Ketamine is a synthetic drug, designed and first made in a laboratory in 1962. It does not come from a plant, animal, or mineral the way morphine comes from poppies or penicillin comes from mold. That said, a surprising 2020 discovery found that a soil fungus can produce ketamine on its own, which complicates the clean “purely synthetic” label. The full story is more interesting than either category alone.
How Ketamine Was Invented
Ketamine’s origin traces back to a deliberate pharmaceutical project, not a lucky find in nature. In 1962, chemist Calvin Stevens, working at the Parke-Davis pharmaceutical company, synthesized ketamine as a derivative of phencyclidine (PCP).1PubMed. History of Ketamine: An ancient molecule that is still popular today PCP had shown promise as an anesthetic but turned out to be a terrible candidate for human use: patients waking up from PCP anesthesia experienced prolonged delirium, hallucinations, and symptoms resembling schizophrenia.2Acta Neuropsychiatrica. A brief history of antidepressant drug development: from tricyclics to beyond ketamine Parke-Davis wanted the anesthetic benefits of PCP without the nightmarish aftermath, so they tasked their chemists with creating shorter-acting analogs that would wear off before those side effects set in.3Frontiers in Human Neuroscience. Ketamine: 50 Years of Modulating the Mind
Stevens succeeded. Ketamine proved to be a powerful anesthetic with a much shorter duration of action than PCP. The emergence delirium still occurred but was far milder and briefer. Within a few years, ketamine entered human clinical trials and was approved for medical use. Its safety profile was good enough that it became a battlefield anesthetic during the Vietnam War, and it remains on the World Health Organization’s List of Essential Medicines today. None of this happened by extracting a compound from a natural source. Ketamine was built from scratch on a lab bench, one chemical reaction at a time.
The Fungus That Makes Ketamine
In 2020, a research team studying the soil fungus Pochonia chlamydosporia reported something unexpected. When they separated and purified chemical compounds from extracts of this fungus, they identified the major substance in certain sub-fractions as ketamine.4PubMed Central. Ketamine can be produced by Pochonia chlamydosporia: an old molecule and a new anthelmintic? This was the first report of any organism in nature producing ketamine without human intervention.
Pochonia chlamydosporia is not some exotic organism. It is a common fungus found in soils around the world, primarily known for its ability to parasitize the eggs of plant-parasitic nematodes, which makes it useful in biological pest control. The researchers were investigating what chemical compounds the fungus uses to kill parasitic worms when they stumbled onto something already sitting in pharmacy shelves worldwide.
This discovery matters because it blurs the line between “synthetic” and “natural.” Ketamine was invented in a lab with no knowledge that any organism produced it. Decades later, nature turned out to have arrived at the same molecule independently. The fungal ketamine is chemically identical to the lab-made version. It is worth noting, though, that the discovery has not yet been widely replicated by other research groups, and the quantities involved are tiny compared to industrial production. No one is harvesting fungal ketamine for medical use or likely ever will. The finding is scientifically fascinating but practically irrelevant to the drug supply.
Why the “Synthetic” Label Still Applies
Even with the fungal discovery, calling ketamine a synthetic drug remains accurate for almost every context a person would encounter. Every vial of ketamine used in hospitals, veterinary clinics, and mental health treatment centers worldwide is produced through chemical synthesis in a factory. The molecule is built through a series of carefully controlled reactions, not harvested from any organism.
Modern industrial synthesis of ketamine involves multiple steps. One recent process development described using specific chemical reagents to achieve a bromination reaction with a conversion rate of about 99%, followed by a methylamination step that shortened the reaction time from 80 hours down to 15 hours while maintaining high purity.5Organic Process Research & Development. Optimized Process and Quality Evaluation for Ketamine Hydrochloride The goal is to produce pharmaceutical-grade ketamine at industrial scale with consistent quality, something that cannot be done by growing fungus in a petri dish.
This is different from drugs like aspirin, which was originally derived from willow bark but is now made synthetically. Aspirin’s story starts in nature and moves to the lab. Ketamine’s story starts in the lab, and the natural occurrence was only noticed afterward. The practical supply chain has always been, and remains, entirely synthetic.
