Most people start with six to eight ketamine treatments over two to four weeks, though the total number depends on how you respond and whether you continue with maintenance sessions afterward. That initial series is just the beginning of the conversation. Some people feel significant relief within the first few infusions, while others need the full course before noticing a change.
The Initial Treatment Series
The standard approach begins with what clinicians call an induction phase. This typically involves IV ketamine infusions given twice per week for about four to five weeks, with a gradual taper. Many providers start with a shorter “challenge” of three to five treatments, spaced every other day or twice weekly, to see whether you respond to ketamine at all before committing to the full series.
Response rates illustrate why completing the full induction matters. In one study of patients with treatment-resistant depression, only 7% showed a meaningful response after the first three infusions. After all six infusions, that number jumped to 42%, and 17% achieved full remission. Stopping early can mean missing the window where the treatment actually starts working.
How Spravato (Esketamine) Differs
Spravato, the FDA-approved nasal spray form of ketamine, follows a more structured schedule. For treatment-resistant depression, you’ll visit a clinic twice per week for the first four weeks (eight sessions). Weeks five through eight drop to once weekly (four more sessions). After that, sessions spread to every one or two weeks depending on how well you’re doing. That’s a minimum of 12 sessions in the first two months before settling into a maintenance rhythm.
For people with major depression and acute suicidal thoughts, the protocol is more concentrated: twice-weekly sessions at a higher dose for four weeks, totaling eight treatments. After those four weeks, your provider evaluates whether to continue.
How Long the Benefits Last
One of the most common questions after finishing induction is whether you’ll need more treatments. The short answer: probably, but not necessarily right away. Research tracking patients after their initial series found that about 80% of responders still felt better at four weeks post-treatment, even without additional sessions. By eight weeks, that dropped to around 60%.
Those numbers mean that for a significant portion of people, the antidepressant effect fades over one to two months without follow-up treatment. This is why most providers plan for some form of ongoing care rather than treating the initial six to eight sessions as a one-and-done cure.
Maintenance Sessions After Induction
If you respond well to the initial series, your provider will typically recommend periodic booster infusions. In a randomized controlled trial, responders who received once-weekly maintenance infusions held onto their improvements, with no further decline in depression scores during the maintenance phase. The frequency of these boosters varies from person to person. Some people do well with monthly sessions, while others need them every two to three weeks.
The goal is finding the least frequent schedule that keeps your symptoms in check. Over time, some patients are able to space their sessions further apart, while others maintain a steady interval indefinitely. There’s no universal endpoint. Your total number of treatments over the first year could range from the initial six to eight up to 20 or more if you include regular maintenance.
What This Costs in Practice
Because most IV ketamine treatment is not covered by insurance, the number of sessions has real financial implications. IV infusions run $400 to $800 per session nationally, with prices as low as $350 in some areas and above $1,000 in premium clinics in cities like Los Angeles and San Francisco. A six-session induction at a mid-range clinic might cost $2,400 to $4,800 out of pocket.
Intramuscular injections are somewhat cheaper at $275 to $400 per session. Oral ketamine (lozenges or troches) is the most affordable option, running $75 to $200 per treatment, with some patients paying as little as $60 per month for maintenance.
Spravato is a different calculation. Without insurance, each visit costs $900 to $1,300 when you factor in the medication and the required two-hour monitoring period. With insurance, out-of-pocket costs drop significantly, since Spravato is the only FDA-approved ketamine product for depression and many plans cover it. The manufacturer also offers a savings program for eligible patients.
Factors That Affect How Many You’ll Need
Several things influence whether you’ll be on the lower or higher end of total treatments. The severity and duration of your depression matters. People who have been depressed for decades or who have failed multiple antidepressants sometimes need a longer induction or more frequent maintenance. How quickly you respond also plays a role. Some people notice improvement after two or three sessions, while others don’t feel a shift until session five or six.
Whether you’re using ketamine alongside other treatments can also make a difference. Spravato is always prescribed with an oral antidepressant, and many IV ketamine providers recommend continuing or starting traditional antidepressants and therapy to extend the benefits between sessions. The combination may allow you to space boosters further apart over time.
Your route of administration matters too. IV and intramuscular ketamine allow for precise dosing and tend to produce more consistent effects per session, but they require clinic visits. Oral ketamine can be taken at home and costs less, making frequent dosing more practical, but absorption varies and the effects per dose are generally milder. Your provider will help match the format to your situation, and some people switch between modalities as they move from induction to maintenance.