Ketamine Dosage: How Much is OK and How Much is Too Much?

We’ll start with the most important thing to know: Ketamine is powerful. The drug first appeared in clinical practice as an anesthetic in the 1960s. Doctors use ketamine in surgery to prevent people from feeling the pain of the operation. In veterinary science, ketamine tranquilizes large animals like horses. More recently, ketamine has a new purpose: treating depression and other mental health ailments. Ketamine is not considered a psychedelic in the usual sense—it’s a dissociative. But it can produce profound experiences comparable to classical psychedelics like LSD or psilocybin. Practitioners are leveraging these psychedelic properties to aid in the alleviation of mental health issues, particularly in the most complex and resistant cases. 

These same mind-altering properties also make ketamine a popular recreational drug: it’s a common find at music festivals and in the club scene. However, using ketamine outside of a medical provider’s care comes with a unique set of risks. Ketamine’s effects are dose-dependent, meaning that it can have drastically different effects depending on the dose. Further, different bodies respond differently to ketamine, meaning that the same dosage may affect every individual in unique ways. 

Taking too much ketamine can lead to a complete dissociation called a “K-hole,” making it risky to take alone. Many people find deep personal and spiritual meaning in their ketamine experiences—both in and outside of the clinic. However, having a skilled and trusted sitter or provider can be lifesaving. Ketamine can impact motor function after you cross a certain dosage threshold, making it difficult to move and easier to accidentally asphyxiate (suffocate) vomit. Mixing ketamine with other substances—particularly sedatives—can increase the likelihood of a deadly overdose. Those with pre-existing heart conditions and seizure disorders should be particularly mindful and seek medical supervision while using ketamine. 

What is the ketamine experience like? 

Ketamine is a dissociative anesthetic with psychedelic properties. Dissociative drugs can cause both amnesia and pain relief, which is why they are commonly used in surgery. Overall, ketamine is a versatile molecule. It has a wide range of uses and effects. You can also take it in a variety of different ways—from nasal sprays to oral pills and powders. The drug has a short duration, around 45 minutes to 75 minutes, with an afterglow that can last a couple of hours. Generally speaking, low doses of ketamine will allow you to remain grounded in the “real world,” albeit in a dreamy floaty state where you can remain standing and—somewhat—interact with the people and things around you. People find that low doses cause increased sociability, mild inebriation, and a sense of seeing the world differently.

Higher doses can increase negative side effects like nausea and confusion. Increasingly higher doses will make physical movement hard or impossible, culminating in a K-hole. The K-hole experience can be risky and challenging, affecting both mental and physical safety. During a k-hole, your ability to move is decreased substantially. This means that it will be very difficult to move your body away from danger or help yourself if you begin to vomit while lying on your back. For this reason, it’s not recommended to use ketamine alone. The safest way to consume ketamine is under the guidance of professional care, someone who can address medical emergencies if they arise. 

During a k-hole or therapeutic ketamine experience, a person may undergo a partial or complete dissociation. This experience can be intensely visionary in the appropriate supportive circumstances. You may feel that your mind leaves your body and journeys into other realms. Your sense of self may disappear. Ego death is possible. But, while this experience can be fascinating and healing, it can also be disturbing and scary if not well supported or later integrated. Ketamine dosages used in surgery and anesthesiology go beyond these visionary doses, requiring continuous medical monitoring for heart rate and other complications. 

Read: There are 3 Types of Ketamine—Which One Works Best?

So, is there a “safe” ketamine dosage?

Ketamine is a legal substance with ample medical use. So, precise dosage is generally calculated easily in medical centers. It is manufactured industrially in liquid form. In underground markets, liquid ketamine is often dried into a powder and sold in this crystalline form. Calculating doses is much easier with measurement devices.  Doctors and medical practitioners calculate ketamine dosage in milligrams per unit of body weight (kilos or pounds). The same should be done in non-medical settings to reduce accidental overdosing. You can always take more, but never less. 60 milligrams is a starting dose for intramuscular (IM) and intravenous (IV) treatments in clinics that use ketamine to treat mental health ailments. But, in an underground setting, it’s imperative to keep in mind that this amount can do little to a seasoned ketamine user, but it can send a first-timer directly into a K-hole. This is a very powerful medicine, and caution is always advised.

The website Erowid is one of the most popular online resources to find information on all kinds of mind-altering substances and plants that aren’t often talked about in mainstream media, with abundant information and practical advice. The guidelines in this article should be taken as an orientation and not as medical advice, and as Erowid reminds us: “Every individual reacts differently to every chemical. Know your body, know your mind, know your substance, know your source…Individuals can respond differently to the same dosage. What is safe for one, can be deadly for another. Start low with new substances. Have a trusted companion/guide/sitter/friend present and/or available.”

