The Moment of Infusion

When ketamine enters the bloodstream via IV, the delivery method used at Soft Reboot Wellness, it reaches peak plasma concentration quickly and crosses the blood-brain barrier efficiently. Within minutes of infusion onset, the drug begins binding to NMDA receptors: N-methyl-D-aspartate receptors that sit on the surface of neurons and play a central role in regulating how those neurons communicate.

NMDA receptors are part of the glutamate system (the brain’s primary excitatory neurotransmitter network), responsible for the majority of signaling between neurons (National Institutes of Health). Under normal circumstances, NMDA receptors open in response to glutamate binding and allow ions to flow across the neuron membrane, initiating electrical signals. Ketamine enters the receptor channel and blocks this flow. The receptor is occupied but not activated.

This blockade sounds suppressive, and in one narrow sense it is. But the downstream consequence is counterintuitive: blocking NMDA receptors transiently causes a compensatory surge of glutamate release in surrounding circuits. That surplus glutamate then activates a different receptor type, AMPA receptors, which triggers a cascade of intracellular signaling that ultimately promotes synaptic plasticity, or the strengthening and reorganization of neural connections (National Institutes of Health).

The Neuroplasticity Cascade

The AMPA activation that follows NMDA blockade sets off a series of events inside the neuron. Among the most important is the production and release of BDNF (brain-derived neurotrophic factor), a protein that supports the growth, survival, and formation of new synaptic connections (National Institutes of Health). BDNF is often called the brain’s fertilizer, and the analogy holds: it is what allows neurons to grow new dendritic spines: the tiny projections through which neurons receive signals from neighboring cells.

In a brain affected by depression or PTSD, this infrastructure has often been degraded. Chronic stress hormones suppress BDNF, weaken synaptic connections, and reduce the density of dendritic spines in regions like the prefrontal cortex and hippocampus, areas central to mood regulation, decision-making, and emotional context. Ketamine’s BDNF-stimulating effect begins reversing this within hours of infusion, which is the most credible explanation for why antidepressant effects appear so quickly compared to medications that require weeks to achieve similar downstream results.

Research published in Nature also points to a secondary mechanism: ketamine appears to interact with the brain’s opioid system in ways that may contribute independently to its antidepressant action (Nature). This suggests ketamine is not a single-pathway drug, it works through at least two distinct systems simultaneously, which may explain both its breadth of effect across different conditions and the variation in how individual patients respond.

Why IV Delivery Matters

Ketamine can be administered in several ways, intravenously, intramuscularly, as an intranasal spray, or as oral lozenges. Each route produces a different pharmacokinetic profile: different rates of absorption, different peak concentrations, different durations of effect.

IV delivery, the method used at Soft Reboot Wellness, produces the most precise and controllable pharmacological profile. The dose enters the bloodstream directly, with no absorption variability from the gut or nasal mucosa. Peak plasma levels are reached quickly and predictably. The physician can adjust the infusion rate in real time based on the patient’s response. For patients whose treatment history involves partial or inconsistent responses to other medication forms, this precision matters.

Dr. Sara Herman, our Harvard-trained anesthesiologist with more than two decades of experience administering IV medications, personally provides and monitors all infusion sessions. The clinical environment at our Menlo Park clinic includes continuous vital sign monitoring and immediate access to intervention if needed. The dose used in mental health treatment is a fraction of what is administered for surgical anesthesia, sub-anesthetic dosing is well-tolerated and carries a well-established safety profile when administered by qualified clinicians in an appropriately equipped setting.

The Hours and Days After Infusion

The acute pharmacological effects of a ketamine infusion, the altered perception, the dissociative quality, resolve fully within one to two hours of infusion completion. What persists is the neuroplastic change the infusion has initiated. BDNF levels remain elevated. New synaptic connections are forming. The brain’s default circuitry, including the default mode network, which governs self-referential thinking and is often overactive in depression, is temporarily reorganized.

The 48 to 72 hours following infusion represent what many clinicians describe as an integration window: the period during which the brain is most receptive to the consolidation of new patterns. This is why the timing of integration work matters. At Soft Reboot Wellness, our KAP program is structured specifically around this window, the preparation session happens before infusion, and the integration coaching sessions are timed to the period when the brain is most able to use the new neural architecture the infusion has created.

