K therapy, short for ketamine therapy, is a treatment that uses low doses of the anesthetic ketamine to manage depression, anxiety, PTSD, and chronic pain. Originally developed as a surgical anesthetic in the 1960s, ketamine gained attention in psychiatry after researchers discovered that small, sub-anesthetic doses could produce rapid relief from severe depression, sometimes within hours rather than the weeks typical of standard antidepressants.
How Ketamine Works in the Brain
Most antidepressants target serotonin or norepinephrine. Ketamine takes a completely different route. It blocks a specific type of receptor involved in glutamate signaling, the brain’s primary excitatory chemical messenger. By doing so, it triggers a cascade of activity that strengthens communication between nerve cells and promotes the growth of new synaptic connections, a process called synaptogenesis.
This is why ketamine can work so much faster than traditional antidepressants. Rather than slowly shifting chemical levels over weeks, it essentially helps the brain rewire weakened circuits. Researchers believe this burst of new neural connectivity is what produces the rapid mood improvements patients report, often after a single session. The effects tend to fade over days to weeks, which is why repeated treatments are typically needed.
Conditions It Treats
Ketamine therapy is used for several conditions, though most of these uses are considered off-label, meaning the FDA has not specifically approved ketamine for them. The primary conditions include:
- Treatment-resistant depression: This is the most common reason people seek ketamine therapy. It refers to major depression that hasn’t improved after trying two or more standard antidepressants.
- PTSD: Research has shown ketamine can be an effective intervention for post-traumatic stress disorder that hasn’t responded to conventional approaches.
- Chronic pain: Ketamine has emerged as a treatment alternative for long-term pain conditions, particularly when other pain management strategies have failed.
- Anxiety and suicidal ideation: Some clinics use ketamine to address severe anxiety and acute suicidal thoughts, taking advantage of its rapid onset.
The only FDA-approved form of ketamine for a psychiatric condition is esketamine, a nasal spray marketed under the brand name Spravato. It is specifically approved for adults with treatment-resistant depression. All other psychiatric and pain-related uses of ketamine are off-label.
IV Ketamine vs. Nasal Spray vs. Other Forms
Ketamine can be delivered several ways, and the method matters. Intravenous (IV) infusion is the most studied and most common route in clinical settings. The standard dose is 0.5 mg per kilogram of body weight, infused over about 40 minutes. Research has shown efficacy at doses as low as 0.2 mg/kg, and higher doses above 0.5 mg/kg don’t appear to produce better results.
The FDA-approved nasal spray, esketamine, is a more potent version of the molecule. It has roughly four times the strength at brain receptors compared to the standard IV form, and effective doses range from 56 to 84 mg per session. It must be administered in a certified healthcare setting where you’re monitored for at least two hours afterward.
Some providers also prescribe oral lozenges, intramuscular injections, or compounded nasal sprays. These are all off-label, and the FDA has issued specific warnings about compounded ketamine products used at home without medical supervision, citing risks of sedation and dissociation that can become dangerous without monitoring.
In head-to-head comparisons, IV ketamine shows a larger effect on depression symptoms than intranasal esketamine. However, esketamine has the advantage of being FDA-approved, which can matter for insurance coverage and standardized safety protocols.
What a Treatment Course Looks Like
A typical course begins with an induction phase: a series of closely spaced sessions designed to build up the therapeutic effect. Most protocols call for six to eight sessions over the first two to four weeks. Some clinics use a “ketamine challenge” of three to five infusions, given every other day or twice per week, to assess whether you respond to the treatment before committing to a full course.
Each session lasts roughly 40 minutes for the infusion itself, though you’ll likely be at the clinic for one to two hours total, including pre-treatment preparation and post-infusion monitoring. During the infusion, you remain awake but may feel drowsy, detached, or experience mild perceptual changes. A healthcare provider monitors your blood pressure, heart rate, and level of consciousness throughout.
If the induction phase works, you move into maintenance. The goal is to find the minimum number of sessions needed to sustain the benefit. Maintenance typically means one to two sessions per month, though some people need them more or less frequently. The spacing is adjusted based on how long the effects last for each individual.
How Effective It Is
Ketamine therapy helps a meaningful number of people, but it’s not a guaranteed fix. In a large study of veterans treated through the VA health system, 26% of patients achieved a treatment response (defined as a 50% improvement in depression scores) after six weeks. About 15% reached full remission. Those numbers may sound modest, but these were patients with treatment-resistant depression who had already failed multiple other therapies.
The speed of relief is what sets ketamine apart. Many patients notice improvement within hours to days of their first infusion, compared to four to six weeks with standard antidepressants. For people experiencing severe depressive episodes or suicidal thoughts, that rapid timeline can be critical.
The main limitation is durability. The antidepressant effects of a single infusion typically wear off within one to two weeks, which is why ongoing maintenance sessions are usually necessary. Researchers are still working to understand why some people respond robustly while others see little benefit.
Side Effects and Safety Concerns
The most common side effect during a session is dissociation: a feeling of disconnection from your thoughts, body, or surroundings. This is temporary and usually resolves within an hour or two after the infusion ends. Other short-term effects include increased blood pressure, nausea, dizziness, and drowsiness. You won’t be able to drive for the rest of the day after a session.
The FDA has flagged several safety concerns, particularly with unsupervised use. These include the potential for abuse and misuse (ketamine is a Schedule III controlled substance), psychiatric events, respiratory depression, and urinary tract or bladder symptoms with repeated use. The long-term benefit-risk profile of ketamine for psychiatric conditions is still not fully established, according to the FDA.
At-home use of compounded ketamine products carries additional risk because no healthcare provider is present to respond if sedation or dissociation becomes severe. Some telehealth companies have offered mail-order ketamine lozenges, but the FDA has warned that this model may put patients at risk for serious adverse events.
Cost and Insurance Coverage
Ketamine therapy is expensive, and most of the cost comes out of pocket. Individual sessions typically run $400 to $800 each. With an initial course of six to eight sessions in the first month, you’re looking at $2,400 to $6,400 upfront. Maintenance sessions of one to two per month add $400 to $1,600 monthly, putting the annual cost somewhere between $7,200 and $19,200.
Most insurance companies still consider ketamine therapy experimental for mental health conditions, so coverage is limited or nonexistent for IV infusions. The FDA-approved nasal spray, esketamine, is more likely to be covered, though insurers often require documentation that you’ve failed other treatments first. If your insurance won’t cover any form of ketamine therapy, you may be able to pay using a flexible spending account (FSA) or health savings account (HSA).
Who Should Not Receive Ketamine Therapy
Ketamine is not appropriate for everyone. People with uncontrolled high blood pressure face elevated risk because ketamine raises blood pressure during administration. Those with a history of psychosis or active psychotic symptoms are generally excluded, since ketamine can trigger or worsen psychiatric events. A history of substance abuse, particularly with ketamine or other dissociative drugs, is also a concern given ketamine’s potential for misuse. Pregnant individuals and people with certain cardiovascular conditions are typically not candidates either.
Before starting treatment, clinics generally conduct a thorough medical and psychiatric evaluation. This includes reviewing your medication history, previous treatment failures, and any conditions that might make ketamine unsafe. The assessment helps determine both whether you’re a good candidate and which administration route makes the most sense for your situation.