Ketamine itself has not been approved by the FDA for any psychiatric condition, including depression. What the FDA did approve, in 2019, was esketamine, a chemical cousin of ketamine delivered as a nasal spray under the brand name Spravato, specifically for treatment-resistant depression. That one-word difference between “ketamine” and “esketamine” creates enormous confusion, because the two drugs share a family tree but have followed completely different regulatory and commercial paths. Meanwhile, generic ketamine is administered off-label for depression in hundreds of clinics across the United States, operating in a gray zone that the FDA has publicly flagged with safety concerns.
What the FDA Actually Approved
Ketamine has been an FDA-approved anesthetic since 1970. For more than five decades, its legal standing in medicine has been as a tool for putting people under during surgery and certain painful procedures. It has never received FDA approval for depression, anxiety, PTSD, or any other psychiatric use. When clinics advertise “FDA-approved ketamine treatment for depression,” they are either being imprecise or deliberately misleading.
Esketamine, marketed as Spravato, received FDA approval in 2019 for patients with treatment-resistant depression, meaning people whose symptoms have not improved after trying at least two different antidepressants.1PubMed Central. Ketamine and Esketamine in Clinical Trials: FDA-Approved and Emerging Indications, Trial Trends With Putative Mechanistic Explanations It later gained a supplemental approval for adults with major depressive disorder who have active suicidal thoughts or behavior. Spravato is administered as a nasal spray in a certified healthcare setting under a restricted distribution program called a Risk Evaluation and Mitigation Strategy (REMS), which means you cannot simply pick it up at a pharmacy and take it at home.
Ketamine and Esketamine Are Not the Same Drug
Ketamine as it has existed for decades is a racemic mixture, meaning it contains equal amounts of two mirror-image molecules: (S)-ketamine and (R)-ketamine. Esketamine is purely the (S)-ketamine half. The (S) form binds to the brain’s NMDA receptors roughly three to four times more strongly than the (R) form, which is one reason the pharmaceutical company developing Spravato chose to isolate it rather than use the full mixture.2PubMed Central. Ketamine: A tale of two enantiomers
Whether that stronger receptor binding actually translates to better antidepressant results is a separate question, and one that researchers are still working through. A network meta-analysis comparing the two found that intravenous racemic ketamine was significantly more effective and more acceptable to patients than intranasal esketamine.3PubMed. Comparative efficacy, tolerability and acceptability of intravenous racemic ketamine with intranasal esketamine, aripiprazole and lithium as augmentative treatments for treatment-resistant unipolar depression A separate systematic review pooling observational data from over 900 patients found that response and remission rates were slightly higher for IV ketamine than intranasal esketamine, though the differences were not statistically significant.4PubMed Central. Intravenous ketamine versus esketamine for depression: a systematic review and meta-analysis In other words, the FDA-approved version may not be the most effective form of the drug, which is part of why the off-label ketamine landscape exists at all.
Why Ketamine Is Used Off-Label for Depression
The FDA has not approved racemic ketamine for depression, but that does not make it illegal for doctors to prescribe it that way. Off-label prescribing is legal, common, and sometimes even the standard of care for certain conditions. What it means is that the manufacturer has not gone through the formal approval process for that specific use, so the drug’s label does not list it. A physician who believes the evidence supports its use can still prescribe it at their clinical judgment.
A growing number of specialized ketamine clinics have emerged across the United States, offering intravenous infusions of generic ketamine for treatment-resistant depression and other psychiatric conditions.5PubMed Central. Considerations on the Off-label Use of Ketamine as a Treatment for Mood Disorders These clinics typically administer ketamine by IV at subanesthetic doses, which means the dose is well below what would be used to knock someone out for surgery. The appeal is straightforward: traditional antidepressants take weeks to start working and fail to help a significant portion of patients. Ketamine can reduce depressive symptoms within hours of a single dose, even in people who have not responded to other treatments.6PubMed Central. Ketamine and the Future of Rapid-Acting Antidepressants
That speed is what makes ketamine genuinely novel. Most antidepressants work by gradually adjusting serotonin or related chemicals over weeks. Ketamine works through a different pathway, blocking NMDA receptors and triggering a surge of glutamate that appears to help the brain form new synaptic connections, essentially helping repair some of the neural damage caused by chronic stress and depression.7PubMed Central. Ketamine’s Mechanism of Action: A Path to Rapid-Acting Antidepressants This is not just a faster version of what other antidepressants do. It appears to be a fundamentally different mechanism.