Intranasal Ketamine Dosage

Intranasal Ketamine Dosage

Powdered ketamine is the most usual route of administration (ROA) for people who use it outside of medical settings. It’s usually diverted from medical sources to the underground market, where it’s manufactured in liquid form and then dried up into a white powder. As a form of harm reduction, it’s a good idea to grind it well to reduce abrasion in the nasal mucosa. According to Erowid: 

• A threshold dose is 0.1mg/lb, approximately 10 to 15 milligrams. 
• A light dose is 0.15mg/lb, approximately 15 to 30 milligrams, enough for a beginner to experiment it’s effects. 
• A common dose is 0.3mg/lb, approximately 30 to 75 milligrams. 
• A strong dose is 0.5 to 0.75 mg/lb, approximately 60 to 125 milligrams. The K-hole can be reached with 1 mg/lb, approximately 100-250 milligrams.

Tolerance is a very important concept to take into consideration with ketamine. Heavy users take larger quantities to achieve desired effects, and reports of people snorting very large quantities of ketamine at once, sometimes 500 milligrams or more, are not unheard of—and also not recommended. Regardless of tolerance, the same harm reduction practices apply: Even experienced consumers can risk their physical safety by assuming they need a higher dose and falling into an unexpected K-hole at the wrong place at the wrong time.

New users need much less ketamine. The onset of insufflated (snorted) ketamine takes about 10 to 15 minutes. It is always smart to weigh doses, at least at the beginning, when unfamiliar with the substance, one can be surprised at how many milligrams fit on the tip of a key or miniature spoon, a common method to insufflate small doses or ‘bumps’ of ketamine. The bioavailability of intranasal ketamine is considered low compared to IV and IM administration. Bioavailability refers to the amount of the substance that enters circulation through your body via different administration routes. According to most sources, insufflated ketamine has an availability of between 25 to 50 percent.

Snorting ketamine is likely to be one of the greatest risks of developing ketamine abuse and dependence/addiction. While addiction and dependence are rare, most people addicted to ketamine today are using this medicine via snorting from street dealers. Testing underground ketamine with an at-home drug-checking kit is also extremely important: Underground powders and tablets can contain adulterants. Testing is the only way to make sure you’re getting what you expect.

Ketamine Dosage: Intranasal Spray

While this ROA is the same as insufflated, the method of delivery is different. An intranasal ketamine spray is a device designed to deliver a predetermined dose through the nasal mucosa, with the substance dissolved in a saline water solution at different concentrations. K-sprays make ketamine consumption less messy than snorting and also offer the advantage of knowing that each hit is the same dose. It is also more readily absorbable by the mucosa as it is in liquid form. Some users may opt to obtain or prepare their own makeshift sprays, but they are also made to order in pharmacies with a doctor’s prescription with a predetermined dose.

In 2019, the FDA approved Spravato, a ketamine nasal spray manufactured by the pharmaceutical Jansen, containing a filtered version of the medicine, esketamine. Esketamine is supposed to be more effective for treatment-resistant depression, although there is an ongoing debate around this aspect. Esketamine is the s-enantiomer of ketamine. Ketamine is a mixture of two enantiomers (mirror image molecules, like your hands): S-ketamine and R-ketamine (more on that here). Spravato comes in prefixed single-use dose units of 56 and 84 milligrams, meant to be taken only in a physician’s office for treatment-resistant depression.

Intramuscular (IM) Ketamine Dosage

This ROA is used by therapists and psychiatrists in their practices who offer ketamine-assisted psychotherapy to treat depression and other mental health conditions. Therapists, treating conditions like depression, utilize a standardized dosage of 1 milligram per kilo of body weight with the goal of providing a “powerful interruption of the ordinary mind,” according to ketamine therapist Lauren Taus LCSW. Naturally, the dose is adjusted at the discretion of the therapist, starting lower or increasing it, depending on multiple factors. The onset of the medicine is around three minutes, and its bioavailability is almost total, at 93 percent.

The threshold for IM ketamine is at 0.1 milligram per pound; a light dose at 0.15 milligrams/lb; common is 0.2 mg/lb; strong is 0.5 mg/lb; the K-hole can be reached at 0.75 mg/lb and anesthetic doses at 1mg/lb. It’s not recommended to self-inject outside of a provider’s care; it’s not necessary, and it poses risks that other forms don’t while producing a similar experience. 

John Lilly MD (1915-2001) was a key figure in the history of ketamine. A neuroscientist, inventor, and writer, he explored human consciousness, dolphin communication, and described his experiments with high doses of ketamine. He mapped the inner realms of the ketamine experience and explained it in his book The Scientist: A Metaphysical Autobiography. Using IM ketamine injections, he established the areas reached with a graph of increasing dosages: At 30 milligrams, the “I” or Internal Reality was reached; at 75 milligrams, the “They” or Extraterrestrial Reality; at 150 milligrams, the “We” or Network of Creation; and at 300 milligrams the “Unknown” could be reached. But, these dosages are best saved for the guidance and supervision of a trained practitioner. It’s dangerous to self-experiment with high dosages, especially for people unfamiliar with ketamine. High dosages can severely limit your ability to move your body and make you more likely to overdose, which can be fatal.

