Breaking down LSD to unlock new therapeutic discoveries

In a result that is already sending ripples through the fields of neuroscience and drug design, chemists at the University of California, Davis have performed something akin to a molecular autopsy on lysergic acid diethylamide — better known as LSD — and lived to publish the findings. By systematically dismantling the most famous psychedelic molecule in history, piece by piece, and then rebuilding simplified versions of it in the laboratory, the research team has identified which parts of the compound drive its mind-altering hallucinations and which parts hold the keys to its promising therapeutic effects. The study, published in the Proceedings of the National Academy of Sciences, does more than dissect an iconic drug: it hands the emerging field of psychedelic medicine a set of new, more workable starting points for designing the next generation of neurotherapeutics.

Led by David E. Olson, director of the Institute for Psychedelics and Neurotherapeutics and a professor of chemistry and of biochemistry and molecular medicine at UC Davis, the team approached LSD not as an untouchable chemical monument but as an engineering problem. LSD’s core structure, known as the ergoline scaffold, consists of four fused ring-like shapes that form the molecule’s rigid backbone. That complexity has long been both the source of LSD’s remarkable pharmacology and the bane of medicinal chemists hoping to improve upon it. “We’ve known the structure of LSD for a long time, but the complexity of its core has really limited our ability to engineer optimized drugs based on its structure,” Olson explained. “If you can only modify a couple of spots, you’re limited in what you can do.” With so few chemically addressable positions on the fused ring system, researchers have historically been stuck tweaking the periphery of the molecule rather than interrogating its architectural logic.

The conceptual breakthrough of the new study lies in its willingness to ask a deceptively simple question: what happens if you start deleting rings? Olson framed the ergoline core as a molecular hybrid of the two great families of psychedelic compounds — the tryptamine family, which includes psilocybin and DMT, and the phenethylamine family, which includes mescaline and MDMA. “If you take those structures and overlap them, they basically produce LSD,” he noted. “The big question is, which one of those is more important for the hallucinogenic effects of LSD?” The molecule, in other words, wears the chemical fingerprints of both lineages simultaneously, and no one had definitively established which contribution mattered most for the psychedelic experience — and, by extension, whether the two could be separated.

The answer turned out to be the phenethylamine-like traits. When the researchers surgically removed the tryptamine-like portions of the molecule, the resulting simplified analogues retained their ability to stimulate the 5-HT2A serotonin receptor — the receptor widely regarded as the primary driver of psychedelic hallucinations. But when other segments of the ergoline scaffold were removed, a striking and clinically valuable trade-off emerged: hallucinogenic activity diminished, and so did cardiotoxicity. That toxicity is mediated by the 5-HT2B receptor, whose chronic activation is associated with potentially fatal cardiac valvulopathy — the same liability that has doomed several once-promising drug candidates, including the fenfluramine component of the notorious fen-phen weight-loss combination. Any psychedelic-inspired medicine intended for repeated, long-term dosing must therefore steer clear of 5-HT2B, and the UC Davis strategy offered a systematic route to doing exactly that.

To map the functional landscape of the ergoline scaffold in full, the team synthesized nine modified versions of LSD’s core, each representing a different degree of molecular deconstruction. The work is a tour de force of synthetic chemistry, because stripping rings from a fused polycyclic system while preserving receptor-binding geometry is far harder than it might sound. Each deletion changes the molecule’s shape, rigidity, and electronic distribution, all of which influence how it docks into serotonin receptors. Among the nine analogues, two compounds emerged with substantially improved safety profiles — reduced hallucinogenic potential paired with reduced cardiotoxicity. The researchers named them UCD0094 and UCD0076, and both now stand as proof that LSD’s therapeutic signal can be uncoupled from its psychedelic noise.

