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Cbd oil dosage for endometriosis

CBD Oil for Endometriosis Pain – June 2022

Why Women Are Turning to CBD for Endometriosis Pain

Endometriosis (EM) is a condition caused by endometrial tissue growth outside of the uterus. This condition often causes severe menstrual pain and cramping .

Treatment options include hormone therapy, pain medication, or laparoscopic surgery. Hormone therapies, such as contraceptives ( birth control ), gonadotropin-releasing hormone (Gn-RH), and progestin therapy, may cause undesirable side effects .

For example, Gn-RH may cause artificial menopause (5 ) . Contraceptives and progestin therapies may cause headaches and bloating (6 ) .

Also, studies have debated the efficacy of non-steroidal anti-inflammatory drugs ( NSAIDs ), such as ibuprofen , on EM-associated pain (7 ) .

A review published by Deutsche Ärzteblatt International mentioned that 70% of young women with EM do not respond to NSAID treatments (8 ) .

These factors are why women with EM are turning to alternative options to improve quality of life.

The BMC Complementary and Alternative Medicine posted a cross-sectional online survey that measured the efficacy of self-management strategies. The strategies women used for EM pain were exercising, yoga, diet changes, hot compress, and CBD oil .

The study found that CBD oil produced the highest pain relief scores among women who participated in the survey (9 ) .

This anecdotal evidence from the survey may be explained by studies supporting CBD’s therapeutic benefits.

A study posted by Therapeutics and Clinical Risk Management mentioned that CBD has anti-inflammatory and analgesic properties. The author added that CBD was able to inhibit proinflammatory cytokines on animal subjects (10 ) .

Cytokines are cell-signaling proteins that trigger systemic inflammation in the body (11 ) .

This hypothesis was supported by an animal cross-study posted by Proc Natl Acad Sci USA. Study results showed that CBD’s immunosuppressive action decreased cytokine production, resulting in reduced inflammation in knockout mice (12 ) .

Although positive results have been observed from anecdotal and animal studies, more research is needed to determine CBD ’s clinical value as an endometriosis treatment.

How CBD Oil Works to Help With Endometriosis Pain

The endocannabinoid system (ECS) is a complex system composed of endogenous cannabinoids and G-coupled receptors. The human body is filled with these receptors (13 ) .

The endocannabinoid receptors, cannabinoid 1 (CB1) and cannabinoid 2 (CB2), are present in the central nervous system, immune system , and peripheral organs. The ECS’s function is to promote and maintain body homeostasis (14 ) .

Modulating the ECS has therapeutic benefits in several health problems, such as chronic pain (15 ) , anxiety, insomnia (16 ) , neurodegenerative diseases (17 ) , and epilepsy (18 ) .

CB1, the more abundant receptor, can be found in pain circuits. CB1 receptors also participate in producing analgesic and anti-inflammatory effects (19 ) . Meanwhile, CB2 receptors are mostly expressed in the intestines and the immune system.

A 2017 study explained how cannabinoid receptor agonists might stimulate CB1 receptors and CB2 receptors. This activity might be beneficial in treating EM pain and other chronic pain conditions (20 ) .

Phytocannabinoids, such as CBD , tetrahydrocannabinol ( THC ), and cannabigerol (CBG), have an affinity to CB1 receptors (21 ) .

Several studies suggested CBD ’s ECS modulation might inhibit proinflammatory cytokines (22 ) .

It has also been observed that CBD might act as an agonist for endocannabinoid receptors, therefore modulating the ECS (23 ) .

A study from Pain journal mentioned that CB1 could be found in rodent uterus. The authors added that CB1 receptors in the uterus are a potential target treatment to reduce endo-induced hyperalgesia (sensitivity to pain) (24 ) .

The authors mentioned that studies in EM rat models provided evidence that endocannabinoids and cannabinoids could be useful in reducing endometriosis symptoms (25 ) .

Although rats models have significant ECS differences with EM in human models, a study recognized that there might also be lateral aspects (26 ) .

