Scientists Strip LSD Apart And Discover What Keeps Its Psychedelic Effects Alive

Scientists have been pulling apart one of the most famous psychedelic molecules in chemistry, and the strangest discovery came when there was barely any LSD left. A team led by UC Davis researcher David E. Olson removed structural pieces from LSD one by one, then tested what the resulting molecules could still do.

Some simplified versions retained psychedelic activity, while another appeared to lose the trip while keeping properties researchers are interested in for psychiatric disorders. The work gives scientists a molecular map showing which parts of LSD appear to control different biological effects.

Researchers Started Cutting LSD Apart

LSD has a notoriously complicated molecular structure, which creates a problem for researchers trying to turn its biological effects into useful medicines. “If you can only modify a couple of spots, you’re limited in what you can do,” Olson said, according to UC Davis.

Instead of making small changes to the intact molecule, Olson and his colleagues took a more radical approach. They built nine simplified versions of LSD, with each molecule missing different structural components.

Some retained three of LSD’s four rings, while others had only two. One was reduced to a single ring, allowing researchers to compare how much biological activity survived as the structure became progressively simpler.

The Psychedelic Effect Survived an Unexpected Cut

The first major surprise involved the parts of LSD most closely associated with its psychedelic activity. LSD’s structure contains features resembling two familiar chemical families, tryptamines and phenethylamines, while serotonin and psilocybin contain tryptamine-related structures.

That made the tryptamine-like portion an obvious candidate for the part responsible for LSD’s hallucinogenic effects. The experiments pointed elsewhere, because removing those portions still left compounds capable of activating the 5-HT2A receptor.

That receptor is strongly associated with the psychedelic effects produced by LSD and related compounds. “If you delete certain structural elements of LSD, you can still produce psychedelic effects,” Olson explained.

The finding suggested that the phenethylamine-like features were doing much of the work behind the psychedelic response. That gave the researchers a clearer target as they continued simplifying the molecule.

Two Rings Were Enough To Keep The Trip Alive

The team kept removing structural components to see how far the psychedelic activity could be pushed. In mice, researchers can measure a characteristic behavior called the head twitch response, which is commonly used as an indicator of psychedelic-like activity in rodents.

The smallest structure that still produced the response contained two rings corresponding to positions known as A and D in the original LSD structure. When researchers simplified the molecule beyond that point, the psychedelic-like response disappeared in the mouse experiments.

The Chemical Boundary Was More Complicated

The result does not establish a universal point where LSD suddenly “stops being LSD,” because chemical identity and biological activity are separate questions. What the experiments showed was more specific: certain structural features were sufficient to preserve psychedelic-like activity in mice.

That distinction matters because the researchers were not simply trying to create a smaller version of LSD. They wanted to discover which parts could be removed while leaving useful biological effects behind.

One Stripped-Down Molecule Did Something Completely Different

The most intriguing result appeared after researchers removed even more of the original structure. One compound, called UCD0076, showed little interaction with the 5-HT2A receptor and instead acted on 5-HT2C, another serotonin receptor involved in processes connected to mood and dopamine regulation.

In mice, UCD0076 produced no head twitch response, and researchers then tested whether it could interfere with the response produced by a known hallucinogen. The compound blocked the head twitch response and also reduced amphetamine-driven hyperactivity in another mouse experiment.

Olson described the result as an unexpected transformation. “It’s interesting that you could take LSD’s structure, chop off a part of it and you’re left with a molecule that is fundamentally antipsychotic,” he said, adding that it was “a great starting point for those conditions.”

The finding does not establish that UCD0076 is an antipsychotic treatment for people. Instead, it gives researchers a new compound to investigate as they search for medicines that can influence relevant brain pathways without producing psychedelic effects.

Another Molecule Lost Some Of LSD’s Risky Activity

The researchers also identified another simplified compound, UCD0094, that could prove useful for a different reason. UCD0094 is essentially LSD with one ring removed, and that relatively small structural change sharply reduced its activity at both 5-HT2A and 5-HT2B receptors.

The compound retained much of its activity at 5-HT2C. The 5-HT2B receptor has attracted particular attention in psychedelic drug development because activating it has been associated with heart-valve damage.

That makes receptor selectivity an important consideration when researchers evaluate compounds related to psychedelic drugs. UCD0094 therefore offered an intriguing combination in the early experiments, with reduced activity associated with hallucination and 5-HT2B activation while retaining activity at another serotonin receptor.

Both UCD0094 and UCD0076 were flagged by the researchers as compounds with potentially improved safety profiles. Those findings remain preliminary because the compounds have not been tested in humans.

The Biggest Caveat Is Sitting In The Lab

The results are interesting, but the experiments have not reached human testing. The compounds were evaluated using engineered cells and mice, and no human has taken UCD0094 or UCD0076 based on the work described here.

Several limitations are especially important: mouse behavior cannot reproduce human perception, the compounds were not all tested in purified mirror-image forms, and LSD interacts with dopamine and adrenergic receptors that were outside the main scope of the study. The researchers also found that UCD0179 produced potent hallucinogenic activity in cells but failed to produce the same effect in mice.

That last result shows why moving from a laboratory dish to a living organism is such a major step. A molecule can interact strongly with a target in engineered cells and still fail to reach or affect that target in the body.

Human LSD Research Is Moving In A Different Direction

While researchers are stripping pieces away from LSD in the laboratory, other teams are studying the complete molecule in people. MindMed’s MM120, a proprietary form of LSD, has been investigated in clinical trials for generalized anxiety.

According to the supplied source material, nearly half of participants receiving the two highest doses were in remission at the three-month follow-up, while lower doses did not outperform placebo. Another investigational treatment, DT120, was tested in a Phase 3 trial involving 149 adults with major depression.

At six weeks, the treatment group improved by roughly eight additional points compared with placebo on a standard depression rating scale. The treatment remains investigational and has not been approved by the FDA.

Psychiatrist Joao L. de Quevedo described the findings for UTHealth Houston as part of an increasingly recognized biological theme involving “the promotion of adaptive neuroplasticity.” That raises a central question for psychedelic medicine: how much of the therapeutic effect depends on the psychedelic experience itself?

The Real Prize May Be LSD Without The LSD Experience

The new research offers scientists a different way to approach psychedelic drug development. Instead of asking how to make LSD safer while keeping the molecule intact, researchers can ask which structural components are responsible for individual effects.

The experiments suggest that one arrangement can preserve psychedelic-like activity, while another can reduce that activity and alter which serotonin receptors the molecule targets. Remove even more structure, and a compound derived from LSD can begin behaving very differently.

The researchers have not shown that these new compounds can treat depression, anxiety, or psychosis in humans. What they have produced is a detailed set of clues about which pieces of LSD appear to control different effects.

That could give medicinal chemists more freedom to build compounds around specific biological targets rather than carrying the entire LSD structure into every experiment. For a molecule that has resisted easy modification for decades, knowing what can be removed may prove just as valuable as knowing what has to stay.

The strange part of the experiment is that the less LSD the researchers had left, the more clearly they could see what each piece was doing. Somewhere between the four-ring molecule and the stripped-down compounds, the famous psychedelic stopped being the point and became a blueprint.