The second compound delivered an even more surprising twist. UCD0076 displayed a strong preference for binding the 5-HT2C receptor, a serotonin receptor subtype that has attracted growing pharmaceutical interest for reasons that have nothing to do with psychedelia. When the compound was tested in standard mouse behavioral assays, it produced antipsychotic-like effects rather than psychedelic ones. “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,” Olson said. He pointed out that compounds activating 5-HT2C receptors are currently being explored as treatments not only for schizophrenia but also for epilepsy and substance use disorders. “This is a great starting point for those conditions.” The irony is hard to miss: a molecule distilled from one of the most famously hallucinogenic substances on Earth may point the way toward drugs designed to quell psychosis, not provoke it.

The broader context for this work is the intense scientific and commercial race to harness psychedelics for psychiatry. A wide range of neuropsychiatric and neurodegenerative diseases — depression, anxiety, PTSD, and others — are characterized by the withering of neural connections, and psychedelics have shown a remarkable ability to spur the growth of neurons and strengthen the connections between them, a process Olson and others refer to as psychoplastogenic or neuroplastic effects. The obstacle has always been the hallucinations. Classic psychedelics like LSD and psilocybin produce profound subjective experiences that require supervised clinical sessions, driving up the cost, complexity, and regulatory burden of therapy. The holy grail of the field is a non-hallucinogenic compound that preserves the neural-repair benefits — a goal this deconstruction strategy brings measurably closer.

That is what makes the “molecular autopsy” approach so consequential for drug discovery. Rather than accepting LSD as an indivisible gift from nature, the UC Davis team treated it as a puzzle to be solved, testing hypotheses about structure-function relationships that had remained speculative for decades. “We found that when you start deleting portions of LSD’s molecular structure, you can retain some properties and eliminate others,” Olson said. “By systematically deleting these rings, we can figure out what rings are important for what effects.” The method generalizes: the same systematic deconstruction logic could now be applied to other complex natural-product psychedelics, such as ibogaine or salvinorin A, whose formidable molecular architecture has similarly resisted optimization. In effect, the study converts LSD from a single, pharmacologically messy endpoint into a family of chemically tractable launchpads.

For the pharmaceutical industry, the practical implications are immediate. Simplified analogues like UCD0094 and UCD0076 are smaller, more synthetically accessible molecules than LSD itself, meaning they can be manufactured, modified, and patented with far greater ease. Their defined receptor-selectivity profiles — retaining activity at 5-HT2A while shedding 5-HT2B in one case, or pivoting entirely toward 5-HT2C in the other — give medicinal chemists precisely the kind of structure-activity data needed to begin iterative optimization. A 5-HT2C agonist derived from LSD, for example, would enter a therapeutic space where selectivity is everything: the receptor is implicated in appetite regulation, mood, and impulse control, and untoward activity at 5-HT2A or 5-HT2B has historically limited candidate drugs. Starting from a deconstructed psychedelic offers a pharmacological foundation that conventional medicinal chemistry might never have reached on its own.

The study also carries a symbolic weight for a field still fighting for scientific legitimacy. For half a century, research on LSD was effectively frozen by restrictive drug policies, and only in recent years has the molecule been examined with modern tools of pharmacology, receptor structural biology, and behavioral neuroscience. The UC Davis findings demonstrate that LSD is not merely a relic of the 1960s counterculture but a rich chemical resource whose full therapeutic potential may still be hiding in its substructures. The deconstruction revealed that the molecule’s celebrated psychedelic identity and its medicinally useful properties are not inextricably fused — they are separable, and once separated, each can be pursued on its own terms.

Funding for the research came from the National Institutes of Health, the National Science Foundation, the Camille and Henry Dreyfus Foundation, and the Pershing Square Foundation — a mix of federal agencies and private philanthropy that reflects the unusual position psychedelic science now occupies: rigorous academic chemistry aimed at one of the most commercially and clinically dynamic frontiers in medicine. Whether UCD0094, UCD0076, or their descendants ultimately reach the clinic remains to be seen; both compounds will need extensive preclinical safety testing, optimization of pharmacokinetics, and eventually carefully designed human trials. But the conceptual achievement is already secure. By taking LSD apart ring by ring, the UC Davis team has shown that the road to safer, more targeted neurotherapeutics may run straight through the wreckage of the most famous psychedelic molecule ever synthesized — and that what remains after the autopsy may be more valuable than the original.