LSD

LSD (lysergic acid diethylamide, also known as "acid," "Lucy," or "tabs") is one of the most potent psychoactive substances known, active at microgram doses. First synthesized in 1938 and discovered to be psychoactive in 1943, it produces profound changes in perception, thought, and emotion lasting 8-12 hours. LSD has extremely low physical toxicity—there are no confirmed deaths from LSD overdose alone—but it carries real psychological risks that depend on your preparation, environment, dose, and personal vulnerabilities.

This page helps you understand and estimate those risks based on the best available evidence.

Your Situation

How well have you prepared?

Where will you be, and who will you be with?

What dose are you taking?

Have you tested your substance?

Do you have a history of mental health conditions?

Are you taking any medications?

Have you planned for the duration?

Your Estimated Risks

Make selections above to see your personalized risk estimates...

Show Data and Models

Risk Factor Data

Preparation and Mindset

LSD:LSD Preparation
Preparation_Description	Preparation_Multiplier
Thorough preparation (researched, clear intention, good mental state, trip sitter arranged)	0.5
Moderate preparation (some research, positive mood, plan in place)	0.75
Minimal preparation (little research, spontaneous decision)	1.2
Poor preparation (stressed, anxious, no plan, impulsive use)	2.0

"Set" encompasses your mental state, expectations, and preparation. Research consistently shows that intention-setting, education about effects, and positive expectancy reduce difficult experiences. The Griffiths lab at Johns Hopkins found that careful preparation was one of the strongest predictors of positive outcomes in clinical trials.

Setting and Social Environment

LSD:LSD Setting
Setting_Description	Setting_Multiplier	Setting_Safety_Level
Clinical/research setting (medical supervision, controlled environment)	0.4	Very_High
Safe home with experienced sitter (comfortable, private, trusted guide)	0.6	High
Safe home alone or with trusted friends (comfortable, familiar)	0.9	Moderate
Social gathering (party, small festival, people you mostly know)	1.5	Low
Public/unfamiliar setting (concert, large festival, strangers)	2.2	Very_Low
Chaotic or hostile environment	3.0	Dangerous

Setting dramatically influences outcomes. Clinical trials achieve low adverse event rates partly through carefully controlled environments. The 8-12 hour duration of LSD makes setting especially important—you need a space where you can safely remain for an extended period.

Dose

LSD:LSD Dose
Dose_Description	Dose_Base_Risk	Dose_mcg_Low	Dose_mcg_High
Microdose (sub-perceptual, 5-20 mcg)	0.01	5	20
Low/threshold (light effects, 25-75 mcg)	0.08	25	75
Common (full experience, 75-150 mcg)	0.18	75	150
Strong (intense experience, 150-300 mcg)	0.32	150	300
Heavy (overwhelming, 300+ mcg)	0.45	300	500

Dose is a primary determinant of challenging experiences. In the 2016 Global Drug Survey, 21% of LSD users reported seeking emergency medical help at some point—but dose strongly predicted this. Higher doses increase both the depth of experience and probability of difficulty. Note: street tabs are notoriously variable; a "150 mcg" tab may contain anywhere from 50-150 mcg.

Substance Testing

LSD:LSD Testing
Testing_Description	Testing_Risk_Modifier	Testing_Confidence
Lab-tested (verified LSD, known dose)	0.7	High
Reagent-tested (Ehrlich/Hofmann positive, dose unknown)	0.85	Moderate
Trusted source (not tested, but reliable history)	1.0	Low
Untested from unknown source	1.4	Very_Low

LSD cannot cause fatal overdose, but substances sold as LSD sometimes contain dangerous adulterants. NBOMe compounds (sometimes sold as LSD) have caused deaths at doses that would be safe for actual LSD. Ehrlich reagent testing can distinguish LSD from NBOMe. Knowing the actual dose also helps with harm reduction planning.

Mental Health History

LSD:LSD MentalHealth
MentalHealth_Description	MentalHealth_Multiplier	MentalHealth_HPPD_Factor	MentalHealth_Contraindicated
No significant mental health history	1.0	1.0	No
Anxiety disorder (stable, managed)	1.3	1.2	Caution
Depression (stable, not severe)	1.2	1.1	Caution
Family history of psychosis, schizophrenia, or bipolar	2.5	1.5	Strong_Caution
Personal history of psychosis or schizophrenia	6.0	2.0	Yes
Bipolar disorder	4.0	1.8	Yes
Current psychological crisis or instability	3.5	1.5	Yes

Personal or family history of psychotic spectrum disorders significantly increases risk of adverse psychological outcomes. While LSD does not "cause" schizophrenia, it may precipitate onset in vulnerable individuals or trigger episodes in those with existing conditions. Most clinical trials exclude participants with these histories.

