients produce a short-term “high.” Common effects include:
- sense of well-being
- sense of relaxation
- feeling that time is slowing down
- giggling or chattiness
- altered sensory perception
Other short-term effects include:
- inability to focus
- increased appetite
- coordination problems
- rapid heart rate
- dry mouth and eyes
- feeling sick or faint
- anxiety or paranoia
In rare cases, high doses of weed can cause hallucinations, delusions, and psychosis.
Smoking or ingesting weed on a regular basis can have additional effects on your mind and body. You might be at an increased risk of developing:
- cognitive impairments
- memory impairments
- learning impairments
- cardiovascular diseases, such as heart disease and stroke
- respiratory illnesses, such as bronchitis and lung infections
- mood disorders, such as depression and anxiety
- hallucinations and psychosis
If you use weed while you’re pregnant or breastfeeding, there’s a greater chance that your baby will have birth defects or problems with brain development.
Weed’s short-term effects start to taper off after one to three hours. Some effects, like memory problems or trouble sleeping, can last a few days.
Researchers don’t know how long the effects of chronic use last. Long-term effects can last days, weeks, or months after weed use has ended. Some effects may be permanent.
Weed may stay in your system anywhere from several days to several months after last use. Detection windows depend on the drug test used and other factors, such as whether you smoke or ingest weed on a regular basis.
Weed is detectable in bodily fluids for up to 30 days after last use. For daily users, weed may be detectable for several months after last use. The longest-reported detection times are more than 90 days. Here’s how long it’s detectable via each type of drug test, whether you can metabolize it faster, and more.
Cannabis can be smoked, eaten and vaped – and is the UK’s most widely-used illegal drug
How it looks, tastes and smells
What does it look like?
Soft black resin, furry green leaves and hard brown lumps, cannabis can look very different depending on its type – but it all comes from cannabis plants.
You’re most likely to come across these types:
Also known as grass, weed is made from drying out the leaves and flowering parts of the cannabis plant. It can look like dried herbs and is usually brownish-green in colour.
This is the name given for particular strains of grass that are very strong. Skunk’s become very popular in recent years and is often bright, pale or dark green in colour and covered in tiny crystals.
Not nearly as common as it used to be, hash (or hashish) is made from the resin of the cannabis plant and can be black, brown, soft or hard – depending on the type.
This is a dark, sticky and honey-coloured substance that’s much less common than other types.
These are highly concentrated forms of cannabis that are extracted using butane. They come in a solid form known as ‘dab’ or ‘shatter’ and can be used as e-liquids in vape pens.
What does it taste/smell like?
Cannabis has a musky, sweet smell. Some of the more potent types of cannabis can have a stronger smell, but this isn’t a reliable guide to the strength of any particular batch.
How do people take it?
In the UK, most people mix it with tobacco and roll it into a cannabis cigarette known as a spliff or joint. Some people don’t use tobacco at all and make weed-only spliffs – either because they prefer it that way or to avoid becoming dependent on nictotine.
Users do this mix by mixing the drug with tobacco and putting it in a pipe, lighting it, and then inhaling the smoke through water out of a large tube. There are many types of bongs, and not everyone uses tobacco. Like with joints, using tobacco in bongs increases the risk of nicotine dependence.
Eat and drink it (edibles)
People do this by mixing it into cakes (hash brownies), tea, yoghurt or sweets (gummies/lollipops). The amount of cannabis in these products can vary greatly and sometimes other harmful drugs are added too. The effects of consuming edibles are unpredictable and it can be very easy to accidentally take a larger dose than you wanted to.
This method has become more popular in recent years. Most people use a vapouriser which heats the cannabis, rather than burning it. Very little is known about the health impact of vaping cannabis.
Smoking cannabis with tobacco increases the risk of becoming dependent on nicotine. To avoid this, don’t use tobacco in bongs and spliffs.
How it feels
How does it make you feel?
The effects of cannabis can vary massively. Some people say feeling ‘stoned’ makes them feel chilled out and happy in their own thoughts, while others say it makes them giggly and chatty. But it can also make people feel lethargic, unmotivated and some people become paranoid, confused and anxious.
The sort of experience you have depends on a lot of thinks like;
- the kind of person you are (e.g. outgoing or shy)
- the mood you’re in, (if you’re feeling down it will probably make you feel worse)
- the environment you’re in (you’re more likely to feel paranoid or anxious if you don’t feel comfortable where you are or if you’re with people you don’t trust)
- how much THC it has (the main psychoactive compound in cannabis)
- how much CBD it has (which is thought to make users less likely to feel anxious and paranoid)
- how much you take
- how often you take it
Cannabis changes how you think and some people say it gives them a different perspective on things. It does affect your judgement though and people often think conversations or thoughts they have (whether good or bad) are much more deep or important when they’re stoned than they would do normally.
It can also make you hungry, known as having ‘the munchies’, or make you feel sick, known as ‘a whitey’. It can make you feel drowsy or sleepy and can give you the sense that time is slowing down.
THC & CBD
The hallucinogenic effects of cannabis are mainly due to a compound in cannabis called THC (tetrahydrocannabinol).
The other important compound in cannabis is CBD (cannabidiol). Skunk and other forms of strong cannabis contain high levels of THC but very little, or no, CBD.
It’s thought that CBD can balance out some of the effects of THC and make users less likely to feel anxious and paranoid. You can’t tell from looking or smelling cannabis whether there’s a balance of CBD and THC in it, but in general, hash may have more CBD than skunk.