The Pros and Cons of CBD Oil for Endometriosis Pain

The Pros
  • A study has acknowledged that CBD might influence receptors to suppress proinflammatory cytokine production (27 ) .
  • A study mentioned that CBD has anti-inflammatory and analgesic properties (28) .
  • A study found that CBD oil had the highest pain relief scores among women who self-managed their EM pain using alternative strategies (29 ) .
  • Studies acknowledged that CBD has an excellent safety profile and is well-tolerated (30 ) .
The Cons
  • There is a lack of clinical studies on how CBD may affect endometriosis pain in humans. Most existing studies are done on animal subjects.
  • The CBD industry lacks regulation. Customers must thoroughly research before buying any CBD product .
  • CBD may cause adverse effects, such as loss of appetite, dry mouth, diarrhea, and sleepiness (31 ) .
  • CBD may cause liver injury when used in extremely high doses (32 ) .

How CBD Oil Compares to Alternative Treatments for Endometriosis Pain

There is no cure for EM. The main goals of therapies are pain management and improving quality of life (33 ) .

There are several alternative medicines available for managing EM pain.

Xuefu Zhuyu decoction (XZD) is an herb used in treating EM pain in China. Clinical studies have shown that XZD has therapeutic benefits in relieving dysmenorrhea , promoting fertility, and shrinking ectopic lesions (34 ) .

Another herb, Qu Yi Kang (QYK), has been shown to alleviate dysmenorrhea symptoms and reduce endometrial lesions (35 ) .

Green Tea Epigallocatechin-3-Gallate (EGCG) is a compound extracted from green tea leaves. ECG might enhance apoptosis and inhibit lesion growth in rat models (36 ) .

Ginsenoside Rg3 is found in Panax plants. An animal study has shown that ginsenoside Rg3 reduced lesions in EM rat models (37 ) .

These herbs are some of the several alternative medicines for treating EM pain. Mostly, these herbs are geared toward pain management .

These herbal medications like XZD, QYK, EGCG, and ginsenoside Rg3 have been clinically studied due to their popularity as EM treatments in China.

Studies have shown that CBD might also reduce pain and inflammation (38 ) . Like ECGC, CBD might also enhance apoptosis and suppress cytokine production (39 ) .

However, CBD ’s efficacy on EM pain is not yet supported by clinical trials.

How to Choose the Best CBD Oil for Endometriosis Pain

Women with EM may opt for full-spectrum CBD or broad-spectrum CBD .

Full-spectrum CBD oil contains all the cannabinoids found in the hemp plants, such as CBD , 0.3% tetrahydrocannabinol ( THC ), cannabigerol (CBG), and cannabinol (CBN).

Broad-spectrum CBD contains all the same cannabinoids except for THC .

Both full-spectrum and broad-spectrum create the “entourage effect.” This term is named after the cannabis synergy, wherein an individual takes in the supposed health benefits of all the cannabinoids in one dose.

The entourage effect has been demonstrated by an animal study published by Frontiers in Plant Science . The author mentioned that cannabis extracts with predominant CBD concentrations might deliver better analgesic results than pure THC or CBD (40 ) .

Women who have an intolerance to other cannabinoids may opt for CBD isolate (90% pure CBD ).

CBD Dosage for Endometriosis Pain

There is a lack of clinical studies on the appropriate CBD dosage for EM pain.

However, a study from the British Journal of Pharmacology recommended that individuals start with less than 1 to 5 mg per kilogram a day. This dose can gradually increase once the system gets used to taking CBD (41 ) .

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Another study also mentioned that pure CBD produced a dose-response curve. The author observed that a smaller dose was effective until the peak is reached. Afterwhich, additional dosings no longer induce any response (42 ) .

This dose-response curve was demonstrated by a cross-study posted in the Brazilian Journal of Psychiatry . The authors showed that 300mg pure CBD produced better results compared to 150mg and 600mg (43 ) .

