All drug use has risks. This page is for information only and does not constitute or replace medical advice. If you have medical concerns about your drug use, please speak to a medical professional.

Methamphetamine is a long lasting, synthetic (lab-made) central nervous system stimulant.

Other names

crystal meth, crystal, meth, tina, ice, shard, glass, tweak, yaba (pills)


Clear, colourless crystal

Drugs Wheel Category



Misuse of Drugs Act (1971) – Class A.

Penalties for possession are up to 7 years in prison and/or an unlimited fine. Penalties for supply are up to life in prison and/or an unlimited fine.

How it’s taken

Methamphetamine is most commonly heated and vapourized in a pipe but it can also be snorted, swallowed, bumped (up the bum) and injected. Injecting is almost always the riskiest way of taking drugs and is strongly discouraged. 


The following information on dosage was taken from PsychonautWiki, but this should not be taken as a recommendation: duration and effects of any drug will depend on purity, regularity of use, other medications or drugs you have taken, your body and how it is taken (route of administration).  

Inhale (smoke/vape): 

  • Light: 5-10 milligrams (mg) – this would give 100 to 200 doses from a gram 
  • Common: 10-20 milligrams (mg) – this would give 50 to 100 doses from a gram 
  • Strong: 20-60 milligrams (mg) – this would give 17 to 50 doses from a gram 

Accessed November 2020  

It is essential to use accurate scales – ones that are capable of measuring to 10 milligrams (0.01 of a gram). Knowledge of how to use them and how to ensure they are measuring accurately is important.  

A slight difference in dose can create a different experience or effect. Find out more about reducing the risk from dosing including volumetric dosing.

General information on dosing.


Methamphetamine is a central nervous system stimulant which means it increases your heart rate and breathing. When smoked, it will take less than a minute to start to feel the effects. These effects peak after a few hours but can last up to 12 hours and aftereffects may be felt for up to a day.   

Methamphetamine may make you temporarily feel happy, chatty, confident and alert. People taking it report experiencing an initial rush, followed by a euphoric high, followed by a strong urge to re-dose.

It can also increase energy, motivation, focus and sex drive whilst reducing the desire to eat or sleep. Other effects include restlessness (constant movement, inability to sit still), aggression and compulsive behaviour such as cleaning, pacing or skin picking. These negative effects can last for hours after the initial euphoria has worn off.

Frequent/high doses increases the risk of mental health difficulties such as paranoia, anxiety and psychosis. This might also be characterised by sensory disturbances including visual (seeing things i.e. shadows, people), auditory (hearing things i.e voices, guns shots) or tactile (feeling things i.e bugs or insects crawling over or under the skin) hallucinations. These sensations/experiences are common in people who are sleep deprived.

As well as physical and mental health harms, problematic methamphetamine use is linked to issues including loss of employment, breakdown of relationships and risky sexual behaviour.  

Harm reduction

If you choose to take methamphetamine then the following steps can help to reduce harm.


