How to Take Kanna: What the Evidence and the Label Say
Vendors disagree about the best way to take kanna. Here is what was actually studied, what was not, and where the honest answer is 'we don't know.'
Search "how to take kanna" and you get a pile of confident, conflicting advice: empty stomach, with food, under the tongue, in tea, in a can. Most of it comes from people selling something. The honest picture is shorter. A handful of small trials gave one standardized extract as a capsule, and nobody has tested the rest. This post covers the common oral forms, what is known and unknown, and the safety checks that matter more than the method.
Kanna is sold as drinks, capsules, tablets, tinctures, teas and powders. The human trials we found gave a standardized extract, Zembrin, as a capsule taken orally, once daily [1][2]. No study compared forms or tested food, timing or under-the-tongue use in people, so there is no evidence-based "best" way. Follow your product's label and check with a clinician first.
How have people taken kanna in studies?
In the trials we found, participants swallowed a capsule. That is the whole method.
In a 2014 trial of 21 healthy adults, participants took a 25 mg Zembrin capsule or a placebo capsule "once daily orally" for three weeks. The paper does not say whether this was with food or at a particular time of day [1]. In a 2013 brain-imaging study of 16 healthy volunteers, each person took a single 25 mg capsule, and scanning began "promptly at 2 h" after dosing. That paper does not say whether participants had eaten [2]. A 2013 safety trial of 37 healthy adults used 8 mg or 25 mg once daily for three months [4].
Two cautions. The two-hour scan time was a design choice for the experiment, not a measurement of when anything starts or ends; our post on how long kanna lasts covers that gap. And all of these trials used Zembrin, a 2:1 standardized extract, in healthy volunteers. Amounts and methods from them do not transfer to other products. See kanna dosage for the full trial table.
What oral forms of kanna are sold?
Drinks, capsules and tablets, tinctures or liquid extracts, teas, and powders, according to the sources we checked.
WebMD lists a liquid extract, dried ground powder, capsule, tea and gummy [5]. A 2012 lab paper describes tablets, capsules, teas, decoctions and tinctures as common, noting that traditionally the dried plant was chewed [3]. Ready-to-drink cans are the newest format; our kanna drink ranking lists what each label says.
| Form | What to look for on the label | Evidence on how to take it |
|---|---|---|
| Ready-to-drink can or shot | Kanna per serving, extract named or not, other active ingredients, servings per container | No published trial of a kanna drink that we found |
| Capsule or tablet | Supplement Facts panel, extract name, amount per unit | Closest to the trial method (oral capsule) [1][2] |
| Tincture or liquid extract | Concentration, dropper size, whether it contains alcohol | None; concentration varies by maker |
| Tea or powder | Whether it is dried plant or an extract | None; alkaloid content of plant material varies |
For how labeling differs between a can and a capsule, see kanna drinks vs capsules.
Should you take kanna with food or on an empty stomach?
We do not know. We searched PubMed on October 29, 2026 for human studies of Sceletium, Zembrin or mesembrine together with food, fasting or bioavailability and found none that tested it.
Vendor pages state a preference with great confidence, but we found nothing behind it. Food can change how some supplements are absorbed, but for kanna that is a general possibility, not a finding. The practical answer is the boring one: read the directions on your product. The FDA says to "take only as described on the label" [7]. If a product's label is silent, that is information too.
What about taking kanna under the tongue?
There is lab evidence that the alkaloids can cross mouth tissue, but no human trial of it, and we are not suggesting it.
A 2012 Planta Medica study placed the four main kanna alkaloids on pig intestinal, under-the-tongue and cheek-lining tissue in a lab. All four crossed all three tissues. They crossed the mouth tissues less readily than intestinal tissue, though the authors suggested absorption in the mouth might still contribute when the plant is chewed and held there for a long time [3]. That is animal tissue in a dish. It does not tell you how a tincture held under the tongue behaves in a person, and the amount that ends up in the blood was not measured in people.
What should a first-timer check before taking it?
Medications, pregnancy status, the label, and whether the product contains anything else.
- Medications. Concerns have been raised with MAOIs, SSRIs, SNRIs, tricyclic antidepressants, antipsychotics, triptans and St. John's wort, and how these interactions work is not fully understood [5]. The FDA and NCCIH both advise talking to a health care professional before using a supplement [6][7]. See is kanna safe.
