Three ways to deliver ketamine. They differ in how much reaches you, what the FDA has approved, and what it costs.
Table of Contents
- IM Ketamine vs IV vs Spravato: The Short Answer
- Same Family, Different Forms
- How Much Reaches the Bloodstream
- FDA Status and What It Changes
- What the Evidence Says About IM
- Time in the Clinic
- Cost and Insurance
- How the Choice Gets Made
- FAQs About Ketamine Routes
Once ketamine comes up as an option for depression, a second question follows quickly. Which kind?
Clinics offer it as an IV infusion, as an intramuscular (IM) injection, or as Spravato, a nasal spray. The marketing around each can make them sound like competing products. They are closer relatives than that, but the differences are real and they affect your experience.
IM Ketamine vs IV vs Spravato: The Short Answer
IV ketamine runs through a vein over a set period. It is the route most of the early depression research used.
IM ketamine is a single injection into a muscle. Almost all of the dose reaches the bloodstream within minutes, and no IV line is needed.
Spravato is esketamine nasal spray. It is the only one of the three with FDA approval for depression, and it comes with strict rules about where and how it is given.
IV and IM ketamine are both used off-label for depression. None of the three is right for everyone.
Same Family, Different Forms
Ketamine is made of two mirror-image forms of the same molecule. Esketamine, the drug in Spravato, is one of those two forms on its own. The FDA noted this when it approved Spravato, calling esketamine the s-enantiomer of ketamine.
IV and IM clinics use standard ketamine, which contains both forms.
All of them act on the brain’s glutamate system. A review in Pharmacological Reviews describes ketamine as blocking the NMDA receptor, a different target from the serotonin and norepinephrine systems that standard antidepressants work on. That difference is why ketamine is considered when standard medication has not helped.
How Much Reaches the Bloodstream
Bioavailability is the share of a dose that actually makes it into circulation. It varies a lot by route.
- IV: all of it, with peak levels immediately.
- IM: about 93%, with peak levels within 5 to 30 minutes, per the Pharmacological Reviews paper.
- Esketamine nasal spray: about 48% on average, reaching peak levels 20 to 40 minutes after the last spray, according to the Spravato prescribing information.
- Oral ketamine: only 16% to 29%, because the liver breaks down much of it first.
The Spravato label also reports wide differences between individuals in how much drug they absorb from the spray. IV delivery removes absorption as a variable, IM absorption in adults is high, and doses for both are usually calculated from body weight.
Higher bioavailability is not automatically better. It does make the delivered dose easier to control.
FDA Status and What It Changes
Spravato is FDA approved for adults with treatment-resistant depression, either alone or with an oral antidepressant. It is also approved, alongside an oral antidepressant, for depressive symptoms in adults with major depression and acute suicidal thoughts or behavior.
Approval comes with a Risk Evaluation and Mitigation Strategy (REMS). Under the label, Spravato is only given in certified healthcare settings. You spray it yourself under direct observation, and you are monitored for at least 2 hours afterward. It never goes home with you.
IV and IM ketamine have no psychiatric approval. The FDA stated in an October 2023 compounding risk alert that ketamine is not approved for the treatment of any psychiatric disorder. Off-label prescribing is legal and common in medicine, but it places the responsibility for dose, schedule and monitoring on the treating physician rather than on a label.
That is why the qualifications and protocols of whoever gives the treatment matter so much for IM and IV ketamine.
What the Evidence Says About IM
Most of the controlled research on ketamine for depression used IV infusions. The American Psychiatric Association task force behind the 2017 consensus statement on ketamine noted that studies of other routes and doses varied widely in design and were too few to support firm conclusions.
The IM evidence has grown since. A 2026 study from the VA San Diego compared 179 veterans with treatment-resistant depression who received eight treatments of either IM ketamine or Spravato over four weeks. IM ketamine was non-inferior to Spravato on depression scores, and safety outcomes were comparable.