Medications

LSD:LSD Medications
Medication_Description	Medication_Risk_Level	Medication_Warning_Text
No concerning medications	None
SSRIs/SNRIs (antidepressants)	Reduced	About half of people on these medications report weaker effects from psychedelics. Do not stop your medication suddenly to try to get stronger effects.
Lithium	Dangerous	Seizures have happened to many people who took LSD while on lithium. Do not use LSD while taking lithium.
Tricyclic antidepressants	Increased	May intensify LSD effects unpredictably. Not recommended.
MAOIs	Dangerous	Can cause dangerous reactions and unpredictable intensification. Do not combine.
Tramadol	Dangerous	Seizure risk. Do not combine.
Antipsychotics	Blocks	Will likely block or greatly reduce effects.

Drug interactions with LSD are important safety considerations. Lithium is the most dangerous combination—a study of online reports found that nearly half of people who reported combining lithium with psychedelics experienced seizures. SSRIs reduce effects in about half of users (47% for SSRIs, 55% for SNRIs in a Johns Hopkins survey) but are not acutely dangerous. MAOIs can dangerously potentiate effects.

Duration Planning

LSD:LSD Duration
Duration_Description	Duration_Risk_Factor	Duration_Hours_Needed
Full day cleared (12+ hours free, no obligations)	0.7	12
Adequate time (8-10 hours available, flexible schedule)	0.9	10
Marginal time (6-8 hours, some time pressure)	1.3	8
Insufficient time (obligations within 6 hours)	2.0	6

LSD's 8-12 hour duration is substantially longer than psilocybin (4-6 hours) or MDMA (4-6 hours). Having obligations or time pressure during this window significantly increases anxiety and the likelihood of challenging experiences. Sleep is often difficult for several hours after primary effects subside.

Dose-response relationships of LSD-induced subjective experiences | PMC

Risk Models

RiskModel: LSD:LSD_ChallengingExperience
Sorted Parameters:
  base_risk = {{#expr: {Dose_Base_Risk} * {Preparation_Multiplier} * {Setting_Multiplier} * {MentalHealth_Multiplier} * {Testing_Risk_Modifier} * {Duration_Risk_Factor} }}
Content: 
===Risk of Challenging Experience===
Based on your selections, your estimated risk of a '''significantly challenging experience''' (intense anxiety, fear, paranoia, or feeling out of control) is approximately '''{{One_In_X|{base_risk} }}'''.

{{#ifeq: {Testing_Confidence}|Very_Low|'''Note:''' Using untested substances increases both risk and uncertainty in this estimate. Consider using a reagent test kit.}}

{{#ifexpr: {base_risk} > 0.35|'''Your risk factors suggest a high probability of difficulty.''' Consider whether this is the right time and context for this experience.}}

A challenging experience is not necessarily harmful—many people find that working through difficult material leads to valuable insights. However, without proper support, challenging experiences can be traumatic and occasionally lead to dangerous behavior.

RiskModel: LSD:LSD_PhysicalSafety
Content: 
===Physical Safety===
LSD has '''no known lethal dose''' in humans. The few deaths attributed to LSD were from accidents or dangerous behavior, not pharmacological toxicity. The estimated lethal dose based on animal studies would require consuming thousands of typical doses.

{{#switch: {Setting_Safety_Level}
|Very_High=In your controlled setting with supervision, physical risks are minimal. Primary physical effects are mild: pupil dilation, slightly elevated heart rate and temperature, and possible jaw tension.
|High=In your safe setting, the main physical risk is minimal. Having a sober sitter available means help is accessible if needed. Stay hydrated and in a comfortable temperature.
|Moderate=Physical risks remain low, but without a sitter, ensure you've removed hazards (sharp objects, access to heights, car keys). The 8-12 hour duration means you should not plan to drive or operate machinery for the entire day.
|Low='''Your setting increases risk of accidental injury.''' Social or public environments during a strong psychedelic experience can lead to disorientation, getting lost, or accidents. Consider relocating to a safer space.
|Very_Low='''Caution: Your setting significantly increases physical risk.''' Impaired judgment in unfamiliar or chaotic environments has led to accidents and injuries. Strongly consider a different setting.
|Dangerous='''Warning: Your environment poses serious physical risks.''' Hostile or chaotic settings have been associated with severe adverse outcomes. This is not a safe context for LSD use.
|In any setting, physical risks are low but context-dependent.
}}