Intravenous (IV) Ketamine Dosage

The intravenous route is mainly used by clinicians offering ketamine treatment for depression. It is done in a medical setting with a dripper and a needle inserted in the patient’s arm, wrist, or hand. The infusion is slowly paced in a period of time, usually around an hour. Most reports indicate a standardized dosage of 0.5 milligrams per kilo of body weight, but again, with this method being the domain of licensed medical practitioners, doctors may adjust the dose anywhere from 0.1 to 0.75 milligrams per kilo of weight at their discretion, taking multiple factors into consideration. The bioavailability of this delivery method is the highest at 100 percent.

Oral Ketamine Dosage

Swallowing ketamine is the least efficient method to take ketamine, as its bioavailability is the lowest among all the ROA at around 17 percent. The onset comes slowly, depending on stomach contents.The duration is longer, but the peak is not as high. It is considered by many to be a waste of medicine, as you are only effectively using a small percentage of it. Dosage ranges from 0.3 milligrams per pound for a threshold dose (40-50 milligrams); 0.6mg/lb for a light dose; 0.75-2mg/lb for a common dose; 1.5-2.5mg/lb for a strong dose; and 3-4 mg/lb to reach the k-hole.

Another method is to use ketamine troches or lozenges, meant to be swooshed in the mouth until complete dissolution and absorbed by the mouth’s mucosa. This method offers a bioavailability of around 25 to 30 percent, rendering a slower onset than IM, IV, or intranasal methods. As ketamine’s taste is pretty unpleasant, it is usually masked with some fruity flavoring. Troches and lozenges are compounded by specialized pharmacies with a doctor’s prescription, establishing the desired dosage, which can be anywhere from 100 mg to 1 gr troches, again at the discretion of a licensed medical practitioner.

Rectal Ketamine Dosage

Rectal administration of drugs is common for medical treatments, and people have used recreational drugs like amphetamines, MDMA, or cocaine with this method (called plugging or boofing in non-medical jargon). Ketamine is no different. The bioavailability is at 25 percent. The threshold starts at 0.3 mg/lb; a light dose 0.6mg/lb; a common dose 0.75-2mg/lb; a strong dose at 1.5-2.5 mg/lb; and the k-hole at 3-4 mg/lb. The onset is slow from five to 20 minutes, and the duration is longer, lasting one to two hours. Being the availability on the low side and a rather complex operation, it is not a common ROA for recreational users of ketamine. Rectal administration can also be quite dangerous as it more easily leads to overdose. Most patients who use this as such may have localized chronic pain to the rectum or pelvic region. 

Ketamine Dosage for Anesthesia

While this is the domain of anesthesiologists, it is interesting to note dosage values for anesthesia, compared to recreational dosages or for the treatment of mental health issues. The usual dose to induce anesthesia for surgery is at 1-4.5 mg/kg IV, repeated as needed to maintain this state. IM dosages are 6.5-13mg/kg for surgical anesthesia, repeated as needed to maintain it. This is how they started using ketamine for soldiers wounded in Vietnam in the Seventies, where respiratory monitoring was not available. Ketamine is widely used in veterinary medicine, hence the horse-tranquilizer stigma. Your cat or dog have probably taken more ketamine at once for surgery when spayed or neutered than many people. Dosages of this level require medical supervision.

In summary, ketamine is a very versatile medicine and recreational substance. It can be delivered in many different forms to target pain, prepare for surgery, or alleviate mental pain and suffering. Many self-medicate with ketamine and may choose more riskier methods of consumption (snorting). It is prudent to always speak to a medical provider before engaging in the use of any substances. Ketamine addiction, while rare, can be extremely destabilizing and harmful.

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High doses of ketamine can cause a “k-hole,” a period of complete dissociation that can also cause temporary paralysis, which can be distressing and unsafe, particularly in the wrong set and setting. We asked the experts how to navigate the abyss.

Disclaimer

In the event of an emergency, please dial local emergency services. For mental health assistance in the US, dial 988. For substance abuse help in the US, please dial the Substance Abuse and Mental Health Services Administration National Helpline at +1 (800) 662-4357.

This article is intended for educational and harm reduction purposes and should not be used in place of medical advice or treatment. DoubleBlind does not advocate participating in illicit activities. Always consult your local drug laws before engaging with illicit substances. Those who consume ketamine outside of medical supervision do so at their own risk.