Research confirms that a series of infusions produces cumulative neuroplastic benefit, repeated sessions extend and deepen the changes initiated by the first (National Institutes of Health). Our standard induction protocol involves four to six IV infusions over four to six weeks, with the specific protocol calibrated to your clinical response and informed by mood data tracked through the Osmind platform throughout your treatment.

What the Pharmacology Means for Candidacy

The same mechanism that makes ketamine effective for many patients also creates genuine contraindications for others. Because ketamine increases blood pressure transiently during infusion, patients with uncontrolled hypertension or certain cardiovascular conditions require additional clinical judgment before proceeding. Patients with a history of psychosis or certain personality disorders may not be appropriate candidates, as the dissociative properties of ketamine carry different risk profiles in those populations. Active substance use disorders also require careful evaluation.

This is why the consultation and review process at Soft Reboot Wellness is thorough, not perfunctory. We review your full medical and psychiatric history, your current medications, and your prior treatment responses before making any recommendation. Results vary by individual, and we encourage you to discuss all options with your existing healthcare provider before deciding whether IV ketamine therapy is appropriate for you.

IV ketamine for mental health is an off-label treatment, and insurance coverage is not standard. We recommend contacting our team at 650-419-3330 or hello@softrebootwellness.com before your consultation so that cost is a clear part of your decision-making rather than a surprise afterward.

Frequently Asked Questions

Why does IV ketamine work faster than oral or nasal forms? IV delivery bypasses the absorption variability that affects oral and intranasal routes. The medication enters the bloodstream directly, reaching predictable peak plasma concentrations quickly and allowing the administering physician to adjust the dose in real time. This precision produces a more reliable pharmacological effect, which is one reason IV remains the method with the strongest clinical evidence base for psychiatric indications.

What is the difference between the acute effects of ketamine and the lasting antidepressant effects? The acute effects, altered perception, dissociation, dreamlike quality, are a product of active NMDA receptor blockade during the infusion and resolve within one to two hours. The lasting antidepressant effects are a product of the downstream neuroplastic cascade: BDNF elevation, synaptic connection formation, and dendritic spine growth that continue developing in the hours and days after the infusion ends. The experience and the therapeutic mechanism are related but distinct.

Does ketamine lose effectiveness over time with repeated infusions? Some patients do find that the response to maintenance infusions shifts over time, either diminishing or requiring different spacing. This is not universal, and the clinical picture varies considerably between individuals. We monitor response throughout treatment using mood tracking data and adjust the protocol accordingly. Some patients require only occasional boosters; others benefit from a more regular maintenance schedule.

How does the opioid system interaction affect the risk of dependence? The opioid system interaction identified in recent research does not mean ketamine functions as an opioid or carries comparable dependence risk. The interaction appears to occur at different receptor subtypes and at a different scale than classical opioid medications. Ketamine does carry its own potential for misuse at high doses outside clinical settings, which is one reason administration in a supervised clinical environment with appropriate screening is medically required.

Key Takeaways

• IV ketamine blocks NMDA receptors, triggering a compensatory glutamate surge that activates AMPA receptors and initiates a neuroplasticity cascade, the core mechanism of its antidepressant effect.
• BDNF elevation following infusion supports new synaptic connection formation in brain regions degraded by chronic depression or trauma.
• Emerging research suggests ketamine also interacts with the opioid system as a secondary pathway, pointing to a multi-mechanism pharmacological profile.
• IV delivery produces the most precise and controllable pharmacokinetic profile; Dr. Herman personally monitors all infusion sessions at our Menlo Park clinic.
• The 48 to 72 hours following infusion are the prime integration window; our KAP program is timed around this period to maximize the value of the neuroplastic changes ketamine initiates.

Knowing what ketamine does in the body, not just that it works, but how and why, puts you in a better position to decide whether it belongs in your treatment plan. We are glad to walk through that conversation in depth. Call us at 650-419-3330 or email hello@softrebootwellness.com to start the conversation.