When taking CBD for EM pain, women must remember to be cautious. An extremely high CBD dose has been shown to cause liver damage (44 ) .

How to Take CBD Oil for Endometriosis Pain

When taking CBD oil for EM pain, an individual may want quick pain relief . Therefore, the recommended administration is through inhalation of CBD vapors (45 ) .

A study mentioned that the lungs are very efficient in absorbing cannabinoids. Plasma concentrations can be delivered into the bloodstream in 10 minutes or less (46 ) .

However, vaping may also cause adverse effects, such as allergic reactions, shortness of breath, and chest pains (47 ) .

Oral CBD deliveries are available in the form of capsules, softgels, and gummies. This method is recommended to be taken with or without a meal.

CBD tinctures may be taken through sublingual delivery. This method can be done by using an applicator to drop CBD tinctures under the tongue.

Compared to vaping, oral and sublingual delivery may take longer to be absorbed into the body, but these methods allow for optimal absorption (48 ) .

Some CBD companies have designed CBD suppositories for painful periods . However, there are no studies on how CBD suppositories might help in relieving EM pain.

CBD isolate is often sold in powder form. Women may mix this in a carrier oil, like virgin coconut oil, olive oil, or hempseed oil. CBD crystalline isolate may be dissolved under the tongue.

Meanwhile, transdermal CBD is not recommended for EM pain.

What is Endometriosis?

The endometrium is a tissue lining inside the uterus. During each menstrual cycle , the endometrium thickens and bleeds.

In some women, endometrial cells can be found outside the uterus, particularly in the fallopian tubes , ovaries, and pelvic lining.

During the monthly cycle, the endometrial tissues thicken and bleed, irritating the surrounding tissues and organs. The blood clot buildup eventually becomes scar tissue and causes organs to stick to each other.

  • Severe menstrual cramps
  • Dysmenorrhea
  • Chronic pelvic pain
  • Pain during urination and bowel movements .
  • Lower back or abdominal pain
  • Pain with intercourse
  • Infertility

The exact cause of EM is unknown, but experts believe that EM can be caused by heredity, c-section and hysterectomy procedures, and immune system disorders.

Effective treatments are available, but the surgery produces the best result. Laparoscopic surgery can remove the lesions, adhesions, and scar tissue.

The laparoscopic procedure may also restore fertility. A study mentioned that the postoperative fertility rate was 43% (50 ) .

However, the study also mentioned that the recurrence of EM after laparoscopic surgery is 20% after five years (51 ) .

What is Deep Infiltrating Endometriosis?

Deep Infiltrating Endometriosis (DIE) is when scar tissues caused by endometrial lesions have infiltrated 5 millimeters into the tissues of pelvic organs (52 ) .

DIE is considered stages 3 and 4 of endometriosis . Stages 1 and 2 involve minimal lesions and superficial implants on surrounding organs, while stages 3 and 4 are when cysts are formed in the ovaries (53 ) .

The late stages also mean that surrounding organs have deep implants and dense adhesions (54 ) .

Treatments for DIE often involve surgery, NSAIDs , and hormonal therapies. DIE can lead to infertility and multiple cyst growths if left untreated (55 ) .

How is CBD Oil Different from Medical Marijuana?

CBD is a cannabinoid extracted from Cannabis sativa plants. Manufacturers use an extraction method to produce a concentrated version without the psychoactive effects one may get from cannabis products or medical marijuana .

Depending on the cannabis strains used by the dispensary, medical marijuana can contain up to 17-28% THC (56 ) . Federal law prohibits CBD oil from carrying more than 0.3% THC .

Hemp derivatives, such as CBD oil , hemp oil, and hemp seed oil, are legal in the United States.

Unlike medical cannabis or medical marijuana , CBD oil is legal in all 50 US states and territories. Medical and recreational cannabis use is only allowed in 11 US states.

Although CBD is legal, it remains highly unregulated. Some questionable CBD brands are not held accountable for falsely advertising their products as high-quality.

