Ketamine Dosage for Depression: A Dose-by-Route Guide

What Is the Typical Ketamine Dosage for Depression?

For IV ketamine, the most-studied dose is 0.5 mg/kg, infused over about 40 minutes.¹ Doses at or below 0.5 mg/kg are common in published studies. In practical terms, 0.5 mg/kg works out to roughly 35 mg for a person weighing about 70 kg (154 lb), which is why IV milligram numbers look small next to at-home tablets.

A dose-ranging trial in Molecular Psychiatry found evidence for both the 0.5 mg/kg and 1.0 mg/kg subanesthetic doses of IV ketamine.¹ Lower doses did not reliably help.

Ketamine for depression, apart from esketamine, is prescribed off-label. Off-label use is a routine, legal part of medicine. According to the U.S. Agency for Healthcare Research and Quality, for years about one in five prescriptions have been written for off-label use.²

There is no single universal milligram number for everyone. The right dose depends on the route, your body weight, and how you respond. The single biggest reason the numbers vary is the route, so start there.

Why 0.5 mg/kg Became the Reference Dose

Early controlled trials used 0.5 mg/kg over about 40 minutes, so that amount became the default reference point. It is now the benchmark other routes and doses are compared against.

In the same dose-ranging trial by Fava and colleagues, both 0.5 mg/kg and 1.0 mg/kg outperformed placebo, while lower doses were not consistently effective.¹

In short, 0.5 mg/kg is the best-studied dose, not a limit above which treatment becomes unsafe. Because 0.5 mg/kg is an IV number, it helps to know what "sub-anesthetic" means.

What "Sub-Anesthetic" Dosing Means

Sub-anesthetic simply means a dose well below what would be used to put someone to sleep for surgery. Antidepressant dosing sits in this lower range on purpose.

For contrast, the FDA label for anesthetic ketamine lists an IV anesthetic dose of 1 mg/kg to 4.5 mg/kg.³ The average for 5 to 10 minutes of surgical anesthesia is about 2 mg/kg. That is several times higher than the roughly 0.5 mg/kg antidepressant dose.

At antidepressant doses, many people remain awake and aware throughout the session. Safe treatment comes from supervision, screening, and clear protocols, not from the size of the dose alone. With that baseline, here is how the dose changes from route to route.

How Ketamine Dosing Differs by Route

The same medicine reaches your bloodstream differently depending on how you take it. So the milligram number that looks "right" changes with the route. The key idea is bioavailability, meaning how much of a dose actually reaches your bloodstream.

A 2026 best-practice review in Frontiers in Psychiatry describes IV racemic ketamine dosing recommendations at 0.5 mg/kg as the reference standard.⁴ This matches the dose-ranging trial evidence above.¹ The review notes that dosing is individualized across oral, subcutaneous, and nasal forms.

The table below compares the main routes. You can also read a plain-language overview of the types of ketamine therapy and how each is dosed.

Absorption explains why the milligram numbers differ so much between routes. In short: IV is about 0.5 mg/kg, esketamine is a fixed 56 to 84 mg, and sublingual and subcutaneous racemic ketamine are weight- or provider-set at higher milligram amounts to offset lower absorption.

To make that concrete, here is what 0.5 mg/kg looks like across routes for one example weight. Every route aims to get a similar amount of ketamine into the bloodstream. Because absorption differs, the dose taken changes a lot, while the amount that actually reaches the bloodstream stays in a similar range.⁴⁻⁵

Notice that the dose taken swings from 35 mg to nearly 200 mg, but the amount reaching the bloodstream stays close to 35 mg. That is the point: a larger milligram number offsets lower absorption, it does not mean more medicine reaches you or a stronger effect. These figures illustrate the math for one example weight and are not a dosing guide. Your clinician sets your actual amount, and at-home providers including Mindbloom set tablet and injection amounts individually rather than by a standard number.

The sections below walk through each one.

