GHB and GBL are the most dangerous commonly used drugs in chemsex contexts — not because they're the most toxic, but because the margin between an enjoyable dose and an overdose is tiny, and because they interact fatally with alcohol.
This article exists because knowing this information before you're in a situation is the only time it's useful.
What They Are
GHB (gamma-hydroxybutyrate) is a CNS depressant that occurs naturally in the brain in small amounts. Synthesised GHB is used recreationally for its relaxant, disinhibiting, and euphoric effects.
GBL (gamma-butyrolactone) is a prodrug — a precursor that your body converts to GHB after ingestion. GBL is more potent by volume, has a slightly faster onset, and is more corrosive to tissues (including the mouth and oesophagus). It requires careful dilution before use.
For practical purposes, the risks, effects, and harm reduction principles for both are similar. GBL requires more caution because it is stronger by volume and more chemically aggressive.
Street names: G, Gina, Liquid X, Liquid E, Blue Nitro, fantasy.
What It Does (Effects by Dose)
The effect of GHB is highly dose-dependent — and that dose-effect curve is steep.
| Approximate dose (GHB) | Effect |
|---|---|
| 0.5–1.0g | Mild relaxation, slight disinhibition |
| 1.0–2.5g | Euphoria, increased sociability, sexual disinhibition |
| 2.5–4.0g | Stronger sedation, coordination impairment, memory effects |
| 4.0–5.0g | High overdose risk — nausea, confusion, unresponsiveness |
| >5g (with alcohol) | Respiratory depression, unconsciousness, death |
The critical issue: these dose ranges vary significantly between individuals based on body weight, tolerance, what they've eaten, and other substances present. The difference between "enjoyable" and "unconscious" for a given person on a given night can be less than a millilitre of liquid.
There is no antidote for GHB overdose. Naloxone (used for opioid overdose) does not reverse GHB. The only treatment is supportive — keeping airways open, calling emergency services, and waiting. Act early; don't wait to see if they "come out of it."
The Alcohol Interaction
GHB is a CNS depressant. Alcohol is a CNS depressant. Combining them is additive and unpredictable.
At doses that would be manageable alone, the combination can produce rapid loss of consciousness and respiratory depression. This is not hypothetical — it is the mechanism behind the majority of G-related deaths.
Zero alcohol if GHB is in the room. This is the single most important rule.
The Re-dosing Problem
GHB has a delayed onset — it can take 15–45 minutes to fully kick in, depending on whether you've eaten and individual variation. People who don't feel effects and re-dose before the first dose peaks are the most common overdose scenario.
Wait at least 2 hours before considering a second dose. Set a phone alarm. If you don't feel the first dose after 45 minutes, the answer is patience — not more G.
Pre-marking small cups or syringes with the dose removes the "how much was that" ambiguity that makes group use risky.
Signs of GHB Overdose
Recognising an overdose early is the difference between a recovery position call and an emergency ambulance call.
Early signs:
- Sudden extreme drowsiness
- Slurred speech beyond typical intoxication
- Confusion, disorientation
- Nausea, vomiting
Escalating:
- Unresponsive to voice or touch
- Breathing slows or becomes irregular
- Blue tinge to lips (cyanosis)
If someone goes unresponsive:
- Do not leave them alone
- Recovery position immediately — on their side, airway clear
- Call emergency services
- Stay with them until help arrives
- Tell the paramedics what they took — this is not about you getting in trouble, it's about them getting the right treatment
Someone who appears to be "sleeping off" G can stop breathing. An unconscious person left face-up can aspirate vomit. The recovery position and emergency services call are not optional steps to skip to avoid drama.
Longer-Term Risks
Tolerance and dependence: Regular GHB use develops tolerance quickly. Daily or near-daily use can produce physical dependence. GHB withdrawal is one of the few recreational drug withdrawals that can be medically dangerous (similar to alcohol withdrawal: seizures, delirium). Stopping suddenly after heavy, prolonged use requires medical supervision.
Memory and cognitive effects: Frequent use can impair memory encoding during sessions. Long-term heavy use is associated with broader cognitive effects.
Sleep disruption: GHB disrupts sleep architecture even as it induces sedation. Regular use correlates with worsening sleep quality over time.
Harm Reduction Summary
| Risk | Mitigation |
|---|---|
| Overdose from incorrect dose | Use measuring equipment — never eyeball. Start low. |
| Overdose from re-dosing | Wait minimum 2 hours. Use phone alarm. |
| Fatal interaction with alcohol | Absolute rule: zero alcohol if G is in the room. |
| Unconscious person | Recovery position + call emergency services immediately. |
| Dependent use needing to stop | Medical supervision for withdrawal — do not stop cold turkey after heavy daily use. |
| Unknown concentration (street GHB/GBL) | Test kits exist but don't confirm concentration. Treat every new batch as unknown strength. |
If You Think You Need Help
If G has started to feel like something you need rather than something you choose — if you're using it regularly, increasing your dose, or using it to function — that's worth talking to someone about.
Harm reduction services and sexual health clinics with chemsex-trained staff can provide non-judgmental support. You don't have to be in crisis to ask for help; you just need to notice the pattern.
Related:
- > Lethal Combos: The Math That Kills — the full interaction table
- > Chemsex: Harm Reduction When Substances Are Part of the Scene — the broader chemsex context
- > EMERGENCY: Overdose — emergency response protocol
- > Recognizing When Use Becomes a Problem — if the pattern has shifted