What Is LSD?

Written by Wayne Drash
Medically Reviewed by Carol DerSarkissian, MD on June 10, 2025
9 min read

LSD (lysergic acid diethylamide), also called “acid,” is a type of synthetic and mind-altering substance (psychedelic). This belongs to a class of drugs called hallucinogens. When you take LSD, even in small doses, it can make you hallucinate — hear, see, and smell things that aren’t really there.

People tend to take LSD to get a high, “trippy” feeling that one can’t get from reality. LSD remains one of the go-to ways to change the way you see the world around you, even though it’s illegal.

Scientists first made LSD in 1938, from a chemical they took from a type of fungus called ergot. This fungus often infects rye plants.

Here’s a look at what LSD is, how it works, and its short- and long-term effects on your health.

In its purest form, LSD looks like a white or colorless crystalline powder, has no smell, and might taste bitter. But in this form, even the smallest dose can be strong and dangerous. 

To lower the strength, drug droplets are often mixed with other substances such as absorbent paper like gelatin sheets. It’s also infused into sugar cubes.

When you place it on your tongue or swallow it, it releases the drug into your system. You can also buy LSD in pill, capsule, or liquid form.

Besides “acid,” LSD sold on the streets might be called other names, such as:

  • Sugar cubes
  • White lightning
  • Dose
  • Tripping
  • Blotter
  • Mellow yellow
  • Lucy
  • Dots
  • Windowpane

How do people make acid?

LSD is made in illegal labs. Because LSD is a type of synthetic substance and relatively hard to make, the labs rely on experienced chemists to make the drug.

Experts don’t fully understand how LSD affects your brain and central nervous system to cause the psychoactive effects that make you see colors, hear sounds, or lose the sense of time. But it belongs to the same class of drugs — ergolines — that treats migraine and Parkinson’s disease, though its effects on the brain are very different. If scientists can figure out the reason why it affects your brain like this, it could potentially help treat other conditions in a safe and effective way.

What researchers do know is that LSD attaches to serotonin receptors on your brain cells. Serotonin is a chemical that your brain uses to communicate with the rest of your body. It also controls behavior, mood, the senses, and thinking. 

When you take LSD, it reacts with these receptors to trigger the hallucinogenic effects within your senses. Researchers believe this reaction is also what causes the long-lasting high.

LSD can affect your senses, causing you to hallucinate and see and hear things that do not exist — or distort what is happening around you. LSD can alter your thinking, emotions, and sense of time.

The intensity of an LSD trip depends on things such as:

  • Your size, weight, and health
  • Whether your body is used to taking LSD
  • The amount of LSD you take
  • The strength of the LSD
  • Whether you mix LSD with other drugs

LSD effects

When LSD kicks in, a “trip” — the state in which you feel the drug’s mind-bending effects — can look or feel like:

  • Greater awareness or clarity
  • Euphoria and well-being
  • Lack of control over how and what you’ll see or hear
  • Distorted images that change in shape or size
  • Seeing sounds or hearing colors, also known as synesthesia
  • Emotional feelings or insights
  • Mood swings
  • Feeling detached from your body or mind
  • Loss of understanding of time or reality
  • Lack of focus or concentration 

Other effects may include:

  • Dilation of pupils
  • Headaches
  • Nausea
  • Fast or irregular heartbeat
  • Chills and sweating
  • Quick breathing

When does LSD kick in?

Within the first hour after taking LSD, you might start seeing things and experience mood swings with extreme highs and lows. Your sense of time, space, color, and even your own body can get twisted.

An LSD trip makes it harder to think clearly, and that confusion can lead to dangerous decisions. 

How long does an LSD trip last?

The effects of LSD usually kick in within the first 20-90 minutes and can last about 8-12 hours.

What to expect from the comedown

How you feel while coming down from LSD may be different from how someone else feels. These are the most common symptoms:

  • Muscle twitching
  • Shaking
  • Restless legs
  • Nausea
  • Headaches
  • Mouth ulcers
  • Feeling anxious, depressed, or irritable
  • Feeling tired or exhausted
  • Trouble concentrating
  • Trouble sleeping
  • No appetite

A bad trip can happen to anyone, especially if you take LSD in high doses. 

The psychological side effects of a bad trip include:

  • Dilated pupils
  • High body temperature
  • High heart rate 
  • High blood pressure
  • Lots of sweating
  • Loss of appetite
  • Sleeplessness
  • Dry mouth
  • Tremors (body shakes)
  • Serious feelings of anxiousness
  • Panic
  • Confusion
  • Violence

A bad trip is very different from an LSD overdose. In most cases, while a bad trip may make you feel anxious or frightened, the effects of the LSD are typically not life-threatening and will wear off over time.

