Cannabidiol (CBD) is emerging as a powerful supplement, a safe anti-inflammatory that can help with several chronic diseases. CBD oil can help fight cancer and irritable bowel disease, improve schizophrenia symptoms, relieve anxiety and help you get more sleep.


What is CBD?

Cannabidiol (CBD) is one of over 100 cannabinoids, natural compounds found in Cannabis sativa– the marijuana plant [1, 2].

CBD and THC are the 2 main active compounds found in the cannabis plant and the most well recognized and studied.

Unlike THC, CBD is not psychoactive. This means it won’t cause all the negative effects linked to THC, like paranoia, anxiety, and memory problems. Instead, it seems to naturally protect against the marijuana high [3, 4].

CBD has shown promising benefits for a variety of hard-to-treat conditions [5].

Although CBD counters the THC high in normal doses, large amounts of CBD could enhance the effects of THC (in monkeys). This is likely because high CBD doses mimic serotonin, which can boost THC’s psychoactive effects [6].

Health Benefits of CBD/Cannabidiol

1) Anti-Cancer Properties

CBD and other chemicals from cannabis show promising cancer-fighting properties. Although THC has similar cancer-fighting effects, its use in high doses causes too many psychoactive side effects.

In fact, cannabinoids similar to THC were first used to reduce nausea, pain, and improve appetite in cancer patients. Some synthetic cannabinoids are still used for this indication. But only recently did researchers uncover more about natural cannabinoids like CBD and their ability to combat various types of cancers [7].

Overall, CBD is safe, non-psychoactive compound with anti-cancer potential. It might be used to improve the efficacy of standard treatments or as an anti-cancer substance on it’s own with more research [8].

CBD prevented cancer cell growth and killed cervical cancer, leukemia, lung, thyroid, and colon cancer in cells [9, 10, 11, 12, 13].

It also decreased human brain cancer (glioma) cell growth and invasion, which offers hope for combating this hard-to-treat and deadly type of cancer [14, 15].

CBD holds promise for fighting breast and prostate cancer, since it directly reduces tumors, alleviates pain, and can improve the effectiveness of conventional drugs [16, 17, 18].

CBD probably works by starving cancer cells of energy, making them more sensitive to the body’s immune response, and by blocking a newly discovered cannabinoid-related cancer pathway (GPR55) [9, 19, 13, 15, 20, 21].

Although these studies are exciting, most of the research so far is limited to cells. It’s unknown if taking CBD will help combat cancer in humans.

2) Inflammation and Autoimmunity

CBD is a very promising remedy for a variety of inflammatory and pain-associated conditions. It acts on the body’s cannabinoid system to reduce inflammation, balance the immune system, and protect from oxidative stress [22].

Our immune system has sensors for the cannabinoids our own body produces, as well as for those we take in. This internal cannabinoid system can become unbalanced in autoimmune disease and inflammation, which was something scientists had no clue a couple of decades ago [22].

CBD acts on the immune cells to trigger a host of anti-inflammatory and antioxidant reactions:

CBD Can Blunt Th1 and Th2 Dominance

CBD reduced both Th1 (IL-6 and TNF-alpha) and Th2 (IL-4, IL-5, IL-13) responses in rats with asthma [23].

CBD reduced inflammation and pain in mice [24].

It also decreased the production of inflammatory substances in immune cells (Th1: TNF-alpha, IFN-gamma, and IL-6; Th2: IL-4 and IL-8) [25].

CBD Helps with Th17 Dominance

CBD can help suppress Th17 dominance, which means that it can help with some Th17-dominant autoimmune diseases [26].

CBD also switches neutrophils to their anti-inflammatory state [27, 28], along with reducing other inflammatory immune products (Macrophage Inflammatory Protein-1) [28].

If you’re looking to learn more about ways to reduce inflammation and stress in your daily life, check out our Free 6 part eCourse to get you started biohacking to better health.

3) Neurodegenerative Diseases

CBD protects brain cells. It countered the effects of toxic substances and oxidative stress in brain cells, which would be important for recovering from stroke or other forms of brain damage [29, 30].

