Kanna: meet the plant behind the extracts

Kanna has a way of turning up on smartshop shelves in more disguises than a spy film: dried leaf, powder, capsules, tinctures and a row of extracts with numbers on the label. They all say "kanna", so it's fair to assume they're the same thing. They aren't. Let's start with the plant, then work out why the products around it can be so different.

Kanna in a nutshell: a plant, a mechanism and a few small trials

Kanna is the common name for Sceletium tortuosum, a succulent from South Africa that has been chewed, brewed and smoked for centuries. The plant contains mesembrine-type alkaloids, and lab work shows they can act on a serotonin-transport protein and on an enzyme called PDE4. Small human studies of one branded extract (Zembrin) have looked at anxiety, cognition and tolerability, mostly in healthy adults. They're interesting, but they're small and short, and none was in people with a diagnosed condition. Kanna isn't an antidepressant substitute, and it shouldn't be combined with antidepressants or other serotonergic drugs without a pharmacist or doctor looking at the actual products.

In the Netherlands, kanna isn't on the Opium Act lists, and it isn't in the annex of the Dutch herbal-preparations decree either (both read on 8 October 2026). That isn't the same as every kanna product being approved as a food in the EU, as the legal section below explains.

Five things worth knowing before the shelf

• Plant vs product: kanna the plant, a fermented dried herb, and a standardised extract are three different things. The alkaloid mix changes with the plant, the processing and the extraction.
• Mechanism vs evidence: the serotonin-transporter and PDE4 findings come from lab assays and animal work. They explain why researchers got curious; they aren't proof of a benefit in people.
• Human research: a handful of small trials, mostly of one 25 mg extract, in healthy volunteers. Results are mixed, and none tested people with depression or an anxiety disorder.
• Interactions: Jellinek says not to combine kanna with SSRIs, MAO inhibitors or MDMA; a 2021 review advises avoiding SSRIs, SNRIs and other serotonergic antidepressants. Serotonin syndrome is the concern.
• Law: not an Opium Act substance in the Netherlands as of 8 October 2026; EU food rules are a separate question, and national rules vary.

What kanna actually is

Sceletium tortuosum (now often listed as Mesembryanthemum tortuosum) is a low-growing succulent native to the dry west of South Africa. "Kanna" is one of several traditional names; "kougoed" (roughly "chewable") is another. A 2021 review of the plant's regulatory history describes its traditional use by the San and Khoikhoi peoples, and early colonial records of it being chewed, brewed as tea or tincture, and used as a snuff or smoked (Brendler et al., 2021, Current Neuropharmacology, full text). That is history and ethnobotany: a long record of use, not evidence that a modern capsule does anything in particular.

Traditional "kougoed" involved fermenting the plant material, and that changes the chemistry. In a controlled experiment on S. tortuosum leaves, mesembrine fell from 1.33% to 0.05% over ten days of fermentation while another alkaloid, Δ7-mesembrenone, rose from undetectable to 0.11% (Patnala & Kanfer, 2009, Journal of Ethnopharmacology, abstract). Fermentation doesn't just dry the plant. It can change what's in it.

Why "kanna extract" isn't one product

Walk along a shelf and you'll see "10x", "standardised", "full-spectrum" or a brand name. These words describe different things, and a number on the front doesn't say how much of which alkaloid is inside.

The alkaloids differ between extracts. The best-documented commercial extract in the research is Zembrin, a standardised hydroethanolic extract. A rat toxicology paper reports it's standardised to 0.35–0.45% total alkaloids, with mesembrenone and mesembrenol making up at least 60% of those and mesembrine under 20% (Murbach et al., 2014, Food and Chemical Toxicology, abstract). Another extract, Trimesemine, is described as a "high-mesembrine" extract in a cell study (Coetzee et al., 2016, abstract). So two products that both say "standardised Sceletium extract" may be rich in different alkaloids.

The plants differ. A 2025 mouse study compared two wild-collected chemotypes (plants from different locations with different alkaloid profiles) with a commercial extract and found they changed brain neurotransmitter levels differently (Kaschula et al., 2025, Journal of Ethnopharmacology, abstract). It's a mouse study, so it doesn't tell us what happens in people. It does show that "Sceletium" is not a single chemical recipe.

A "10x" label alone doesn't tell you the amount of mesembrine or total alkaloids. The number doesn't spell out its own definition, and no independent source we found converts such labels into comparable amounts across brands. That's why there's no strength table in this article.