Intravenous (IV) and Intramuscular (IM) Ketamine

IV ketamine uses about 0.5 mg/kg infused over roughly 40 minutes. It is the reference route because it delivers the full dose directly into the bloodstream. Intramuscular ketamine is also weight-based, given as a single injection commonly near 0.5 mg/kg, and it is less studied than IV.⁴

Both routes are usually given in a clinic because they reach the bloodstream quickly and more completely than tablets. That fast, fuller absorption is why the milligram numbers look small compared with at-home tablets. At home, the routes, and therefore the doses, look different.

Sublingual and Oral Ketamine at Home

Sublingual tablets are held in the mouth so the medicine absorbs through the lining, or mucosa. A pharmacokinetic study in the British Journal of Clinical Pharmacology by Rolan and colleagues (2014) found sublingual ketamine's bioavailability is only about 29%.⁵ So the tablet dose is larger than an IV dose to reach a comparable effect.

Oral ketamine that you swallow absorbs even less. First-pass metabolism in the liver breaks down much of it before it reaches the bloodstream. That may be one reason some clinicians use it less often.

Tablet doses are fixed milligram amounts, set individually for each person rather than a single standard number. That larger tablet number can look alarming next to an IV dose, but it reflects the absorption math, not a stronger drug. Mindbloom, for example, has clients hold the tablet between the cheek and gum for about seven minutes and then spit it out, pairing that fixed hold with a clinician-matched dose so the milligram amount reflects controlled absorption rather than a bigger effect. This is offered only if a licensed clinician determines it is medically appropriate.

The dose is set by your clinician. If a licensed clinician determines it is medically appropriate, a newer at-home option is subcutaneous injection.

Subcutaneous Ketamine at Home

Subcutaneous injection places the medicine just under the skin with a small needle. It is weight-based and set to your body, and it tends to absorb more completely and steadily than a sublingual tablet.

Given at home, subcutaneous ketamine uses a tiny insulin needle in the abdomen, and for some people effects may begin within about five minutes, though this varies. It is offered only if a licensed clinician determines it is medically appropriate.

Sublingual and subcutaneous are individualized choices, not a better-or-worse ranking. Comfort, preference, tolerability, and fit all matter when matching a route to a person. Among at-home providers, offering both a sublingual and a subcutaneous option from the same clinical team is uncommon. Mindbloom provides both, so a clinician can match the route to you and adjust or switch it later if your needs change. Some at-home programs advertise very different milligram numbers, which raises a common question about sub-perceptual and microdose approaches.

Sub-Perceptual and Microdose Ketamine

Sub-perceptual or microdose ketamine usually means very small amounts, sometimes taken daily. The goal is a subtle effect rather than the fuller sub-anesthetic experience used in the most-studied protocols.

The evidence for daily sub-perceptual ketamine is limited compared with the standard sub-anesthetic approach. A bigger milligram number is not automatically better, and a smaller one is not automatically safer.

The right dose is the amount matched to your route and your response, and sub-perceptual protocols do suit some people's goals. One route deserves its own section because it is dosed as a fixed, FDA-approved product: esketamine.

Spravato (Esketamine) Nasal Spray Dosing

For treatment-resistant depression, the FDA-approved Spravato dose is a fixed 56 mg or 84 mg.⁶ It is taken twice per week for the first four weeks, then less often. Spravato is a self-administered nasal spray. It is used under supervision in a certified healthcare setting, with about two hours of monitoring afterward.

Here is the key distinction. Esketamine is the FDA-approved form of the medicine, the S-enantiomer, which is one specific molecular form of ketamine. It is dosed in fixed milligrams. IV and at-home racemic ketamine, by contrast, are weight-based and prescribed off-label.

FDA approval reflects the regulatory pathway esketamine took to market. The routes simply use different delivery models: a fixed-dose nasal spray in a certified setting, or weight-based dosing by IV, injection, or tablet. Beyond the route and the drug, a few practical factors shape the exact dose you receive.

What Else Informs Dosing?

