DOSINA

GBL

Depressant

A prodrug of GHB, roughly 1.65x more potent by volume and faster-acting. Same narrow margin, same medical risks, more dosing errors because it is usually dispensed as liquid.

gamma-Butyrolactone

Dose and effect data: PsychonautWiki (CC BY-SA 4.0) and TripSit (PolyForm Noncommercial 1.0.0).

Before you dose

⚠This substance has combinations that are life-threatening. Check the Interactions tab before mixing anything.

Dose

Published population range

Threshold0.3 ml
Light0.3–0.9 ml
Common0.9–1.5 ml
Strong1.5–3 ml
Heavy / risk zone≥ 3 ml

Basis: Scaled from the published 70 kg range. GBL is roughly 1.65x more potent than GHB by volume.

Measure with a syringe, never a bottle cap or a 'glug'.

Showing published ranges.

Check an amount you already have

Timeline (oral)

Onset3–10 minutes
Come-up5–15 minutes
Peak30–45 minutes
Offset15–30 minutes
Afterglow60–180 minutes
Total60–120 minutes

Bars show relative time in each phase, scaled to the total duration. Each phase keeps its colour in the list above.

Expected effects

  • Euphoria
  • Sociability
  • Relaxation
  • Increased libido

Possible side effects

  • Very fast onset that makes re-dosing errors easy
  • Sudden unconsciousness
  • Respiratory depression when mixed
  • Nausea and vomiting
  • Amnesia
  • Tissue irritation (GBL is caustic)
  • Severe dependence and withdrawal

Harm reduction

  • Depressants are the class where mixing kills most often: alcohol, benzodiazepines, GHB/GBL and opioids all suppress breathing when combined.
  • Never use alone. If you use alone, set up a check-in call with someone who will call emergency services if you do not answer.
  • Measure liquid doses with a syringe. Bottle caps, teaspoons and 'glugs' are how people take ten times the intended dose.
  • Sedation can be delayed. Do not re-dose before you can feel the previous dose fully.
  • Do not stop daily benzodiazepine or alcohol use abruptly - withdrawal can cause seizures and is potentially fatal. Taper with medical help.
  • Signs that someone needs emergency help: breathing slower than one breath every 4-5 seconds, blue lips, snoring that will not stop, unrousable, vomiting while unconscious.

Mixing

KetamineDangerous

See interaction notes for details.

MXEDangerous

See interaction notes for details.

DXMDangerous

See interaction notes for details.

PCPDangerous

See interaction notes for details.

AlcoholDangerous

See interaction notes for details.

OpioidsDangerous

See interaction notes for details.

TramadolDangerous

See interaction notes for details.

BenzodiazepinesDangerous

See interaction notes for details.

NitrousCaution

See interaction notes for details.

AmphetaminesCaution

See interaction notes for details.

MDMACaution

See interaction notes for details.

CocaineCaution

See interaction notes for details.

Tolerance, dependence and detection

Toleranceback to baseline after 7 - 14 days
Addiction potentialhighly physically and moderately to highly psychologically addictive
After-effects1-2

Sources

• PsychonautWiki — GBL (CC BY-SA 4.0)
https://psychonautwiki.org/wiki/GBL

• TripSit wiki — GBL (PolyForm Noncommercial)
https://wiki.tripsit.me

• Erowid experience reports (external)
https://www.erowid.org/experiences/subs/exp_GBL.shtml

Dosina is educational harm-reduction information, not medical advice. Doses are population ranges from published sources and cannot account for your tolerance, health conditions or what is actually in your substance. Possession and use may be illegal where you live.