Ketamine comes in several distinct forms: injectable liquid, nasal spray, oral lozenges and tablets, topical creams, and dried powder. Some of these are FDA-approved pharmaceuticals, others are made by compounding pharmacies, and some exist only on the illicit market. The form matters because it dramatically affects how quickly ketamine works, how long it lasts, and how much of the drug actually reaches your bloodstream.
Injectable Liquid
The original and most common medical form of ketamine is a clear, slightly acidic sterile solution sold under the brand name Ketalar. It comes in multi-dose vials at three concentrations: 10, 50, or 100 milligrams per milliliter. Healthcare providers administer it either into a vein (IV) or into a muscle (IM), and less commonly under the skin (subcutaneous).
IV ketamine is the fastest-acting form, taking effect within one to five minutes. It’s also the shortest-lasting when given as a single dose, wearing off in roughly 10 to 15 minutes without repeated dosing. For depression treatment, clinics typically deliver it as a slow IV infusion over 40 minutes, which extends the experience. Intramuscular and subcutaneous injections take longer to kick in, around 15 to 30 minutes for subcutaneous, but the effects last longer per dose. Injectable ketamine has the highest bioavailability of any form, meaning nearly all of the drug reaches your system.
Nasal Spray (Spravato)
Esketamine nasal spray, sold as Spravato, is the only FDA-approved form of any ketamine product specifically for psychiatric use. It’s approved for treatment-resistant depression in adults and for depressive symptoms with acute suicidal thoughts. Esketamine is not identical to standard ketamine. It’s one half of the ketamine molecule, the S-isomer, isolated on its own.
Spravato is only available through a restricted program called REMS. You can’t pick it up at a pharmacy and use it at home. Instead, you self-administer the spray in a clinic or medical office while a healthcare provider watches. After each dose, you’re monitored for at least two hours, including blood pressure checks and pulse oximetry. You’re advised to skip food for at least two hours beforehand and liquids for 30 minutes before dosing, because nausea and vomiting are common side effects.
Oral and Sublingual Forms
Compounding pharmacies produce ketamine in several forms designed to be taken by mouth: sublingual troches (small lozenges you dissolve under your tongue), rapidly dissolving tablets, and liquid solutions meant to be swallowed. These are not FDA-approved products. They’re prepared by compounding pharmacies based on individual prescriptions, and the FDA has issued warnings about potential risks tied to their increasing use for psychiatric conditions.
Oral ketamine has the lowest bioavailability of any route. A large portion of the drug is broken down by your liver before it ever reaches your brain, which is why doses tend to be higher than what you’d receive through an IV. The tradeoff is convenience: oral forms can be prescribed for at-home use, which has made them popular through telehealth ketamine services. Effects take about 30 minutes to begin but last considerably longer than IV, typically 4 to 12 hours depending on the dose and formulation. Sublingual absorption is somewhat better than swallowing, since the drug enters the bloodstream directly through the tissue under the tongue, bypassing some of that liver metabolism.
Topical Creams and Gels
Compounding pharmacies also produce ketamine as a topical cream, often mixed with other pain-relieving ingredients like lidocaine. These creams are used primarily for nerve pain and certain skin conditions. Concentrations in research studies are typically low, around 0.5% to 1% ketamine, though compounded products can vary widely. One published case report described a patient who developed systemic ketamine toxicity after applying a cream containing 10% ketamine to open skin wounds, a concentration far above what studies have found to be safe.
Topical ketamine is a niche application. The drug is meant to act locally at the site of pain rather than throughout the body, which is why systemic side effects are rare at appropriate concentrations. But because these are compounded products without standardized FDA oversight, the actual formulation can differ significantly from one pharmacy to another.
Racemic Ketamine vs. Esketamine
Standard ketamine, the kind used in IV infusions and compounded products, is “racemic,” meaning it contains equal parts of two mirror-image molecules: S-ketamine (esketamine) and R-ketamine (arketamine). Spravato contains only the S-isomer. This distinction matters more than it might seem.
Preclinical research suggests the R-isomer may actually be the more potent antidepressant of the two, producing stronger and longer-lasting effects in animal models despite being weaker at blocking the brain receptor most commonly associated with ketamine’s action. The R-isomer also appears to cause fewer dissociative and psychosis-like side effects, with lower potential for misuse. Some researchers believe standard racemic ketamine outperforms esketamine nasal spray for depression precisely because it includes that R-isomer. Arketamine is not yet available as a standalone product, but it represents a distinct molecular form that may eventually reach the market.
Illicit Powder and Liquid
Outside medical settings, ketamine circulates as a white crystalline powder or as a liquid. According to the Drug Enforcement Administration, the powder form is typically made by evaporating the liquid from diverted pharmaceutical vials. The resulting powder is snorted, pressed into tablets, or dissolved back into liquid.
The hydrochloride salt of ketamine is a white crystalline powder that dissolves easily in water. On the street, there’s no way to verify purity, concentration, or whether the product has been cut with other substances. Ketamine is classified as a Schedule III controlled substance in the United States, meaning it has accepted medical uses but also recognized potential for misuse.
How the Form Affects Your Experience
The route of administration changes three things that matter to anyone considering ketamine treatment: how fast it works, how long it lasts, and how much actually enters your system. IV delivery is fastest (one to five minutes) and most efficient but requires a clinical setting. Oral forms are slowest to start (around 30 minutes) and lose the most drug to liver metabolism, but they last the longest and can be used at home. Nasal delivery falls somewhere in between on all three measures, with bioavailability better than oral but lower than injection.
These differences also shape the side effect profile. Faster delivery tends to produce more intense dissociative effects in a shorter window. Oral and sublingual forms produce a more gradual, drawn-out experience. For pain management, the choice of form depends on whether the goal is local relief (topical cream) or whole-body effect (IV, oral, or nasal). For depression, IV infusions and nasal spray are the most studied, though at-home oral protocols are growing rapidly despite limited long-term safety data.