RiskModel: LSD:LSD_HPPD
Sorted Parameters:
  hppd_base = {{#expr: 0.04 * {MentalHealth_HPPD_Factor} }}
  hppd_adjusted = {{#expr: {hppd_base} * (1 + ({Dose_Base_Risk} * 0.5)) }}
Content: 
===HPPD (Hallucinogen Persisting Perception Disorder)===
HPPD involves visual disturbances (trails, halos, static, geometric patterns) that persist after the drug has worn off. Your estimated HPPD risk is approximately '''{{One_In_X|{hppd_adjusted} }}''' based on your selections.

'''What the research shows:'''
* A 2022 survey found '''4.2%''' of psychedelic users reported symptoms consistent with HPPD
* Most cases are '''mild and transient''', resolving within weeks to months
* Severe, distressing HPPD is rare (estimated <0.5% of users)
* Risk factors include: repeated use, high doses, cannabis co-use, and pre-existing anxiety

HPPD is '''not psychosis'''—people with HPPD have full insight that their perceptions are drug-related artifacts, not reality. However, it can be distressing, particularly for those with anxiety.

{{#ifexpr: {MentalHealth_HPPD_Factor} > 1.2|Your mental health history may increase HPPD risk. Monitor for persistent visual changes after use.}}

RiskModel: LSD:LSD_EmergencyRisk
Sorted Parameters:
  emergency_base = {{#expr: 0.01 * {Dose_Base_Risk} * {Setting_Multiplier} * {MentalHealth_Multiplier} / 0.18 }}
Content: 
===Emergency Medical Treatment Risk===
Based on population surveys, your estimated risk of seeking '''emergency medical treatment''' for this experience is approximately '''{{One_In_X|{emergency_base} }}'''.

'''Context for this number:'''
* The Global Drug Survey found 1.0% of past-year LSD users sought emergency treatment
* This is higher than psilocybin (0.2%) but lower than MDMA (1.2%) or synthetic cannabis (3.2%)
* Most emergency visits are for psychological distress (anxiety, panic), not medical emergencies
* Visits often occur in unsupervised settings without access to reassurance and support

{{#ifeq: {Setting_Safety_Level}|Very_High|In clinical settings with trained support, emergency medical treatment is rarely needed—distress can usually be managed with reassurance and a calm environment.}}

RiskModel: LSD:LSD_MedicationWarning
Content: 
===Medication Interactions===
{{#switch: {Medication_Risk_Level}
|Dangerous='''⚠️ CRITICAL WARNING:''' You have indicated a medication with '''dangerous''' interactions with LSD. {Medication_Warning_Text} '''Do not use LSD with this medication.'''
|Increased='''⚠️ Caution:''' Your medication may intensify LSD effects in unpredictable ways. {Medication_Warning_Text} Consider consulting a healthcare provider.
|Reduced='''Note:''' {Medication_Warning_Text}
|Blocks=Your medication will likely block most or all LSD effects.
|None=No specific medication interactions identified for your selection.
}}

RiskModel: LSD:LSD_DurationAdvice
Content: 
===Duration and Timing===
{{#switch: {Duration_Hours_Needed}
|12=You've planned well. With 12+ hours available, you have ample time for the full experience (8-12 hours) plus wind-down time. Consider having easy snacks available—appetite often returns toward the end.
|10=You have adequate time for most experiences. Effects typically last 8-12 hours depending on dose. Avoid scheduling anything important for the following morning, as sleep may be delayed.
|8='''Time may be tight.''' LSD typically lasts 8-12 hours, and you've indicated 6-8 hours available. This time pressure may increase anxiety during the experience. Consider rescheduling obligations if possible.
|6='''Warning: Insufficient time.''' Having obligations within 6 hours creates significant time pressure and is likely to cause anxiety. LSD effects cannot be reliably shortened. '''Strongly recommend rescheduling.'''
}}

'''Planning tips:'''
* Effects begin 20-60 minutes after ingestion
* Peak effects last 3-5 hours
* Gradual return to baseline over 4-6 more hours
* Sleep is often difficult for 2-4 hours after effects subside
* Avoid driving for at least 12 hours after ingestion

References and Further Reading

Clinical Research

Harm Reduction

Drug Interactions

Initially created by Claude.