How you take a dose changes how much of it actually works. With sublingual tablets, holding the tablet against the cheek and gum lets the medicine absorb through the mouth lining. Swallowing sends more of it through the stomach and liver, where first-pass metabolism reduces how much reaches the bloodstream and lowers the effective dose.

That is why hold time and following the protocol matter, and why the same milligram number can feel different depending on how it is taken. Food or timing before a session may also affect how the medicine is absorbed.

This is why sublingual protocols specify a hold time, often several minutes, before the tablet is spit out rather than swallowed. Learning how your route is chosen is part of the care process, and those mechanics set the effective dose while a clinician sets the prescribed dose.

How Your Personalized Ketamine Dose Is Determined

There is no one-size-fits-all dose. A licensed clinician sets your starting dose and adjusts it based on how you respond over time. The next two sections explain what goes into that decision and how the dose can change.

What a Clinician Weighs When Setting Your Dose

Several inputs shape your starting dose. Your care team reviews these together during screening rather than applying rigid pass-or-fail rules:

• Body weight and route: weight-based routes such as IV, intramuscular, and subcutaneous scale the dose to your weight.
• Medical screening: your provider reviews conditions such as blood pressure to confirm treatment is appropriate for you.
• Medication history: current medications are checked for interactions that could affect dosing.
• Prior response: how you have responded to earlier treatments helps guide the starting point.

Weight-based routes scale with your body weight, while sublingual tablets and esketamine use fixed milligram amounts. Your first dose is a starting point, not a fixed setting.

How Your Dose Can Change Over Time

Your prescriber may adjust the dose across a course of sessions based on how you respond and how well you tolerate it. Adjustment is normal and expected, not a sign that something went wrong.

Changes follow your personalized response rather than a fixed calendar. Mindbloom's at-home program, for instance, builds in ongoing dosage support, adjusting the dose as your response evolves. Because a dose is per session, the next question is how many sessions.

How Many Ketamine Sessions Will You Need?

A "dose" is per session, and treating depression is usually a series rather than a single dose. A typical induction is a short series of sessions over a few weeks. Maintenance or repeat sessions may follow on a personalized schedule.

The right number of sessions is a clinical decision, not a fixed package. As one at-home example, Mindbloom offers programs of 6, 12, or 18 sessions. Treatment proceeds only if a licensed clinician determines it is medically appropriate during the first consult.

You can read more about how many ketamine sessions people typically need. Whatever the number of sessions, people want to know what a therapeutic dose actually feels like.

What a Therapeutic Dose Feels Like

Many people notice improvement within hours or days of a session, though responses vary. More durable benefit tends to build over a series of sessions. Integration practices and ongoing support help sustain that progress.

At therapeutic doses, many people remain awake and aware. Most people find the dissociative state, a temporary sense of distance from your body or surroundings, therapeutically meaningful within a supervised setting. If it feels unfamiliar, preparation materials and a support person or in-session monitor can help you navigate it.

Some people may also experience temporary effects such as dizziness, nausea, or a short-term rise in blood pressure. Such effects are possible, not guaranteed, and they tend to ease as the session ends.

Serious problems are uncommon. In a 2024 systematic review by Hovda and colleagues in the Journal of Affective Disorders, about 0.1% of people who received sub-anesthetic ketamine for psychiatric disorders had a serious medical adverse event.⁷

Monitoring is part of the protocol. Esketamine, for example, requires about two hours of observation in a certified setting.

Whatever the route, avoid driving until after a full night of sleep. You can read more about what a session feels like. Putting it together, the right dose is a conversation with a clinician.

Finding the Right Ketamine Dose With a Clinician

The "typical" 0.5 mg/kg IV figure is a useful reference point, but it is not your dose. The right amount depends on the route, your body weight, and how you respond, and a licensed provider sets and adjusts it with you.

If you are weighing IV clinics, at-home options, or esketamine, consider a conversation about dosing. A licensed clinician can determine whether any option is medically appropriate for you and explain how each route would be dosed for your goals. You can learn more about guided ketamine therapy for depression and what a personalized program includes.

Book My Breakthrough‍