November 7, 2018

Fennel for Postmenopausal Sexual Dysfunction

A novel phytoestrogen vaginal cream
A randomized controlled trial compared a phytoestrogen cream to placebo for treatment of postmenopausal sexual dysfunction. Both groups benefited, but why?


Abedi P, Najafian M, Yaralizadeh M, Namjoyan F. Effect of fennel vaginal cream on sexual function in postmenopausal women: a double blind randomized controlled trial. J Med Life. 2018;11(1):24-28.


To assess the effect of fennel vaginal cream on symptoms of sexual dysfunction in postmenopausal women


Randomized double-blind placebo-controlled trial


Sixty Iranian women, aged 45 to 65, with confirmed natural postmenopausal status (cessation of menses>1 year; FSH>40 IU/l). All participants were married/sexually active and had Female Sexual Function Index [FSFI]<26; women with vaginal bleeding or infection and women using hormone replacement therapy (HRT) or phytoestrogens were excluded from the study.


Patients in the experimental group (n=30) were instructed to use the 5% fennel vaginal cream (5 g) each night for 8 weeks, while patients in the control group (n=30) were instructed to use a placebo cream nightly.

The fennel cream was prepared from an 80% ethanol extraction of fennel seeds stored for 3 days, then freeze-dried. This dried extract was then mixed with a 5% emulsion cream base, preserved with methyl- and propyl-parabens, and mixed with a “proper” carrier (not specified) to a concentration of 5%. The placebo cream was manufactured with the same carrier and had a “similar color and appearance” to the fennel cream. Details of what “similar color and appearance” meant were not specified.

Study Parameters Assessed

FSFI, assessed for all participants at baseline and after 8 weeks

Primary Outcome Measures

Changes in FSFI and individual markers such as arousal, lubrication, ability to orgasm, sexual satisfaction, and pain after 8 weeks of either fennel cream or placebo

Key Findings

All of the areas of sexual function of the FSFI, including arousal, lubrication, orgasm, sexual satisfaction, and pain improved in both the fennel and placebo groups. The total FSFI score, however, was higher in the fennel group than the placebo group (P<0.001). No adverse effects of the vaginal preparations were reported by either group. There were no withdrawals from this study.

Practice Implications

The FSFI is a clinical self-reporting tool that assesses multiple dimensions of female sexual functioning and is often used in clinical trials to assess female sexual function disorders.1,2 It was designed as a diagnostic tool to assess the specific dysfunctions of women regardless of socioeconomic status, age, ethnicity, or sexual orientation.1 It has been found to have high validity and reliability for both diagnosing female sexual disorders and monitoring changes from treatment.

Menopause, defined as the cessation of menses for at least 1 full year, is often associated with physical and symptomatic changes of sexual function related to genitourinary symptoms of menopause (GSM), including dryness, dyspareunia, and bleeding. According to some estimates, approximately 50% of women experience atrophic vulvovaginal changes within 7 to 10 years after menopause, along with commonly reported changes in physical sexual function, including decreased arousal, sexual response, and dryness or pain with intercourse.3,4 In clinical practice, however, presenting symptoms may or may not correlate well with objective signs such as vulvovaginal atrophy and/or prolapse; therefore, a clinically sensitive approach to questions of stress, sleep, relational and personal well-being, and other factors is required. Many women may also believe that these changes are a natural part of aging, and so may not be aware that effective treatments exist.5,6

This raises the question of whether there are clinical effects of a local topical preparation for menopausal sexual dysfunctions outside of their objective effects on local vaginal cytology and pH—essentially, a positive placebo effect.

In conventional therapeutics, oral and/or topical applications of synthetic or bioidentical estrogens are standard, but as the Women’s Health Initiative data showed, oral estrogen therapies carried risks of increased coronary heart disease, breast cancer, and endometrial cancer over 5 years of follow-up.5 While topical vulvovaginal estrogen therapy is believed to carry fewer of these risks, there are concerns about ingredients in many commercial preparations, and individually compounded preparations may be expensive and increasingly difficult to have covered under health benefit plans or private insurance.5

Phytoestrogens such as fennel are believed to have an insignificant to mildly beneficial effect for menopausal symptoms including hot flashes, GSMs, and sexual function.6,7 To date, however, there has been little attention given to the use of phytoestrogenic compounds in local topical preparations, either for GSMs or sexual functioning in postmenopausal women.

Using the same treatment and placebo groups, the authors of this study had previously found that nightly application of the topical 5% fennel compound to the vulvovaginal area resulted in statistically significant changes in maturation vaginal index and decreased vaginal pH, indicating decreased signs of atrophy in the treatment subjects over an 8-week period, compared to controls.8

In this broader study of sexual function, however, both the placebo and treatment groups reported improvements in all measured areas of sexual dysfunction, although effects were larger in the treatment group. This raises the question of whether there are clinical effects of a local topical preparation for menopausal sexual dysfunctions outside of their objective effects on local vaginal cytology and pH—essentially, a positive placebo effect.

An important potential confounder, however, could be the presence of an active ingredient in the placebo preparation. Given that the authors did not give details of the placebo preparation, other than to say that it was manufactured using “the proper carrier” and had “a similar odor, color, and appearance to the fennel cream,” it raises the question about whether a partial effect could be had from an active ingredient in the placebo cream not specified in this study. In their methods section, the authors stated that details of the preparation of the placebo had been published previously; however, the cited reference was only available as an abstract, and did not contain the relevant details.8

Overall, this study raises some very interesting questions about whether the positive benefits of any topical treatments for postmenopausal sexual dysfunction (as opposed to effects on cellular vaginal atrophy per se) are at least partly placebo effects. For patients who may be at higher risk for the pelvic pathologies, who may not tolerate vaginal estrogens, or who may want to avoid prescription hormone therapies, the use of a 5% topical phytoestrogen compound looks eminently feasible for compounding either in office or through a pharmacy familiar with natural product dispensing.

Categorized Under


  1. Rosen R, Brown C, Heiman J, et al. The Female Sexual Function Index (FSFI): a multidimensional self-report instrument for the assessment of female sexual function. J Sex Mar Ther. 2000;26(2):191-208.
  2. Meston CM. Validation of the Female Sexual Function Index (FSFI) in women with female orgasmic disorder and in women with hypoactive sexual desire disorder. J Sex Marital Ther. 2003;29(1):39-46.
  3. Naumova I, Castelo-Branco C. Current treatment options for postmenopausal vaginal atrophy. Int J Womens Health. 2018:10:387-395.
  4. Smith R, Gallicchio L, Flaws JA. Factors affecting sexual function in midlife women: results from the midlife women’s health study. J Womens Health. 2016;26(9):923-932.
  5. Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women’s Health Initiative randomized controlled trial. JAMA. 2002;288(3):321-333.
  6. Franco OH, Chowdury R, Troup J, et al. Use of plant-based therapies and menopausal symptoms: a systematic review and meta-analysis. JAMA. 2016;315(23):2554-2563.
  7. Gharazfarpour M, Shokrollahi P, Khadivzadeh T, et al. Effect of foenicular vulgar (fennel) on vaginal atrophy in postmenopausal women: a double blind, randomized placebo-controlled trial. Post Reprod Health. 2017;23(4):171-176.
  8. Yaralizadeh M, Abedi P, Najar S, Namjoyan F, Saki A. Effect of foeniculum vulgare (fennel) vaginal cream on vaginal atrophy in postmenopausal women: a double-blind placebo-controlled trial. Maturitas. 2016;84:75-80.