Ketamine vs Esketamine: Key Differences Explained

When traditional treatments haven't worked, the search for relief becomes its own burden. About one-third of people with major depression don't respond to standard medications, which is why ketamine-based treatments have gained attention as a different path forward.

But there are two main options, and they're not the same. Racemic ketamine contains the complete molecule, and some research suggests it may offer advantages in speed or magnitude of response. Esketamine (Spravato) uses half the molecule and comes with access and logistical considerations.

This guide explains the differences and what they mean for your decision, including why ketamine therapy you can do at home, has become a compelling option for many.

What Is Ketamine?

Ketamine is a medication with over 50 years of clinical safety data, FDA-approved as an anesthetic since 1970. Doctors have used it off-label since the early 2000s for depression, anxiety, PTSD, trauma, chronic pain, and other conditions.

Unlike traditional psychiatric medications that adjust serotonin over four to six weeks, ketamine works through the glutamate system—your brain's primary excitatory neurotransmitter. This different pathway is why ketamine can produce noticeable effects within hours rather than weeks, making it particularly appealing for people who haven't responded to conventional treatments.

The effects of a single ketamine session typically last one to three weeks, which is why most treatment protocols involve multiple sessions. This isn't a one-and-done solution—but for many people, the relatively rapid relief provides a window to build momentum with therapy and other support.

Ketamine is a "racemic mixture," meaning it contains two mirror-image molecules: S-ketamine and R-ketamine. This distinction matters—and we'll explain why shortly. Ketamine can be administered via IV infusion, intramuscular injection, or sublingual tablets.

What Is Esketamine (Spravato)?

Esketamine uses only one half of the ketamine molecule—the S-ketamine portion, isolated and formulated as a nasal spray called Spravato. It received FDA approval in March 2019 for treatment-resistant depression and major depressive disorder with acute suicidal ideation.

The spray is self-administered under medical supervision at certified clinics. Because of risks including sedation and dissociation, the FDA requires a REMS program—staff monitor blood pressure and symptoms throughout a mandatory two-hour observation period before patients are cleared to leave.

Treatment typically starts with twice-weekly visits for the first month (eight sessions minimum), then tapers to weekly or biweekly depending on response.

What's the Difference Between S-Ketamine and R-Ketamine?

This distinction is central to understanding which treatment may work better.

Racemic ketamine contains both S-ketamine and R-ketamine working together. Esketamine contains only S-ketamine—the R-ketamine half is removed.

Why does this matter? Early research suggests that R-ketamine may have longer-lasting effects with fewer side effects than S-ketamine alone, though human evidence is still preliminary and largely based on limited trials. A clinical study of 153 patients found that IV racemic ketamine produced faster and greater improvement than intranasal esketamine. The delivery methods differed, and broader meta-analyses show mixed results—but the findings add to the case for exploring the complete molecule.

So what does this mean for you? Racemic ketamine gives you both components working together—which some studies suggest may offer advantages, though the evidence is still evolving. For people weighing their options, this research is one reason at-home racemic ketamine programs have drawn interest as an alternative to esketamine clinics.

How Do Ketamine and Esketamine Work in the Brain?

Both ketamine and esketamine block NMDA receptors, triggering changes in your brain's glutamate system. This rapidly increases Brain-Derived Neurotrophic Factor (BDNF)—a protein that helps brain cells grow and form new connections.

Mental health conditions appear to physically affect brain structures, weakening connections in areas that regulate mood and stress. According to research in Nature, ketamine helps rebuild these pathways by promoting synapse formation and enhancing neuroplasticity—your brain's ability to form new neural connections.

This is why many clinicians emphasize pairing ketamine with therapy. The medication opens a window of neuroplasticity; therapeutic support helps you make the most of it. Without that integration, the benefits may fade faster.

Racemic ketamine activates these processes through both enantiomers, while esketamine relies on only one.

Want to understand the mechanism more deeply? See our guide on the science behind ketamine.

Spravato vs Ketamine: How Do Access, Cost, and Risks Compare?

Understanding the practical differences between these treatments is just as important as understanding how they work. Here's how they stack up:

Access

Esketamine requires in-person treatment at certified clinics—and access is limited. According to Medicare claims data, 24 states had zero clinic-billed esketamine use in 2023, meaning nearly half of U.S. states had no documented access through Medicare.

Ketamine is more widely available since it doesn't require REMS-certified facilities, but without federal standardization, the quality of treatment depends entirely on the provider you choose.

Cost

Esketamine is expensive. Preliminary cost analyses estimate expenses can reach $6,785 for the first month, plus facility and transportation fees. Insurance may help, but coverage varies widely.

