Δ9-tetrahydrocannabinol Reduces Frequency of Heat Cycles

Updated: Mar 17, 2020

There are countless scientific studies that show the effects of Δ9-tetrahydrocannabinol (THC) on the reproductive hormone levels in numerous species (1) and its influence on ovulation and sperm production (2).

Several studies involving rhesus monkeys have found promising effects on THC slowing (but not completely inhibiting or stopping) the production of progesterone as well as prolonging heat cycles. A control group cycled with ranges from 26-34 days while THC treated participants had cycles of “145, 76, 22, 94, and 59 days”. Other studies involving the injection of THC concluded the elongation of heat cycles for several months (3). Another study showed rhesus monkeys that had their ovaries removed and that were injected with a single dose of THC ranging from 0.65 mg/kg-5.0 mg/kg, reduced levels of luteinizing hormone (LH) and follicle stimulating hormone (FHS) by 50-88%. This effect with a single dose lasted for 6-24 hours (4). Studies involving rats showed the inhibition of the development of follicles as well as ovulation by THC (5,6). In addition THC, inhibited the conversion of pregnenolone to progesterone (7,8). Other studies showed Gonadotropin Releasing Hormone was completely blocked using cannabinoid 1 (CB1) antagonists in the hypothalamus and in turn influenced the release of FSH, LH, estrogen and progesterone (9, 10, 11).

In a study involving humans it was found high dose intake was discovered to slow or decrease normal reproductive function on the hormonal level (1). Another study reported “reduced circulating GnRH, anovulatory cycles, and prolonged follicular phase thus delaying ovulation.” (12, 13, 14).

Cannabis needless to say is a VERY controversial and in many places an illegal topic. Simply put it’s fairly taboo to even mention it. The stigma often comes from TV and media, portraying dopey potheads with incoherent thoughts and inability to see straight, giggling over a bag of chips. It also seems to be associated with criminals, leading people down a dark path of other serious and addictive drugs. We won’t get into all that within this article. What’s more important is the emerging information of its therapeutic benefits for those with cancer and epilepsy as well as many more conditions such as personality disorders, pain, IBD/IBS, anxiety and insomnia. Cannabis can not only be used for illness and disease to prevent conditions but it can help maintain optimum health. As breeders one thing we have to manage are heat cycles in our breeding females. For cats this is especially important because the more our cats cycle without being bred the higher the risk for a condition called pyometra. This is an infection of the uterus, where the uterus fills with pus. This can be extremely dangerous for a cat. Not only could you have no choice but to spay your female, but it can be life threatening.

Most breeders prefer to have no more than two litters from each girl each year however this can be hard. Some girls don’t care to space their litters out (this is nature after all) and tend to cycle more than what most would like. Furthermore there are times where mothers start heat cycles quite early postpartum, as early as 5 weeks after giving birth….way too early in my opinion (15).

The solution for most breeders is a conventional commercial birth control product. Unfortunately just like human birth control there are many concerns with using it including infertility, pyometra, diabetes, tumor formation and liver disease. Obviously this presents some hesitation.

After EXTENSIVE research there seems to be very few natural products available that not only are natural and balance hormones but were without restrictions like specific time frames you needed to give the medication. This really narrowed down the options. With all the side effects and restrictions in mind, Δ9-tetrahydrocannabinol or THC starts to look like a great option.

What is THC?

Δ9-tetrahydrocannabinol or THC was isolated in 1964 (16,17) and is one of over a hundred cannabinoids found in the cannabis plant. Cannabinoids are chemical compounds that act as a key to receptors (the lock) found within the endocannabinoid system that influence the release of chemical messengers or neurotransmitters throughout the entire body. There are three types. Endogenous cannabinoids or endocannabinoids found in the body, herbal cannabinoids or phytocannabinoids found in plants and synthetic cannabinoids (18). Phytocannabinoids and synthetic cannabinoids imitate endocannabinoids naturally found in the body (9).

The Endocannabinoid system The Endocannabinoid System or ECS is a biological system found in all living beings including humans, cats, dogs and even the most primitive organisms (10). It is not found in insects however. Animals such as cats and dogs as well as children tend to have more cannabinoid receptors than adults which means sometimes it takes higher therapeutic doses to have a positive and healing effect.

The system works like many biological systems in the body. When signals are sent that an imbalance is occuring, specific cannabinoids are produced. The classic example is the flight or fight response. When signals are sent that the organism is in danger all the senses are heightened, heart rate and breathing increases. When the situation calms down signals are then sent to relax the body down again. If there is unbalance in any of our natural cycles then we suffer illness, disease and other conditions.

