Short answer: LSD (lysergic acid diethylamide) is a very potent psychedelic, active in millionths of a gram, with effects lasting 8 to 12 hours. It is Schedule I in the US. It has very low physical toxicity, but it can cause frightening experiences and risky behavior, and blotters sold as LSD sometimes contain more dangerous NBOMe drugs. A form of LSD is in late-stage trials for generalized anxiety disorder.
Key takeaways
- What it is: LSD is a serotonergic psychedelic (ergoline) and a Schedule I controlled substance in the US.
- Medical use: Investigational (anxiety).
- Timing: effects start in 30 to 90 minutes and last 8 to 12 hours.
- Most dangerous mix: Lithium, which can cause seizures and dangerous reactions reported.
- Naloxone: it does not reverse this drug, but give it whenever opioids could be involved.
- Dependence risk: Low.
- Legal route: none. Schedule I substances cannot be prescribed.
What is LSD?
LSD is a semi-synthetic compound first made in 1938 from ergot, a fungus on rye. It strongly activates serotonin 5-HT2A receptors and is active at doses of micrograms.
LSD alters perception, causing vivid colors, patterns, visual distortions, mixed senses (synesthesia), changes in thinking and sense of self, and strong emotions. Physical effects include dilated pupils, higher heart rate and temperature, sweating, and sleeplessness.
Quick facts
| Fact | LSD |
|---|---|
| Chemical name | Lysergic acid diethylamide |
| Street names | Acid, tabs, blotter, Lucy |
| Drug class | Serotonergic psychedelic (ergoline) |
| US legal status | Schedule I |
| Medical status | Investigational (MM120 for generalized anxiety disorder in phase 3) |
| How it is used | Blotter paper, liquid drops, gel tabs, swallowed |
| Active dose | Micrograms |
| Onset | 30 to 90 minutes |
| Duration | 8 to 12 hours |
How long does LSD last?
- Starts working: 30 to 90 minutes
- Effects last: 8 to 12 hours
Usually 8 to 12 hours.
Timing varies with the dose, the form, how it is taken, liver and kidney function, age, and other drugs taken at the same time.
What are the biggest risks of LSD?
Psychological risks: panic, paranoia, and confusion can lead to accidents or self-harm. People with a personal or family history of psychosis are at higher risk.
Counterfeits: blotters sold as LSD sometimes contain NBOMe compounds (such as 25I-NBOMe), which are active at similar doses but have caused seizures, very high temperatures, and deaths. A bitter or numbing taste is a warning sign.
HPPD: rare lasting visual disturbances.
What should you never mix with LSD?
| Combined with | What happens | Risk level |
|---|---|---|
| Lithium | Seizures and dangerous reactions reported | Avoid |
| MAOIs (and ayahuasca) | Greatly intensified, unpredictable effects | High risk |
| SSRIs and SNRIs | Usually blunted effects; serotonin syndrome possible with some combinations | Use caution |
| Cannabis | More intense, sometimes frightening experiences | Use caution |
| Stimulants (amphetamines, cocaine) | Anxiety, heart strain, overheating | Use caution |
| Tramadol | Seizures and serotonin syndrome | Avoid |
Check any combination with the DoseUses combination checker or ask a pharmacist.
What are the signs of a LSD overdose, and what should you do?
LSD itself has very low physical toxicity, and deaths from LSD alone are extremely rare. Very large doses can cause vomiting, high temperature, and extreme agitation. Most serious harm comes from accidents, dangerous behavior, other drugs, or NBOMe counterfeits.
If someone is having a dangerous reaction
- Call 911 for a seizure, chest pain, a very high temperature, trouble breathing, unresponsiveness, or if the person may harm themselves or others.
- Move them to a quiet, safe place away from roads, water, heights, and crowds. Stay with them and speak calmly.
- Do not leave the person alone and do not give them other drugs or alcohol to calm them down.
- If they become unresponsive, place them on their side and give naloxone in case opioids are involved.
Is LSD addictive?
LSD is not considered physically addictive and does not cause a withdrawal syndrome. Tolerance develops after a single dose and lasts several days, and there is cross-tolerance with psilocybin. Some people use it compulsively, but this is uncommon.
See the withdrawal timelines and the full LSD withdrawal guide.
Is LSD legal?
LSD is a Schedule I controlled substance under federal law, meaning it is considered to have a high potential for abuse and no currently accepted medical use. It cannot be prescribed, and possessing, making, or selling it is a federal crime.
- Possession: under federal law, a first conviction for possessing any controlled substance without a valid prescription can bring up to one year in prison and a minimum fine of $1,000. Penalties rise with prior convictions.
- Trafficking: trafficking 1 gram or more of a mixture containing LSD carries a mandatory minimum of 5 years in federal prison, and 10 grams or more carries 10 years. Because the weight includes the blotter paper, small numbers of doses can trigger these minimums.
- State law: states set their own penalties, and most drug cases are prosecuted under state law. Penalties range from a civil fine to long prison terms depending on the state, the amount, and prior record.
Outside the United States
| Country | Status |
|---|---|
| United Kingdom | Class A |
| Canada | Schedule III |
| Australia | Schedule 9 prohibited substance |
| International | Schedule I of the 1971 Convention on Psychotropic Substances |
Frequently asked questions about LSD
How long does an LSD trip last?
Usually 8 to 12 hours.
Is LSD addictive?
No. It does not cause physical dependence, and tolerance builds after one dose.
What is NBOMe?
A group of synthetic psychedelics sometimes sold as LSD. They are more toxic and have caused deaths.
Is LSD being studied as medicine?
Yes. A form of LSD called MM120 has been in phase 3 trials for generalized anxiety disorder.
Does LSD show on drug tests?
Standard drug screens do not test for LSD. Specialized tests can detect it for 1 to 3 days.
Sources
- Psychedelic and Dissociative Drugs, National Institute on Drug Abuse.
- Controlled Substance Schedules, DEA Diversion Control Division.
- 21 U.S.C. 844, Penalties for simple possession, Legal Information Institute, Cornell Law School.
- 21 U.S.C. 841, Prohibited acts A (trafficking penalties), Legal Information Institute, Cornell Law School.
- Executive order aims to accelerate approval of therapeutic psychedelics, Morgan Lewis, April 2026.
- National Helpline, Substance Abuse and Mental Health Services Administration.
- FindTreatment.gov, Substance Abuse and Mental Health Services Administration.
- International drug control conventions, United Nations Office on Drugs and Crime.
This guide summarizes the sourced DoseUses LSD profile, written from FDA labels, DEA rules, and federal health agencies. It is educational and is not medical advice. Last updated October 5, 2026.
