How many ketamine treatments do you need?

Most IV ketamine programs start with an induction series of roughly six infusions spread over two to three weeks. For treatment-resistant depression, Spravato® follows a fixed, FDA-defined schedule: twice a week for the first four weeks, then weekly for four weeks, then weekly or every other week after that. Those are the standard answers. They leave out how long benefits last, when more sessions stop making sense, and what the ongoing commitment looks like. Those decide whether this treatment fits your life and budget.

Why a series instead of one dose

A single infusion can lift symptoms within hours to days, which is the property that made ketamine famous. But the effect of one dose is short-lived: for many people, days to a couple of weeks. Repeated dosing during induction tends to deepen and extend the response, which is why programs treat the series, not the single session, as the unit of treatment. It's also why paying for one infusion "to see if it works" tells you less than clinics sometimes imply: some people respond after the first session, others not until the third or fourth.

When you should know whether it's working

By the end of induction, the answer is usually clear. Response in the research typically means at least a 50% reduction in symptom scores. In one trial of 41 people, those who responded needed a median of three infusions, and an international expert review says most responders improve within the first one or two infusions, though some take four to six. A good program measures this with the same scales each visit rather than asking "how are you feeling?" on the way out.

Just as important: if there's no meaningful change after a full induction series, more of the same is unlikely to rescue it. Continuing to sell infusions to a non-responder is a red flag. A trustworthy clinician treats non-response as information: time to revisit the diagnosis, the treatment plan, or a different modality entirely, like TMS or a medication change. Our guide to what to do if ketamine didn't work covers the questions to ask and the evidence for each option. For the most common comparison, see ketamine vs. TMS.

How long does ketamine last?

It varies widely, and a tidy number from anyone is a guess. After a successful induction, some people hold their improvement for months; others feel symptoms creeping back within a few weeks. In the main esketamine maintenance trial, run by the manufacturer, people already in stable remission who kept taking esketamine alongside an oral antidepressant had about half the relapse risk of those switched to placebo spray. That is one trial of one drug, and a published critique noted that results from a single study site accounted for much of the effect. Evidence for IV ketamine maintenance is thinner. Many people do relapse after stopping, which is why every program should discuss a maintenance plan before you start.

What maintenance looks like

There is no established maintenance schedule for IV ketamine; clinics commonly space boosters from every few weeks to every two months, adjusted to how long your improvement holds, with the goal of stretching the interval over time. For Spravato, maintenance is the weekly-or-biweekly phase of the schedule, and because it is often covered with prior authorization, the ongoing cost picture can be very different. To check your own plan, see does private insurance cover Spravato?

Run the math before you commit. At roughly $300–$800 per infusion, six infusions come to about $1,800–$4,800 for induction, and boosters every four to eight weeks add roughly $1,800–$9,600 a year at cash rates, depending on price and frequency. That's the realistic price of staying well on cash-pay ketamine, and it's why coverage questions belong at the start of this decision. Our cost and insurance page goes deeper. A frequency that keeps increasing, on the other hand, is a warning sign worth raising directly with your prescriber, and escalating dosing carries its own risks.

Questions worth asking any program

• How do you measure response, and at what session do we evaluate whether to continue?
• What's your definition of non-response, and what do you recommend when it happens?
• What does your typical patient's maintenance schedule look like after six months?
• What's the plan for stretching intervals, or stopping entirely?

Warning signs to watch for between sessions

The Spravato® label asks family members or caregivers to help watch for changes. This matters most in the first few months and after any dose change. Its Medication Guide says to tell the healthcare provider or get emergency help right away if any of these signs are new, worse, or worrying:

• New or worse depression.
• Thoughts about suicide or dying, or suicide attempts.
• New or worse anxiety, panic attacks, agitation, or restlessness.
• Trouble sleeping.
• Acting aggressive, angry, or violent, or acting on dangerous impulses.
• New or worse irritability.
• An extreme increase in activity and talking (mania).
• Other unusual changes in mood or behavior.

One more sign is not on the label list: needing sessions more and more often. As noted above, a frequency that keeps increasing is a warning sign worth raising with the prescriber. Spravato® carries a misuse warning, and its label recommends that clinicians monitor for signs of misuse.

If someone is in immediate danger or having a medical emergency, call 911. For a mental health crisis, call or text 988.

Good treatment gets you well and then finds the least treatment that keeps you there. Programs that talk comfortably about stopping rules are usually the ones worth starting with. More on that in choosing a clinic.