How Ketamine Compares to Other Dissociatives in Terms of Origin
Ketamine belongs to a class of drugs called dissociative anesthetics, which produce feelings of detachment from the body and environment. Not all dissociatives share ketamine’s synthetic pedigree. Salvinorin A, for instance, is a naturally occurring dissociative compound found in the plant Salvia divinorum. Despite both being described as dissociatives, salvinorin A and ketamine work through entirely different mechanisms. In studies where primates were trained to recognize the effects of salvinorin A, the animals did not generalize those effects to ketamine, meaning the two drugs feel fundamentally different from the inside.6PubMed Central. The discriminative effects of the kappa-opioid hallucinogen salvinorin A in nonhuman primates: dissociation from classic hallucinogen effects
PCP, ketamine’s parent compound, is also fully synthetic. It was first made in a lab in the 1950s, and no natural source has ever been identified for it. Methoxetamine, deschloroketamine, and the other designer dissociatives that have appeared in recreational drug markets over the past two decades are all synthetic as well. Among the commonly discussed dissociatives, natural origin is actually the exception, not the rule. Ibogaine, a naturally occurring compound from the African shrub Tabernanthe iboga, is sometimes grouped loosely with dissociatives, but its pharmacology is complex and doesn’t fit neatly into the category. The upshot is that if you encounter ketamine or anything closely related to it, you are dealing with a molecule that was made in a lab.
The Two Mirror-Image Forms
One detail that underscores ketamine’s synthetic nature is the precision with which chemists can now produce specific versions of the molecule. Ketamine exists as two mirror-image forms, called enantiomers. Standard ketamine is a 50/50 mixture of both forms. The S-form (esketamine) has been found to produce roughly three times stronger pain relief and about one and a half times greater anesthetic effect compared to the R-form (arketamine).7PubMed Central. Ketamine, Esketamine, and Arketamine: Their Mechanisms of Action and Applications in the Treatment of Depression and Alleviation of Depressive Symptoms
Separating these two forms requires sophisticated chemistry. One published method uses a chiral resolution approach with L-(+)-tartaric acid to isolate pure S-ketamine from the racemic mixture.8PubMed. Process for (S)-Ketamine and (S)-Norketamine via Resolution Combined with Racemization This level of molecular control is only possible through synthetic chemistry. The FDA-approved nasal spray for treatment-resistant depression (marketed as Spravato) uses pure esketamine, not the standard racemic mixture. Researchers are also investigating arketamine, the R-form, for its own potential antidepressant properties with possibly fewer dissociative side effects. Whether either enantiomer ultimately proves superior for depression treatment is still being worked out, but the point is that synthesizing ketamine in a factory allows manufacturers to produce whichever form is needed at whatever purity the application demands.
What Happens to Ketamine in the Body
Once ketamine enters your body, your liver breaks it down primarily into norketamine, an active metabolite that retains some anesthetic and psychoactive properties of its own.9PubMed Central. Metabolism and metabolomics of ketamine: a toxicological approach This is one reason ketamine’s effects can linger even as blood levels of the parent drug drop. Norketamine is further broken down into hydroxynorketamines, which researchers have found can activate certain signaling pathways in the brain, particularly in the prefrontal cortex.10PubMed Central. (R,S)-Ketamine metabolites (R,S)-norketamine and (2S,6S)-hydroxynorketamine increase the mammalian target of rapamycin (mTOR) function These downstream metabolites make things more interesting for researchers, since ketamine’s therapeutic benefits for depression might not come entirely from the drug itself but partly from what your body converts it into.
Eventually, the hydroxylated metabolites are tagged with glucuronic acid, a molecular label that makes them water-soluble enough to be filtered out by the kidneys. This is standard drug metabolism: fat-soluble compounds get processed into water-soluble ones so you can urinate them out. The cascade of metabolites is relevant because some of them end up in the environment, a topic covered below.
