GBL & GHB:
what you need to know

This page explains what GBL and GHB are, how they’re used, what the effects and risks are, and how to stay safer if you choose to use them. It also covers mixing risks, consent, withdrawal, and where to get support.

🕒 Estimated read time: 6–7 minutes

Are GHB and GBL the same drug?

GBL (gamma-butyrolactone) and GHB (gamma-hydroxybutyrate) are related but different chemicals. When you take GBL, your body quickly converts it into GHB, which is the active drug. GHB is sometimes prescribed for narcolepsy, but it’s rare on the illicit market.

Recreational use of GHB began in the 1980s and 90s in clubs and chemsex scenes. GBL followed because it was easier to get hold of and produced similar effects. By the 2000s, most use in the UK involved GBL rather than GHB.

GBL became more common because it’s cheaper, more available, and legal to sell for industrial use. It’s found in products like paint strippers, degreasers, and alloy cleaners, which makes it easier to access than GHB.

Both GBL and GHB can make you feel relaxed, euphoric, and uninhibited — but they also carry serious risks, especially if you take too much or mix them with other depressants.

If you hear people talking about “G,” it’s safest to assume they mean GBL unless you know for sure. GBL is more potent and faster-acting than GHB, and it’s easier to overdose on if you misjudge your dose or mix it with alcohol or other sedatives.

This page focuses on GBL because it’s now the substance most commonly used in the UK.

Do GBL and GHB smell or taste different?

Yes — they smell, taste, and feel different, which can help you figure out which one you've taken.

GBL

Smell: Strong, sharp chemical or solvent smell — often like nail polish remover or paint thinner.
Taste: Very bitter, chemical, and unpleasant. Some people describe it as “burning” or “plastic-like.”
Texture: Oily and slightly thicker than water.

People often dilute GBL in juice or soft drinks to mask the taste, but it’s still noticeable.

GHB

Smell: Usually no smell, or faintly sweet.
Taste: Salty or soapy, but not as harsh as GBL.
Texture: Thin and watery — it mixes easily into drinks.

How do you take GBL?

People usually swallow GBL in small doses, either on its own or diluted in a drink. You’ll start to feel the effects after 10 to 20 minutes. The effects can last between 1.5 and 4 hours.

What does GBL feel like?

People report positive effects such as:

Feeling relaxed or euphoric
Being more chatty or sociable
Drowsiness or a sense of calm

But there are also unwanted or risky effects:

Nausea or vomiting
Confusion or memory loss
Loss of coordination
Passing out, especially if you take too much or mix it with other drugs

How much is too much?

GBL is very dose-sensitive. Even small differences in dose can completely change how it affects you.

These are not recommended doses — they’re just here to help you understand the risks:

Low dose (0.5 to 1 ml): You may feel relaxed, calm, or chatty.
Moderate dose (1 to 1.5 ml): You’ll likely feel heavier, drowsier, or sedated.
High dose (1.5 ml or more): High risk of vomiting, confusion, unconsciousness, or overdose.
Redosing too soon: Even a small top-up can make you 'G-out'. Wait at least 90 minutes before redosing.

The difference between a euphoric dose and an overdose can be as little as 0.2–0.4 mL.

What happens if you mix GBL with other drugs?

GBL slows your brain and body down. If you mix it with other depressants like alcohol, benzos, or opioids, the risk of overdose or unconsciousness increases sharply. It can stop your breathing.

Alcohol: A very dangerous combo. GBL and alcohol together are behind most hospital admissions involving GBL. High risk of choking, blackout, and overdose.
Benzos: Adds to sedation and memory loss. Can be fatal.
Opioids: Strong depressant effects. High risk of your breathing stopping.
Stimulants: Can mask how strong GBL feels, making you more likely to redose and overdose. Also strains your heart.
Ketamine: Increases confusion and unconsciousness. People might not realise you need help.

Can you get addicted to GBL?

Yes. If you use GBL often, especially daily, you can become dependent on it. Your body gets used to having it, and stopping suddenly can lead to serious withdrawal symptoms.

GBL works on the brain in a similar way to alcohol or sedatives. It slows things down and can make you feel calm, relaxed or sleepy. Over time, your brain adjusts and starts relying on GBL to feel normal. This means you might need more of it to get the same effects. If you stop suddenly, your body can go into withdrawal.

Withdrawal from GBL can be dangerous and may include symptoms like:

Anxiety
Insomnia
Shaking or tremors
Hallucinations
In severe cases, seizures

If you think you’re dependent on GBL, it’s important not to stop using it suddenly. Trying to detox on your own can be dangerous. Medical support and professional help can make withdrawal safer and reduce the risk of harm.

Is GBL legal in the UK?

GHB is a Class C drug under the Misuse of Drugs Act. GBL is also Class C if it’s going to be used recreationally or consumed by a person.

That means it’s illegal to possess, supply, import, or use GBL as a drug. It can be legally sold for industrial use (like cleaning products), but the moment it’s used as a drug it becomes illegal.

How can you reduce the risks of using GBL?

Start low, go slow — no more than 0.5 mL to start. Wait at least 90 minutes to redose.
Use a syringe or pipette. Never guess or use a cap/spoon.
Set a timer so you don’t redose by accident.
Don’t mix with alcohol, benzos, or opioids.
Use with someone you trust. Don’t use alone.
Label your GBL. Don’t leave it near drinks.
Stick to calm, familiar places. Avoid chaotic environments.
Know the signs of overdose: unresponsiveness, slow breathing, pale lips, gurgling. Call 999.
Avoid daily use. If you’re struggling to stop, get support.

Sexual harm reduction tips

Decide your boundaries before you use. Let a trusted friend know if you’re meeting someone new.
G can increase feelings of arousal and sensuality — but it can also blur judgement. Make sure you and your partner are both enthusiastically consenting before and during any sexual activity.
Use condoms, dams, and lube, it reduces the risk of condoms breaking and helps prevent injury to soft tissue.
Stay with people who respect your boundaries and won’t pressure you to do anything you’re unsure about.
Never assume consent. If someone is very intoxicated or unconscious, they can’t give informed consent.
If someone looks vulnerable, help them or get help.
Get tested regularly for STIs and blood-borne viruses.