References

1. National Institutes of Health. The glutamate neurotransmitter system is the brain’s primary excitatory system and a key pathway through which ketamine produces its therapeutic effects. https://www.ncbi.nlm.nih.gov/books/NBK62187/
2. National Institutes of Health. Ketamine promotes neuroplasticity, the brain’s ability to form new neural connections, which may explain its rapid and sustained antidepressant effects. https://pmc.ncbi.nlm.nih.gov/articles/PMC8190578/
3. National Institutes of Health. Ketamine has been shown to increase brain-derived neurotrophic factor (BDNF), a protein essential for neuron growth and long-term mood regulation. https://pubmed.ncbi.nlm.nih.gov/39684808/
4. Nature. Research suggests ketamine may also produce antidepressant effects by interacting with the brain’s opioid system, pointing to multiple mechanisms of action. https://www.nature.com/articles/s41591-025-03800-w
5. National Institutes of Health. Multiple ketamine infusion sessions have been shown to produce cumulative antidepressant benefits and extend remission periods in patients with depression. https://pmc.ncbi.nlm.nih.gov/articles/PMC6236511/

Medical Disclaimer: The information in this blog is for educational purposes only and does not constitute medical advice. Ketamine therapy should only be pursued under the supervision of a licensed medical provider familiar with your full medical and psychiatric history. Individual results vary. Off-label treatments like IV ketamine for mental health conditions carry risks that should be discussed thoroughly with a qualified provider before beginning. If you are experiencing a mental health crisis or thoughts of self-harm, please call or text 988 to reach the Suicide and Crisis Lifeline or go to your nearest emergency room.

Reviewed by Dr. Sara Herman

The post How Ketamine Works in the Body: From Infusion to Brain Changes appeared first on Soft Reboot Wellness.

What Ketamine Does in the Brain

Ketamine’s primary action is on NMDA receptors (N-methyl-D-aspartate receptors), which are part of the glutamate system (the brain’s main excitatory neurotransmitter network). By temporarily blocking these receptors, ketamine triggers a cascade of downstream effects that standard antidepressants (which work through serotonin and norepinephrine) do not produce (National Institutes of Health).

The most clinically important of these downstream effects is a rapid increase in synaptic plasticity: the brain’s ability to strengthen and reorganize connections between neurons. In depression, anxiety, and PTSD, neural circuits involved in mood regulation, fear processing, and self-referential thinking tend to become rigid and entrenched. Ketamine disrupts that rigidity. Research shows it promotes neuroplasticity in ways that standard antidepressants approximate only after weeks of daily dosing, and ketamine can produce this effect within hours of a single infusion (National Institutes of Health).

Ketamine also increases BDNF (brain-derived neurotrophic factor), a protein that supports neuron survival, growth, and the formation of new synaptic connections (National Institutes of Health). BDNF is often depleted in people with depression, and restoring it is thought to be one of the mechanisms through which antidepressant effects are sustained beyond the immediate post-infusion period. Additionally, emerging research published in Nature suggests ketamine may interact with the brain’s opioid system as a secondary mechanism, pointing to a treatment with more than one pathway of therapeutic action (Nature).

What Ketamine Therapy Does Clinically

The clinical picture that emerges from research is striking. Ketamine produces rapid and significant antidepressant effects, often within hours, in patients who have not responded to multiple prior treatments (National Institutes of Health). For patients with treatment-resistant depression, anxiety, or PTSD, this speed is not a minor detail. It represents a fundamentally different experience of treatment: rather than waiting six to eight weeks to know whether a medication is working, patients often know within days.

The effects of a single infusion are real but typically time-limited, most patients experience meaningful symptom relief for days to weeks following the first session. This is why a series of infusions is the standard approach rather than a single treatment. Research shows that both single and repeated ketamine infusions can treat depression and related conditions, with repeated infusions extending the duration and depth of benefit (American Journal of Psychiatry). Our standard induction protocol at Soft Reboot Wellness involves four to six IV infusions over four to six weeks, personalized to your clinical response.

