In both women and men the biological systems and pathways that mediate the sexual response are surprisingly the same. Ranging from our brain (cerebral cortex) where sexual thoughts and fantasies originate to the sensory mechanisms in our sex organs that perceive pleasurable sensations. The nervous system is intimately involved including the sympathetic, parasympathetic, sensory and motor nervous systems. Your vascular system is profoundly involved. Your hormones are critical and surprisingly many of the same hormones are at work in both women and men.
The components of women’s and men’s sexual health are also similar in many ways. These are Libido, Arousal, Orgasm, and Fertility. Each is affected by a myriad of bodily mechanisms, cerebral (brain) and hormonal input. Unbalanced hormones are a frequent cause for many of the sexual issues we address here
Your libido is your overall sexual desire or drive for sexual activity. Testosterone is the hormone you most likely associate with sex drive in men but did you know this is true for you also? Studies show that the frequency of sexual arousal for both women and men increases with increased testosterone levels. So with higher levels of testosterone your libido will likely increase. Your testosterone levels also cycle with the rest of your hormones. Your testosterone increases from day 1 to day 14 of your cycle and following ovulation decreases again and this coincides with an increase in sexual arousal with a peak at ovulation and then a decrease in libido. This varies depending on your cycle and the amount of your testosterone production. Unlike men, where the hormonal symphony of falling in love decreases testosterone levels, falling in love increases your testosterone levels.
Your testosterone level peaks later than a man’s – in your 20s – and then begins to decline. As with men, your sexual desire will decline along with declining levels of testosterone. By menopause, your testosterone levels are about half their peak levels. There is an acceleration of testosterone decline being identified mostly in men (they are the ones being studied) due to hormone disruptors – toxins such as pesticides, herbicides and others. This is most likely also occurring in women. Oral contraceptives also interfere with your production of testosterone, which is why your sexual desire may wane while on them. (This will increase their ability to prevent pregnancy, but is unlikely the effect you are looking for.)
Your ability to be aroused is the response of your body to your own libido, the libido of another, and ultimately that magical mixture of the two. Testosterone enters the nuclei of your cells and turns on genes that produce critical proteins that maintain the structure and function of your clitoris, vaginal muscularis, labia minora, G-spot and vestibular glands. Testosterone is also thought to increase your sensation in these structures. Known to be a vasodilator, testosterone contributes to engorgement of your nipples, labia, clitoris, G-spot and vagina, which in turn both causes and increases heat and sensitivity of these tissues. Testosterone has also been shown to increase with sexual thoughts (libido), implicating its importance for the next stage, which is arousal. The health of the endothelial cells that line your blood vessels are maintained by testosterone and this is very important to your ability to be sexually aroused as we will see later.
Because of the roles of testosterone mentioned above, your testosterone levels are critical to your ability to have an orgasm.
Testosterone also plays a role in fertility, though not the way you might think. It has been found that when the testosterone and endorphins, in ejaculated semen, meet the cervical wall after sexual intercourse, women receive a spike in testosterone, endorphin, and oxytocin levels. This adds to a nurturing environment in your reproductive tract for conceiving, nurturing the pre-embryonic stages before implantation, and stimulates feelings of love, desire, and maternal care.
Estrogen has been shown to be important in increasing libido along with testosterone. Estrogen is produced from testosterone by the aromatase enzyme, so both women and men have both hormones. A surprising study done in men, that blocked their aromatase enzyme so their estrogen levels dropped, showed their libido dropped also. The studies in women show your estrogen levels are directly correlated to your sexual desire. Estrogen also increases your serotonin and endorphins, which help you feel more “in the mood”. If you have an imbalance of estrogen relative to progesterone, where your estrogen is too high and progesterone too low, you may have a decrease in your sexual desire. This is known as estrogen dominance and is associated with many other symptoms one of which is increased anxiety. Also, elevated progesterone has a dampening effect on your sexual desire. It is highest during the luteal phase – right after you ovulate – and even higher during pregnancy (see below).
Estrogen has an even more profound effect on your ability to be aroused than testosterone when it comes to the health of your sex organs. Estrogen increases tissue hydration and the production of hyaluronic acid, which is important for the thickness and firmness of your skin and mucous membranes including your vulva and vagina. It also maintains the glands which provide lubrication during arousal and sex. Both of these effects lead to healthy tissues that both provide and respond with increased pleasurable sensations. Estrogen has a direct effect on engorgement of your labia, clitoris and G-spot and is critical to endothelial cell health and endothelial cell health is critical to arousal as we will see later.