How Well Does It Work
The evidence base for both ketamine and esketamine in depression is now substantial, though the two drugs have been studied somewhat differently. Esketamine has the larger body of randomized, placebo-controlled trial data because that is what the FDA approval process required. A meta-analysis of randomized controlled trials found that esketamine nasal spray significantly reduced depression scores compared to placebo, with roughly double the response rate.8PubMed Central. Efficacy of esketamine nasal spray for treatment-resistant depression: A meta-analysis of randomized controlled studies A 2025 trial testing esketamine as a standalone treatment (rather than added on top of another antidepressant) found moderate effect sizes for both the 56-mg and 84-mg doses at four weeks.9JAMA Psychiatry. Esketamine Monotherapy in Adults With Treatment-Resistant Depression: A Randomized Clinical Trial
Racemic ketamine, typically given intravenously, has also shown clear antidepressant effects across multiple randomized trials. Researchers have documented significant improvement in depression and anxiety starting as early as one hour after the first infusion, with benefits persisting at one month after a treatment course.10PubMed Central. Efficacy of ketamine therapy in the treatment of depression Several controlled trials have confirmed rapid antidepressant effects specifically in severe treatment-resistant cases.11PubMed Central. Clinical Efficacy of Ketamine for Treatment-resistant Depression
These findings are promising, but they come with an important caveat: ketamine’s antidepressant effect, while rapid, tends to be transient. A single infusion might produce relief that lasts days to about a week. Without repeated treatments, most people relapse. This is the central clinical challenge with ketamine for depression, and it is why much of the current research focuses on how to make the benefits last.
Maintenance Treatment and How Long Effects Last
Because a single ketamine dose wears off relatively quickly, clinicians have turned to repeated and maintenance infusion schedules. A randomized controlled trial found that repeated ketamine infusions produced cumulative antidepressant effects that built on one another, and that once-weekly infusions sustained symptom reductions among people who responded to the initial treatment course.12PubMed. Single, Repeated, and Maintenance Ketamine Infusions for Treatment-Resistant Depression: A Randomized Controlled Trial
A systematic review examining maintenance ketamine across multiple routes of administration, including intravenous, intranasal, oral, intramuscular, and subcutaneous, found the approach effective at sustaining antidepressant effects in treatment-resistant depression, though it noted that the overall evidence remains limited.13PubMed. Maintenance ketamine treatment for depression: a systematic review of efficacy, safety, and tolerability A retrospective chart review found that patients on maintenance infusions received treatments roughly once a month on average. Depression scores held steady over that period, but the estimated relapse rate after one year still ranged from about one in five to one in three patients, depending on how relapse was defined.14European Psychiatry. Long-term maintenance therapy with ketamine infusions for treatment-resistant depression: a retrospective chart review
There is no standardized protocol. Some clinics start with a series of six infusions over two to three weeks, then space out follow-up sessions based on individual response. Others use different schedules entirely. The lack of a universal dosing guideline is one of the realities of working with an off-label treatment that has not gone through the formal approval process for this specific use.
Side Effects During and After Treatment
Ketamine at subanesthetic doses is not a smooth, side-effect-free experience. During an infusion, people commonly experience dissociation, a feeling of being detached from their body or surroundings. Blood pressure and heart rate rise, and some people experience brief manic-like symptoms or perceptual disturbances. In a controlled study comparing ketamine to placebo, dissociative symptoms, blood pressure elevations, and increased heart rate were all significantly greater on ketamine, peaking around 40 minutes into the infusion.15PubMed Central. Do the dissociative side effects of ketamine mediate its antidepressant effects? These acute effects typically resolve within a couple of hours, which is why clinical settings monitor patients for a period after each treatment.
Nausea, dizziness, and headache are also frequently reported. Some people find the dissociative experience deeply unpleasant, while others describe it as neutral or even integral to the therapeutic process. The relationship between dissociation and antidepressant response has been debated; some studies have investigated whether greater dissociation predicts better outcomes, but the connection is not firmly established.
For Spravato specifically, the REMS program exists partly because of these short-term side effects. Patients must be observed in a certified healthcare setting for at least two hours after each dose, and they cannot drive for the rest of the day. This is a meaningful constraint on access, since it requires significant time commitments and proximity to a certified clinic for every treatment session.
Long-Term Safety Concerns
The short-term side effects of clinical ketamine treatment are well-documented and generally manageable. The longer-term picture is less clear, in large part because maintenance ketamine for depression is still a relatively young practice. Some of the most concerning long-term data comes from the recreational ketamine literature, where heavy and frequent use has been linked to serious urinary tract problems. Regular ketamine consumption increases the risk of cystitis symptoms by three to four times, and the resulting damage can include bladder pain, reduced bladder capacity, ureteral narrowing, and in extreme cases, kidney failure.16PubMed Central. Ketamine-Induced Cystitis: A Comprehensive Review of the Urologic Effects of This Psychoactive Drug
The doses and frequency used recreationally tend to be far higher than what is given in clinical depression treatment, so the direct applicability of those findings to patients getting monthly infusions is uncertain. But it is a risk that clinicians and patients should be aware of, particularly for anyone on an open-ended maintenance schedule. Cognitive effects with repeated dosing and the potential for psychological dependence are additional areas where the evidence is still thin. Most clinical studies have followed patients for months, not years, so the long-term safety profile of repeated low-dose ketamine for depression remains genuinely unknown.