Ketamine-assisted psychotherapy (KAP) pairs infusions with structured preparation and integration work, and research supports the combination producing more durable outcomes than ketamine alone (National Institutes of Health). Our KAP program includes a preparation session, two 2-hour in-office infusion sessions, and integration coaching with a certified psychedelic integration coach.

What the Experience Is Like

Patients considering ketamine therapy understandably want to know what they are signing up for on a sensory level. The honest answer is that experiences vary, but certain qualities are consistent.

During an IV ketamine infusion, patients typically notice the onset of effects within minutes. The experience often includes a sense of mental quieting, a loosening of the grip of ordinary anxious or depressive thought patterns. Some patients describe mild perceptual shifts: altered time perception, a floating or dreamlike quality, or vivid inner imagery. Some experience emotional content that feels meaningful or revealing. Others find it largely calm and neutral.

What the experience is not: frightening in the way many patients expect. The dissociative quality that makes some people hesitant tends, in practice, to feel more like relief than threat for most patients in a supervised clinical setting. Dr. Sara Herman personally monitors all infusion sessions at our Menlo Park clinic. Vital signs are tracked continuously. The altered state resolves fully before patients leave, typically within an hour of the infusion ending, and patients are required to have a ride home.

The 48 to 72 hours following a session are considered particularly significant for integration: the neuroplastic window opened by the infusion is still active, and this is an optimal time for reflection, journaling, and the kind of internal work our integration coaching is designed to support.

What Ketamine Therapy Does Not Do

Being clear about limitations is as important as explaining the evidence. Ketamine therapy is not a cure, and we do not present it as one. Results vary by individual, and some patients do not respond to ketamine in the way they hope. Some patients require ongoing maintenance infusions, single booster sessions typically scheduled three weeks to three months after the initial series, to sustain the benefits they achieve during induction.

Ketamine’s mental health applications are also off-label. The medication has been FDA-approved as an anesthetic since 1970, and its safety profile at therapeutic doses is well-established. But its use for depression, anxiety, and PTSD has not received formal FDA approval for those specific psychiatric indications, which means insurance coverage is inconsistent. We are transparent about this from the start of the process, contact our team at 650-419-3330 or hello@softrebootwellness.com before your consultation to discuss the financial realities clearly.

Ketamine is also not appropriate for everyone. Patients with certain psychiatric histories, active substance use disorders, or specific medical conditions may not be suitable candidates. Every patient undergoes a thorough medical and psychiatric review before any treatment is recommended, and we will tell you honestly if we think a different approach is better suited to your situation.

How Soft Reboot’s Approach Shapes the Outcome

The same medication administered in different contexts produces different results. This is not a marketing claim. It is a documented feature of how ketamine works. Research on KAP shows that the integration of psychotherapy with infusion treatment improves outcomes relative to infusion alone, which is why our clinical model is built around that integration rather than treating it as optional (National Institutes of Health).

Dr. Herman’s credentials reflect this philosophy directly. She holds an Advanced Certificate in Psilocybin-Assisted Therapy from the Integrative Psychiatry Institute, has completed training in Internal Family Systems (IFS) combined with ketamine-assisted psychotherapy, and has personally guided more than 10,000 patients through anesthesia, pain management, and ketamine therapy over her career. Dr. Natasha, our board-certified anesthesiologist who trained at UCSF, brings additional clinical depth to the monitoring and safety dimension of every session.

We also use the Osmind EHR and mood-tracking platform to document your progress throughout treatment. This means your response is tracked objectively, not reconstructed from memory at occasional check-ins, and can be reviewed alongside your existing treatment team if you have one. We actively coordinate with outside providers, with your consent, because we believe integrative care produces better outcomes than any single clinic working in isolation. You can learn more on our frequently asked questions page.

Frequently Asked Questions

How long does the antidepressant effect of ketamine last after an infusion series? For most patients completing a standard induction series, the reduction in depressive symptoms lasts approximately five weeks on average, with a range of roughly three weeks to two months. Individual responses vary considerably. Maintenance infusions, single booster sessions, can be used to sustain the benefit when symptoms begin to return, and some patients find they need these infrequently while others use them more regularly.