The system consists of receptors located throughout the entire body that help regulate:

  • The immune system

  • Emotional Regulation including mood

  • Creating new nerve cells

  • Sleep

  • Pain management (11,12,13,14)

  • Food intake (activation and suppression) and digestion (15)

  • Brain function including memory

  • Muscle movement, balance and coordination

  • Heart function including heart rate and blood pressure (16, 17, 18, 19)

  • Reproduction including fertility (20) pregnancy (21) and development (22)


Due to the widespread reach of the ECS and it’s receptors primarily CB1 and CB2 (24) the medicinal use of cannabis is near endless and can be used to aid many conditions. In short, when the body is unbalanced in whatever capacity, the medicinal aspects of cannabis can be used to rebalance. It can help therapeutically to manage:

  • Chronic pain (25) and inflammation associated with arthritis, inflammatory bowel disease, pancreatitis, and FIC/FLUTD (feline lower urinary tract disease) (26).

  • Act as a neuroprotective agent, reducing seizure frequency and intensity (27).

  • Decrease nausea and stimulate appetite (28).

  • Reduce cancer and associated symptoms (29, 30)

  • Reduce bronchial spasms in asthmatics (31, 32)

  • Lower anxiety (33), which can help correct or modify behavior issues.

  • Support the immune system (34) for conditions like food allergies and immune-mediated diseases.

It's overwhelmingly clear that the ECS plays a huge part in maintaining health and balance with the body (35).

The Receptors

CB1 and CB2 are cannabinoid receptors found in the ECS (36). CB1 is found widely throughout the body and tends to be higher in receptors than CB2 (37).

CB1 receptors are primarily in the central nervous system including parts of the brain known to regulate, pain management, movement and memory (37). They can also be found in the “pituitary gland, immune cells, reproductive tissues, gastrointestinal tissues, ganglia, heart, lungs, bladder and adrenal gland” (38).

CB2 receptors on the other hand are primarily found within the immune system (39). This also includes organs like the tonsils and spleen (40).

What is FECO?

Typically when people hear about cannabis they assume it’s all about smoking a joint in the basement of your parents’ house, but when we are talking about therapeutic use we are talking about full extract cannabis oil (FECO).

Through a food grade ethanol extraction process the medicinal properties are separated from the plant. The result is a concentrate. Via this process all medicinal properties of the plant retained including

Cannabinoids, terpenes, flavonoids and essential fatty acids. this also means less chlorophyll which is essential for our obligate carnivore companions.

FECO also uses a food grade ethanol extraction process while many commercial products are extracted with non-medicinal, non-food grade, or down right dangerous solvents, including added preservatives, flavorings, etc. These ingredients are not required to be on the label! These ingredients not only are dangerous but they also take away from the end product, how it functions including on the therapeutic level.

Is it Really Safe though?

It's not uncommon to hear veterinarians and other pet owners claim THC is toxic to cats and it will kill them if it's used. Yes, you will find numerous studies that back these claims and in unhealthy cats such as those suffering from liver disease or heart abnormalities harm can come to your companion. The only thing is that many of these studies are based on situations where animals have consumed various products containing other ingredients like dangerous solvents, edibles (that may include chocolate which is known to poisonous to cats) or other ingredients not safe for companion animals. Animals that ingest cannabis smoke is 100% dangerous! Why? Because when you burn cannabis it releases carcinogens (yet another reason FECO is the way to therapeutically heal the body NOT smoking cannabis). This is also the source for problems during reproduction, pregnancy/the developing fetus and birth.

While THC as a schedule I drug presents obstacles when it comes to research and research funding as well as manufacturing (41), over 100 controlled trials have been conducted with cannabinoids since 1975 leading to the approval of medical cannabis in numerous countries and states (42).

In 2003 the World Health Organization Expert Committee on Drug Dependence even petitioned to have THC moved to Schedule IV because of its low potential for abuse (43).

In reality when THC use stops, the body can easily return back to normal hormone function and release (40).

If the listed studies above aren’t enough to prove the benefits just look up the US Patent number 6630507 filed April 1998, and approved in 2003. This patent is for Cannabis as Antioxidants and Neuroprotectants (44). Remember. it also comes down to knowing what you doing! Cannabis can help many conditions if used correctly!

