GHB and GBL can be very easy to overdose on because there is a small difference between a common dose and a dangerous dose.
Key things to know
The high from both takes 15–20 minutes to kick in and lasts for 1–4 hours.▼ More info
GBL is turned into GHB in your body after you take it. GBL is faster, stronger and easier to overdose on than GHB.▼ More info
Avoid mixing with other drugs, especially ones that slow your body down like alcohol.▼ More info
They can make you feel horny - so plan beforehand (e.g. talk about consent with your partner, use condoms).▼ More info
Use drug checking services or reagent tests to make sure it isn’t mixed with something else.▼ More info
What to expect
How does GHB/GBL make you feel?
The doses for GHB and GBL are very different. GBL is stronger and easier to overdose on, but you cannot tell the difference between the two by looking at them. It is important to know whether you have GHB or GBL when deciding what dose to take. The effects of GHB and GBL usually start 15–20 minutes after taking them and last for 1–4 hours. They slow your body down and may make you feel euphoric, sexually aroused, groggy and nauseous. Some people describe the feeling of GHB and GBL as similar to being drunk.
It is best not mix alcohol with GBL and GHB as it increases unpleasant effects and your chance of overdose. Remember, a low dose for one person can be a high dose for another as people’s bodies process drugs differently.
Also keep in mind that, when mixed with alcohol or other drugs, GHB and GBL can have different effects to those listed below.
An Erowid user talks about a friend’s experience using GBL:
“My friend drank a ‘capful’ of GBL – an amount he had done before with no problems – as I drove him to a club where we were going, he told me he was ‘really starting to feel it’ and then IMMEDIATELY became incoherent. It happened so quickly I honestly thought he was messing around with me – until he started drooling on himself. He did not respond to my voice – so I stopped the car and an ambulance was called – he vomited twice in my car not knowing what was going on at all – during the next 10 minutes, his seizure remained but he started moving less and less – like he was passing out.”
Increased sense of touch and sound
Increased connection to others
Drowsy or groggy
Agitated and irritable
Difficulty concentrating or thinking
Stumbling, tripping or falling over
Making risky decisions or judgements
Having mood swings
Seeing double or having blurred vision
Engaging in sexually risky behaviour
Increased feelings of wellbeing
Feeling very relaxed
Feeling ‘out of body’
Increased sexual arousal
Very agitated or irritable
Increased mood swings
Increased risky decisions or judgements
Increased memory loss
Falling asleep suddenly
Increased lack of coordination
Difficulty moving your body
Difficulty breathing or slowed breathing
Feeling cold and clammy
Very high dose
Severe loss of control of body movements
Severe panic attacks
Slipping into a ‘g-hole’ or coma-like sleep
How can you be safer when using GHB/GBL?
An addictions practitioner talks about the importance of being careful with doses because GBL is much stronger than GHB and you can't tell the difference by looking at them.
If you are not sure whether you have GHB or GBL than always dose it as if it is GBL.
There are many other things you can do to keep safer when using GHB and GBL:
Wait at least an hour before re-dosing.
GHB and GBL are most commonly mixed into a drink and swallowed, which releases them into your body slower than by snorting or injecting. If you swallow GHB or GBL, try to wait for 1 hour before re-dosing as you may not feel the effects right away. If you plan on re-dosing, consider separating out your doses into small containers and use a phone alarm to schedule when you'll take them.
A person who uses GHB talks about how they measure their doses
I use one of those small soy fish containers from the sushi shop to carry my doses. I fill up half of the fish, which is about 1.5mL of GHB, and it wont melt it like other plastics!
Be aware that other methods of using GHB and GBL (snorting/injecting) can increase your risk of overdose.
Snorting or injecting GHB or GBL will deliver these drugs to your body much quicker, which can increase your chances of overdosing. These methods can also cause damage and infection to your body. If you do chose to snort or inject these drugs, use new and sterile utensils and equipment every time.
Avoid mixing GHB and GBL with other drugs, especially alcohol and depressants.
GHB and GBL have very strong effects, and when mixed with other drugs, they can become more dangerous. This is especially the case for alcohol and other depressant drugs as effects become more intense and the risk of overdose increases.
GHB and GBL can make you horny- so plan how to keep yourself safe!
You may be more likely to engage in risky sexual behaviours when using GHB or GBL. Or you may end up in situations where you are not sober enough to enthusiastically gain or give consent. It is good to think about how you might keep yourself and others safe before you use. For example, using condoms to prevent pregnancy and STIs. It can also be a good idea to colour liquid GHB and GBL with blue food colouring. This way, it will not be mistaken for water and added to your or someone else’s drink without knowing.
Test your GHB or GBL to make sure it isn't mixed with other drugs.
You can test GHB and GBL yourself with some reagent tests or at a drug checking clinic with a spectrometer. How reliable these tests are can depend on how concentrated your GHB or GBL is. If it has been mixed with lots of water, it may be hard for the spectrometer to detect it.