Customers can quickly identify legitimate CBD brands by checking the company’s transparency. High-quality CBD brands often post the certificate of analysis (COA) on their website.

The COA is a third-party lab result from ISO-certified laboratories. With the COA, consumers know exactly how much cannabinoids are contained in the product.

The COA also tests for heavy metals, fungicides, pesticides, and other contaminants. The COA ensures that the product is safe for use on humans or pets.

Conclusion

Animal studies have shown that CBD has anti-inflammatory and analgesic properties (57 ) . These findings suggest that CBD might be useful in alleviating difficult-to-treat pain.

Also, CBD oil has reduced EM pain among women who tried self-management strategies (58 ) .

Researchers also mentioned that studies in EM rat models provided evidence that modulating the ECS might reduce endometriosis symptoms (59) .

CBD Oil for Endometriosis Pain: Does It Help?

Endometriosis is an autoimmune disease involving the abnormal growth of cells similar to those found in the womb’s lining. According to statistics, the condition affects 1 in 10 of women of reproductive age — contributing to 176 million instances worldwide.

Researchers still don’t understand why endometrial tissue begins to grow in the uterus, spreading to the nearby pelvic organs, such as ovaries, bladder, and bowel.

The problem with endometriosis is that the errand cells start to bleed during the bleeding phase of a woman’s menstrual cycle. But unlike the normal cells, the ones triggered by endometriosis can’t pass their blood outside, causing inflammation, pain, and formation of scar tissues.

Today, we explore the benefits of using CBD oil and other types of cannabis extracts for endometriosis pain and related symptoms.

Can CBD Help with Endometriosis?

Women with endometriosis are typically prescribed pain medication, hormone therapy, or need to undergo laparoscopic surgery.

Hormonal treatments are known to cause undesirable side effects; for example, Gn-RH, a popular hormone, may trigger artificial menopause on top of causing headaches and bloating.

The efficacy of NSAIDs, such as ibuprofen, for EM-associated pain, is also questionable.

According to a review published in Deutsche Arzteblatt International, 70% of young women with endometriosis don’t respond to NSAID treatments .

That’s why alternative options, such as CBD oil, are becoming more popular for this disease.

The BMC Complementary and Alternative Medicine published a cross-sectional online survey that evaluated the efficacy of self-management strategies .

Among the most popular choices, such as hot compress, diet changes, yoga, and exercising, CBD oil scored a high place.

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The study found that women who took CBD oil reported the highest pain relief scores among women who participated in the study.

Another study posted in Therapeutics and Clinical Risk Management mentioned that CBD produces anti-inflammatory effects. The author added that CBD was able to stop the release of proinflammatory cytokines in animals .

A follow-up cross-study published by Proc Natl Acad Sci USA confirmed these results, showing CBD’s immunosuppressive action through decreasing cytokine production .

Clinical Research On CBD & Endometriosis

So far, there have been no clinical trials examining the efficacy of cannabis medicine in women with endometriosis.

Two clinical trials are about to investigate the effects of phytocannabinoids on endometriosis pain and related symptoms.

In a Spanish open-label phase II trial, women with endometriosis-induced hyperalgesia will receive an oral spray with a 1:1 ratio of THC and CBD .

In another phase III double-blind placebo study, patients will be administered norethindrone acetate, a hormonal treatment, supplemented with either 10 mg or 20 mg of CBD for the management of endometriosis pain .

Gathering sufficient robust evidence to convince the medical world that cannabinoids are effective for endometriosis may take years. In the meantime, cannabis will undoubtedly play a significant role in the self-care routine of women around the world when it comes to easing their endometriosis pain.

How Does CBD Oil Work to Help with Endometriosis Pain?

The endocannabinoid system (ECS) is a vast network of endogenous cannabinoids, enzymes, and G-coupled receptors that are spread throughout the body.

These receptors (type 1 and 2) are present in the central nervous system, immune system, and peripheral organs. The main role of the ECS is to promote and maintain homeostasis in the body.