How to lower your chances of having a bad trip

You can lessen your chances of a bad trip by making sure you’re in a good headspace when you take LSD — surrounded by close friends in a safe environment. If you’re in a loud setting than a quiet one, the chances of a bad experience with LSD increase.

No. It is a Schedule I substance under the Controlled Substance Act. If you’re caught with it, you could face jail time. LSD is not approved for medical use either.

It is rare for someone to die from taking LSD. Most deaths tied to LSD are almost always from falls, car crashes, and other accidents — not from the acid itself.

That said, if you take a very high dose of LSD, you can overdose and have serious LSD toxicity in your body. This can cause:

  • Coma
  • Breathing problems
  • Vomiting 
  • Heightened anxiety, depression, and paranoia
  • Hyperthermia (very high body temperatures)
  • High heart rate and blood pressure
  • Bleeding problems 

If you notice these signs, get immediate medical attention. Call 911 or head to the nearest hospital.

LSD isn’t considered an addictive drug. It also doesn’t create the need for you to take it to complete daily tasks.

But it’s possible to build a tolerance for it, even after one or two uses. This means the more you take, the higher the doses you’ll need in order to feel the same level of high.

Some long-term LSD users may experience “flashbacks.” This comes from stress, where feelings or visuals that you once had during a trip might pop back into your head. This happens even when you’re not using the drug.

Flashbacks can often take a toll on your quality of life. But how often they happen and how intense they are tend to dip after you stop using LSD for a while.

Some people might also develop a condition called hallucinogen persisting perception disorder (HPPD). It’s similar to flashbacks, but if you have HPPD, you might get flashbacks long after you stop using LSD.

A few LSD users could also develop drug-induced psychosis, a mental disorder that causes you to have delusions, hallucinations, and unusual physical behaviors and speech. 

If LSD use begins to interfere with the quality of your life and that of your loved ones, talk to your doctor about getting professional help and support to gain back control.

To avoid a relapse, try talk therapy with a certified mental health expert. You can also join a recovery program to help you quit LSD or cut back. 

If you have flashbacks or HPPD, your doctor might prescribe medications to keep mental health symptoms such as anxiety, depression, and certain psychiatric behavior under control. These can include:

  • Calcium channel blockers
  • Selective serotonin reuptake inhibitors (SSRIs)
  • Beta-blockers
  • Antiepileptic drugs

It’s best not to use LSD. But if you or your loved one plans to, there are steps you can take to lower your odds of an overdose.

You should:

  • Understand LSD’s dosages and its effects on the body.
  • Start with a small amount to test how you’ll react. 
  • Use in a safe environment with people you trust.
  • Have a sober friend with you, especially if it’s your first time using LSD.
  • Drink plenty of fluids.
  • Set a limit on how much you’ll try. 
  • Space your LSD trips apart by days, weeks, or months.
  • Throw the tab away if it has a bitter taste. It most likely isn’t LSD; it's possibly another more dangerous illicit drug.

Don’t: 

  • Operate heavy machinery or sharp tools when you take LSD
  • Swim or drive
  • Take LSD if you’re feeling down, depressed, or paranoid; LSD can make these symptoms worse.

Avoid mixing LSD with alcohol, marijuana, or other drugs. Doing so can lead to unexpected reactions. For instance, mixing LSD with alcohol can trigger nausea and cancel out any desirable effects. 

LSD mixed with marijuana ups your chances of unpredictable mood swings and other side effects, including psychosis in rare cases. Mixing LSD with stimulants such as cocaine can increase the risk of heart problems, severe anxiety, paranoia, and psychosis.

If a loved one or friend takes LSD, keep a close eye on them to make sure they don’t have negative effects. If you or a loved one is showing signs of an overdose, it’s a medical emergency. Call 911 or get to the hospital as soon as possible.

What is LSD?

LSD (lysergic acid diethylamide) is a powerful hallucinogenic drug that alters mood, perception, and thought. It is commonly called acid.

What does an LSD trip feel like?

LSD remains one of the go-to ways to change the way you see the world around you. Effects include hallucinations, sensory changes, intense mood swings, distorted time perception, and general loss of concentration.

What are the effects of a bad trip?

You may have hallucinations that cause anxiety, terror, thoughts of suicide, or fear of death. You may see disturbing images that cause mental distress. Some trips may cause a person to become paranoid about other people or things, and they might even become aggressive.

What are the biggest risks with LSD?

LSD can cause extreme mood swings, paranoia, and panic that can lead to dangerous behaviors. Some people may develop hallucinogen persisting perception disorder, such as flashbacks, even after they stop using LSD. In rare cases, LSD can trigger psychosis, especially in people with underlying mental health conditions.

Is LSD addictive?

LSD is not considered addictive. But you can develop tolerance over time, meaning you may need more LSD to get the same “trippy” feeling.

Is LSD legal?

No. LSD is a Schedule I substance in the U.S., meaning you could face jail time if you’re caught with it.