Ketamine costs vary by provider and delivery method. At-home sublingual programs like Innerwell can bring costs significantly lower—as low as $54 per treatment with insurance partnerships in select states.

Clinical oversight

Esketamine comes with structured oversight through the REMS program: mandatory observation periods, blood pressure monitoring, and certified clinic requirements. However, this oversight focuses on safety monitoring—not therapeutic integration or mental health support.

Ketamine oversight depends entirely on the provider. The FDA has cautioned against compounded products distributed without proper safeguards. This makes choosing a provider with comprehensive screening, licensed clinicians, and built-in therapeutic support essential.

Safety considerations

Both treatments carry similar side effect profiles: headache, dizziness, nausea, dissociation, and drowsiness are most common. These effects are generally short-lived, with over 90% of people ready to resume normal activities within 90 minutes.

The FDA has documented respiratory concerns with esketamine when combined with benzodiazepines, opioids, or alcohol. Esketamine may also not be appropriate for those with vascular abnormalities or history of brain hemorrhage.

Both medications are Schedule III controlled substances. Long-term use may cause bladder issues, so ongoing monitoring should include screening for urinary symptoms.

How Does Innerwell's At-Home Ketamine Therapy Work?

Innerwell was designed to address the limitations of both esketamine clinics and inconsistent ketamine providers. The program delivers racemic ketamine with built-in therapeutic support through four phases:

1. Evaluation: A comprehensive virtual psychiatric assessment determines whether ketamine is appropriate and builds your personalized protocol.
2. Delivery: Once cleared, you receive sublingual ketamine tablets shipped securely to your door with dosing instructions and direct clinician access.
3. Preparation and integration: Preparation sessions help you set intentions before treatment. Integration exercises help you process insights afterward. Experts warn that ketamine without mental health follow-up can be risky—Innerwell builds this support into every plan.
4. Ongoing monitoring: Your care team tracks progress and adjusts treatment as needed.

For details on the experience, see what to expect. Innerwell offers transparent pricing with insurance partnerships in select states bringing costs as low as $54 per treatment. Review ketamine laws to understand regulations in your area.

Is Ketamine or Esketamine Right for You?

The right choice depends on your circumstances, and this is a decision worth discussing with a clinician who knows your history.

Esketamine may make sense if you have specific reasons to prefer FDA-approved treatment, have insurance that covers it well, and can commit to twice-weekly clinic visits with two-hour observation periods. Some patients—particularly those who benefit from structured clinical oversight—may be better served in a REMS clinic setting.

At-home ketamine may be a better fit if you need flexible scheduling, live in an area without esketamine access, want therapist support built into your plan, or find the emerging research on racemic formulations compelling.

Red flags to watch for: Any program that skips mental health follow-up, promises permanent cures, or lacks proper supervision isn't prioritizing your safety. Innerwell was built to address these gaps.

Both treatments require ongoing sessions—most people need multiple treatments for sustained benefit. If you’re still weighing your options, read our guide to find out if ketamine is right for you.

Explore Your Options With Innerwell

Ketamine and esketamine both offer a path forward when traditional treatments haven't worked—but the experience, accessibility, and support around each differ significantly. Innerwell also works with people navigating childhood trauma, veterans seeking support, and couples looking to deepen their connection.

With Innerwell, you get licensed clinicians guiding your treatment, therapists helping you prepare and integrate, and monitoring that evolves with your progress. Every step turns a window of neuroplasticity into lasting change.

If you've been searching for relief that fits your life, we're here to help.

Ready to learn more? Take our free assessment.

Frequently Asked Questions

How Long Does It Take for Ketamine to Work?

Most people notice effects within two to four hours—a dramatic difference from traditional medications that take weeks. Lasting improvement typically builds over multiple sessions as your brain forms new pathways.

How Long Do the Effects Last?

Single doses typically last about one week; repeated treatments can extend benefits to two to three weeks. Neither ketamine nor esketamine provides a permanent cure, which is why Innerwell builds maintenance planning into every care plan. Learn more about whether ketamine is permanent.

Does Insurance Cover These Treatments?

Esketamine may have better coverage due to FDA approval, but costs can still be substantial. Innerwell has insurance partnerships in California and New York—and transparent self-pay pricing for everyone else.

Does Ketamine Show Up on a Drug Test?

Standard employment panels don't include ketamine, but specialized tests can detect it. Read our guide on ketamine and drug tests.

What Does Ketamine Treatment Feel Like?

You may experience dissociation—a floating sensation—along with perception changes. Effects typically peak around 40 minutes and resolve within two hours. Many find the experience meaningful with proper intention setting. For details, read about what ketamine feels like.