ECS modulation has been associated with therapeutic effects in several health conditions, including anxiety, insomnia, neurodegeneration, epilepsy, and chronic pain.

The CB1 receptor can be found in pain circuits; it also participates in producing pain-killing and anti-inflammatory effects. Meanwhile, the effects of CB2 receptor activity are mostly expressed in the immune system.

A 2017 study explained how THC and CBD act on these receptors. Their activity might be beneficial for women with endometriosis pain or even when their menstruation stops and other chronic pain conditions .

Several studies have implicated that CBD and other cannabis compounds can inhibit proinflammatory cytokines.

One study published in Pain journal found CB1 receptors in the rodent uterus. The research team suggested that CB1 receptors are a potential target treatment to curb hyperalgesia (sensitivity to pain) in that area .

The study also provided evidence that endocannabinoids and phytocannabinoids could be useful in alleviating endometriosis symptoms.

How to Use CBD for Endometriosis

There are several types of CBD to choose from; the three main types include full-spectrum CBD, broad-spectrum CBD, and CBD isolate.

Full-spectrum CBD contains the original phytochemical profile of the source plant, including minor cannabinoids, terpenes, flavonoids, and traces of THC. Read our Full-Spectrum CBD guide to learn more.

These compounds work synergistically to enhance the beneficial effects of the major cannabinoids and mitigate their potential side effects. This concept is known as the entourage effect.

Broad-spectrum CBD is much like its full-spectrum counterpart, save for the lack of THC. The intoxicating compound is removed from the extract after the initial extraction.

CBD isolate is exactly what it sounds like — pure cannabidiol. It occurs as whitish crystals that are then turned into a powder and mixed into different products. Isolates have no odor or flavor, and they also don’t evoke the entourage effect.

Let’s take a look at which type of CBD is more helpful in managing endometriosis pain.

Full-spectrum vs. Isolate: Which is Better for Endometriosis?

Focusing on individual cannabinoids and their mechanisms makes it easy to think that the cannabis plant has little to do with endometriosis.

Dr. Ethan Russo, a neuroscientist and passionate proponent of the entourage effect, underlines the importance of whole-plant cannabis medicine as a treatment for endometriosis and other conditions.

Russo says that there are “multiple components of cannabis that can be put together in the right preparation to treat endometriosis, both in terms of symptoms, the pain, and affecting the disease process itself. It’s rare these days that an issue like endometriosis or cancer or diabetes is going to be successfully treated with one agent.”

Conventional pharmacology tends to isolate a compound, give it a target, and observe how it deals with it — which can be very specific.

However, this pharmacology ignores the bigger picture, so it’s unlikely that one molecular mechanism will take care of the whole symptoms associated with endometriosis.

It’s worth noting that throughout human history, plants have been used medicinally. Synthetic drugs were developed later, but many of them are based directly or indirectly on plant-based chemicals.

CBD Oil for Endometriosis

CBD oil is the most popular form of CBD for endometriosis. It’s a thick hemp extract that is further diluted with a carrier oil for improved bioavailability — and bottled up with a dropper to make dosing easier.

CBD oil can be ingested in different ways. It can be taken under the tongue, where it should sit for around 60 seconds. The sublingual mechanism ensures a faster onset of effects, higher bioavailability, and better absorption. That’s because CBD enters the bloodstream directly through the tiny blood vessels in your mouth.

Other popular formats include capsules and gummies, which are better for people who dislike the taste of natural CBD oil and are looking for a precise dose in each serving.

Vaping is the fastest and most effective way to deliver CBD to your system. When you inhale CBD through a vape pen, it enters the bloodstream through the lung tissue, providing almost instantaneous effects.

CBD Cream for Endometriosis

A lot of women with endometriosis combine two forms of CBD oil — oral and topical.

When you take CBD oil, gummies, or capsules, they target EM symptoms from within, which is great for symptom control and reaching the underlying cause.

But, when you experience endometriosis flare-ups, they may require a more localized approach, such as a topical formulation.

