Gotu kola

The human evidence is small. The main synthesis, a 2017 systematic review and meta-analysis funded by the Thai Traditional Medical Knowledge Fund, included five randomized trials of gotu kola alone and six of products that contained it [1]. Most of the trials were in healthy volunteers, and the review rated only one of the 11 at low risk of bias [1]. Some findings below come from clinical populations, and results in clinical groups may not apply to healthy adults. Our grades are proposals per outcome; the evidence grading method explains what each grade requires.

Does gotu kola improve working memory?

Evidence is mixed. When the 2017 meta-analysis pooled the two trials of gotu kola alone, 54 participants in total, working memory scores showed no statistically significant difference from placebo (SMD 0.19, 95% CI −0.35 to 0.72) [1]. Pooling all three trials with working memory scores, including an open-label trial of a combination product in children, also gave a non-significant result (SMD 0.61, 95% CI −0.25 to 1.48) [1].

The positive signal comes from one trial. In a randomized, placebo-controlled, double-blind study, 28 healthy older adults were split into four groups of 7: placebo or 250, 500 or 750 mg of a water extract once daily for 2 months [2][1]. The highest dose enhanced working memory and changed one brain-wave measure (the N100 component of the event-related potential) [2]. The meta-analysis notes the 750 mg dose shortened working time on a numeric working memory test 1 hour after a dose, and it rated this trial at low risk of bias [1]. With so few participants per dose, one trial cannot settle the question.

Does gotu kola affect mood or alertness?

The findings point in different directions, and they rest on self-ratings. The 2017 meta-analysis reported higher self-rated alertness (SMD 0.71, 95% CI 0.01 to 1.41) and lower anger scores 1 hour after a dose (SMD −0.81, 95% CI −1.51 to −0.09) compared with placebo [1]. Each of these pooled estimates combined one gotu kola trial with one trial of a multi-ingredient product, a vitamin-and-herb tablet for alertness and a mixed-herb product for anger [1]. No other mood or quality-of-life measure showed a statistically significant difference from placebo [1].

On its own, the 2-month trial in older adults measured mood with the Bond-Lader visual analogue scales and reported improvements [2]. The meta-analysis extracted higher alertness (mean difference 9.38) and calmness (mean difference 2.37) at 750 mg a day [1]. In contrast, a double-blind trial in 40 healthy adults found that a single 12 g dose had no significant effect on self-rated mood, heart rate or blood pressure compared with placebo [3]. That trial did find a smaller startle reflex to a sudden loud sound 30 and 60 minutes after the dose [3], a laboratory measure rather than a mood outcome.

A 2026 scoping review counted two randomized trials in healthy participants (58 people) reporting better alertness, and concluded the evidence was insufficient for a pooled analysis [9]. That review was framed around the ingredients of a commercial product, Neurotain Plus [9].

Does gotu kola help global cognition in older adults?

Not in the one randomized comparison we found. In a 12-week trial, 60 older adults with mild cognitive impairment (a clinical population, average age 74.6) were assigned to exercise, exercise plus 500 mg of gotu kola extract twice a day, or a placebo control [5]. Both exercise groups improved, but gotu kola had no additional effect on cognitive function beyond exercise [5]. The trial was supported by Kasetsart University [5].

A 6-week quasi-experimental study in 48 people with cognitive impairment after stroke compared 750 or 1000 mg a day of gotu kola extract with 3 mg a day of folic acid [6]. The difference in overall score changes between the three groups was not statistically significant; the authors report a larger gain in the memory domain with gotu kola [6]. The study was not randomized against placebo, so it cannot show an effect of the herb itself [6].

A 2026 systematic review of 62 studies, eight of them clinical trials, described the clinical evidence for gotu kola as limited and inconsistent [7]. It was funded by Thai government research funds and Thammasat University [7]. In the 2017 meta-analysis, overall cognitive status in double-blind trials showed no statistically significant difference from placebo (SMD −0.01, 95% CI −0.52 to 0.51), and those two trials were in children with a diagnosis and of a combination product [1].

Does gotu kola affect strength in older adults?

One pilot trial reports a gain on one test [4]. It was funded by Khon Kaen University research groups and shares seven of its eight authors with the working memory trial [4][2]. Eighty healthy older adults were randomly assigned to placebo or 250, 500 or 750 mg a day of a standardized water extract for 90 days [4]; almost all were women, with one man in each group of 20 [1]. After 2 months, the 500 and 750 mg doses improved the 30-second chair stand test, a measure of leg strength [4]. In the paper's results table, both doses differed from placebo as well as from baseline at 2 months, while the extract did not improve hand grip or the 6-minute walk test [4]. The authors found no clear dose-response pattern [4].