- Pregnancy and nursing. No data exist on kanna in pregnancy or breastfeeding [5]. NCCIH notes many supplements have not been tested in pregnant or nursing women [6].
- The label. Check the amount per serving, the servings per container, and whether the extract is named. NCCIH cautions that "standardized" on a label does not necessarily guarantee quality or consistency [6].
- Other ingredients. Many kanna drinks also contain kava, caffeine or other botanicals. Each brings its own cautions.
- Alcohol. Some tinctures contain alcohol, and we found no human study of kanna combined with alcohol. See kanna and alcohol.
Common sense also applies to a new product of any kind. The commonly reported side effects of sceletium are headache and upset stomach [5]. If you have a reaction, NCCIH advises stopping the supplement and contacting your health care provider [6].
How do you keep track of kanna across products?
Write down the amount per serving for each product you use, because nothing adds them up for you.
A can, a capsule and a tincture can each list a different kind of milligram: milligrams of a named extract, of an unnamed extract, or of alkaloids. They do not add up cleanly. The longest published trial lasted three months at 8 or 25 mg of Zembrin a day [4], and no official recommended amount exists. If the label gives a daily maximum, that is the brand's statement, not a clinical finding. Our dosage page explains why milligrams differ between brands.
What does this page not cover?
Non-oral routes. Kanna has a documented history of being chewed or smoked [8], but we do not give instructions for smoking, snorting or vaping any plant material, and no trial of those routes informed this page. For history, see what is kanna.
This page is general information, not medical advice. These statements have not been evaluated by the FDA. Kanna products are not intended for any disease or health condition.
References
- Chiu S et al. Proof-of-concept randomized controlled study of cognition effects of the proprietary extract Sceletium tortuosum (Zembrin) targeting phosphodiesterase-4 in cognitively healthy subjects. Evid Based Complement Alternat Med 2014;2014:682014. PubMed Central
- Terburg D et al. Acute effects of Sceletium tortuosum (Zembrin), a dual 5-HT reuptake and PDE4 inhibitor, in the human amygdala and its connection to the hypothalamus. Neuropsychopharmacology 2013;38(13):2708-16. PubMed Central
- Shikanga EA et al. In vitro permeation of mesembrine alkaloids from Sceletium tortuosum across porcine buccal, sublingual, and intestinal mucosa. Planta Med 2012;78(3):260-8. PubMed
- Nell H et al. A randomized, double-blind, parallel-group, placebo-controlled trial of extract Sceletium tortuosum (Zembrin) in healthy adults. J Altern Complement Med 2013;19(11):898-904. PubMed
- WebMD. Sceletium: uses, side effects, interactions. webmd.com
- National Center for Complementary and Integrative Health. Using dietary supplements wisely. nccih.nih.gov
- U.S. Food and Drug Administration. FDA 101: Dietary supplements. fda.gov
- Olatunji TL et al. Sceletium tortuosum: a review on its phytochemistry, pharmacokinetics, biological and clinical activities. J Ethnopharmacol 2021;280:114476. PubMed
Frequently asked questions
What is the best way to take kanna?
No study has compared forms head to head, so there is no evidence-based 'best' way. The human trials we found gave Zembrin extract as a capsule taken orally [1][2]. Drinks, capsules, tinctures and teas are all sold; follow the product label and ask a clinician if you are unsure [6][7].
Should I take kanna with food or on an empty stomach?
We found no published study that tested this. The trials we read did not report whether capsules were taken with food [1][2]. Follow the directions on your product's label.
Does kanna work under the tongue?
A lab study on pig tissue found kanna alkaloids can cross mouth-lining and under-the-tongue tissue, though less readily than gut tissue [3]. That is not a human study and it is not an instruction. We found no human trial of sublingual use.
Can I take kanna every day?
Published human trials ran for up to three months, always with a single extract at fixed doses [1][4]. Nothing longer is established, and no official daily amount exists. Check the label and talk to a doctor, especially if you take medication. See is kanna safe.
Is it safe to take kanna with antidepressants?
Not without medical advice. Interaction concerns have been raised with SSRIs, SNRIs, MAOIs and other serotonergic medicines, and how they work is not fully understood [5].