Topical products like CBD creams, lotions, gels, and salves, are applied directly to the skin. From there, they interact with the skin’s CB2 receptors, producing a relaxing and anti-inflammatory response.

This, in turn, may contribute to effective pain control. Topicals can take between 10 and 60 minutes to start working, depending on the formulation.

CBD Dosage for Endometriosis

Most of our modern pharmaceutical medications come with standardized dosages and guidelines regarding their use.

On the other hand, CBD is a very personalized substance and can have different dosages even for people of the same height, weight, and lifestyle.

Cannabis dosages always start from low amounts and take time to gauge the effective dosage for each individual. Doctors will start you on a medication they believe will work best for you and then titrate the dose to adjust it to the severity of your symptoms and your individual body chemistry.

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The goal of successful CBD dosage for endometriosis is to find the amount that gets you maximum effects with few side effects.

Can You Use Medical Marijuana for Endometriosis?

Yes, medical marijuana can be helpful in endometriosis. While CBD can effectively reduce EM pain, THC uses another important mechanism to benefit women with endometriosis.

With fewer CB1 and CB2 receptors in endometrial tissue available for endocannabinoids to bind with, the natural process of cell death (apoptosis) may be compromised, allowing for the malignant cells to multiply and spread.

Preclinical research indicates that endogenous, Phyto, or synthetic cannabinoids that target these two receptors can control the development of endometriosis.

In a 2017 study, the authors showed that drugs stimulating CB1 and CB2 receptors contributed to decreased proliferation and growth of endometrial tissue and its breakdown or what we call apoptosis .

While this may sound bad, apoptosis is a normal programmed cell death that’s part of their life cycle, and it’s disrupted in abnormal growth such as cancer or endometriosis.

This would explain why THC and potentially other molecules in cannabis would be symptomatically helpful and also target the actual pathology of endometriosis.

A recent study evaluating the effect of THC on a mouse model of endometriosis concluded that THC not only reduced pain markers but also inhibited the growth of an endometrial cyst.

Final Thoughts on CBD and Endometriosis

Animal and preclinical human studies have shown that CBD has anti-inflammatory and analgesic properties. These effects may be useful in targeting pain that is difficult to treat, such as the one triggered by endometriosis.

Since all cannabinoids and terpenes can interact with the endocannabinoid system, many of them have similar anti-inflammatory and antioxidative properties, whole-plant extracts appear to be the most effective form of cannabis treatment.

If you live in a place with a legal medical marijuana program, you can combine CBD oil with a high-THC product to optimize your treatment and use a holistic approach.

Currently, the only federally legal way to use CBD for endometriosis is by taking CBD oil and/or cream. This way, you can both support your endocannabinoid system and target localized pain.

A consultation with a doctor experienced in cannabis use should help you determine the right dosage and avoid negative interactions with any medication you might be taking.

  1. Armour, M., Sinclair, J., Chalmers, K.J. et al. Self-management strategies amongst Australian women with endometriosis: a national online survey. BMC Complement Altern Med 19, 17 (2019). https://doi.org/10.1186/s12906-019-2431-x (1)
  2. David Garcia Cinca, Hospital Clinic of Barcelona. (2019). Effect of Cannabinoid (THC / CBD 50%) on Hyperalgesia of Patients with Deep Endometriosis (EndomTHC). Available at: https://clinicaltrials.gov/ct2/show/NCT03875261 (2)
  3. Deimling, A.T. (2020). Cannabidiol and Management of Endometriosis Pain. Available at: https://clinicaltrials.gov/ct2/show/NCT04527003 (3)
  4. Dmitrieva, N., Nagabukuro, H., Resuehr, D., Zhang, G., McAllister, S. L., McGinty, K. A., Mackie, K., & Berkley, K. J. (2010). Endocannabinoid involvement in endometriosis. Pain , 151 (3), 703–710. https://doi.org/10.1016/j.pain.2010.08.037 (4)
  5. Bilgic, E., Guzel, E., Kose, S., Aydin, M. C., Karaismailoglu, E., Akar, I., Usubutun, A., & Korkusuz, P. (2017). Endocannabinoids modulate apoptosis in endometriosis and adenomyosis. Acta histochemical , 119 (5), 523–532. https://doi.org/10.1016/j.acthis.2017.05.005 (5)
Nina Julia

Nina created CFAH.org following the birth of her second child. She was a science and math teacher for 6 years prior to becoming a parent — teaching in schools in White Plains, New York and later in Paterson, New Jersey.