For more information on how to be safer when using drugs and alcohol, see Safer using.
To order self-help workbooks and other free resources for safer use, see Resources.
A Reddit user talks about their experience with GHB:
“It can make you tired, sort of feels like a mix between alcohol and MDMA with a vastly different character to it, in my experience anyway, dosage wise I’m not sure, only took it for the first time this year so just start very low if you’re concerned.”
What do comedowns from GHB/GBL feel like, and how can you feel better?
The effects of GHB and GBL are relatively short-lived compared with other drugs. The peak effects of GBL last for about 1–2 hours but this is slightly longer for GHB, with effects completely wearing off after about 4 hours. GHB and GBL comedowns are generally not severe, and effects usually pass within a day.
Some people report using GHB and GBL to come down off other drugs, like MDMA. The effects of a GHB or GBL comedown from this type of use can be unpredictable.
- Have trouble sleeping
- Feel very hungry
- Sweat or feel very hot or very cold
- Have trouble concentrating or thinking
- Feel agitated, irritable, anxious, low or paranoid
- Feel tired
- Have headaches
- Have bad dreams or nightmares
You can try...
- Get plenty of rest and sleep.
- Remember to eat and drink plenty of water.
- Get moving to release feel-good brain chemicals.
- Reach out and talk with friends and whānau for support.
- Relax and do things that you enjoy to take your mind off not feeling well.
- Avoid caffeine, alcohol and other drugs.
- Practise mindfulness and deep breathing, and try writing down your thoughts and feelings.
If any of these symptoms intensify or don't go away then call a doctor or Healthline 0800 611 116. They can talk you through the next steps.
If your symptoms worsen or you are with somebody who:
- Experience psychosis
- Feel suicidal
- Have chest pains
- Have trouble breathing
- Have a seizure
- Lose consciousness
Call 111. These are signs that something more serious is going on. You or the people around you should act quickly.
The Erowid vault talks about someone’s experience with a high dose of GHB at a festival:
“He had a terrible hangover the next day and claimed that he felt negative after-effects for more than 2 weeks after the event, particularly during the first week, he felt foggy, had difficulty concentrating, and somewhat ‘anhedonous’ meaning he didn’t enjoy anything.”
If you've taken too much
What happens if you have too much GHB/GBL?
You might feel confused, have memory problems, have jitters or feel anxious, feel nauseous or dizzy, feel disinhibited or make risky decisions, feel anxious or paranoid, feel unable to stay awake, stumble or fall over or experience unwanted sexual arousal.
Try these things at home:
- Focus on breathing – try taking slow, deep breaths.
- If you are able, call and talk to somebody you trust and ask them to help keep you calm.
- Do not take more GHB/GBL, caffeine, alcohol or other drugs, as these can make you feel worse.
- Move to somewhere quiet – try to sit or lie down and do something relaxing.
- Drink water to stay hydrated.
If your symptoms get worse or don't go away, or you experience rapid personality changes, vomiting, tremors, panic attacks, heart palpitations or feeling breathless, call a doctor or Healthline (0800 611 116). You won't get in trouble if you tell them you've used drugs. They can talk you through the next steps.
If you have severe muscle jerks or tremors, lose you control of your body movements, choke on vomit, have difficulty breathing, have chest pains, become unresponsive, slip into a ‘g-hole’ or coma-like sleep, experience psychosis, have a seizure, lose consciousness, these are signs of an overdose. You or the people around you should act quickly. Call 111.
If you experience unexpected or concerning effects from GHB or GBL you can notify High Alert to help keep others safe.
A Reddit user gives their advice to people looking to take GHB:
“It’s addictive, destructive, and extremely easy to overdose with. It’s nearly killed me on more than one occasion involving my bad choices. If you decide to use it, just remember it deserves great respect. Inform yourself about dosages, interactions, and I remember to always set a timer when I dose. When you’re high on this stuff, you have no concept of time at all, and it’s super easy to double dose and never even think about it. A double dose can put you in the hospital. Also remember no alcohol at all. Don’t let anyone talk you into drinking with it. Just be safe.”
What are the long-term effects of using GHB/GBL?
GHB and GBL are not often seen as addictive substances by people who use them. Most people who use GHB and GBL will only use them from time to time and are unlikely to develop addiction or dependence to the drug. However, people who use these drugs often or for a long period of time may experience long-term issues.
Even if you only use GHB or GBL a few times a year, it’s important to be safe to avoid long-term issues. One of the bigger concerns with these drugs is that they can result in sexually risky behaviour. GHB and GBL are often used in ‘chem sex’ or to heighten other sexual experiences. These drugs can cause poor judgement and result in an increased risk of transmitting sexually transmitted infections like HIV because of not using condoms.