The Compounding and At-Home Ketamine Market
Beyond clinical infusion centers and Spravato clinics, a separate market has developed for compounded ketamine, often prescribed via telehealth and shipped to patients as lozenges, troches, or nasal sprays for at-home use. Compounded drugs are mixed by compounding pharmacies rather than manufactured by a pharmaceutical company, and they are not individually FDA-approved. The FDA has issued warnings about compounded ketamine products, flagging concerns about their safety and the lack of evidence supporting at-home use for psychiatric conditions.17PubMed. FDA Issues Warning on Ketamine Compounds
The concern is not just theoretical. At-home ketamine lacks the monitoring that clinic-based treatment provides. There is no clinician checking your blood pressure during the experience, no controlled environment to manage adverse reactions, and limited oversight of how often you are using it. Several high-profile adverse events involving at-home ketamine have intensified regulatory scrutiny of this market. In Australia, private ketamine services that offered off-label psychiatric treatment in the mid-2010s were closed following regulatory investigations that uncovered inadequate clinical oversight, provision of take-home ketamine, and marketing that outpaced the evidence.18PubMed Central. Ketamine in psychiatry: Ethical imperatives in harnessing a controversial yet promising therapy
If you are considering ketamine treatment for depression, the distinction between these settings matters. A certified Spravato clinic operates under a strict REMS framework with mandatory monitoring. An IV ketamine clinic typically has medical staff present during infusions, though the level of psychiatric expertise varies widely. An at-home compounded ketamine prescription from a telehealth platform offers convenience but the fewest safeguards.
Why Racemic Ketamine Has Not Been Submitted for FDA Approval
A reasonable question is why, if racemic ketamine works as well or possibly better than esketamine for depression, nobody has pursued FDA approval for it. The answer is largely economic. Ketamine is a generic drug. Its patent expired decades ago, which means any company that invested the hundreds of millions of dollars required to run the clinical trials for an FDA approval could not recoup that investment, because competitors could immediately sell the same generic drug for the same indication. There is no financial incentive to fund the approval process.
Esketamine, by contrast, could be patented as a distinct molecular entity. Janssen (a subsidiary of Johnson & Johnson) developed the nasal spray formulation, ran the required trials, and now holds exclusive marketing rights for Spravato. The FDA approval process is designed to ensure safety and efficacy, but it is also deeply intertwined with commercial incentives. A drug that works well but cannot generate patent-protected revenue is unlikely to ever get a company to sponsor its approval for a new indication.
This leaves racemic ketamine in an awkward position. Clinicians and researchers widely acknowledge its antidepressant effects. Patients are receiving it at clinics across the country. But without a formal FDA indication for depression, insurance coverage is inconsistent, clinical standards vary from clinic to clinic, and the regulatory framework remains patchy. The drug’s legal status as an approved anesthetic means it can be prescribed off-label, but the infrastructure of quality control that usually accompanies an FDA-approved psychiatric treatment simply is not there.
Arketamine and What Comes Next
The other half of the ketamine molecule, (R)-ketamine or arketamine, has attracted growing research interest. Early findings suggest it may have antidepressant effects through mechanisms partly distinct from esketamine, with potential anti-inflammatory properties and possible applications in neurological conditions like Alzheimer’s and Parkinson’s disease.19PubMed Central. Ketamine, Esketamine, and Arketamine: Their Mechanisms of Action and Applications in the Treatment of Depression and Alleviation of Depressive Symptoms Some preclinical research has suggested arketamine could deliver antidepressant effects with fewer dissociative side effects than esketamine, since it binds NMDA receptors less aggressively. Clinical trials in humans are underway, but arketamine is years away from any potential approval.
The broader landscape of rapid-acting antidepressants is expanding beyond ketamine entirely. Several pharmaceutical companies are developing drugs that target the same glutamate pathways ketamine acts on but with more selective mechanisms, potentially offering the speed of ketamine’s antidepressant effects with improved side-effect profiles. Whether any of these pan out remains to be seen, but ketamine’s role in depression treatment has already reshaped how researchers think about what antidepressants can do and how quickly they should work.
What This Means If You Are Considering Ketamine for Depression
If your doctor or a clinic is recommending ketamine for depression, the first thing to clarify is which form you would be receiving and in what setting. Spravato (esketamine nasal spray) is the only FDA-approved option for depression. It is available only through certified treatment centers, requires in-office administration with post-dose monitoring, and is more likely to be covered by insurance, though prior authorizations and out-of-pocket costs can still be significant. You will typically need documented evidence of treatment resistance, meaning you have tried and failed at least two antidepressants.
Generic IV ketamine infusions are available at a growing number of clinics and do not require the same level of treatment resistance to qualify. They are almost always paid out of pocket, with a single infusion typically costing several hundred dollars. A standard initial course of six infusions represents a considerable financial commitment, and maintenance sessions add ongoing costs. The quality and safety standards of these clinics vary. Look for settings with medical professionals who monitor vitals during infusions, have protocols for managing adverse reactions, and conduct psychiatric evaluations rather than simply providing infusions on demand.
Compounded at-home ketamine is the least regulated option. While it may be appropriate for some patients under careful psychiatric supervision, the FDA’s warnings and the track record of regulatory problems in unregulated ketamine services should give anyone pause. The convenience of at-home treatment comes with real tradeoffs in safety monitoring. If you go this route, ensure you have an ongoing relationship with a psychiatrist who is actively managing your care, not just a prescribing platform that checks in occasionally.