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Effects of cannabis ingestion on endometriosis-associated pelvic pain and related symptoms

Background: The use of cannabis for symptoms of endometriosis was investigated utilising retrospective archival data from Strainprint Technologies Ltd., a Canadian data technology company with a mobile phone application that tracks a range of data including dose, mode of administration, chemovar and their effects on various self-reported outcomes, including pelvic pain.

Methods: A retrospective, electronic record-based cohort study of StrainprintTM users with self-reported endometriosis was conducted. Self-rated cannabis efficacy, defined as a function of initial and final symptom ratings, was investigated across the included symptom clusters of cramps, pelvic pain, gastrointestinal pain, nausea, depression, and low libido. Cannabis dosage form, dose and cannabinoid ratio information was also recorded.

Results: A total number of 252 participants identifying as suffering endometriosis recorded 16193 sessions using cannabis between April 2017 and February 2020. The most common method of ingestion was inhalation (n = 10914, 67.4%), with pain as the most common reported symptom being treated by cannabis (n = 9281, 57.3%). Gastrointestinal symptoms, though a less common reason for cannabis usage (15.2%), had the greatest self-reported improvement after use. Inhaled forms had higher efficacy for pain, while oral forms were superior for mood and gastrointestinal symptoms. Dosage varied across ingestion methods, with a median dose of 9 inhalations (IQR 5 to 11) for inhaled dosage forms and 1 mg/mL (IQR 0.5 to 2) for other ingested dosage forms. The ratio of THC to CBD had a statistically significant, yet clinically small, differential effect on efficacy, depending on method of ingestion.

Conclusions: Cannabis appears to be effective for pelvic pain, gastrointestinal issues and mood, with effectiveness differing based on method of ingestion. The greater propensity for use of an inhaled dosage delivery may be due to the rapid onset of pain-relieving effects versus the slower onset of oral products. Oral forms appeared to be superior compared to inhaled forms in the less commonly reported mood or gastrointestinal categories. Clinical trials investigating the tolerability and effectiveness of cannabis for endometriosis pain and associated symptoms are urgently required.

Conflict of interest statement

I have read the journal’s policy and the authors of this manuscript have the following competing interests: As a medical research institute, NICM Health Research Institute receives research grants and donations from foundations, universities, government agencies, individuals and industry. Sponsors and donors also provide untied funding for work to advance the vision and mission of the Institute. The authors declare no competing financial interests. JS is the recipient of a Western Sydney University Postgraduate Research Scholarship. J.Sarris has received either presentation honoraria, travel support, clinical trial grants, book royalties, or independent consultancy payments from: Australian Natural Therapeutics Group (being a scientific advisor to Australian Natural Therapeutics Group: a cannabis grower and manufacturer), Integria Healthcare & MediHerb, Pfizer, Scius Health, Key Pharmaceuticals, Taki Mai, Fiji Kava, FIT-BioCeuticals, Blackmores, Soho-Flordis, Healthworld, HealthEd, HealthMasters, Kantar Consulting, Angelini Pharmaceuticals, Grunbiotics, Polistudium, Research Reviews, Elsevier, Chaminade University, International Society for Affective Disorders, Complementary Medicines Australia, SPRIM, Terry White Chemists, ANS, Society for Medicinal Plant and Natural Product Research, Sanofi-Aventis, Omega-3 Centre, the National Health and Medical Research Council, CR Roper Fellowship. This does not alter our adherence to PLOS ONE policies on sharing data and materials.