Estrogen’s effect on your ability to achieve orgasm is based on its effects on libido and arousal.
The effective cycling of estrogen along with progesterone is the primary hormonal basis of your ability to become pregnant. One important role of estrogen in fertility is its induction of uterine lining growth during the follicular phase of your cycle. If an egg is fertilized, this will be where the embryo implants to be nurtured until birth. There are many things that can disturb this hormonal flow and interfere with your fertility cycle.
Nitric Oxide (NO)
NO is produced from arginine in the endothelial cells and is a hormone that works locally to dilate your blood vessels. These are the cells that line the blood vessels. Their health is improved by multiple hormones – 2 of which are testosterone & estrogen. Vasodilation is critical to your ability to be aroused. When NO is low, your clitoris, vulva, vagina and G spot cannot become engorged, which is the biggest contributor to arousal. This is the equivalent in men of Erectile Dysfunction – the inability of the penis to become engorged. And, as in men, if there is low NO production the rest of your vascular health is at risk contributing to high blood pressure, heart disease, carotid disease, heart attack, stroke, arrhythmia and sudden death. This is called Endothelial Dysfunction. So, as with optimal balance of other hormones, optimal NO levels are not only important to your sexual health but to your overall health as well.
When progesterone increases, your libido decreases. Your progesterone is highest days 15-24 of your cycle and even higher during pregnancy. There are a few rare conditions that can cause elevated progesterone, but if you are on HRT, you can be overdosed. If your progesterone is low relative to your estrogen – estrogen dominance – you may experience decreased sexual desire. One of the metabolites of progesterone is allo-pregnenolone, which crosses the blood brain barrier and is a neurosteroid that stimulates GABA receptors promoting a sense of calm and well-being – frequently a prerequisite to sexual desire. When progesterone is too low it can increase anxiety, irritability and depression – all of which can decrease your libido.
Progesterone in some ways counters the effects of estrogen; however, it is important to maintain a good balance between the two because estrogen dominance can cause painful breasts, symptoms of PMS (Premenstrual Syndrome) & PMDD (Premenstrual Dysphoric Disorder), and other issues that will interfere with arousal.
By inhibiting the above two (libido and arousal), progesterone can decrease orgasm. Elevated progesterone can decrease your orgasm, possibly through a direct inhibiting affect as well. The most common cause of elevated progesterone is overdosed HRT. But with low progesterone (estrogen dominance) your orgasms can be inhibited also. This can manifest as delayed, less intense or inability to achieve orgasm.
Progesterone has a profound effect on fertility. First, there are progesterone receptors on the endothelial cells (cells that line the blood vessels) in your uterus. When progesterone attaches to these during and after ovulation, your uterine blood vessels become leaky allowing serum to escape the blood vessels into your uterine lining, awaiting the embryo. This provides a nourishing environment for the embryo to attach. Progesterone also maintains the uterine lining (produced by estrogen). If an embryo implants, continued progesterone secretion maintains your uterine lining throughout your entire pregnancy. Progesterone also inhibits the uterine muscles from contracting during pregnancy until you are ready to give birth. Low progesterone levels during pregnancy can lead to miscarriages.
Your thyroid hormone increases the speed, energy and power of cellular functions and metabolism in your body. It is therefore necessary for all human endeavors including libido. If you have the symptoms of hypothyroidism and are fatigued, sluggish, depressed, anxious, or have brain fog, interest in sex may be the last thing on your mind. Thyroid hormone is also important to make all your other hormones work effectively, including your sex hormones. While thyroid controls the “clock speed” of your neurons (how fast signals are transmitted & how fast you think), a slowing of these processes will decrease the neurologic inputs to sexual desire. Hyperthyroidism – too much thyroid hormone can also cause problems with libido and has its own set of symptoms. It can specifically cause depression and low levels of free testosterone among others symptoms
Your body’s ability to function is dependent on metabolism, if your metabolism is too slow or fast, your body’s ability to respond may be profoundly affected making arousal difficult or even impossible. Thyroid hormone affects the ability of your glands to secrete, providing adequate lubrication and comfort necessary for arousal. It affects blood pressure & blood flow. It affects the speed & ability of tissues to respond. It affects local energy production and supply for tissues to even be able to mount a response. Thyroid hormone upregulates uncoupling protein thereby increasing your ability to produce body heat – a whole body and local tissue characteristic of arousal.
