IV Ketamine Dosing and the Six-Infusion Induction Series

A single ketamine infusion reliably produces rapid but short-lived antidepressant effects — often fading within about a week. [Berman 2000] [Zarate 2006] The idea behind a multi-infusion induction series is to build on that initial response rather than let it lapse. The foundational study behind this structure gave ten treatment-resistant patients six infusions over 12 days and found the response was not only maintained but deepened — nine of ten patients met response criteria after the sixth infusion, with an average 85% reduction in depression rating scale scores. [aan het Rot 2010] That was a small early study, not a large trial, but it is the actual origin of the structure. Later work extended those findings and examined durability over a longer follow-up period. [Murrough 2013] A 2–3 week course of six infusions is now the structure most clinics use for induction, including ours.

This dose and infusion time is not specific to Innerbloom — it is the dose used in nearly every major ketamine-depression trial since the field’s earliest studies, selected because it reliably produces antidepressant effects at a sub-anesthetic level with a well-characterized safety profile. [Berman 2000] [Zarate 2006] A later dose-comparison trial tested both 0.5 mg/kg and 0.75 mg/kg against a low-dose control, confirming both as effective, with dissociative side effects that lessened with repeated dosing. [Singh 2016] Starting at 0.5 mg/kg — the lower, better-established of the two — is the conservative, evidence-based starting point, particularly for a first infusion where we do not yet know how you will respond.

There is no universal escalation schedule in the literature — the trials that established this treatment either used a single fixed dose throughout, or, when they varied it, did so within a narrow, closely studied range (0.5–0.75 mg/kg). That is part of why the field’s own consensus statement on ketamine in psychiatric practice explicitly describes its guidance as individualized rather than protocolized, given how limited the long-term, real-world dosing data still are. [Sanacora 2017]

In practice, that means: your first infusion establishes a baseline at 0.5 mg/kg. From there, Dr. Zabel adjusts your dose for subsequent infusions in your series based on how you responded — both how effective it was and how you tolerated it — rather than following a fixed increase for every patient. Some patients see a strong response and stay at or near the starting dose for their full series; others are titrated upward. This is a case-by-case clinical decision, not a formula.

Response can build across the six infusions rather than appearing all at once — some patients notice a shift after the first or second infusion, others later in the series. As with the original repeated-dosing research, effects after a course of infusions tend to be more durable than after a single infusion, though relapse over the following weeks is common and expected, not a sign that treatment failed. [aan het Rot 2010] This is exactly why an induction series is followed by a maintenance plan rather than treated as a one-time fix — see the ketamine infusion membership on our pricing page.

Every number in this article — 0.5 mg/kg, 40 minutes, six infusions, 2–3 weeks — is either a cited trial figure or Innerbloom’s stated protocol. What is not a number is the titration after infusion one, because the literature does not supply one and patients differ.

Expect a series that builds, a response that may arrive early or late, and a plan for what happens after the sixth infusion rather than a finish line.