Strongest evidence: The most robust research on passion flower involves its effect on anxiety. Across 11 studies (moderate evidence strength), 8 reported beneficial effects with small effect sizes. The effective dose range was 260–500 mg, mainly studied in adults undergoing dental procedures (e.g., third molar extraction) or elective surgery. Effects were often comparable to midazolam but not consistently superior to placebo.
Mixed or weaker evidence: For reduced heart rate, only 3 studies (low evidence strength) were identified, all showing neutral, small-sized effects with no statistically significant findings. All studies were conducted in dental extraction settings, limiting generalizability. This outcome currently lacks clear evidence of benefit.
Effective dose patterns: Both outcomes used a similar dose range of 260–500 mg, suggesting that this is the most commonly studied range in clinical trials. No dose-response data are available from these syntheses.
Population insights: The majority of research was conducted in adults undergoing acute peri-procedural anxiety (dental or surgical). No studies in chronic anxiety disorders or other populations (e.g., elderly, deficient groups) were included. Generalizability beyond acute procedural settings is limited.
Notable caveats: The anxiety evidence is subject to publication bias, as null-result studies are less likely to be published. Many included studies did not reach statistical significance, indicating the true effect may be smaller than the observed direction. Several studies lacked placebo controls or had small sample sizes. For heart rate, the evidence base is too small to draw firm conclusions.