Andrew Siegel MD 4/15/2023
The oral erectile dysfunction medications – Viagra, Cialis, Levitra, and Stendra – are commonly used by men who have problems obtaining or maintaining an erection, or alternatively by men who are functioning reasonably well, but use them on a “recreational basis” for a performance boost. These meds do not affect sexual desire nor ejaculation, although arguably ejaculation is perceived as a better experience with a more rigid erection. These drugs require sexual stimulation and function by enhancing blood flow to the spongy vascular sinus tissue of the erectile chambers of the penis, resulting in engorgement and erectile rigidity. Viagra was the first of the group, initially available 25 years ago, so in the discussion that follows, note that when I refer to Viagra, I am also referring to any of the four medications in the group. Today’s entry addresses whether these erectile dysfunction medications might offer some sexual benefit to females.
Sex organ embryology 101
First, a brief review of comparative sex organ embryology to provide the anatomical background to help answer this question. Believe it or not, the male and female genitals are remarkably similar. In fact, in the first few weeks of embryonic existence, the external genitals are identical.
In the presence of testosterone (the male sex hormone), the genital tubercle (a midline swelling) becomes the penile shaft and head; the urogenital folds (two vertically oriented folds of tissue below the genital tubercle) fuse and become the urethra and part of the penile shaft; and the labio-scrotal swellings (two vertically oriented bulges outside the urogenital folds) fuse and become the scrotum. The right hormone at the right time magically converts the default model into male sex organs.
In the absence of testosterone (as is the case with the female embryo), the genital tubercle becomes the clitoris, the urogenital folds become the inner lips (labia minora), and the labio-scrotal swellings become the outer lips (labia majora). Thus, the female is the default model.
So, the male penis and the female clitoris are essentially the same structure, differing only in size and with the male model containing the urethra within and the female model having a separated urethra located below the clitoris. The male scrotum and the female outer labia are essentially identical, differing only with the male model being fused in the midline and housing the testes and the female model remaining split off the midline with the ovaries housed internally within the pelvis.
By Esseh (Self-made. Based on various anatomy texts.) [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC BY-SA 2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/2.5-2.0-1.0)%5D, via Wikimedia Commons
The bottom line is that every penis essentially starts out as a clitoris until hormones kick in and “sex” it into becoming a penis. The penis and the clitoris are thus homologous structures, both with a glans (head), body and prepuce (foreskin), an astonishingly rich supply of nerves, and the capacity for achieving erections. Similarly, the scrotum and the female outer lips are virtually the same, aside from the midline fusion in the male and the presence of the testicles housed within.
Clitoral anatomy 101
(By Remas6 [CC0], via Wikimedia Commons)
The glans (head) is the external and visible part of the clitoris. It is located just above the opening of the urethra. The remainder of the clitoris is internal and consists of the clitoral shaft (body) and its extensions, known as crura (legs). The prepuce (foreskin), a hood of skin formed by the inner vaginal lips, covers the clitoral shaft.
The crura are wishbone-shaped and are attached to the pubic arch as it diverges on each side. The shaft and crura contain erectile tissue, consisting of spongy sinuses that become engorged with blood at the time of sexual stimulation, resulting in clitoral engorgement and erection. Beneath the crura on either side of the vaginal opening are the clitoral bulbs, sac-shaped erectile tissues that lie beneath the outer vaginal lips. With sexual stimulation, they become full, plumping up and tightening the vaginal opening.
One can think of the crura and bulbs as the roots of a tree, hidden from view and extending deeply below the surface, yet fundamental to the support and function of the clitoral shaft and head above that are comparable to a tree’s trunk and branches.
Chemistry of erections 101
In an erotic situation, penile and clitoral nerves release nitric oxide that cause release of cyclic guanosine monophosphate (cGMP). cGMP relaxes penile and clitoral arterial and erectile chamber smooth muscle causing blood to flood into the erectile chambers; thereafter, outflow of blood is pinched off and voila, an erection of the penis and clitoris.
After completion of sex, the release of the enzyme phosphodiesterase5 (PDE5) decreases levels of cGMP, which constricts penile and clitoral arterial and erectile chamber smooth muscle and causes penile and clitoral anatomy to return to their flaccid state.
