A randomised placebo controlled clinical trial on the efficacy of Caralluma fimbriata supplement for reducing anxiety and stress in healthy adults over eight weeks

J Affect Disord. 2019 Mar 1:246:619-626. doi: 10.1016/j.jad.2018.12.062. Epub 2018 Dec 21.


Background: This study investigated the efficacy of a succulent, Caralluma fimbriata extract (CFE) in reducing anxiety and stress in healthy adults.

Methods: An 8 week double-blind randomised clinical trial, in which 97 adults self-reporting mild to moderate anxiety were given 500 mg b.d. CFE (n = 49), or 500 mg b.d. placebo (n = 48). Anxiety and stress were measured at baseline, week 4, and week 8 to investigate the timing of treatment effect using the GAD-7, Perceived Stress Scale (PSS), Positive and Negative Affect Schedule (PANAS), and salivary cortisol. Data were analysed using mixed ANOVAs on SPSS v.24.

Results: Results indicated a significant reduction in anxiety and stress in both groups at week 4 and week 8. The reduction in the CFE group was significantly greater (p < .05) than in the placebo group on the GAD-7 and PSS at week 4 and week 8, and in Negative affect at week 4. Improvement in Positive affect was greater in the CFE group than in the placebo group at week 8. Cortisol analysis indicated that CFE may act through the Hypothalamic-Pituitary-Adrenal (HPA) axis, showing statistically significant changes in males, but not in females.

Limitations: Self-reported instruments involve subjective interpretation thus salivary cortisol was employed as a more objective measure. The study would benefit from a larger sample and longer trial, and the inclusion of a wait-list group to allow comparison between treatment and no treatment.

Conclusions: The findings indicate that CFE is superior to placebo in reducing subclinical anxiety and stress over 8 weeks.

Keywords: Anxiety; Caralluma; Complementary therapy; Cortisol; HPA axis; Pregnane glycosides; Stress.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anxiety Disorders / drug therapy*
  • Anxiety Disorders / physiopathology
  • Apocynaceae / chemistry*
  • Double-Blind Method
  • Female
  • Humans
  • Hydrocortisone / blood
  • Hypothalamo-Hypophyseal System / physiology
  • Male
  • Middle Aged
  • Phytotherapy*
  • Pituitary-Adrenal System / physiology
  • Plant Extracts / therapeutic use*
  • Stress, Psychological / drug therapy*
  • Stress, Psychological / physiopathology
  • Young Adult


  • Plant Extracts
  • Hydrocortisone