How does it make people behave?
Cannabis can make some people giggly and chatty, and other people paranoid, confused and anxious – it really depends on the type of person taking it and the circumstances they take it under.
Experience mild hallucinations if they take particularly strong cannabis.
Become lethargic and unmotivated.
Have problems concentrating and learning new information. This is because studies suggest that cannabis effects the part of the brain we use for learning and remembering things.
Perform badly in exams. Because cannabis impacts the part of the brain we use for learning and remembering things, regular use by young people (whose brains are still developing) has been linked to poor exam results.
How long the effects last and the drug stays in your system depends on how much you’ve taken, your size, whether you’ve eaten and what other drugs you may have also taken.
To kick in:
When smoked, it normally takes a minute or two to feel stoned. If you eat cannabis, it can up to an hour.
How long it lasts:
This depends on how much you smoke. Generally, the effect is strongest for about 10 minutes to half an hour after smoking cannabis, but if you smoke a lot, you may still feel stoned for a couple of hours. If you eat cannabis, the peak effects can last for 2 to 4 hours, and there may even be a few more hours before the effects wear off completely.
People may still feel the effects the next day, particularly after a heavy session.
How long will it be detectable?
If you’ve used cannabis as a one-off, it will show up in a urine test for around 2 to 3 days afterwards.
However, this can go up to a month for regular users.
How long a drug can be detected for depends on how much is taken and which testing kit is used. This is only a general guide.
Physical health risks
Smoking cannabis can;
- make you wheeze and out of breath
- make you cough uncomfortably or painfully
- make your asthma worse if you have it
There’s been less research on it but smoking cannabis is likely to have many of the long term physical health risk as smoking tobacco (even if you don’t mix the cannabis with tobacco). So smoking cannabis can also;
- increase the risk of lung cancer
- increase your heart rate and affect your blood pressure, which makes it particularly harmful for people with heart disease
- reduce your sperm count if you’re male, affecting your ability to have children
- suppress your ovulation if you’re female, affecting your ability to have children
- increase the risk of your baby being born smaller than expected if you smoke it while pregnant
Mental health risks
Using cannabis can:
- affect your motivation to do things
- impair your memory so you can’t remember things or learn new information
- give you mood swings
- disturb your sleep and make you depressed
- make you anxious, panicky, or even aggressive
- make you see or hear things that aren’t there (known as hallucinating or tripping)
- cause hours (or days) of anxiety, paranoia and hallucinations, which only settle down if the person stops taking it – and sometimes don’t settle down at all
- cause a serious relapse for people with psychotic illnesses like schizophrenia
- increase your chances of developing illnesses like schizophrenia, especially if you have a family background of mental illness and you start smoking in your teenage years
What is cannabis cut with?
Lots of things. Dealers cut hash with similar-looking substances or heavy materials to increase the weight of the drug and make a bigger profit.
Although not all cannabis is cut, it’s very hard to know when it is or isn’t – so you could be smoking, eating or vaping chemicals from all sorts of unknown substances, including pesticides used when growing the cannabis.
Tobacco is often mixed with cannabis, for making joints or smoking bongs. If you mix cannabis with tobacco you’ll be taking on the same risks you get from smoking tobacco.
These are: addiction to nicotine (the drug in tobacco), coughs, chest infections and in the longer-term, cancer and heart disease.
Is it dangerous to mix with other drugs?
Yes, any time you mix drugs together you take on new risks.
For example, if you drive when stoned or high you double your chances of having a fatal or serious injury car crash, but if you drive after mixing cannabis with alcohol, you’re 16 times more likely to crash.
Smoking or vaping cannabis with tobacco increases the risk of becoming addicted to nicotine which is the addictive drug in tobacco.
Can you get addicted?
Yes. Heavy cannabis users often get cravings and find it hard not to take the drug – even when they know it’s causing them physical, mental or social problems.
When heavy users do try to stop they can:
- feel moody and irritable
- feel sick
- find it hard to sleep
- find it hard to eat
- experience sweating and shaking
- get diarrhoea
If you roll your spliffs with tobacco, you’re also at risk of getting addicted (or staying addicted) to nicotine.
This is a Class B drug, which means it’s illegal to have for yourself, give away or sell.
Possession can get you up to 5 years in prison, an unlimited fine or both.
Supplying someone else, even your friends, can get you up to 14 years in prison, an unlimited fine or both.
Like drink-driving, driving when high is dangerous and illegal. If you’re caught driving under the influence, you may receive a heavy fine, driving ban, or prison sentence.
If the police catch people supplying illegal drugs in a home, club, bar or hostel, they can potentially prosecute the landlord, club owner or any other person concerned in the management of the premises.
Additional law details
Cannabis is different to other Class B drugs as it comes under the discretionary warning scheme.
This means that a police officer can choose to issue you with a street warning only (which doesn’t form a criminal record, though it will be recorded), so long as:
- you’re in possession of a small amount of cannabis only, and for your personal use
- it’s the first time you’ve been caught with an illicit drug and you have no previous record of offence
- you are compliant, non-aggressive and admit that the cannabis is for your own use only
If you’re caught with cannabis and it’s your second offence, the police can issue with a fixed-term fee notice, which is an on-the-spot fine for £80.
As long as you pay that within 21 days, there’s no criminal record. If there’s a third occasion, you will be arrested and taken to the police station.
The main active chemical in Cannabis (Weed) is THC which can have various effects on the brain. Find out the effects, the risks and the law from FRANK.