  • Spend at least two hours researching the drug you are planning to take. 
  • Test the drug. If you don’t have access to a drug testing service, reagent testing kits are available online and can give a greater understanding of what the drug contains, but they may not be suitable for identifying newer compounds or adulterants and can tell you nothing about purity or strength.
  • Avoid taking drugs alone and have a ‘sober’ friend around if possible. 
  • Grind or crush substances down as fine as possible before use. This makes it easier to judge a dose, speeds up absorption into the body and reduces the damage to soft tissue from abrasion. 
  • Plan your doses and use a watch or timer to keep track of how frequently you are dosing. 
  • Only carry what you plan on taking. If you have a couple of grams in your pocket it is easy to take more than you anticipated. Leave what you don’t need at home (in a safe place). 
  • There is no standard amount of methamphetamine in crystals or powder. Purity can vary, even within the same batch. You can’t judge content or purity by appearance. 
  • Use scales to measure the dose – you can’t judge an accurate dose just by looking. Start with a small dose and go slow! Remember, that the more of a drug you take, the riskier it is and the more likely you are to experience negative effects. 
  • Avoid mixing different drugs including alcohol and medicines as this can cause dangerous, unintended or unpredictable effects. Take time to research possible interactions with your medication or health condition. 
  • If you do mix drugs, do your research, ensure you are somewhere safe and take way less of both substances than you would if you were only taking one. 
  • The increased risk when mixing different drugs, includes drugs like Viagra. Anyone who has an erection for more than four hours should seek urgent medical attention.  
  • Methamphetamine can cause vasoconstriction (narrowing of the blood vessels) which increases the risk of high blood pressure, headaches, cramps and strokes – avoid mixing with drugs that also cause vasoconstriction such as amphetamine and caffeine. 
  • Mixing methamphetamine with cannabis, psychedelics (such as LSD) or dissociatives (such as ketamine) can increase bodily sensations, increase heart rate and increase the risk of experiencing nausea, feeling anxious and/or losing control. Reduce feelings of anxiety by staying calm, controlling your breathing and telling someone how you are feeling! 
  • Mixing methamphetamine with downers including opioids (such as heroin) or depressants (such as alcohol, GHB and benzodiazepines like Valium and Xanax) is dangerous. Depressant drugs depress your central nervous system which means they slow your heart rate, response time and breathing.
  • Mixing methamphetamine with alcohol (or other drugs) can mask the effects of each drug while increasing the risk – you will still be intoxicated but your perception of how drunk or high you are will change.
  • If you are taking methamphetamine and can’t avoid alcohol completely, try to limit yourself to only a few drinks, choose drinks with a lower alcohol content and drink water or soft drinks between alcoholic ones.
  • Avoid taking methamphetamine if you are experiencing anxiety or if you don’t feel completely comfortable, as you may heighten these feelings.
  • Reduced inhibitions mean you may not spot dangers, so be careful. Look out for any potential hazards (e.g. water, glass tables, heights or things you may fall over). 
  • Methamphetamine can cause jaw clenching so have chewing gum handy to keep your mouth moving, you can roll the chewing gum on your tongue to give your jaw a break from chewing. If you have been jaw clenching, rinse your mouth out with salty water.
  • People should sleep on their side to avoid choking on vomit in their sleep. 
  • If you experience vomiting this could reduce the effectiveness of the contraceptive pill – use alternative methods to avoid unintended pregnancy.  
  • Think about safe sex – grab condoms, dams and whatever else will help keep you safe depending on how you have sexLike other stimulant drugs, methamphetamine can instantly and significantly increase your feelings of arousal so it’s important to think about consent. Are you really feeling it? Are they? Ensure you have full consent before, and during, any sexual activity. Check out our resource on consent.
  • If you start to feel any negative effects, simple things like changing your environment may help. If the effects are too strong, try to stay relaxed and take small sips of water or flat sugary juice. Let someone know how you are feeling – sometimes just sharing that feeling can help ease it. 
  • Take regular breaks, stay hydrated (about half a pint of water or isotonic drink per hour) and look out for signs of overheating.
  • Regular hydration can also prevent dryness in the mouth and reduce the impact on oral health/gums
  • Look after your pals and seek medical help as soon as possible if needed. Be honest about what has been taken. 
  • Call 999 and ask for an ambulance if you see the signs of an overdose: confusion, unconsciousness (won’t wake with a shout or a shake), severe nausea and vomiting, fitting, hyperthermia (overheating), rapid heart rate/chest pains/heart attack, hallucinations, difficulty breathing, anxiety/fear/panic.
  • Make sure you have time to rest afterwards and chill out. Like all stimulant drugs, methamphetamine can affect your sleeping pattern which can have an impact on your mental wellbeing. 


Inhaling methamphetamine can damage the mouth, throat and lungs and can cause breathing difficulties, wheezing, chest pain, shortness of breath and in extreme cases, respiratory failure. It can also impact negatively on oral health and can cause sores, cuts and blisters on the lips and in the mouth. 

  • Crush the crystal into small pieces. 
  • When smoking, the effects are intense and when they wear off it may leave you immediately craving more. Use a timer to keep track of use and try to wait as long as possible between doses. 
  • If smoking from foil, use clean foil each time. This is available from injecting equipment providers (IEPs or needle exchanges). 
  • If smoking from a pipe, use a clean glass pipe with a metal gauze. Pipes made from bottles and cans release fumes when heated. Glass pipes are less harmful and more efficient. They can be purchased cheaply from a headshop, or on online.
  • Allow the pipe to cool down between uses and hold the pipe as far away from the flame as possible to reduce the chance of burns. Keep all burns clean and dry. If they do not start to heal, and instead become more red, hot or inflamed, please seek medical help. 
  • Stay hydrated. Smoking methamphetamine dries out the mouth so it’s important to use lip balm, drink small sips of water regularly and brush your teeth twice a day.
  • Sharing pipes can spread infections and blood borne viruses (e.g. hepatitis C, HIV) – only use your own equipment. Get tested regularly for BBVs.
  • Avoid holding the smoke in your lungs, as this can damage tissue without giving a better ‘hit’.  