All the gains disappeared 1 month after people stopped taking the extract [4].

What the evidence does not show

The five trials of gotu kola alone in the 2017 meta-analysis each enrolled between 27 and 80 people [1]. A 2026 systematic review that searched specifically for randomized trials of gotu kola and six other plants on cognition in healthy people found none of gotu kola that met its criteria [8]. That review was co-funded by Pukka Herbs Limited, and one author works for Pukka Herbs, a herbal tea maker [8].

A 2025 trial in 180 healthy boys aged 8 to 10 compared gotu kola with bacopa for 91 days and reported similar memory gains for both [10]. It had no placebo group, so practice and expectation cannot be ruled out [10].

The 2017 meta-analysis also noted that most trials used less than 3 g of the herb a day, and that dose, preparation, standardization and product variation limit what the trials can show [1].

The main triterpenes in gotu kola are poorly absorbed in their original form. In a phase 1 crossover trial of single 2 g and 4 g doses of a standardized water extract in eight healthy older adults, asiaticoside and madecassoside were not detected in blood, while their breakdown products, asiatic acid and madecassic acid, were readily measured over 12 hours [12]. A similar trial in four older adults with mild dementia (a clinical population) found the same pattern [11]. Both trials were funded by the US National Institutes of Health (one also by the US Department of Veterans Affairs), and one author is a consultant for Oregon's Wild Harvest, which made the study product [11][12].

In an open-label study in twelve healthy Thai volunteers, a modified standardized extract (ECa 233) at 250 and 500 mg was also converted to asiatic and madecassic acid, and asiatic acid built up over 7 days of dosing [13]. The study was funded by Chulalongkorn University [13].

In short trials, side effects were few. The 2017 meta-analysis found no adverse effects reported in any trial of gotu kola alone, and trials of combination products reported events such as stomach discomfort, nausea, headache and rash [1]. LiverTox describes extracts as well tolerated in small trials, with mild, nonspecific effects (headache, dizziness, bloating, diarrhea, nausea) often similar in frequency to placebo [17]. Single 2 g and 4 g doses were well tolerated in two phase 1 trials of 8 and 4 people [12][11].

The main safety concern is the liver (hepatotoxicity). LiverTox gives Centella asiatica a likelihood score of C, a probable rare cause of clinically apparent liver injury [17]. It cites published cases: three women in Argentina and a single case report from Switzerland [17]. In the case series, the women were 61, 52 and 49 years old and developed jaundice after 30, 20 and 60 days of use; all improved after stopping, and one had a recurrence when she took it again [15].

LiverTox reports an onset of 3 to 8 weeks, a hepatocellular pattern of injury, and complete recovery within 1 to 2 months of stopping [17]. LiverTox notes immunoallergic and autoimmune features in some cases [17]. It adds that contamination or other liver toxins in the products were not ruled out [17], and that the injury is generally self-limited and mild to moderate [17]. Routine liver tests in trials have not shown enzyme changes, but few trials measured them [17], and no liver injury was seen in the trials the meta-analysis included [1]. A 2024 review of herbs used in Indian traditional medicine names Centella asiatica among herbs with an emerging liver-toxicity profile [16].

Allergic reactions have been reported rarely, mostly with use on the skin [17]. MSKCC lists contact dermatitis among reported adverse reactions [18].

No human study of gotu kola with medicines was found (PubMed search, November 11, 2026). The interaction evidence is from the laboratory. MSKCC reports that gotu kola inhibits the liver enzymes CYP1A2, CYP2C9, CYP2D6, CYP3A4 and CYP2C19 in vitro, which may affect medicines those enzymes break down; it says clinical relevance has yet to be determined [18]. MSKCC lists people taking CYP450 substrate drugs under "Do Not Take if" [18].

An NIH-funded laboratory study of one water extract found no enzyme induction and only weak inhibition of most enzymes tested, strongest for CYP2C9 (IC50 of 330 µg/ml) [14]. Its authors say the clinical relevance depends on the concentrations reached in people [14].

If you take any medicines broken down by these liver enzymes, talk to your doctor or pharmacist before combining them with gotu kola.