When approaching any mind-altering substance, it is crucial to know as much as possible about how it behaves in your body, how much you should take for your intended purposes, and how much may be too much. With ketamine this is especially important, as the effects are very dose dependent and the results also vary greatly depending on the route of administration (ROA)—that is, how you take it—the kind of ketamine you are using, and your tolerance level.
Ketamine, a dissociative anesthetic with psychedelic properties, is a very versatile molecule. It has a wide range of uses, effects, and a number of different ways of taking it, with the added advantage of its short duration, around 45 minutes to 75 minutes, with an afterglow that can last a couple of hours. It is used in medical settings by anesthesiologists for anesthesia and analgesia, by therapists for depression and other mental ailments, and recreationally—be it at home for meditation and spiritual purposes, at a party setting, or for whatever someone’s intention may be. It is active through a number of ROA: intranasally, intramuscularly (IM), intravenously (IV), swallowed, sublingually, and also through the rectal mucosa. It’s bioavailability, meaning the amount of the substance that effectively reaches your brain, varies depending on each ROA, with IM and IV being the most efficient, and swallowing being the least.
Generally speaking, low doses of ketamine will keep you in this world, albeit in a dreamy floaty state where you can remain standing and somewhat interacting with people and the environment, with increased sociability, mild enabration and a sense of seeing the world differently. Higher doses, which can increase the appearance of negative side effects like nausea and confusion, will put you in a state where moving will be hard or impossible, while increasingly higher doses will eventually produce an intense inner visionary experience, which is colloquially referred to as a k-hole: a partial or complete dissociation, where your mind leaves your body and journeys into other realms, your sense of self disappears, and ego death is possible. This can be an incredibly fascinating and healing experience, but also very disturbing and scary if not well integrated. Even higher doses are considered anesthetic and remain the domain of licensed medical practitioners.
Unlike other substances where it may be difficult to calculate precise doses (LSD or plant medicines, for example), in the case of ketamine, being a legal substance with ample medical use that is manufactured industrially in liquid form which can be dried into powder, calculating doses should be easy with the help of a precision scale or a syringe. Dosing by medical practitioners is calculated in milligrams per unit of body weight (kilos or pounds), and the same should be done in non-medical settings for best results and to reduce accidental overdosing. You can always take more, but never less. Always work your way up: a line of 60 milligrams can do little to a seasoned user, but can send a first timer directly into a k-hole. This a very powerful medicine and caution is always advised.
The website Erowid is one of the most trusted online resources to find information on all kinds of mind-altering substances and plants, with abundant information and useful intelligent 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 trusted companion/guide/sitter/friend present and/or available”.
Intranasal Ketamine Dosage
This is the most usual ROA for people to use ketamine out of medical settings. Usually diverted from legit medical sources to the black market, it is manufactured in liquid form and then dried up into a white crystalline 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 the threshold dose is 0.1mg/lb, approximately 10-15 milligrams. A light dose is 0.15mg/lb, approximately 15-30 milligrams, enough for a beginner to experiment its effects. A common dose is 0.3mg/lb, approximately 30-75 milligrams. A strong dose is 0.5 to 0.75 mg/lb, approximately 60-125 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 need larger quantities to achieve desired effects, and reports of people snorting very large quantities of ketamine at once, sometimes 500 mgs or more, are not unheard of. New users need much less quantity and while 50mg might be a pretty hefty dose for first timers, it may not do much for heavy users that are far up the tolerance curve. The onset of insufflated 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. According to most sources insufflated ketamine has an availability of between 25% to 50%.
Ketamine Dosage: Intranasal Spray
While this ROA is the same as inssuflated (snorted), 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, 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 1mg 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.
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.
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, and 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 way to do it is using a syringe, without needle, with some lubricant and injecting the desired quantity, previously dissolved in distilled water. 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.
Ketamine Dosage for Anesthesia
While this is the domain of anesthesiologists, it is interesting to note its 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.