Yes, people do microdose ketamine, typically through compounded oral formulations prescribed by a provider for at-home use. But the term “microdosing” in the ketamine world is loosely defined and often refers to doses that would more accurately be called “low-dose” or “sub-anesthetic,” ranging from roughly 0.1 to 0.5 mg/kg. Unlike psychedelic microdosing with substances like psilocybin, where the goal is a sub-perceptual dose, most ketamine protocols at these levels still produce noticeable effects like mild dissociation or relaxation.
What “Microdosing” Ketamine Actually Means
There’s no standardized definition of a ketamine microdose. In clinical settings, sub-anesthetic ketamine for depression is most commonly given at 0.5 mg/kg, with some patients responding to doses as low as 0.1 mg/kg. For a 150-pound person, that translates to roughly 7 to 34 milligrams. At-home prescriptions from telehealth companies and compounding pharmacies typically use troches (lozenges) or rapid-dissolve tablets in this general range, though some prescriptions go considerably higher.
People use the term “microdose” to describe taking small amounts on a regular schedule, often several times per week, rather than receiving a single large infusion in a clinic. The intent is usually to manage depression, anxiety, or chronic pain with minimal disruption to daily life. But even at these lower doses, ketamine is psychoactive. Most people feel something: a sense of calm, mild perceptual shifts, or slight detachment that lasts 30 to 60 minutes.
How Low-Dose Ketamine Works in the Brain
Ketamine’s antidepressant effects work through a fundamentally different pathway than traditional antidepressants. Rather than targeting serotonin, ketamine blocks a specific type of glutamate receptor in the brain. Glutamate is the brain’s primary excitatory chemical messenger, and in people experiencing chronic stress or depression, the system that regulates it becomes disrupted. Excess glutamate overstimulates certain receptors, which contributes to the loss of synaptic connections between brain cells.
By temporarily blocking these receptors, ketamine triggers a cascade that promotes the growth of new synaptic connections. It increases levels of a protein called BDNF, which supports the survival and growth of neurons, and activates signaling pathways involved in building new connections between brain cells. This is why ketamine can produce rapid mood improvements, sometimes within hours, compared to the weeks required by conventional antidepressants. The idea behind repeated low dosing is to sustain this process of synaptic repair over time.
What the Evidence Shows for Depression and Anxiety
Most clinical research on ketamine for depression has studied intravenous infusions rather than at-home oral microdosing specifically. However, a proof-of-concept trial using daily oral ketamine at 0.5 mg/kg over 28 days found significant improvements in both depression and anxiety. Anxiety symptoms improved as early as day 3, and depressive symptoms improved significantly by day 14. Those improvements held through the full 28-day trial period. Every participant who completed the study responded to the treatment for both conditions.
That said, this was a small, open-label study with only eight completers and no placebo comparison, which limits how much weight to put on the results. Larger, more rigorous trials of oral ketamine for depression are still limited. Animal research has found that low doses of ketamine can modestly improve motivation and attention, but these effects were largely restricted to subjects that were already performing poorly, suggesting the benefits may be most relevant to people whose cognitive function is impaired by depression rather than healthy individuals looking for a boost.
How At-Home Ketamine Is Taken
Compounded ketamine for home use comes in a few forms. Troches and lozenges are placed under the tongue and held there for at least 10 minutes to absorb through the tissue in your mouth. Whatever remains after that is typically spit out rather than swallowed, which reduces nausea and avoids an unpredictable delayed effect from gut absorption. Rapid-dissolve tablets work similarly but dissolve on top of the tongue within about a minute, after which you swish the saliva around your mouth before swallowing.
Both troches and rapid-dissolve tablets have an absorption rate of roughly 30 to 34%, meaning most of the drug doesn’t actually reach your bloodstream. This is one reason oral doses tend to be numerically higher than IV doses. Effects typically begin about 20 minutes after the tablet dissolves. Most protocols call for use two to three times per week, though some prescribers recommend daily use for a set period. You’re generally advised to be in a calm, safe environment and not drive or operate anything for several hours afterward.
Risks of Regular Ketamine Use
The most well-documented physical risk of chronic ketamine use is bladder damage. Over 25% of recreational ketamine users develop urinary symptoms, and around 20% of frequent users report cystitis-like symptoms compared to about 7% of infrequent users. The severity correlates directly with dose and frequency. One study found that 75% of chronic users showed visible bladder damage on biopsy, including loss of the bladder’s protective lining and tissue swelling. Symptoms include urinary urgency, painful urination, and blood in the urine, and in severe cases, the damage can progress to scarring of the bladder wall, narrowing of the ureters, or kidney failure. Symptoms generally improve when ketamine use stops.
Most of this bladder data comes from recreational users taking much higher doses and more frequently than a clinical microdosing protocol. Whether low therapeutic doses on a two-to-three-times-per-week schedule carry meaningful bladder risk isn’t well established, but the dose-dependent nature of the damage means the risk isn’t zero with any regular use.
Tolerance is another concern. Ketamine tolerance builds in a dose-dependent manner, and over time, some users need dramatically higher amounts to achieve the same effect, with reports of up to a 600% increase over the initial dose. Withdrawal symptoms can include increased anxiety, depression, and cravings, similar to opioid withdrawal. The risk of dependence is highest at higher doses, but any regular use creates some potential for psychological reliance, particularly since the drug produces rapid relief from emotional pain.
Regulatory Status and Safety Oversight
Ketamine itself is not FDA-approved for any psychiatric condition. The only FDA-approved ketamine-related treatment for depression is Spravato (esketamine), a nasal spray that uses one of ketamine’s two mirror-image molecules. Spravato is restricted to certified healthcare settings where patients must be monitored for at least two hours after each dose, due to risks of sedation, dissociation, and misuse potential.
Compounded ketamine products, including the troches and lozenges prescribed through telehealth platforms, have not been evaluated by the FDA for safety, effectiveness, or quality. In October 2023, the FDA issued a specific warning about potential risks associated with compounded ketamine products for psychiatric disorders. The agency has also noted that animal studies with racemic ketamine (the form used in compounding) have shown brain lesions in rodents, a finding not seen with esketamine. Whether this applies to humans is unknown.
This creates an unusual situation: thousands of people are using compounded ketamine at home under a prescriber’s guidance, but without the safety controls that the FDA requires for the approved version of a very similar drug. The quality of compounded products can also vary between pharmacies, since they aren’t subject to the same manufacturing standards as FDA-approved medications. If you’re considering this route, the prescriber’s experience with ketamine, their monitoring protocols, and the compounding pharmacy’s reputation all matter significantly.