Side Effects:

While THC is not toxic and cannot kill your companion if used correctly, there are some side effects if the dose is inappropriate for your companion. However, these side effects are minor and wear off with time. Side effects can include:

-A blank stare, glassy eyes, and/or dopey eye -Unbalanced coordination or bobbing head -Slight paranoia such as hiding from you -Lower body temperatures Basically your companion is stoned and feeling pretty darn good. Your companion WILL be ok, the dose just needs to wear off and it just means that you need to tailor back a little on dosing.

Just like any medication there is a specific dose and ratios that compliments each companion animal. Companion pet owners and breeders alike must be aware of individual differences of their animals. They must be aware of health conditions their pet has, they must be aware of pharmaceutical drugs being given to their companion. If these things are ignored cannabis can easily be misused. THC is NOT harmful to the body if it is used properly.

Why Full Extract THC and not another cannabinoid or commercial products for this topic?

First and foremost, there are many types of cannabis strains and cannabinoids (CBD, THC, CBN, THCA, CBG etc.) Each cannabinoid and combination of cannabinoids help specific conditions.

Currently because THC is illegal federally (even despite many states making medicinal marijuana legal) over a certain percent of THC (according to the DEA) most individuals feel commercial CBD is their only option. Many do not feel comfortable finding a dispensary or other source and thus choose to buy a commercial product. Unfortunately as mentioned above most of these products are made with unnecessary and even harmful ingredients. Furthermore these products are more expensive, more of the product is needed to be consumed and while they may offer some benefits do not act on a truly therapeutic level. Commercial CBD oils found at stores are from Industrial hemp which is the legal term for high cbd content cannabis. Cannabis obviously is a plant. The flowers of the female plants once processed are the medicine. Real Industrial hemp is from male plants.

The healing and beneficial components really do come from the real stuff. Why don’t you want medicine made from industrial hemp? Because while its not anything new as in its been used for paper products, clothing, making plastics and edible foods it is also used to clean up industrial waste like chemical spills for example. It is amazing at removing toxins, heavy metals and other contaminants from the ground, water sources and air and industrial hemp holds all this!

If we want to talk about just the CBD content in cannabis, cannabis contains 150,000 ppm of CBD where as hemp only contains 25 ppm so you can imagine what the THC levels are in industrial hemp.

Heat Cycles in Felines

Cats don’t have heat cycles like dogs who often cycle about twice a

year and felines typically begin cycling at 4-9 months of age on average. Several factors including daylight cycles influence the hormones but in a cattery setting artificial and abnormal light periods and other factors can cause cats to go into heat year round unlike their wild counterparts who often only cycle in the spring and summer. These domestic based cycles often are infrequent and a female will establish her own cycling period.

The hormones that work right before and during the heat cycle are the hormones we are most concerned about and hoping to influence to space out heats and reduce the time that cats are in heat if they go in.

Now that you have the background information surrounding THC, how heat cycles work and the hormones at play, let’s get into the real reason for this article…..managing heat cycles with full extract THC oil.

The ECS as briefly described above deals with many body systems in the feline which certainly does not discriminate against the reproductive system. It greatly influences the development of follicles and hormone secretions (45). Long term exposure to THC and other cannabinoids has resulted in the “delay [of] sexual maturation, cause menstrual cycle disruption, depress ovarian follicular maturation, and reduce serum concentrations of LH and sex hormones” (46).

Females of all species in general possess a higher tolerance for cannabis due to the higher fat content found in the body. THC is lipophilic meaning it likes fat and due to this, there is a slow release of THC and longer periods of cannabinoid receptor stimulation (47).

One thing to keep in mind is that hormones on a regular basis fluctuate and it’s certainly no different when it comes to the menstrual cycle. For example in rat studies females were the most sensitive to THC during the two week estrus period (48). This is important to keep in mind so one can be mindful of small changes in behavior indicating a need for higher or lower doses on a day to day basis.

