Phenazepam Encyclopedic

Encyclopedic

Typical encyclopedia coverage. Cross-reference for important decisions.

3 corroborating sources

partial dose data

duration data present

27 combo interactions documented

classified Research-chemical

Aliases: Fenaz, Panda, Bonsai, Soviet benzo, Bromdihydrochlorphenylbenzodiazepine

Summary dose.wiki TripSit

Phenazepam is an extremely potent, long-acting benzodiazepine developed in the Soviet Union in 1975, reportedly 5-10 times stronger than diazepam. Its extremely long half-life and delayed onset of peak effects create severe risks: users often redose before feeling effects, leading to dangerous accumulation and blackouts lasting days or weeks. Not approved in most Western countries but sometimes sold online or found in counterfeit pharmaceuticals.

Dose Information source varies by band

ROA	Light	Common	Heavy
Oral	0.5-1mg	1-2mg	2-4mg+
Sublingual	0.5-1mg	1-2mg	2-4mg+

Light Common Heavy

Sources· 2 of 2 ladders not fully identified

Oral

Dose ladder — Light, Common: dose.wiki, Drugs.Wiki, TripSit · Heavy: not identified

Sublingual

Dose ladder — Light, Common: Drugs.Wiki · Heavy: not identified

Benzo Equivalence Calculator

Convert from

Convert to

1.0 mg Phenazepam

— mg Diazepam

⚠ These are approximate equivalences for educational and cross-tapering reference. Individual response, tolerance, and half-life differences mean actual equivalence varies. Always consult a healthcare provider for tapering guidance.

Onset, Duration & After-effects dose.wiki TripSit

ROA	Onset	Comeup	Peak	Offset	After Effects	Total
Oral	20-60 min	1-3 hrs	2-4 hrs	24-72 hrs	36 hrs	18-80 hrs
Sublingual	15-45 min	30-90 min	2-4 hrs	24-72 hrs	36 hrs	18-78.25 hrs
Insufflated	10-30 min	30-90 min	2-4 hrs	24-72 hrs	36 hrs	18-78 hrs

Effect Profile

8 reports

Scores (0–10) curated from multiple sources:

Effect keyword matching from PsychonautWiki catalog
Weighted by importance: core (×3), major (×2), minor (×1)

Full methodology

Benzodiazepine 6.6

Strong+ 7/10

Strong anxiolysis with strong cognitive impairment, moderate euphoria, mild sedation

Anxiolysis ×3

anxiety suppression anxiolytic muscle relaxation muscle relaxant emotion suppression

Sedation / Relaxation ×2

sedation muscle relaxation

⚠ Motor / Cognitive Impairment ×1

motor control loss cognitive impairment amnesia delusions of sobriety double vision

Euphoria / Mood Lift ×1

physical euphoria disinhibition

Based on reports from:

Erowid Experience Reports

Tolerance

Build-up develops over 1–4 weeks of daily use; hypnotic tolerance faster than anxiolytic tolerance

Reset Falls after you stop, at a rate that varies from person to person. If you've been using regularly, cut down gradually with medical help rather than stopping suddenly.

No tolerance chart. Our decay curves for these drugs were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.

How fast tolerance to these drugs fades after a break has not been measured well enough to draw, so don't count on a dose you used to take still being safe: after time off, start with a much smaller amount and don't use alone. Mixing sedatives with each other, with alcohol or with opioids sharply raises the risk of a fatal overdose. If you've been using regularly, don't stop suddenly: withdrawal from benzodiazepines, alcohol or GHB/GBL can cause seizures or delirium, so get medical help to cut down gradually.

Sources: FRANK: benzodiazepines · Alcohol and Drug Foundation: GHB · FDA 2020: benzodiazepine boxed warning · FDA 2019: gabapentinoids and breathing · NHS: alcohol use disorder

Cross-Tolerances

Diazepam

Clonazepam

Other benzodiazepines (class)

Effects Erowid

Aggregated from 8 single-substance Erowid experience reports; 3 Erowid reports where another drug was taken too are left out

Each bar shows the share of analyzed reports whose text mentions that effect — a mention is not always a first-hand experience (fear of an effect or something witnessed can count). Mentions saying the effect did not happen are left out; that check reads keywords, so it can miss some. The shaded band on a bar, and the small range after its number, is the 95% interval: where the share could plausibly be with other reports of the same kind. Fewer reports, wider band. Tap or hover any number for details. The second value is the Bluelight extractor's per-effect confidence; a dash means the row is Erowid-derived, which has no confidence measurement.

Too few reports for bars: these effects come from 8 single-substance Erowid reports, and a bar is drawn only from 20 reports or more. With fewer, a percentage cannot tell a common effect from a rare one. Counts are shown instead. Why 20?

Positive Effects 1

3 of 8 –

Adverse Effects 1

3 of 8 –

Also reported in combinations. In the 3 Phenazepam reports where another drug was taken too, 1 mentions hospital, emergency services or an overdose, 0 a seizure and 1 psychosis (too few reports for percentages). In the 8 single-substance reports: 3, 0 and 0. These are not in the figures above: they cannot be put down to Phenazepam alone, and a mention is not always something that happened to the writer.

Combinations TripSit

Cross-Check Phenazepam with another substance

Community Trip Reports

Anecdotal first-person accounts from Reddit, Erowid, Bluelight, and Dose.wiki. Click a source to expand. Reports are harm-reduction context, not medical guidance. Tags summarise each author's own verdict — how reports are classified.

Erowid 8 reports 2 neutral 6 cautionary visit

From Russia - With Not Much Love!! cautionary exp #86485

I felt I had to write this report out of duty to the drugs community and cause I could not find a single decent report online about it. Now I'm all for recreational drug use and advocate the legality of weed, LSD, Shrooms, XTC etc.