Viagra and its cousins work by inhibiting PDE5.
Viagra for the ladies
Viagra and its cousins are not FDA-approved for female, so any use in females is considered “off label.”
The clitoris is arguably the most vital anatomical structure involved with the female sexual response and sexual climax. Like the penis, the clitoris consists largely of spongy erectile sinus tissue that is rich in blood vessels. Unlike the penis that is a multi-tasker with reproductive and urinary roles as well as being a sexual organ, the clitoris is uniquely the only human organ that exists solely for pleasure.
With sexual arousal and stimulation, clitoral spongy erectile sinus tissue becomes engorged, resulting in thickening of the clitoral shaft and swelling of the clitoral head. With increasing stimulation, a clitoral erection occurs and ultimately the clitoral shaft and head withdraw from their overhanging position (clitoral “retraction”), pulling inwards.
Clearly, just as Viagra promotes penile tumescence and rigidity, so it can promote clitoral tumescence and rigidity, one of the key components of the female sexual response. As with men, Viagra does not affect libido, although arguably, an enhanced sexual response may positively affect one’s sex drive. The female lubrication response is predicated on increased pelvic blood flow and transudation of fluid from this enhanced blood flow. Viagra, essentially a vasodilator, may contribute positively to lubrication as well as clitoral erection.
A simplistic deconstruction of the complexity of female sexual function includes components of libido, genital arousal, lubrication, and orgasm. As discussed, Viagra does not modify a lack of or a diminished libido. However, in the situation of compromised genital arousal, as manifested by impaired vulvar swelling, lubrication, and clitoral engorgement, Viagra may be potentially helpful. Certainly, improved arousal, lubrication, and clitoral erection may positively contribute to orgasm potential.
Viagra and its cousins are not devoid of side effects that may include headache, facial, flushing, rhinitis, nasal stuffiness, and visual disturbances. Cialis may cause pain perceived in some of the larger muscles. It is also important to know that this class of medications is not effective in everyone and is contraindicated in those using nitrate medications.
Clinical Trial
A clinical trial of Viagra in over 200 menopausal females who had issues with sexual arousal was done by the Berman sisters (Laura and Jennifer, gynecologist and urologist respectively). The study was placebo-controlled and double blinded. Viagra was shown to enhance the sensation of genital warmth, tingling, and fullness and improved sexual arousal, lubrication, and orgasms. The study concluded that Viagra was not an appropriate treatment for emotional issues, relationship issues, or desire issues, but for women with a decline in ability to achieve sexual arousal, effectively enabled improvement in their sex lives, just as it has for males.
Bottom Line: The genitals of both females and males have a common embryological basis, are remarkably similar in anatomy (despite what you might think), and both rely upon enhanced pelvic blood flow to achieve sexual arousal. Viagra and its “cousins” are highly effective at enhancing erectile rigidity and durability in men and there is no reason why they should not provide parallel advantages to females who would benefit via enhancement of pelvic and genital blood flow.
Wishing you the best of health,
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Dr. Andrew Siegel is a physician and urological surgeon who is board-certified in urology as well as in female pelvic medicine and reconstructive surgery. He is an Assistant Clinical Professor of Surgery at the Rutgers-New Jersey Medical School and is a Castle Connolly Top Doctor New York Metro Area, Inside Jersey Top Doctor and Inside Jersey Top Doctor for Women’s Health. His mission is to “bridge the gap” between the public and the medical community. He is a urologist at New Jersey Urology, one of the largest urology practices in the United States. He is the co-founder of PelvicRx and Private Gym. His latest book is Prostate Cancer 20/20: A Practical Guide to Understanding Management Options for Patients and Their Families.
Video trailer for Prostate Cancer 20/20
Preview of Prostate Cancer 20/20
Andrew Siegel MD Amazon author page
PROSTATE CANCER 20/20 is now available at Audible, iTunes and Amazon as an audiobook read by the author (just over 6 hours).
Dr. Siegel’s other books:
THE KEGEL FIX: Recharging Female Pelvic, Sexual, and Urinary Health
MALE PELVIC FITNESS: Optimizing Sexual and Urinary Health
PROMISCUOUS EATING— Understanding and Ending Our Self-Destructive Relationship with Food
Our Greatest Wealth Is Health 