What is LSD?


Popular in the 1960’s mostly with hippies, LSD, also known as “acid,” was later seen as a threat to society and declared a Schedule I substance in 1970. This means that it is illegal for recreational, medical and research use in the United States.

At present, there is interest in finding out if psychedelics like LSD can treat mental health issues, like anxiety and depression, and substance use disorders. This interest has grown after psilocybin, the active compound found in magic mushrooms, has shown promising results in treating addiction and depression, anxiety and Post-traumatic stress disorder (PTSD). If you want to learn about psilocybin as a treatment, read this article.


What is LSD exactly?

LSD is a powerful psychedelic, which are substances that can alter the way people experience the world. It can impact one’s mood, senses and attention. LSD can be created in a lab but also grows naturally in ergot, a fungus that infects rye.

LSD is considered a classic hallucinogen, along with psilocybin, ayahuasca and mescaline. These psychoactive or mind-altering substances are believed to work mostly by affecting the way serotonin in the brain functions. Serotonin is a chemical in the brain directly linked to our feelings of satisfaction, happiness and optimism. Many modern medications to treat depression act by increasing the amount of serotonin available to brain cells.

How does LSD affect people?

LSD can make:

What does LSD look like?

In its pure state, LSD is a white, odorless liquid with a slightly bitter taste, although it is rarely sold in this form. It’s more common that drops of LSD are dried on blotting paper. The blotting paper is divided into small squares and decorated with designs such as a smiley face. It can also be sold in tablets or capsules.[2] LSD may also be dissolved into liquid sold as small breath-freshener droppers or applied to various products including gum, candy, cookies and sugar cubes.

On the streets and in popular culture, LSD is known as acid but also as tabs, microdots, dots, window panes or mellow yellow.[3]

Why is there growing interest in LSD?

Recently, there has been a lot of focus on studying LSD as a treatment for mental health disorders and addiction. Studies have shown that LSD can increase the connections between different parts of the brain that are usually not well connected. This effect can last for a few days and has been linked to greater creativity, imagination, and insights.[4]

In one study involving patients with anxiety associated with a life-threatening disease, anxiety was reduced for two months after two doses of LSD. In a follow-up study after one year, people in the clinical trial consistently reported feeling freer, less anxious and an increased sense of well-being.[5]

People who have been in clinical trials have reported:[6][7]

These effects, combined with a greater ability to process emotions, may be helpful in LSD-assisted psychotherapy. However, LSD also reduced the ability to identify sad and fearful faces and complex emotions.[8]
Given the general positive outcomes, a growing number of people across the world are using psychedelics outside of clinical settings. This use happens even though research on the medical use of psychedelics is still scarce.[9]

Is LSD legal or illegal?

LSD is not legal in the United States. Researchers have not been granted the ability to conduct trials for scientific purposes by the federal government. So, its potential for treatment is far less explored than in the case of other psychedelics.

However, LSD was studied somewhat from the 1950s to the 1970s before it was placed on Schedule 1.  During this time, it was researched as a treatment for anxiety, depression, psychosomatic (mind/body) diseases and addiction. Its effectiveness has not been fully proven by more recent scientific research.[10]

In the United States, the Maryland Psychiatric Research Center in Baltimore conducted clinical trials from 1963 until 1976, when 700 patients were treated for anxiety and depression, with results generally considered encouraging.[11] This institution was the last to stop its clinical research with LSD in the United States, because of tighter regulations to conduct trials on people and lack of federal funding.[12]

In the last decade, clinical research with LSD restarted in Europe, with trials in Switzerland and the United Kingdom. Apart from its healing potential, LSD has been useful, when combined with modern brain imaging methods, to understand how the brain operates.[13]

What is LSD said to be good for?

