Why format matters
The route of administration affects how much of the medication reaches the bloodstream (bioavailability), how quickly it takes effect (onset), how intense the subjective experience is, how long it lasts, and how much clinical supervision is appropriate. Different formats fit different clinical situations.
Oral (troches or capsules)
How it works
Oral ketamine is absorbed through the mouth and gut. Bioavailability is lower than IV or IM, so milligram-for-milligram it produces a milder effect. Onset is slower — usually 15 to 30 minutes — and the experience is generally softer and more gradual than higher-intensity formats.
Where it fits
Low-dose oral protocols are well-suited to medically supervised at-home programs, when patients are appropriately screened. The gentler profile is often better tolerated by patients with high baseline anxiety or who prefer to do this work in their own space.
Trade-offs
Slower onset and lower bioavailability mean oral dosing is inherently less intense — which many patients consider a feature, not a limitation. It is not a good match for situations that require the fastest possible onset.
Intravenous (IV) infusion
How it works
IV infusion delivers ketamine directly into the bloodstream, typically over 40 to 60 minutes in a clinical setting. Bioavailability is essentially 100%, onset is fast, and dose control is precise.
Where it fits
IV is commonly used in ketamine clinics and hospital-affiliated programs, particularly for severe or urgent presentations. It is always delivered in a clinical setting with in-person monitoring.
Trade-offs
IV is more intense and typically more expensive per session. It requires travel to a clinic. Some patients find the intensity therapeutically useful; others find it more than they need.
Intramuscular (IM) injection
IM ketamine is injected into a muscle, usually in a clinical setting. Bioavailability is high (though slightly less than IV), and onset is fast. Compared to IV, IM avoids the need to place a catheter, but dose adjustment during a session is less precise. Like IV, IM is delivered in a supervised clinical setting.
Intranasal esketamine (Spravato)
Spravato is an FDA-approved intranasal form of esketamine, the S-enantiomer of ketamine. In the United States, it must be administered under direct medical supervision in a certified in-office setting under the FDA's REMS program. It is not an at-home treatment. Insurance coverage exists for Spravato for certain indications, though prior authorization is common. Spravato is a distinct product with its own dosing schedule and monitoring requirements.
A side-by-side summary
| Format | Setting | Onset | Intensity | FDA status (psychiatric use) |
|---|---|---|---|---|
| Oral | At-home, medically supervised | 15–30 min | Gentle | Off-label |
| IV | Clinic | Fast | Higher | Off-label |
| IM | Clinic | Fast | Higher | Off-label |
| Spravato | Certified in-office (REMS) | Fast | Moderate–higher | FDA-approved for certain indications |
How to think about format selection
The right format depends on clinical picture, tolerability, logistics, and cost. For many adults with persistent but non-urgent symptoms, a low-dose oral protocol offers a gentler, lower-cost, more integrated-into-daily-life option. For urgent or severe presentations, clinic-based IV or Spravato may be more appropriate.
Our program uses low-dose oral ketamine within a medically supervised at-home model. Whether that is the right fit for your situation is a clinical determination made after a comprehensive evaluation.