Now that you understand how Δ9-tetrahydrocannabinol can prolong heat cycles let's talk about dosing. Like any medication, dosing is subject to the individual animal. For cannabis this means start low and titrate up. 1-2 mg THC FECO twice a day is a great start. When hormones are fluctuating increase to 2-3 drops and reduce as needed when hormones seem to change. Be aware of behavior changes that may indicate when hormones are fluctuating or when your companion may be at their maximum dose. When you are ready to breed, cease dosing and wait for a normal heat cycle to occur. It is not recommended to administer THC during the nursing state of raising kittens. THC slows down the production and release of prolactin, a major hormone involved in the production of breast milk. THCA or CBD would be a better alternative is cannabis therapy is needed. MAIN TEXT REFERENCES: 1. Smith, C G, et al. “Tolerance Develops to the Disruptive Effects of Delta 9-Tetrahydrocannabinol on Primate Menstrual Cycle.” Science (New York, N.Y.), U.S. National Library of Medicine, 25 Mar. 1983, www.ncbi.nlm.nih.gov/pubmed/6298938. 2. Treinen, K.A., et al. “Specific Inhibition of FSH-Stimulated CAMP Accumulation by Δ9-Tetrahydrocannabinol in Cultured Rat Granulosa Cells.” Toxicology and Applied Pharmacology, Academic Press, 25 May 2002, www.sciencedirect.com/science/article/pii/S0041008X83710082. 3. Smith, Carol Grace, et al. “Effect of Tetrahydrocannabinol on the Hypothalamic-Pituitary Axis in the Ovariectomized Rhesus Monkey.” Fertility and Sterility, Elsevier, 6 May 2016, www.sciencedirect.com/science/article/abs/pii/S0015028216438859.

4. Smith, C G, and R H Asch. “Acute, Short-Term, and Chronic Effects of Marijuana on the Female Primate Reproductive Function.” NIDA Research Monograph, U.S. National Library of Medicine, 1984, www.ncbi.nlm.nih.gov/pubmed/6090911.

5. El-Talatini MR, Taylor AH, Elson JC, Brown L, Davidson AC, Konje JC (2009) Localisation and Function of the Endocannabinoid System in the Human Ovary. PLoS ONE 4(2): e4579. https://doi.org/10.1371/journal.pone.0004579

6. Adashi EY, Jones PBC, Hsueh AJW. Direct antigonadal activity of cannabinoids: suppression of rat granulosa cell functions. Am J Phys. 1983;244(2):E177–85.

7. Walker, O.S., Holloway, A.C. & Raha, S. The role of the endocannabinoid system in female reproductive tissues. J Ovarian Res 12, 3 (2019). https://doi.org/10.1186/s13048-018-0478-9

8. Brents, Lisa K. “Marijuana, the Endocannabinoid System and the Female Reproductive System.” The Yale journal of biology and medicine vol. 89,2 175-91. 27 Jun. 2016

9. Hyyppa M, Motta M, Martini L. 'Ultrashort' feedback control of follicle-stimulating hormonereleasing factor secretion. Neuroendocrinology 1971;7:227–235. [PubMed: 4927852

10. Castro JCB, Khorram O, McCann SM. Possible negative ultra-short loop feedback of luteinizing hormone releasing hormone (LHRH) in the ovariectomized rat. Proc Soc Exp Biol Med 1985;179:132–135. [PubMed: 3921973]

11. x

12. Rosaria Meccariello, Rosanna Chianese, Silvia Fasano and Riccardo Pierantoni (February 20th 2013). Endocannabinoids and Kisspeptins: Two Modulators in Fight for the Regulation of GnRH Activity, Gonadotropin, Jorge Vizcarra, IntechOpen, DOI: 10.5772/48443. Available from: https://www.intechopen.com/books/gonadotropin/endocannabinoids-and-kisspeptins-two-modulators-in-fight-for-the-regulation-of-gnrh-activity

13. Gammon, C Michael et al. “Regulation of gonadotropin-releasing hormone secretion by cannabinoids.” Endocrinology vol. 146,10 (2005): 4491-9. doi:10.1210/en.2004-1672

14. Veldhuis J, Johnson M. Cluster analysis: a simple, versatile, and robust algorithm for endocrine pulse detection. Am J Physiol 1986;250:E486–E493. [PubMed: 3008572

15. Verstegen, J.P.: Physiology and endocrinology of reproduction in female cats. Manual of Small Animal Reproduction and Neonatology (Simpson, G.; England, G; Harvey, M. eds). British Small Animal Veterinary Assoc., Cheltenham, U.K., 1998; pp 11-16. Gaoni Y, Mechoulam R (1964). "Isolation, structure and partial synthesis of an active constituent of hashish". Journal of the American Chemical Society. 86 (8): 1646–1647. doi:10.1021/ja01062a046.

17 Mechoulam R (1970). "Marihuana chemistry". Science. 168 (3936): 1159–66. Bibcode:1970Sci...168.1159M. doi:10.1126/science.168.3936.1159. PMID 4910003.

18. Fisar Z (2009): Phytocannabinoids and endocannabinoids. Current Drug Abuse Reviews 2, 51–75

19. Grotenhermen F (2006): Cannabinoids and the endocannabinoid system. Cannabinoids 1, 10–14