Although several studies involving LSD were done in the mid-20th century, only a handful of experimental trials have been conducted in the last 25 years. According to the review of the most rigorous research, there is evidence that LSD may be helpful as a treatment for alcohol use disorder.[14]

The results also suggest that, in general, a few single doses of LSD in a medical setting may be helpful for patients with anxiety related to severe illness, depression, or addiction.[15] One study concluded that LSD produced long-lasting and notable reductions in anxiety and depression symptoms for up to 16 weeks.[16]

Although these results are encouraging, more research is needed to confirm these outcomes and the healing potential of LSD in psychiatry.[17] In 2022, a review of the scientific trials of psychedelic medications studied for mental health and substance use disorders raised concerns about LSD and its potential as a treatment. The reviewers considered that until then no LSD trials had met the expected scientific standards.[18]

However, in March 2024, a research program involving an LSD formulation to treat generalized anxiety disorder was granted breakthrough status by the US Food and Drug Administration. This means that this LSD formulation was shown to be effective in clinical trials and that its development and review as a potential treatment could be expedited. According to the biopharmaceutical company that conducted the trials, a single dose of its LSD formulation led almost half of the participants (48%) to show no symptoms of generalized anxiety disorder after 12 weeks following the drug’s administration. These preliminary results still have to be confirmed in several larger trials in order for the formulation to be approved as a treatment. [19]

What about microdosing? What it is used for?

LSD is such a potent psychedelic that it has effects in very small amounts. A recreational dose of LSD is generally between 100 and 200μg (1μg is one millionth of a gram) or 0.1 to 0.2 mg. Compare this to the 325 mg of active ingredient in a regular aspirin. So, a microdose is a very tiny amount of LSD, between 10 and 20μg.

According to several recent studies conducted in Europe, people who took LSD microdoses reported improvement in their mood, creativity and thinking. It also reduced anxiety and increased energy and friendliness.[20]

In one of these studies, researchers were able to measure increased changes in a blood marker related to neuroplasticity, which is the ability of the brain to rewire itself. These changes are often needed in order to effectively treat depression.[21]

However, some researchers have found similar positive outcomes of microdosing with LSD in individuals who were given placebos. Placebos are substances that cause no effect on the body – like a sugar pill. These results have led some to claim that the positive effect of microdosing is only the belief  that there will be improvement instead of the actual microdose.[22]

In any case, experts agree that the promising early results warrant more research on microdosing.

What are the risks?

As with any substance there can be risks. For LSD they include:

As a recreational drug, there is no evidence that LSD causes physical dependence. Many people who use it claim to experience an improvement in mood after the “high” has worn off. Others report that coming down leave them feeling agitated, anxious, and a bit “off.”[27]

There are no known withdrawal symptoms if a person stops taking it. LSD has very low toxicity, even at very high doses, which means it does not cause damage to the body or the brain.[28]

However, LSD does produce tolerance, so some people who take the drug repeatedly must take higher doses to achieve the same effect.

What if my child is using LSD?

Although LSD does not cause addiction or physical or mental harm, it is important to note that, as with any other illegal substance, nobody really knows what’s in a product that is not regulated. So, many substances sold as LSD may have very different ingredients, increasing their risk significantly. To learn more about counterfeit pills and its risks, read this article.

If you suspect your child is using LSD or any other substance, talk with them. Here are some techniques to help you establish positive and fruitful communication.

Reducing the risks of using LSD

If you think that your loved one is using LSD, talk to them. Here are some useful ideas about how to approach the conversation.

The best course of action is not to use LSD. If your loved one insists on using it despite its downsides, consider sharing ways to reduce the risks. Remember that the most important thing is to keep them safe. Reducing the risks is not encouraging the use of substances. Instead it recognizes that there are ways to minimize the consequences of LSD use.

Here are some risk reduction measures you may wish to share with your loved one. The recommendations are from a survey of people who use LSD and what they do to reduce risks:[29]

What if you or your loved one decide to try LSD?

If you decide to try LSD in the United States for treatment of mental health and substance use problems you can apply to become part of a research study. Check out this database of privately and publicly funded clinical trials.