Two limits apply. The study was observational rather than randomized, and it looked only at the first month. It supports IM as a reasonable option. It does not prove IM is better.
Large head-to-head randomized trials of IM against IV ketamine are still lacking.
Time in the Clinic
None of these is a quick in-and-out appointment.
IV: the standard research protocol delivered the dose over 40 minutes, followed by a period of observation.
IM: the injection takes seconds, and the monitoring sets the length of the visit. One US outpatient study (Ahuja et al., 2022) observed patients for at least 60 minutes. The VA program kept patients 120 minutes for both IM ketamine and Spravato.
Spravato: at least 2 hours of monitoring at every session, set by the label.
With every route you need someone to drive you home. The Spravato label says not to drive until the next day after a restful sleep, and the same caution is sensible after IV or IM ketamine.
Cost and Insurance
Costs vary by clinic and plan, so treat any figure you read as a rough guide.
The VA study offers one clear comparison. Its cost for an eight-treatment course was about $6,069 for Spravato against about $648 for IM ketamine, a gap driven almost entirely by the price of the drug itself. Those are VA costs, not what a private patient pays, but the direction of the difference is instructive.
Insurance runs the other way. Because Spravato is FDA approved for treatment-resistant depression, plans may cover it once their criteria are met. Coverage for off-label ketamine varies from plan to plan. Check with yours before you start.
How the Choice Gets Made
The right route comes from your history, not a brochure.
A psychiatrist will weigh your diagnosis and past treatment, your blood pressure and heart health, and whether you have any history of substance use. Scheduling and cost count too, since a treatment you cannot keep attending is not going to help.
For some people, an FDA-approved option with insurance coverage settles it. For others, the predictable dosing of IM ketamine is the deciding factor. Our guide to what an IM ketamine session involves covers that route step by step.
FAQs About Ketamine Routes
Is IM ketamine as effective as IV ketamine? Direct comparisons are limited. Most controlled trials used IV, and the APA consensus statement cautioned that evidence on other routes was too thin for firm conclusions. IM delivers about 93% of the dose to the bloodstream, and newer research such as the VA study supports its effectiveness, but a large randomized IM-versus-IV trial has not settled the question.
Is Spravato just ketamine in a spray? Not exactly. Spravato contains esketamine, one of the two mirror-image forms that make up standard ketamine. It is the only one of the three routes with FDA approval for depression, and it has its own dosing and safety program.
Why not simply take ketamine as a pill? Only 16% to 29% of an oral dose reaches the bloodstream. The FDA has also warned about compounded ketamine products used at home, noting that taking them without a health care provider monitoring for sedation, dissociation and changes in vital signs may put patients at risk.
Can I switch from one route to another? Sometimes. Switching depends on how you responded, what side effects you had and what your insurance covers. Talk to your psychiatrist before making any change rather than deciding alone.
Do all three have the same side effects? Broadly similar. Dissociation, dizziness, nausea and a temporary rise in blood pressure are among the effects most often reported for both ketamine and esketamine. The screening and monitoring before and after each session are what keep those manageable.
Talk Through Your Options
Choosing a route is easier with someone who knows your full history. Dr. Sambunaris administers ketamine therapy by intramuscular injection in Alpharetta, Georgia. You can also read more about ketamine treatment for depression at our practice.
Book My Consultation or call (770) 817-9200.
Reviewed by Angelo Sambunaris, M.D., with more than 20 years of clinical experience and over 30 years in clinical research.
If you are having thoughts of suicide or self-harm, call or text 988 to reach the Suicide and Crisis Lifeline, available 24 hours a day.
Medical Disclaimer: This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Ketamine is not FDA approved for the treatment of depression or any other psychiatric disorder, and its use for these conditions is off-label. Reading this article does not create a doctor-patient relationship. Always talk to your doctor or another qualified health provider about your own situation, and never start, stop, or change medication without speaking to your prescriber. If you think you may be having a medical emergency, call 911.