Other compounds come along for the ride. One analytical study measured hordenine, a separate plant compound, in six commercial S. tortuosum products and found anywhere from 0.027 to 1.071 mg per gram of plant material (Appley et al., 2022, Drug Testing and Analysis, abstract). The point isn't that hordenine is a hazard; it's that products vary a lot even when they carry the same plant name.

A quick label check

• On the label: "Sceletium tortuosum"; What it tells you: The species; What it doesn't: Plant part, fermented or not, extraction method
• On the label: "10x extract"; What it tells you: That the product is an extract; What it doesn't: Mesembrine or total alkaloid content
• On the label: "Standardised to…"; What it tells you: A named compound has a stated percentage; What it doesn't: Which other alkaloids are present, or whether the product matches the one studied
• On the label: A brand name from a study; What it tells you: A specific extract was used in research; What it doesn't: That a different product with similar wording behaves the same
• On the label: A lab report; What it tells you: That a batch was tested for something; What it doesn't: Anything beyond the tests listed; it's a quality check, not evidence of benefit

Our general guides to reading supplement labels and using supplements wisely go deeper on those last two rows.

What mesembrine does in a dish (and why that isn't the same as in you)

The pharmacology is the reason kanna gets compared with antidepressants, so it's worth getting right.

In laboratory tests, a standardised Zembrin extract affected a protein involved in serotonin transport (the serotonin transporter, or SERT) and an enzyme called PDE4. Of the individual alkaloids, mesembrine was the most active at the transporter, while mesembrenone acted on both (Harvey et al., 2011, Journal of Ethnopharmacology, abstract). SERT is the protein that SSRI antidepressants target, which is why you'll read that mesembrine is "SSRI-like". PDE4 is a separate drug target. That's why researchers are interested in kanna.

Think of it as finding, on a workbench, that a key fits a lock. It's a real finding, but it doesn't tell us how much reaches the brain from a capsule, or what someone would notice after taking it. A few more points keep it in proportion:

• The story isn't settled even in the lab. A 2016 cell study of a high-mesembrine extract concluded its serotonin-related activity looked more like monoamine release than simple reuptake blockade (Coetzee et al., 2016, abstract).
• Animal work is mixed on which compound does what. In zebrafish larvae, mesembrine alone reproduced the anxiolytic-like effect of the whole extract, but no single alkaloid reproduced its antidepressant-like effect (Gericke et al., 2024, abstract). In rats exposed to chronic mild stress, a lower dose of the whole extract improved anxiety- and anhedonia-like behaviour in males while mesembrine alone had a more transient effect, and females didn't develop the stress-induced behaviours (Gericke et al., 2025, Cells, abstract).

"SSRI-like" is therefore a description of one lab mechanism. It doesn't mean kanna works like an SSRI, treats depression or can stand in for one. SSRIs are prescribed after large trials in patients; kanna has nothing like that behind it.

Research detail: the lab numbers

If you want to compare the assay results yourself: the Harvey et al. screen reported that the Zembrin extract blocked the serotonin transporter in binding assays at an IC50 of 4.3 μg/ml and inhibited PDE4 at an IC50 of 8.5 μg/ml, and that mesembrine bound the transporter with a Ki of 1.4 nM (Harvey et al., 2011). Lower values mean a lower concentration was needed in the dish. These are concentrations in an assay, not amounts in a person.

What human studies have found

There are only a handful of human trials, and most used the same 25 mg Zembrin extract. The table shows what each paper reports; the points after it give the overall picture.

• Study: Nell et al., 2013; Who: 37 healthy adults; What they took: 8 mg or 25 mg Zembrin, or placebo, daily for 3 months; What they measured: Safety and tolerability (no efficacy outcomes); What they reported: No apparent differences in vital signs, ECG or blood tests; headache was reported more often with placebo; some participants noted better stress coping and sleep in their diaries, unprompted
• Study: Terburg et al., 2013; Who: 16 healthy participants (crossover); What they took: A single 25 mg dose of Zembrin, or placebo; What they measured: fMRI of amygdala reactivity to fearful faces; What they reported: Amygdala reactivity under low perceptual load was lower after Zembrin; amygdala-hypothalamus coupling was also lower
• Study: Chiu et al., 2014; Who: 21 cognitively healthy adults, mean age 54.6 (crossover); What they took: 25 mg Zembrin or placebo daily for 3 weeks; What they measured: Neuropsychological tests, Hamilton depression scale, side effects; What they reported: Better cognitive set flexibility and executive function than placebo; "positive changes" in mood and sleep reported. Funded by HG&H Pharmaceuticals, the company behind Zembrin
• Study: Reay et al., 2020; Who: Two lab studies, 20 young healthy volunteers; What they took: A single 25 mg dose of Zembrin, or placebo; What they measured: Mood or anxiety and heart rate during a stress task; What they reported: Study 1: no treatment effect. Study 2: lower self-reported anxiety just before the stressor and a treatment-by-time effect on heart rate. Authors call the evidence "tentative"
• Study: Hoffman et al., 2020; Who: 60 recreationally trained adults aged 20-35 (48 men, 12 women); What they took: 25 mg Zembrin or placebo daily for 8 days, tested 2 hours after the day-8 dose; What they measured: Alertness and energy scales, mood questionnaire, reactive agility and visual tracking; What they reported: Better performance on complex reactive tasks with a cognitive load; no difference on the alertness/energy scale, total mood score or simple reaction
• Study: Berry et al., 2021; Who: 16 untrained women; What they took: Zembrin or placebo across a three-day regimen after an arm-exercise session; What they measured: Muscle soreness, range of motion, mood; What they reported: Lower perceived soreness and better range of motion at 48 hours; mood worsened in both groups but less with Zembrin. A small pilot