Does ketamine therapy work better for some conditions than others? The strongest evidence base exists for treatment-resistant depression and PTSD, both of which are conditions we treat at Soft Reboot Wellness. There is also meaningful clinical evidence for ketamine’s effectiveness in anxiety. We assess the fit between your diagnosis and the available evidence during your consultation, so our recommendation is grounded in what the research actually supports for your specific presentation.

Will I remember my infusion sessions? Most patients retain some memory of the experience, though the altered quality of consciousness during infusion means those memories may be impressionistic rather than sequential. Patients are encouraged to journal or reflect in the hours and days following their session, while the experience is still accessible. Our integration coaching component is specifically designed to help you make sense of and work with whatever arises.

Can ketamine therapy be used alongside talk therapy or other psychiatric treatment? Yes, and we actively encourage it. Ketamine therapy works well as a complement to ongoing psychotherapy, many patients find their therapy deepens during and after a ketamine series, precisely because the neuroplastic window makes habitual thought patterns more available for examination. We coordinate with outside therapists and psychiatrists with your consent throughout your treatment.

Key Takeaways

• Ketamine works through NMDA receptor blockade in the glutamate system, triggering rapid neuroplasticity and BDNF increases that standard antidepressants do not produce on the same timeline.
• Clinical research documents significant antidepressant and anti-PTSD effects that often appear within hours, a fundamentally different experience from the weeks-long timeline of standard medications.
• The experience during infusion is time-limited, monitored, and for most patients more calming than distressing.
• Ketamine is an off-label treatment for mental health conditions; insurance coverage is inconsistent, and candidacy is determined individually through a medical and psychiatric review.
• Results vary by individual; combining ketamine with integration support, as in our KAP program, is associated with more durable outcomes.

Understanding what ketamine therapy does is the first step toward knowing whether it might be right for you. We are glad to continue that conversation in person. Call us at 650-419-3330 or email hello@softrebootwellness.com to schedule a consultation at our Menlo Park clinic.

References

1. National Institutes of Health. Ketamine works by blocking NMDA receptors in the glutamate system, producing rapid antidepressant effects through a mechanism distinct from traditional antidepressants. https://pmc.ncbi.nlm.nih.gov/articles/PMC5148235/
2. National Institutes of Health. NMDA receptors play a central role in synaptic plasticity and are the primary target of ketamine’s antidepressant action. https://pmc.ncbi.nlm.nih.gov/articles/PMC9965111/
3. National Institutes of Health. Ketamine has been shown to increase brain-derived neurotrophic factor (BDNF), a protein essential for neuron growth and long-term mood regulation. https://pubmed.ncbi.nlm.nih.gov/39684808/
4. Nature. Research suggests ketamine may also produce antidepressant effects by interacting with the brain’s opioid system, pointing to multiple mechanisms of action. https://www.nature.com/articles/s41591-025-03800-w
5. National Institutes of Health. Ketamine has demonstrated rapid and significant antidepressant effects in clinical studies, often working within hours when traditional medications take weeks. https://www.nimh.nih.gov/news/science-updates/2024/new-hope-for-rapid-acting-depression-treatment
6. American Journal of Psychiatry. Research shows that both single and repeated ketamine infusions can treat treatment-resistant depression, with maintenance infusions extending the duration of benefit. https://psychiatryonline.org/doi/10.1176/appi.ajp.2018.18070834
7. National Institutes of Health. Research supports the integration of psychotherapy with ketamine treatment, showing that the combination may produce more durable and meaningful outcomes than ketamine alone. https://pmc.ncbi.nlm.nih.gov/articles/PMC9207256/

Medical Disclaimer: The information in this blog is for educational purposes only and does not constitute medical advice. Ketamine therapy should only be pursued under the supervision of a licensed medical provider familiar with your full medical and psychiatric history. Individual results vary. Off-label treatments like IV ketamine for mental health conditions carry risks that should be discussed thoroughly with a qualified provider before beginning. If you are experiencing a mental health crisis or thoughts of self-harm, please call or text 988 to reach the Suicide and Crisis Lifeline or go to your nearest emergency room.

Reviewed by Dr. Sara Herman

The post What Does Ketamine Therapy Actually Do? A Complete Guide appeared first on Soft Reboot Wellness.