Clinical Trial to Investigate the Effectiveness of a Dietary Supplement in Increasing Libido and Sexual Function in Postmenopausal Women.


This clinical Trial will assess the effects of a dietary supplement based on Tribulus terrestris on the libido and sexual function in postmenopausal women, by doing a follow up of the FSFI scale and different variables during 3 months period. Participants will be allocated to dietary supplement or placebo, and will attend to 3 visits (baseline, 6 weeks, 12 weeks and at 24 weeks optional).

Full Title of Study: “Multicentre, Randomised, Double-blind, Placebo-controlled, Parallel-group Clinical Trial to Investigate the Effectiveness of a Dietary Supplement in Increasing Libido and Sexual Function in Postmenopausal Women.”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Double (Participant, Investigator)
  • Study Primary Completion Date: August 29, 2019


  • Dietary Supplement: Tribulus Terrestris
    • The experimental arm will receive a dietary supplement to increase the libido and sexual function
  • Other: Placebo treatment
    • The control arm will receive a placebo product with similar organoleptic qualities and the same posology characteristics

Arms, Groups and Cohorts

  • Experimental: Active group
    • One tablet per day in the morning through oral administration of a dietary supplement containing Tribulus terrestris as the main active ingredient. During three months with the possibility to extend for another three months.
  • Placebo Comparator: Control group
    • One tablet per day in the morning through oral administration of Placebo. During three months.

Clinical Trial Outcome Measures

Primary Measures

  • Changes of Score on the Female Sexual Function Index (FSFI)
    • Time Frame: At baseline, at 6 weeks, at 3 months and at 6 months (optional)
    • Score on the Female Sexual Function Index (FSFI) Questionnaire on female libido. The scale has 19 questions divided in 6 Domains. Total score ranges from 2 to 36 with higher scores considered better outcome. Scale subdomains, their scoring range and factor to the total score is the following: Domain: Desire, Range [1 - 5] Factor: 0.6 Domain: Arousal, Range [0 - 5] Factor: 0.3 Domain: Lubrication, Range 0 – 5 Factor: 0.3 Domain: Orgasm Range 0 – 5 Factor: 0.4 Domain: Satisfaction Range [0 (or 1) - 5 ] Factor: 0.4 Domain: Pain Range [0-5] Factor: 0.4

Secondary Measures

  • Variations in testosterone levels (total, bioavailable, and free)
    • Time Frame: Change from baseline to 3 months visit
    • Testosterone levels (total, bioavailable and free) in blood
  • Change in quality of life (QoL) – Measured with Score on the Cervantes Scale.
    • Time Frame: Change from baseline, to 3 months and optional visit at 6 months
    • Score on the Cervantes Scale on quality of life. The scale is composed of 31 questions divided in 4 domains. Each question is punctuated from 0 to 5. And total scale result ranges from 0 to 155, where 0 corresponds to the maximun QoL value and 155 worst value.
  • Number of adverse events
    • Time Frame: Thought the study, an average of 10 months.
    • Number of adverse events (recorded in the investigator’s CRF) to assess the tolerability/safety of the product
  • Compliance with treatment – Measured with the Morisky-Green scale
    • Time Frame: 3 months
    • The Morisky-Green scale measures treatment adherence with four yes or no questions. In which yes punctuates 0 and no punctuates 1. Possible result values for the scale goes from 0 to 4 with 4 being a better outcome than 0.
  • Compliance with treatment – Recount of refounded product by patient.
    • Time Frame: 3 months
    • Recount of product returned at the end of study
  • Compliance with treatment -Therapeutic adherence
    • Time Frame: 3 months
    • Data will be collected by the investigator at participants visit with a unique question about percentage of intake. It will be considered a good compliance if 80% of the medication has been taken.

Participating in This Clinical Trial

Inclusion Criteria

  • Women who report decreased libido and present female sexual arousal disorder according to Diagnostic and Statistical Manual of Mental Disorders (DSM-V) criteria
  • Post-menopause.
  • Age between 45 and 65 years.
  • Sexually active.
  • Agreement to participate and to sign the informed consent documents.

Exclusion Criteria

  • Pregnancy.
  • Women who are on hormone replacement therapy or who need to start it.
  • Cancer treatment or a recent history of cancer (<2 years).
  • Any of the following treatments: serotonin inhibitors, GABAergics, tricyclics, antipsychotics, beta-blockers, thiazide diuretics, dopaminergics and anxiolytics for chronic problems (patients on treatment with anxiolytics without chronic problems are eligible)
  • Fibromyalgia.
  • Treatment for, or a history of, oestrogen-dependent cancer (breast, uterus, endometrium, etc.).
  • Any comorbidity that may interfere with the pathology under study.

Gender Eligibility: Female

Minimum Age: 45 Years

Maximum Age: 65 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Kern Pharma, S.L.
  • Collaborator
    • Analysis and Research Network, S.L
  • Provider of Information About this Clinical Study
    • Sponsor

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