Reading across the table:

1. The same dose keeps turning up. Five of the six studies gave a 25 mg Zembrin dose (Nell et al. also tested 8 mg, and the Berry paper's summary doesn't state a dose). That's useful for comparing study to study, and it means the findings can't be transferred to a different product or a different strength.
2. The populations are healthy volunteers. Nobody here was diagnosed with depression or an anxiety disorder, so these trials can't tell us whether kanna helps with either. A 2026 critical review of the animal and clinical literature reaches a similar view: small samples, studies in clinically irrelevant populations, and outcomes that aren't consistent across studies (de Jong et al., 2026, Planta Medica, abstract).
3. The mood results are mixed. The anxiety-related findings come from a brain scan, one lab stress task, and a pre-stress questionnaire score; the 8-day trial in young adults found no mood effect at all. A 2023 systematic review and meta-analysis pooled four small trials (117 participants) and, according to its published summary, found no clear difference in anxiety and concluded that an anxiolytic effect couldn't be confirmed (Gouhie et al., 2023, Brain Disorders).
4. Who paid and who wrote it matters. The Chiu trial was funded by HG&H Pharmaceuticals, and the paper's disclosures also name a link to its US distributor. HG&H is also the company with an EU novel food application pending for a Sceletium extract (see below). Nigel Gericke, a director at HG&H, is a co-author on the Nell, Terburg, Chiu and Harvey papers, among others. So several of these papers have authors tied to the company behind Zembrin, and independent replication is thin.
5. A trial in progress. A registry entry describes an 8-week randomised, placebo-controlled study from Northumbria University of 25 mg Zembrin a day in healthy adults aged 30-50, marked as enrolling (study listing). There are no results yet.

So kanna is interesting enough to study, but not yet well enough studied to recommend for any specific purpose.

Kanna and antidepressants: not a swap, and not a pairing

Because mesembrine acts on the serotonin transporter in assays, two questions come up. The first is whether kanna can replace an SSRI. The evidence above doesn't support that, and nothing here should lead anyone to change prescribed medicine. If you're taking an antidepressant and wondering about kanna, the conversation belongs with your pharmacist or prescriber, not a shop assistant or a website.

The second is whether the two can be taken together. The 2021 regulatory review notes there were no reports of severe adverse reactions or herb-drug interactions with the plant, and no studies implicating it, but still concludes it would be wise to avoid drugs that alter serotonin uptake or release, naming SSRIs and SNRIs, and says antidepressants in general shouldn't be used alongside it (Brendler et al., 2021). That review doesn't mention MAO inhibitors or MDMA. Dutch drug-information service Jellinek is more direct: kanna shouldn't be combined with SSRIs such as Seroxat or Prozac, or with MAO inhibitors, and combining it with other substances is strongly discouraged (Jellinek, "Wat is kanna?", version June 2021). Jellinek's page lists Erowid and a kanna website as its sources, so treat it as practical caution rather than trial evidence. Serotonin syndrome is the reason behind all of these warnings.

Serotonin syndrome is an excess of serotonin activity. It can cause agitation, fast heart rate, tremor, sweating and fever, and needs urgent medical care. The warning applies to the combination, and nobody has good data on the amount of kanna at which it becomes a problem. If you take any prescription medicine, including for ADHD, pain, migraine or mood, take the exact product labels to a pharmacist. Our guide to supplement and drug interactions explains what to ask.