A one-off bad experience or overdose on GHB or GBL can cause permanent damage to your brain and body. This includes affecting your memory, the way you learn and your mood.
When using regularly, GHB and GBL can change the way your brain works – you may be more forgetful and more impulsive. You can become addicted to GHB and GBL and experience unpleasant effects when you stop taking it. Overall, the long-term effects of GHB and GBL have not been well researched, so it can be hard to predict what might happen if you use this drug regularly for a long time.
How do you manage withdrawal from GHB/GBL?
See the 'Making changes' page for more information on how to Manage withdrawal from drugs and alcohol.
It is not common to become addicted to GHB or GBL. However, if you use these drugs regularly, especially in high doses, you may experience withdrawal symptoms when you want to stop using or take a break. Withdrawal symptoms can start 1–6 hours after the last dose of GHB or GBL wears off and can last from 5–15 days.
In people who have used GHB or GBL regularly for a long time, ‘cold turkey’ withdrawal can sometimes be dangerous. It is important to speak with a medical professional first if you are worried about withdrawing from these drugs.
- Experience diarrhea, constipation (or a change in bowel movements) or nausea
- Have aches and pains
- Feel agitated, irritable, jittery, anxious or low
- Feel sweaty or feel very hot or very cold
- Have difficulty sleeping
You can try:
- Follow a tapering plan from a health professional to reduce your dose slowly.
- Consider counselling or support groups if feelings of anxiety and low mood are getting worse.
- Lean on a support network of friends, family and professionals.
- Stick to a routine – waking up, eating well, keeping active and rewarding yourself with things that bring you joy.
- Practise mindfulness by writing down your feelings, doing breathing exercises or meditating.
If your symptoms get worse, or you experience tremors, severe agitation, aggression, suicidal thoughts or irregular heartbeat, hallucinate or have a panic attack, call a doctor or Healthline (0800 611 116). You can talk to your doctor about:
- other prescription medications to help you get through withdrawal
- rehab or withdrawal clinics in your area – visit Health Point to see what services are available.
Acting violently, having severe changes in heartrate, attempting suicide, having disturbing hallucinations, losing consciousness or experiencing psychosis, call 111
These are signs you could be experiencing GHB/GBL withdrawal syndrome. You or the people around you should act quickly.
For more information on getting support for drug and alcohol use, see Finding support.
One Reddit user talks about running out of GHB and experiencing withdrawal symptoms:
“Been doing G for about 2 years, but twice a day every day for the last 8 months. I ran out, first symptoms: diarrhea, cold sweats, then got worse! At night, severe psychosis and hallucinations where I would see and hear people talk to me, I had to ask my wife what was real and what wasn’t.”
Working and driving
How can GHB/GBL affect your daily activities?
Even at lower doses, GHB and GBL are drugs that can affect your day-to-day activities. The effects of GHB and GBL usually last up to 4 hours, after which you may start to experience a comedown period. The effects may last for a much longer period if you use GHB or GBL regularly, mix it with other drugs or take very large doses.
GHB and GBL can cause dizziness, extreme sleepiness, impaired judgement, and confusion, and people can appear ‘out of it’. Because of this, it is unsafe to drive, operate machinery or do things that need concentration or motor coordination. These drugs can cause euphoria, increased sexual arousal, forgetfulness, slurred speech and risk taking, which can make interacting with others difficult. It may also mean you do or say things or act in ways that are out of character.
If you take GHB/GBL, will it show up on a drug test?
GHB and GBL are usually tested for using hair, urine, saliva (spit) or blood. However, these drugs may not be tested for often as they can only be picked up on in a very short window (1–2 days) and can be unreliable.
GHB and GBL testing windows can change depending on how much you have taken, how often and your individual body. However, it is thought that GHB and GBL can be found for 12 hours in urine and 8 hours in blood – these are the most accurate tests. Saliva tests detect GHB and GBL for up to 6 hours but are mostly used as a secondary test after a urine sample. Hair sample tests can detect GHB and GBL for up to 30 days, but they are not very reliable.
If you believe you have been given GHB or GBL without your consent (sometimes called getting ‘roofied’), you may be asked to have a test to see if it is in your system. If you have been given these drugs without your knowing and are expecting a drug test for work or court, you can speak to a medical professional or Police about your next steps.
Is GHB/GBL illegal?
GHB and GBL are illegal in New Zealand are Class B controlled drugs under the Misuse of Drugs Act. Buying, possessing, selling, making, or importing these drugs is against the law. In some countries, GHB or GBL are used for medical purposes, but this is not the case in New Zealand.
GHB and GBL can sometimes be used for sexual experiences. However, giving any drug including GHB and GBL to someone without their consent is against the law.
You can also get in trouble with the law if you are found to be impaired while driving using GHB or GBL.
To find out more about the law around legal and controlled drugs, including GHB, see Drugs and the law.