Ketamine has one of the most unusual trajectories in modern medicine: an operating-room anesthetic that became one of the most actively studied compounds in psychiatry. The evidence is genuinely promising, but it is also nuanced — many studies are small, effects can be rapid yet temporary, and responses vary from person to person. The summaries below describe the notable peer-reviewed work without overstating what the science shows.
One ground rule for clarity: IV ketamine for depression and pain is used off-label. The only ketamine-derived medication that is FDA-approved for depression is esketamine (Spravato®), for specific indications. Nothing here is medical advice, and reading a study summary is not a substitute for a clinical evaluation.
Concise, cited context before the studies and mechanisms.
Ketamine was first synthesized in 1962 and approved by the FDA as an anesthetic in 1970. Its decades-long use in anesthesia means its acute safety profile under medical supervision is well characterized.[9]
Ketamine appears on the World Health Organization's Model List of Essential Medicines and remains widely used in surgery, emergency care, and pain management — in part because it provides sedation and analgesia while largely preserving airway reflexes and cardiovascular stability.[9][10]
Controlled studies beginning in 2000 reported that a single subanesthetic dose could reduce depressive symptoms within hours — challenging the long-standing assumption that antidepressants must take weeks to work, and redirecting research toward the brain's glutamate system.[1][2]
Unlike serotonin-based antidepressants, ketamine acts on the glutamate system. Researchers have mapped a rapid molecular cascade — from NMDA-receptor blockade to new synaptic connections — that helps explain its speed.
At low, subanesthetic doses ketamine acts as a noncompetitive antagonist at the N-methyl-D-aspartate (NMDA) glutamate receptor. By transiently blocking NMDA receptors — preferentially on inhibitory GABAergic interneurons — it disinhibits excitatory neurons and produces a brief, controlled surge of glutamate in the prefrontal cortex, which in turn activates AMPA receptors. This glutamatergic action is what sets ketamine apart from serotonin-based antidepressants.[13][14]
Downstream of AMPA-receptor activation, ketamine rapidly increases the release of brain-derived neurotrophic factor (BDNF), a protein central to neuronal growth and plasticity, acting through its TrkB receptor. In preclinical models, ketamine's rapid antidepressant-like effects depend on this fast BDNF synthesis — when BDNF signaling is blocked, the effect is lost.[12][14]
BDNF–TrkB signaling converges on the mTOR pathway, which drives the formation of new dendritic-spine synapses in the prefrontal cortex within hours. Landmark animal research found that blocking mTOR abolishes both the new synapses and the behavioral response, and later live-imaging work tied the restoration of these connections to sustained recovery. This synaptic-plasticity model helps explain how benefit can emerge far faster than with traditional antidepressants.[11][15]
Anhedonia — the loss of interest or pleasure — is a core feature of depression that often resists standard treatment. Neuroimaging research has linked ketamine's rapid reduction in anhedonia to changes in reward-related brain regions, including the ventral striatum and anterior cingulate cortex, suggesting a direct effect on the circuitry that governs motivation and reward rather than mood alone.[16]
In plain terms: ketamine briefly increases glutamate signaling, which prompts the release of BDNF and activates growth pathways that can strengthen and rebuild synaptic connections involved in mood, motivation, and reward. Much of this detail comes from preclinical (laboratory and animal) studies; translating it precisely to every patient is still an active area of research.
The early, peer-reviewed trials that established ketamine's rapid antidepressant signal.
A small double-blind, placebo-controlled crossover study reported that a single intravenous dose of ketamine was associated with rapid improvement in depressive symptoms — sometimes within hours — far faster than conventional antidepressants. It was an early signal that opened the field, not proof of long-term benefit.[1]
A National Institute of Mental Health randomized controlled trial found that a single IV ketamine infusion produced rapid, robust reductions in depressive symptoms in patients with treatment-resistant depression, often within about 24 hours. The effect for many participants was meaningful but temporary, underscoring the need for a broader treatment plan.[2]
A two-site randomized controlled trial compared IV ketamine to midazolam (an active placebo) in treatment-resistant major depression and found ketamine was associated with greater symptom improvement at 24 hours. Using an active comparator helped address the question of whether early benefit was simply a placebo response.[3]
How the field has matured — from a major regulatory approval to expert reviews of the accumulated data.