Safety: what the small trials do and don't cover

What exists: a 3-month trial of 8 mg and 25 mg of Zembrin in 37 healthy adults found no differences from placebo in vital signs, ECGs or blood tests (Nell et al., 2013, above). Rat toxicology studies of the same extract reported no treatment-related adverse effects at the highest doses tested: 5000 mg/kg a day for 14 days and 600 mg/kg a day for 90 days (Murbach et al., 2014, above). Those are the doses of a specific extract in rats, not guidance for people.

What's missing:

• Long-term human safety beyond three months, and any trial in people with health conditions.
• Safety of other extracts and forms, including snuffed or smoked preparations.
• Pregnancy and breastfeeding: no data turned up.
• Dependence. Jellinek notes that kanna acts on serotonin and dopamine systems, that formal research on addiction is limited, and discourages daily use (Jellinek). The traditional-use literature records no withdrawal symptoms (Brendler et al., 2021), but tradition isn't a study.
• Driving and operating machinery after products of unknown strength. If something makes you feel noticeably different, treat it like any other psychoactive substance.

In short: kanna hasn't produced alarming safety signals in small, short trials of one extract, and that's as far as the evidence goes. Stronger or different products sit outside it.

Legal status in the Netherlands and the EU (checked 8 October 2026)

Netherlands. The current Opium Act on the government's legal database (version valid from 17 September 2026) doesn't name Sceletium, kanna or mesembrine on its lists (Opiumwet, wetten.overheid.nl). The Dutch herbal-preparations decree has an annex listing plants and fungi that herbal preparations must not contain (Article 4(2); it names kava and yohimbe, for example). Sceletium isn't named there, but that is not an approval: other rules, including EU novel-food law, are separate. Dutch law also has a substance-group ban for some new psychoactive substance families, in force since 1 July 2025, which covers phenylethylamines (including cathinones), synthetic cannabinoids and fentanyl-like substances (Trimbos-instituut). We found nothing indicating those groups capture mesembrine, but we haven't seen a formal Dutch legal opinion on the point.

EU food law. Not being a controlled drug isn't the same as being an approved food ingredient. The European Commission's list of ongoing novel food applications includes a "hydroethanolic extract of Sceletium tortuosum and/or Sceletium crassicaule" from HG&H Pharmaceuticals, in the 2024 section (European Commission, summary of applications). Only an application is listed there, and there is no authorisation. We couldn't confirm the EU novel-food status of kanna itself, so we make no statement about it. Check the Commission's Novel Food Status Catalogue before buying. Questions like this decide how a product can be described and sold, which is why you'll see some retailers list kanna as a herbal or collectable product rather than a health supplement.

Elsewhere in the EU. Dutch rules are not EU-wide, and what's sold in a Dutch shop may be treated differently in another country or at the border. Check the destination country's current rules before sending or carrying anything. Rules change, so treat this section as a dated snapshot, not legal advice.

At the shelf: what to look for

If you're curious and an adult who isn't taking interacting medicines, a calm checklist beats a bold claim:

• Identify the product. Plant material, fermented material, extract, or blend? What's the extract ratio or standardisation, and what's the batch?
• Match the research honestly. If a brand says "clinically studied", ask which extract, what dose and which outcome. A study of one product doesn't carry over to another.
• Read the claims as claims. A retailer's information page can be a helpful starting point for product forms. For example, Zamnesia's kanna information page lists dried plant material and graded extracts and describes low-dose effects as an improved sense of well-being; that's supplier information, not evidence (Zamnesia, kanna information, read 8 October 2026).
• Don't mix it. Antidepressants, MAO inhibitors, MDMA and other serotonergic drugs are the combinations the sources above warn about. Alcohol and cannabis are also reported to change the experience.
• Use the broader basics. Our supplement guide covers deciding whether you need a product at all.

So, where does that leave kanna?

Kanna is a genuinely interesting plant with a long history, a real pharmacological story and a small amount of human research. The products on the shelf aren't interchangeable, the evidence behind the headline claims is thin, and the one clear safety message is about combining it with serotonergic medicines and drugs. If you came for an answer to "is kanna good for me?", the honest one is that it depends on your health, your medicines and the exact product, and the research can't yet say more than that.

Next reading: How to read supplement labels, Supplement and drug interactions and Smart Supplements 101.

Where to read next

From the smartshop shelf:

• Dream herbs explained: African dream root, seed and uvuma-omhlophe, for which plants the labels name, what the sources describe and where the research stops.

Written by Smart Supplements with AI assistance from the sources linked in the text. It has not been reviewed by a clinician.

Last updated: 12 October 2026

This article is for informational purposes only and is not intended as medical advice. Always consult a healthcare professional before starting any new supplement, especially if you take prescription medication.