Racemic Ketamine vs. R-Ketamine vs. S-Ketamine: What's the Difference? | ISHA Health


Racemic Ketamine Vs R-Ketamine Vs S-Ketamine: What You Need to Know | Isha Health

Written by

Isha Team


August 17, 2022


May 2, 2023

If you've been following developments in the field of mental health, you may have heard about Ketamine. Ketamine is a dissociative anesthetic that has been used for many years in clinical settings for pain management and anesthesia. However, in recent years, Ketamine has been found to have a powerful effect on mental health disorders such as depression, bipolar disorders, anxiety disorders, and PTSD.

Ketamine is a chiral molecule, meaning it has two enantiomers - R-Ketamine and S-Ketamine. When both enantiomers are combined in equal parts, it is called Racemic Ketamine. Recent research suggests that both enantiomers have distinct effects on the brain, and it's important to understand the differences between them to get the most out of ketamine-assisted therapy.

In this blog post, we will explore the differences between Racemic Ketamine, R-Ketamine, and S-Ketamine, and their effects on mental health disorders. We will also examine the comparative effects of R/S Racemic Ketamine and S-Ketamine in clinical studies, as well as the neuroplasticity of both enantiomers.

Racemic Ketamine

Racemic Ketamine is a mixture of both R-Ketamine and S-Ketamine in equal parts. It is the most commonly used form of Ketamine in clinical settings. The use of Racemic Ketamine has been shown to be effective in the treatment of depression, anxiety disorders, bipolar disorders, and PTSD.

In clinical studies, Racemic Ketamine has been found to produce a rapid and robust antidepressant effect, with patients showing significant improvement within hours of treatment. This rapid effect is in contrast to traditional antidepressants, which can take several weeks to produce a therapeutic effect.

The exact mechanism of action of Racemic Ketamine is not fully understood, but it is believed to work by increasing the activity of glutamate, a neurotransmitter that is involved in neural plasticity and the formation of new neural connections. It is also believed to work by inhibiting the activity of the N-methyl-D-aspartate (NMDA) receptor, which is involved in learning, memory, and neural plasticity.

While Racemic Ketamine has been shown to be effective in the treatment of depression, anxiety disorders, bipolar disorders, and PTSD, it does have some side effects. The most common side effects of Racemic Ketamine include dissociation, hallucinations, and confusion. These side effects are usually short-lived and resolve quickly once the medication wears off.


R-Ketamine is the pure, isolated form of the R-enantiomer of Ketamine. It has been found to have a longer-lasting antidepressant effect than Racemic Ketamine. In addition, R-Ketamine has been shown to produce fewer side effects than Racemic Ketamine, particularly in terms of dissociation and psychotomimetic effects.

In clinical studies, R-Ketamine has been found to produce a rapid and sustained antidepressant effect, with patients showing significant improvement within hours of treatment that lasts for several days. It is believed that the longer-lasting effect of R-Ketamine is due to its ability to bind more selectively to the NMDA receptor.


S-Ketamine, also known as esketamine, is the enantiomer of ketamine that is known to be responsible for most of the antidepressant effects of the racemic mixture. In fact, S-ketamine has been approved by the US Food and Drug Administration (FDA) as a treatment for treatment-resistant depression in adults in the form of a nasal spray called Spravato.

Clinical studies have shown that S-ketamine has rapid antidepressant effects, with some patients reporting a reduction in symptoms within hours of administration. This is in contrast to traditional antidepressant medications that can take weeks or even months to take effect. Additionally, S-ketamine has been shown to have a longer duration of action than R-ketamine, which may make it a more practical option for maintenance therapy.

However, like racemic ketamine, S-ketamine can also cause side effects such as dissociation, dizziness, and nausea. It can also have an addictive potential, which is why it is only available through a restricted distribution system and can only be administered in a certified healthcare setting under the supervision of a healthcare professional.

Comparing the Effects of Racemic Ketamine and S-Ketamine

Numerous studies have compared the effects of racemic ketamine and S-ketamine in the treatment of depression and other mental health disorders. One study published in the Journal of Psychopharmacology found that S-ketamine was more effective than racemic ketamine in reducing symptoms of depression and anxiety in patients with treatment-resistant depression.

Another study published in the Journal of Affective Disorders compared the effects of racemic ketamine and S-ketamine in patients with bipolar disorder. The study found that both racemic ketamine and S-ketamine were effective in reducing symptoms of depression and mania, but S-ketamine was more effective in reducing suicidal ideation.

While these studies suggest that S-ketamine may be more effective than racemic ketamine in treating certain mental health disorders, more research is needed to fully understand the differences between the two enantiomers and their effects on the brain.

Neuroplasticity of R-Ketamine and S-Ketamine

Recent research has shown that both R-ketamine and S-ketamine have distinct effects on neuroplasticity in the brain. Neuroplasticity refers to the brain's ability to change and adapt in response to experiences and is believed to play a role in the development of mental health disorders.

A study published in the journal Molecular Psychiatry found that S-ketamine was more effective than R-ketamine in increasing the production of brain-derived neurotrophic factor (BDNF), a protein that is involved in the growth and maintenance of neurons in the brain. This suggests that S-ketamine may have a greater impact on neuroplasticity and may be more effective in treating mental health disorders that are associated with decreased levels of BDNF, such as depression and PTSD.

Another study published in the journal Translational Psychiatry found that R-ketamine was more effective than S-ketamine in promoting the formation of new synapses in the brain. Synapses are the connections between neurons in the brain that allow for communication between brain cells. This suggests that R-ketamine may be more effective in treating mental health disorders that are associated with decreased synaptic connectivity, such as schizophrenia.

These findings highlight the importance of understanding the specific effects of each enantiomer of ketamine and tailoring treatment accordingly.

Starting Your Ketamine-Assisted Therapy Journey

If you're considering ketamine-assisted therapy for the treatment of mental health disorders, it's important to approach it with a clear mind and a realistic understanding of what it entails. Here are some things to keep in mind:

Choose a qualified provider: Not all ketamine providers are created equal. Look for a licensed and experienced medical professional who has specialized training in ketamine-assisted therapy.

Consider the cost: Ketamine-assisted therapy can be expensive, especially if it's not covered by insurance. It's important to weigh the potential benefits against the cost and determine if it's a feasible option for you.

Be prepared for the experience: Ketamine-assisted therapy is not a quick fix, and it's not for everyone. It's important to be mentally and emotionally prepared for the experience and to approach it with an open mind and a willingness to explore your innermost thoughts and feelings.

Follow up with aftercare: Ketamine-assisted therapy is just one part of a comprehensive treatment plan. It's important to follow up with aftercare, such as therapy and support groups, to maintain the benefits of the treatment.

At Isha Health, we offer personalized online ketamine-assisted therapy sessions with a licensed medical professional. Our sessions are tailored to meet your individual needs and goals, and we prioritize safety and effectiveness above all else.


Ketamine-assisted therapy has emerged as a promising treatment option for mental health disorders such as depression, anxiety, bipolar disorder, and PTSD. While there are different forms of ketamine, including racemic ketamine, R-ketamine, and S-ketamine, research suggests that S-ketamine may be more effective and have fewer side effects.

It's important to approach ketamine-assisted therapy with a clear mind and a realistic understanding of what it entails. Choosing a qualified provider, considering the cost, being prepared for the experience, and following up with aftercare are all important steps in ensuring a safe and effective treatment.

At Isha Health, we're committed to providing personalized, online ketamine-assisted therapy sessions that prioritize safety, effectiveness, and individualized care. Contact us today to learn more about how we can help you start your journey towards improved mental health.


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