Orgasm occurs as a result of both sensory (touch and sense of engorgement & lubrication) and fantasy (sexual thought) neurologic input to centers in the brain and spinal cord. These centers add together the incoming signals until they reach a critical threshold and then fire off the neural signals causing orgasm. This summation of incoming sensory & fantasy input occur over time and if coming in too slowly they can dissipate. If coming in too fast, they can add too quickly. Thyroid hormone affects the speed with which these sensory & fantasy signals are transmitted. Low thyroid slows neural transmission and high thyroid speeds transmission. Therefore, hypothyroidism may make it more difficult for you to achieve orgasm. This can take the form of delayed orgasm, less intense orgasm or even inability to achieve orgasm. If your thyroid is too high, this can cause premature orgasm, orgasm that is too intense, painful orgasm and also difficulty achieving orgasm. Men can also suffer delayed ejaculation, less intense orgasm or even inability to achieve orgasm (ejaculate). With hyperthyroidism men can also experience premature ejaculation, orgasm that is too intense, painful ejaculation and also difficulty achieving orgasm.
Your fertility can be affected by hypo or hyperthyroidism. Both can affect your cycle and even stop you from having a cycle. Being hypothyroid can increase PMS & PMDD, which may interfere with relationship, mood & libido and these will obviously affect opportunities of fertilization. PCOS has a higher association with hypothyroidism and is often associated with anovulation (lack of ovum production & release). There is also an increase in miscarriages with hypothyroidism – not all the reasons for this are well understood, but developmental abnormalities may play a part. Thyroid hormone is extremely important for neural and other development of your fetus.
Cortisol, Adrenaline & Stress
The effects of stress and stress related hormones are not as well understood and are more varied. Suffice it to say that in many people stress leads to decreased libido, arousaI, orgasm & fertility. There are a tremendous number of conditions ranging from depression to anxiety, obesity to diabetes T2, chronic fatigue to fibromyalgia that may be associated with imbalance in cortisol, adrenaline & stress tolerance/management. And these often lead to decrease in sexual function. For some, however, stress increases libido, arousal & possibly orgasm and this can occasionally lead to hypersexuality. The release associated with orgasm induces a de-stressed state of relaxation. Additionally, studies in both men and women have shown that viewing erotic photographs and video reduce cortisol levels.
Oxytocin is the hormone of sociability, friendliness & bonding. It makes people more warm-hearted, trustful & enjoy the company of others. It reduces social anxiety, enhances attachment and sets the stage for the comfort and trust that increases sexual desire (libido).
Oxytocin increases vaginal lubrication and vaginal contractions, both of which contribute to and are part of arousal.
Oxytocin facilitates orgasm. It shortens the time to orgasm, increases the intensity of orgasm with increased uterine and vaginal contractions and heightens subjective pleasure. It awakens women after orgasm with the effect of increasing memory of positive sexual experience. The opposite effect is true in men – it puts them to sleep.
Fertility per se is not affected; however, delivery is affected through oxytocin release which increases uterine contractions. Oxytocin also stimulates contraction of milk glands to assist in breast feeding. It simultaneously increases mother-child bonding in both these experiences.
Melanocyte Stimulating Hormone (MSH)
MSH increases skin pigmentation, may protect against greying of hair, reduces appetite and reduces inflammation.
MSH also increases erotic fantasies and sexual libido.
In women it has a profound increase in arousal through increased sensitivity of the labia and clitoris and increased vaginal lubrication. But it also makes the whole body more sensual. In animal studies it enhances the sexuality of bodily scents.
MSH also enhances orgasmic capacity.
It does not affect fertility directly, but receptivity to sexual advances of a heterosexual nature definitely increases the odds of pregnancy. And sexologists report that MSH boosts sexuality in women far more than any other hormone.
Click on “Men’s Sexual Health” to read that article. For information on individual hormones to see how they affect your overall health, you may search for the hormone in the search field above or click on the corresponding link: . To see if you may have symptoms of hormonal deficiency or imbalance you may download, fill out, save and return by email to SPHW@6hk.cca.myftpupload.com any of the following questionnaires: Symptoms of Female Hormone Deficiency