LSD (Lysergic Acid Diethylamide): Compound Guide

If someone is in danger right now

If a person is very frightened, confused, hurting themselves or others, or cannot be woken, call 911 in the United States. For a mental health crisis call or text 988 (988 Suicide & Crisis Lifeline, US). US Poison Help is 1-800-222-1222. [1]

What LSD is

LSD stands for lysergic acid diethylamide. It is also called lysergide. The US National Institute on Drug Abuse (NIDA) groups it with psilocybin, DMT and mescaline as a "classic" psychedelic, meaning a drug that mainly acts on the brain's serotonin system. [2] For the wider term, see Classic Psychedelics: What the Term Covers.

LSD is not a plant or a mushroom. A chemistry review describes it as a semisynthetic compound made from lysergic acid, a starting material. [3] It was first made in 1938 by the Swiss chemist Albert Hofmann, who was trying to develop ergot derivatives. [4] It is made in a laboratory, so it belongs with the synthetic and clinical substances in this library, not with traditional plant and fungus preparations.

Regulatory category

Evidence labels used on this page: approved medicine, promising but limited, mixed, insufficient evidence, marketing claim.

• United States (federal). LSD is listed in Schedule I of the Drug Enforcement Administration's regulations (21 CFR 1308.11), under hallucinogenic substances. [5] Read 2026-10-22. Laws change and differ by state and country, and this is not legal advice. For other countries, see Psychedelic Legal Status by Country. Other countries: not verified here.
• Approved medicine: none. NIDA (January 2024) says only esketamine is FDA approved for therapeutic use of these drugs to date. [6]

What research shows

Generalized anxiety disorder (GAD): promising but limited. A phase 2b trial published in JAMA in 2025 randomized 198 adults with moderate to severe GAD at 22 US outpatient sites. It was double-blind and placebo-controlled. Each person received one treatment with one of four study amounts of the investigational product (called MM120) or placebo. The main outcome was change in the Hamilton Anxiety Rating Scale (HAM-A) at week 4. [7]

Two of the four study amounts (100 and 200 micrograms) beat placebo; the two lower study amounts did not. The least-squares mean differences were about 5 and 6 points on a 0 to 56 scale, where the authors set a meaningful difference at 2.5 points. [7] These are study amounts, not advice. Visual perceptual changes were reported by 92.5% and 100% of people at those two study amounts, against 10.3% on placebo. [7] That makes it hard to keep participants and raters unaware of who got the drug, a problem the FDA calls functional unblinding. [8] The abstract reports follow-up to about 4 weeks for the primary outcome; I did not read the full paper, so funding and longer follow-up are not verified here.

What has not been shown yet. Registered phase 3 trials exist for GAD and for major depressive disorder. As read in the ClinicalTrials.gov registry, two GAD trials and one depression trial are listed as active and not recruiting. [9][10][11] A registered trial is not a result. A September 2026 expert review says wider use will depend on full peer-reviewed reports of the sponsor's announced topline phase 3 results; I did not find those reports. [12]

Alcohol use disorder and older trials: mixed. A systematic review of 11 randomized trials (567 patients) found positive short-term changes, strongest for alcoholism, but most studies did not meet modern standards and some differences faded at long-term follow-up. [4]

Depression, PTSD, pain and other conditions: Proper evidence not found. I looked for completed randomized results for LSD in these conditions in PubMed and the trial registry and did not find any to cite here. For how trials like these are judged, see How to Read a Psychedelic Clinical Trial.

Risks and adverse effects

• Unpredictable effects. NIDA says effects depend on the amount, the person's biology, mood, expectations and surroundings, and can include fear, confusion and panic. [2]
• Emergency visits. In US poison-center data from 2000 to 2016, about 17% of callers who had used LSD were admitted to critical care. These callers are a selected group, not all people who use LSD. [2]
• Unsafe behavior. Impaired thinking and perception have been linked to injuries and dangerous behavior. [2]
• Lasting perceptual symptoms. Hallucinogen persisting perception disorder (HPPD) is rare, and research on it is limited. [2]
• Mental illness. NIDA reports some evidence that psychedelics might trigger schizophrenia-like illness in people with predisposing factors. Modern trials exclude people with psychosis or bipolar disorder. [2] See Psychosis Vulnerability.
• Addiction. Limited research suggests classic psychedelics do not typically lead to addiction, though tolerance may develop quickly. [2]

Special groups and interactions

Effects during pregnancy are not well understood because data are limited. [2] NIDA notes that some researchers suspect psychedelics may interact with medicines that raise serotonin, with rare reports of serotonin toxicity. [2] Do not change any medicine because of this page; talk with the prescriber. See Psychedelic Drug Interactions and Toxicology.

Quality and labeling

Illicitly made drugs can contain other substances, including fentanyl, which cannot be seen or smelled. NIDA says more research is needed on how often this happens with psychedelics. [2] A trial product made under medical rules is not the same as a product from an unregulated source. See Clinical Formulations vs Nonmedical Products.