Taking drugs ‘up the bum’ is also called shelving, plugging, bumping, boofing or rectal administration. This route is efficient at absorbing drugs into the bloodstream but regularly shelving methamphetamine can cause soft tissue damage, rectal bleeding and increased sensitivity. 

  • Ensure all equipment is clean and sterile before use – this includes washing your hands. 
  • Dissolve the crushed crystal in sterile water (0.5 millilitres is usually more than enough). 
  • Use a clean, needleless syringe (or single use straw or lube launcher) to draw up the water containing the drug. 
  • Add lube to the outside of the syringe to allow for easier entry and to prevent soft tissue damage. 
  • Lie on your side, insert the syringe into the anus and slowly press the plunger all the way in. After a few minutes, gently and slowly pull the syringe out. 
  • You can also insert the drugs in a gel capsule or cigarette paper, but this is more physically damaging than dissolving the drugs in water. Use lube and wash your hands before and after administration.
  • Some drugs can make the bum numb and you may not be aware of damage – take care and check the area with clean hands. Be aware that this can make it harder for you to feel when you need to go to the toilet.
  • Some drugs (such as GBL) and adulterants (unexpected contents) might burn or damage tissue, which increases the risk of infection.  
  • If you plan to have anal sex, use a condom and check for any reduced sensation or damage beforehand.
  • Sharing water, mixing cups, syringes, straws, lube launchers and lube can spread infections and blood borne viruses (e.g. hepatitis C, HIV) – only use your own. Get tested regularly for STIs and BBVs.
  • Look out for the signs of haemorrhoids (lumps inside and around your bum) or signs of infection and treat them quickly. 
  • Use a vitamin E capsule or apply a thin layer of vitamin E oil to the inside of the anus after a session.


There is a higher risk of overdose if methamphetamine is injected. Injecting methamphetamine also risks damaging veins or the injecting site and can cause life-threatening infections and abscesses. 

  • Only use new, sterile supplies. These are available from injecting equipment providers (IEPs or needle exchanges) or can be bought online.  
  • People who inject stimulant drugs may inject frequently and will therefore need to ensure that they access enough supplies from their IEP. Always ask for extra equipment in case you need more than intended. 
  • Sharing equipment including needles, filters, containers, spoons and water can spread infections and blood borne viruses (e.g. hepatitis C, HIV) – only use your own. Use colour coded equipment to avoid confusion and get tested regularly for BBVs.
  • Follow good hygiene practice and wash your hands and injection sites (before and after).
  • Citric acid, vitamin C and heat aren’t needed to dissolve methamphetamine and their use can increase harms. Methamphetamine can be dissolved in water. 
  • Once dissolved in water, it is important to use a sterile filter to remove non-soluble substances which can cause harms if injected. 
  • Use the smallest needle you can without it becoming blocked or breaking.  
  • Keep the needle sterile and avoid licking the needle as this can transfer bacteria from the mouth into the skin and cause infections.
  • Use a new needle each time – needles become blunt after one use. 
  • Rotate injection sites but try to avoid injecting in high-risk areas such as the neck and groin. 
  • Dispose of equipment responsibly. It can be returned to an IEP.  
  • Seek medical help if the injecting site is painful, tender or hot, or there is swelling for more than a few days.  
  • Methamphetamine is sometimes used alongside heroin (or other opioids). This is extremely risky. Anyone who is at risk, or knows someone who is at risk, of an opioid overdose (e.g. heroin, methadone), should carry naloxone: 


Detection time

People taking methamphetamine have reported the following detection time, but this cannot be taken as a recommendation; detection of any drug will depend on purity, regularity of use, other medications or drugs you have taken, your body and how it’s taken.
  • 1 to 4 days in urine (up to 1 week for heavy use)