A Dangerous, Powerful, Long Acting Benzo cautionary exp #83521

[Erowid Note: The dose described in this report is very high, potentially beyond Erowid's 'heavy' range, and could pose serious health risks or result in unwanted, extreme effects.

Seems More Mainstream Than Often Described neutral exp #114213

So while seeking bzd for some legitimate medical purposes I talked to my doc and ended up with a decent product but which takes too long to kick in. I then resorted to self-medication and got pharma-grade Fenazepam shipped from the East. It has strong anxiolytic effects and naturally some sedative/hypnotic aspect too.

Pleasent Phenazepam neutral exp #84232

4:46 AM - Placed white crystals onto a piece of tin foil. As I began to melt them the crystals became a purple glob and did not yield much smoke. 4:52 AM - Smoking again..

I Had No Idea What I Was Doing cautionary exp #110683

[Erowid Note: Two samples of powder (even of the same chemical) with equivalent volumes won't necessarily weigh the same. For this reason, eyeballing is an inaccurate and potentially dangerous method of measuring, particularly for substances that are active in very small amounts.

Seeking Disaster cautionary exp #96040

Phenazepam...Seeking Disaster Let this story serve as a warning to anyone tempted by this cheap and legal benzo. It put me in the hospital and cost me my job. I am what you may call a benzo afficionado. I have tried them all, with a particular love for Etizolam (also currently legal) and Xanax.

Three-Day Dementia cautionary exp #100260

As an avid research chemical user, I wanted to test out this phenazepam everyone was yapping about. I assumed it would be similar to benzos and produce a mild sleepy feeling, so I took it after a stimulant binge to help me sleep. Mistake #1.

Made Me Realize I Wasn't Invincible cautionary exp #85336

Well, some of you may or may not know about this whole phenazepam craze that started cause it was marketed as 'liquid xanax' if you did a little chemistry with high proof alcohol. But it was sent as powder cause it's pure. I ordered 100mg for like $13 and was real safe with it at first.

Bluelight 6 threads 1 neutral 5 cautionary visit

Phenazepam New Experience Phenazedeath cautionary

He gets up early this one morning awaiting mail, browses the internet, checking this and that. *thunk* He's thinking, "was that the door latch?" It was indeed the door latch, a brown bag with a white envelope and a small plastic bag of some substance, little did he know what he was in for.

Phenazepam Chronicles neutral

In an attempt to provide more information on this particularly interesting and legal benzodiazepine, SWIM will be assaying phenazepam for the next 3-4 weeks. The information SWIM has noted thus far (see the bottom for the initial experience): -Onset of roughly 60-90 minutes when taken orally.

Phenazepam New Experience Phenazepam And Me cautionary

As a long term drug abuser this cheap, legal, fairly easy to obtain, and relatively strong benzo (phenazepam) sounded like a dream drug. I'm not a complete idiot these days though, so I looked around at various trip reports and what the prospective downside of the drug might be.

Phenazepam New Experience Responsible Usage cautionary

After reading the countless countess horror stories on here about encounters with the ultra potent benzo Phenazepam, I reluctantly ordered 100mg from a fairly reliable vendor.

Phenazepam First Time Priceless Warning cautionary

Background: I am heavily experienced with sedatives. My favorites are clonazepam (Klonopin), temazepam (Restoril), and phenobarbital. I'm sure secobarbital (Seconal, Tuinal) would also be added to that list if I were ever given the opportunity to try it.

Phenazepam First Time No Mg Scale Almost Ruined My Life cautionary

Phenazepam ---- experienced with Benzos -No Mg scale, still lived fine (so far) 25-01-2011, 01:31 #1 smokeymcpot42088 Bluelighter Online Join Date: Dec 2006 Posts: 1,029 Phenazepam ---- experienced with Benzos -No Mg scale, still lived fine (so far) ----------------------------------------------------------------------...

Phenazepam's nerd page Pharmacology, chemical data, effect profiles, and more

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Helpful Links

📘 Experience Reports 📖 dose.wiki 📖 TripSit 📖 PsychonautWiki

Add missing routes to PsychonautWiki Journal

The PsychonautWiki Journal app already has Phenazepam, but its built-in entry only covers Oral. Here are the other routes we have data for. You can't edit a built-in substance, but you can add a Custom Unit for any of these routes to log it.

Custom Unit doses

Sublingualcommon ~ 1.5 mg

Dose & duration (reference)

Phenazepam: routes the PsychonautWiki Journal app is missing
Source: SubstanceSearch (substancesearch.com)

Sublingual dose (mg): threshold 0.1 · light 0.5-1 · common 1-2 · heavy 2-4+

Sublingual duration: onset 15-45m · come-up 0.5-1.5h · peak 2-4h · offset 24-72h · total 18-78.25h · after-effects 36h
Insufflated duration: onset 10-30m · come-up 0.5-1.5h · peak 2-4h · offset 24-72h · total 18-78h · after-effects 36h

Note: ranges are harm-reduction guidance, not a prescription. Start low, go slow, and test your substances.

Custom Units carry a single dose per route, so the full ranges live in the reference above. A route's suggested dose is the midpoint of its common range. Ranges are harm-reduction guidance, not a prescription.

Report an issue or suggest an edit

Spotted incorrect or dangerous information, have a correction, a new study, or a useful addition for Phenazepam? Let us know. Reports are reviewed by moderators — this is not posted publicly.

Phenazepam Encyclopedic Encyclopedic Typical encyclopedia coverage. Cross-reference for important decisions. 3 corroborating sources partial dose data duration data present 27 combo interactions documented classified Research-chemical