Hormone Changes and Cannabis: Sperm Count, Fertility, Menstruation, and Pregnancy - RxLeaf

Hormone Changes and Cannabis: Sperm Count, Fertility, Menstruation, and Pregnancy

Dragana Komnenov PhD
Side by side comparison of male and female endocrine systems

The endocannabinoid system has a key role in managing sex hormones within the human body. What happens to hormone regulation when you introduce plant cannabinoids?

The connection between cannabis and human sexuality is almost legendary. It is known fact that cannabis acts as an aphrodisiac and research confirms that the consumption of cannabis can increase sexual pleasure and desire. But does this mean that it will mess with your hormones? It’s likely, actually. In fact, some physicians deny transgenders hormone therapy if they consume cannabis. This is particularly true of patients seeking testosterone, as cannabis is known to suppress the actions of testosterone. Research indicates this may not be justified; more on this in a moment.

Transgender tearing fe off of female

Image Credit: Sandra van der Steen

There are a number of research studies that have discovered important links between endocrine (hormone) regulation and cannabis. In particular, the body’s own endocannabinoid system has a key role in controlling parts of the endocrine system. The endocannabinoid system (ECS) consists of cell receptors (CB1 and CB2) and several small molecules (endocannabinoids) produced by the body that bind to these receptors. The cannabinoids found in the cannabis plant will also bind to these receptors.

Side by side comparison of male and female endocrine systems

Image Credit: Double Brain

Cannabinoid receptors have been found in reproductive tissues like the testes, ovaries, and uterus. They are also found in the areas of the brain that regulate hormone activity, such as the hypothalamus. Research into the role of the endocannabinoid system in fertility and sexuality have found that endocannabinoids can affect, and are affected by, the different sex steroid hormones. Phytocannabinoids like delta-9-tetrahydrocannabinol (THC) can also affect the levels of sex steroid hormones and disrupt the balance of endocannabinoids maintained by the ECS. Here are a few examples from the research.

Sex Hormone Infographic comparing menopause and andropause

Image Credit: Double Brain

How Endocannabinoids Help Regulate Hormones

In the brain, the hypothalamus is rich in CB1 receptors because the endocannabinoid, anandamide is part of a signaling pathway  that inhibits the secretion of gonadotropin-releasing hormone (GnRH). It should be noted, here, that THC will also bind to the CB1 receptors and has a has a similar effect to anandamide.

GnRH stimulates the production of two important sex hormones: Follicle stimulating hormone (FSH) and luteinizing hormone (LH). In men, these hormones work in the testes to produce testosterone. In women, they work in the ovaries to produce progesterone and estradiol. The inhibition of GnRH production by THC could therefore have downstream effects on these critical hormones. Indeed, the research is consistent in finding that both women and men show a decrease in LH after THC exposure.

Infographic showing where in the brain the hypothalamus is located

Image Credit: Double Brain

Will Cannabis Affect Fertility?

In women, progesterone and estrogen interact with anandamide. This endocannabinoid is, therefore, thought to play a critical role in establishing and maintaining a healthy pregnancy. Progesterone signals the body to increase the production of fatty acid amide hydrolase (FAAH), the enzyme responsible for breaking down endocannabinoids like anandamide. As a result, anandamide levels drop, which has been found to assist in implantation of a fertilized embryo.

3-D Illustration of blastocyst implanting into uterine wall

Image Credit: Christoph Burgstedt

Several studies have found that if FAAH levels were too low, or anandamide levels too high, miscarriage is common. This has interesting implications for women struggling with infertility – perhaps an assessment of endocannabinoid levels could reveal an imbalance in this signaling pathway, and the use of cannabinoids would be therapeutic. In those with normal fertility, however, THC may interfere with this process, since it binds to the CB1 receptor just as anandamide, and could simulate high levels of this endocannabinoid.

Young woman crying with hands over face after miscarriage in hospital

Image Credit: Kiefer Pix

Cannabis and Pregnancy

Observations of cannabis consumption during pregnancy does indicate that rates of miscarriage, stillbirths, and other issues like low birthweight could result, although these results are difficult to tease out from influences like concurrent tobacco use. Laboratory studies have found that THC exposure in the early stages of pregnancy could trigger genetic changes that affect the viability of the fetus and placenta, thus causing miscarriage. Research is needed to investigate the risk of all cannabis consumption on pregnancy hormone levels; current research only looks at exposure to smoke.

Pregnant woman holding her belly

Image Credit: Natalia Deriabina

Cannabis Effects on Menstrual Cycle

In women, research into the effects of THC on the menstrual cycle has produced inconclusive results. The decrease of LH that results from THC exposure can affect ovulation and cycle length. However, women who frequently consume cannabis appear to develop a tolerance and exhibit normal menstrual cycles. In addition, one study found that women in menopause did not have any LH decrease after exposure to THC, and other study found that the effect on LH levels was dependent on the phase of the menstrual cycle. Studies using animals have produced more pronounced effects of THC on the menstrual cycle, such as the inhibition of ovulation, but human studies have yet to replicate these results.

Fertility Chart showing when ovulation occurs

Image Credit: Alena TS

Cannabis and Testosterone Levels

In men, the research into the effect of THC on testosterone has also produced mixed results. In general, it appears that THC can decrease testosterone levels, although the effect appears to be temporary. In animals, the effect is more significant than the observations in humans. Most human studies found that, while testosterone levels dip in response to THC exposure, the levels are still within the normal range. Other studies have found that, among men who frequently consume cannabis, the incidence of erectile dysfunction is higher. However, this appears to be related to the effect of cannabis on the hormone insulin and its ability to protect blood vessels, not on sex steroid hormones. In addition, male fertility may be affected, since THC exposure has been shown to affect sperm quality.

Sperm swimming animation

Image Credit: Tatiana Shepeleva

Overall, cannabis does demonstrate an ability to affect levels of sex steroid hormones and potentially interfere with the normal functioning of fertility and sexuality. However, the research is inconclusive as to the extent of this interference and whether these hormones can be manipulated outside of their normal ranges. When prescribing hormone therapy, it is likely that cannabis consumption will be discouraged as a precautionary measure.


Dragana Komnenov
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