title: Efficacy of Tongkat Ali (Eurycoma longifolia) on erectile function improvement: systematic review and meta-analysis of randomized controlled trials.
abstract: OBJECTIVE
  To determine the efficacy of Tongkat Ali (Eurycoma longifolia) herbal extract on erectile function improvement.
  
  
  METHODS
  Comprehensive electronic databases were searched from inception through October 2014. Randomized controlled trials investigating Tongkat Ali compared to placebo were included. Outcome of interest was the improvement of erectile dysfunction. The difference of changes from baseline of the outcome between Tongkat Ali and placebo was pooled using weighted mean difference (WMD). Methodological quality of included studies was assessed using Jadad's quality scale and Cochrane's risk of bias.
  
  
  RESULTS
  Of the 342 articles identified, 2 studies involving a total of 139 participants were analyzed. No significance between group difference was found in the mean WMD of the change in the 5- item version of the international index of erectile function (IIEF-5) at week-12 (0.91; 95% CI: -1.50 to 3.33 with I(2)=89.5%, P-value=0.002) with statistical heterogeneity. Based on the subgroup analysis, significant improved IIEF-5 score of 2.15 (95% CI 1.03-3.27) was found in subjects with lower baseline IIEF-5 score, but this was not seen among those with higher baseline IIEF-5 score.
  
  
  CONCLUSIONS
  Based on current evidence, the herbal extract of Tongkat Ali may have clinical effect on erectile function. However, more efficacy trials are warranted to further support current evidence.
authors.affiliation: School of Pharmacy, Monash University Malaysia, Selangor, Malaysia.
authors.forename: Surachai
authors.initials: S
authors.lastname: Kotirum
authors.affiliation: School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.
authors.forename: Shaiful Bahari
authors.initials: SB
authors.lastname: Ismail
authors.affiliation: School of Pharmacy, Monash University Malaysia, Selangor, Malaysia; Center of Pharmaceutical Outcomes Research (CPOR), Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand; School of Pharmacy, University of Wisconsin, Madison, USA; School of Population Health, University of Queensland, Brisbane, Australia. Electronic address: nathorn.chaiyakunapruk@monash.edu.
authors.forename: Nathorn
authors.initials: N
authors.lastname: Chaiyakunapruk
mesh_terms: D000328:Adult; D000368:Aged; D007172:Erectile Dysfunction / Q000188:drug therapy*; D035701:Eurycoma / Q000737:chemistry*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000009:adverse effects / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic
chemical_list: D010936:Plant Extracts
keywords: Alternative medicine; Erectile dysfunction; Eurycoma longifolia; Extract; Root; Tongkat Ali