The FDA approved esketamine nasal spray — a ketamine-derived medication — for treatment-resistant depression, with labeling later extended to depressive symptoms accompanied by acute suicidal ideation or behavior. It must be given under medical supervision through a restricted REMS program. This is distinct from off-label IV racemic ketamine.[4][8]
An international expert review synthesized the accumulated evidence for ketamine and esketamine in treatment-resistant depression. It described rapid antidepressant effects in carefully selected patients while emphasizing that responses vary, durability differs between people, and ongoing monitoring and maintenance planning matter.[5]
Active areas of study beyond depression. These uses are off-label or investigational, and some remain confined to the laboratory.
Beyond mood, IV ketamine is used off-label for certain treatment-resistant chronic-pain conditions. Multi-society consensus guidelines from anesthesiology and pain-medicine organizations concluded there is moderate evidence supporting ketamine infusions for some neuropathic pain syndromes — such as complex regional pain syndrome — likely by reversing 'central sensitization' in the nervous system. Evidence quality varies and careful patient selection is essential.[17]
Because the NMDA receptor is involved in glutamate-mediated excitotoxicity — a process implicated in neuroinflammatory and neurodegenerative disorders — researchers are studying whether NMDA antagonism might have neuroprotective or anti-inflammatory effects. A 2025 narrative review summarized this emerging work across several neurological and psychiatric conditions. Importantly, this research is largely preclinical and early: ketamine is not an approved or established treatment for conditions such as multiple sclerosis, and we do not offer it for that purpose.[18]
At Infinity Medical Wellness, ketamine therapy is delivered as part of an individualized plan. Depending on a patient's evaluation, Diana may integrate complementary IV wellness therapies — such as NAD+ infusions and select nutrient or peptide protocols — alongside ketamine to support overall recovery and well-being.
To be clear about the evidence: NAD+ (a cellular coenzyme involved in energy metabolism) and similar supportive therapies are pursued for general wellness, and rigorous clinical trials specifically testing a ketamine-plus-NAD+ "synergy" are limited. Any combination is decided case-by-case during a clinical consultation, with realistic expectations and no guarantee of outcome.
Learn more on our NAD+ & integrative IV wellness guide.
For context only. The studies below involve compounds we do NOT offer.
Important: Infinity Medical Wellness provides medically supervised ketamine therapy only. Psilocybin and MDMA-assisted therapy are investigational, not FDA-approved for general clinical use, and are not offered here. They are included purely to help you understand where ketamine fits within the larger psychedelic-medicine conversation.
A phase 2 trial published in the New England Journal of Medicine compared psilocybin-assisted therapy with a commonly used SSRI for depression. On the study's primary measure there was no statistically significant difference between groups, though some secondary measures favored psilocybin. Psilocybin remains investigational and is not FDA-approved for general clinical use.[6]
A phase 3 randomized controlled trial in Nature Medicine reported that MDMA-assisted therapy reduced PTSD symptom severity compared with placebo plus therapy in people with severe PTSD. MDMA-assisted therapy remains investigational, is not FDA-approved, and continues to move through regulatory review.[7]
Research into ketamine and psychedelic-assisted therapies is moving quickly, with new trials, meta-analyses, and regulatory decisions appearing regularly. Promising early findings still need larger, longer studies to clarify who benefits most, how to sustain improvements, and how these therapies compare with established care.
If you'd like to understand how the current evidence applies to your situation, the best next step is a conversation with a licensed provider who can review your history and goals.
How the treatment works, what it helps, and what a session is like.
A step-by-step walk-through of your first session.
How IV ketamine compares to FDA-approved esketamine.
How NAD+ and integrative IV wellness may fit alongside ketamine care.
Begin with a consultation. We'll review your history, answer your questions, and help you decide if IV ketamine therapy is right for you.
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Consultations are scheduled privately by phone and email — no online intake form.
Medical disclaimer. This page is for educational purposes only and does not provide medical advice, diagnosis, or treatment. Ketamine is used off-label for mental health conditions, is not appropriate for everyone, and individual results vary. Candidacy is determined only after a clinical evaluation by a licensed medical provider. If you are in crisis or thinking about harming yourself, call or text 988 or go to the nearest emergency room.