Ketamine in the Water Supply
Because ketamine and its metabolites are excreted in urine, they can show up in wastewater and eventually in natural bodies of water. One study that surveyed 20 natural water bodies, effluents from 13 hospitals, two wastewater treatment plants, and a water supply plant found ketamine at concentrations as high as 10 micrograms per liter. Norketamine showed up consistently at similar levels.11Water Research. Ketamine and the metabolite norketamine: Persistence and phototransformation toxicity in hospital wastewater and surface water
These concentrations are far too low to produce any pharmacological effect in a person drinking the water, but the concern is about aquatic organisms that live in it continuously. Ketamine and norketamine have been detected at meaningful levels in effluents and aquatic environments, yet the ecological effects on organisms like water fleas and fish remain poorly understood.12PubMed. Ecotoxicological effect of ketamine: Evidence of acute, chronic and photolysis toxicity to Daphnia magna Standard wastewater treatment processes do not fully remove ketamine, so in areas with heavy hospital use (ketamine is widely used in surgical and emergency settings), it accumulates in downstream waterways.
This environmental footprint is entirely a consequence of ketamine being a mass-produced synthetic drug used in hospitals worldwide. The trace amounts that might be produced by soil fungi would never reach detectable levels in water. What ends up in rivers is human-administered ketamine, metabolized and flushed. It is a small but growing area of environmental pharmacology, and regulators have not yet established clear guidelines for acceptable ketamine levels in surface water.
Common Misconceptions About Ketamine’s Origins
A few misunderstandings circulate online about where ketamine comes from, and they are worth clearing up.
The first is the idea that ketamine is “natural” in the way that psilocybin or cannabis is natural. This comes from people encountering the Pochonia chlamydosporia research and concluding that ketamine has always been a natural product that humans merely rediscovered. The timeline tells a different story. Ketamine was invented in 1962 with no awareness that any organism produced it. The fungal discovery came nearly 60 years later, and it does not change the fact that all medical and recreational ketamine is made synthetically. Calling ketamine “natural” based on the fungus finding would be like calling nylon natural because a chemist someday found a spider that produces an identical polymer. The origin of the supply is what matters for practical classification.
The second misconception is that ketamine is “made from PCP” in a way that implies PCP is somehow in the final product. Ketamine was derived from PCP in the sense that chemists used PCP’s molecular structure as a starting blueprint and then modified it. The finished ketamine molecule is a distinct chemical compound. Taking ketamine does not expose you to PCP. They share a structural family resemblance, much like ibuprofen and naproxen are both related anti-inflammatory drugs but are not the same molecule.
A third point of confusion involves “special K” and veterinary use. Some people believe ketamine is exclusively an animal tranquilizer, which leads them to treat it as something fundamentally different from human medicine. In reality, ketamine has been approved for human anesthesia since the 1970s and is used in emergency rooms, operating rooms, and psychiatric clinics worldwide. The veterinary connection is real but not exclusive. Ketamine is used in veterinary medicine because it is safe, effective, and does not require the sophisticated monitoring equipment that many other anesthetics demand. This practical advantage made it popular with veterinarians, but it was always a human drug too.
Why It Matters Whether a Drug Is Natural or Synthetic
People often assume that “natural” means safer or gentler, while “synthetic” implies something harsher or more dangerous. Neither assumption holds up. Botulinum toxin is natural and is one of the most lethal substances known. Acetaminophen is synthetic and is one of the safest pain relievers when used at appropriate doses. The origin of a molecule tells you almost nothing about its safety profile.
For ketamine specifically, whether it is natural or synthetic has no bearing on its effects, risks, or therapeutic potential. The molecule is the molecule regardless of whether it was assembled in a reactor or by a fungal enzyme. What matters is the dose, the route of administration, the clinical context, and the patient’s individual physiology. The esketamine nasal spray approved for treatment-resistant depression is no more or less “chemical” than the racemic ketamine used in operating rooms; they differ in molecular configuration, not in naturalness.
Where the natural-versus-synthetic question does become practically interesting is in drug discovery. The fact that a soil fungus independently evolved the ability to produce ketamine raises questions about what other pharmaceutical compounds might be lurking in organisms that nobody has thought to look at carefully. Fungi, plants, and marine organisms have historically been rich sources of drug leads, from the cholesterol-lowering statins (originally derived from a mold) to the cancer drug paclitaxel (from Pacific yew bark). The ketamine-producing fungus may be less useful as a production method and more useful as a clue: if evolution arrived at this molecule for its own purposes, perhaps the biological pathways that make it could point toward new compounds worth investigating.