The short answer is it depends on your unique physiology, mental health history, treatment goals, and whether or not ketamine is combined with therapy.
The Immediate Effects (Hours to Days)
Most people begin to feel improvements within hours of a ketamine session.
This is part of what makes ketamine so revolutionary, as traditional antidepressants may take 4 to 6 weeks to kick in (if they work at all). Ketamine can lift the weight of depression in a single afternoon.
These immediate effects reported may include:
- Reduction in suicidal thoughts
- Increased emotional clarity
- Sense of peace or detachment from negative self-beliefs
- Boost in motivation and energy
However, for some, these changes can feel subtle, like a slight shift in emotional weather rather than a dramatic breakthrough. Either way, the initial lift typically lasts a few days to a week after a single dose.
The Short-Term Relief (1 to 3 Weeks)
In clinical research and real-world experience at Eulas, the antidepressant effects of ketamine tend to peak in the first 1 to 7 days after a dose and then gradually taper off.
- One dose can last anywhere from a few days to a couple of weeks.
- Multiple doses, especially when paired with therapy, can extend these benefits substantially.
This is why most protocols, including our six-week ketamine therapy programme, must involve a series of ongoing dedicated psychotherapy sessions as a core part of treatment.
The Long-Term Change (Weeks to Months)
Ketamine itself is metabolised quickly by the body, but the neuroplastic effects (the brain’s ability to rewire and form new connections) can last much longer. This is where therapy makes all the difference.
When used in conjunction with psychotherapy, the changes catalysed by ketamine can be reinforced, integrated, and also sustained. Patients often describe ketamine as opening a door, but it’s the work done after the experience, during integration sessions, that allows a lasting shift to occur.
Many report meaningful relief that lasts for several months, particularly when supported by:
- Regular psychotherapy
- Mindfulness and self-care practices
- Lifestyle changes
- Ongoing support from our clinical team
Why Do Effects Vary from Person to Person?
Everyone’s brain chemistry, life history, and mental health journey is different. Some of the factors that influence how long ketamine works for depression include:
Severity and Duration of Depression
Ketamine therapy is shown to be one of the most effective methods for treatment-resistant depression. However, it may require more sessions or ongoing maintenance to maintain benefits.
Dosage and Administration Method
At Eulas, our expert team determines the most effective and safest dose for each patient. IV ketamine infusion tends to offer the most immediate and intense effect, whereas oral or nasal treatments may be gentler and more flexible.
Therapeutic Support
Without therapy, ketamine’s effects may wear off quickly. But with skilled guidance, individuals are more likely to make lasting changes in how they think, feel, and relate to themselves.
Number and Frequency of Sessions
A single session may be enough to shift suicidal ideation or offer short-term relief. But a structured programme, like our ketamine therapy course with integration therapy, is where the long-term impact is most often seen.