In a small study of 5 patients with movement disorders, CBD reduced uncontrollable muscle twitching, higher doses having a stronger effect. The patients received 100 to 600 mg of CBD per day over a 6-week period. 2 of the included patients with Parkinson’s disease did not do well with doses over 300 mg per day, however [31].

A combination of CBD and THC consistently relieved muscle spasms in patients with multiple sclerosis in one study of 219 participants [32].

However, CBD combined with THC did not improve symptoms in a study of 17 patients with Parkinson’s disease [33].

CBD protected from brain damage in animals (reducing beta-amyloid toxicity), which could potentially help in Alzheimer’s and Parkinson’s disease [34, 35]. It was able to reverse poor cognitive function in animals with Alzheimer’s disease [36].

Plus, CBD also protected the brain from the effects of stroke and reduced blood flow in animals. In cells, it was a stronger antioxidant than vitamin C (ascorbic acid) or vitamin E (α-tocopherol) [37, 38, 29].

By reducing inflammation and raising antioxidants, CBD holds promise for helping people with Amyotrophic Lateral Sclerosis (ALS) [39].

Overall, CBD helps protect the brain from damage and inflammation, but it doesn’t help with Parkinson’s symptoms.

4) Multiple Sclerosis Symptoms

Cannabinoids may relieve symptoms of multiple sclerosis (MS). In a study of 66 patients with MS and chronic pain, a combination of CBD and THC reduced pain over 2 years. The patients determined the dosage by themselves, taking as much as they felt was needed to alleviate the pain [40].

A combination of CBD and THC helped with muscle tightness, pain, sleep disturbances, and bladder control in 189 people with multiple sclerosis over 6 weeks [41, 42, 43].

In another study of 50 MS patients, a CBD/THC combination somewhat reduced muscle tightness and helped with sleep. Lower doses had a weaker effect, so some patients with MS may need higher doses to get relief [44].

5) Schizophrenia

Unlike its cousin THC, CBD may be beneficial for preventing psychosis and reducing symptoms in schizophrenia [45, 46].

While the psychoactive THC in cannabis seems to trigger psychotic episodes, especially in those with schizophrenia, CBD has opposite, antipsychotic effects. More and more studies are pointing to CBD as a natural alternative to antipsychotic drugs, but with far fewer side effects [47].

People who experience psychosis may produce too much or even too little cannabinoids (from overactive dopamine receptors). CBD is milder than our internal cannabinoids and helps to re-establish a balance of cannabinoids in the brain. CBD also helps lower inflammation, which is often increased in schizophrenia. THC, on the other hand, is stronger than our internal cannabinoids (anandamide and 2-AG), this way potentially triggering psychosis [46, 48].

In 42 patients with acute schizophrenia, CBD improved all symptoms after 4 weeks. It worked as well as a strong antipsychotic but was much better tolerated. Interestingly, CBD also reduced the breakdown of anandamide (by blocking FAAH), which was linked to the beneficial effects [49, 50].

Many animal studies also support the antipsychotic benefits of CBD [46].

All in all, recent research reveals that CBD might improve some hard-to-treat schizophrenia symptoms.

6) Seizures

Many people claim that CBD helped them with seizures even when nothing else worked. The research backs them up: CBD may help reduce seizures in people with epilepsy who do not respond to drugs [51, 52].

In a 3-month study of 23 children and young adults (3-26 years of age) with treatment-resistant epilepsy, a purified 98% oil-based CBD extract reduced seizures by half in 39% of the participants. The maximum used dose was 25 mg/kg/day, which would be 1,750 mg per day for a person weighing 155 lbs [51].

CBD also reduced seizures in another trial of 214 children and adults with epilepsy. CBD was safe even at the maximum dose, which was double of the previous study [53].

In one survey, parents of children who suffer from treatment-resistant epilepsy and use CBD were asked about the benefits. 19 parents were included, 84% of which said that CBD reduced the frequency of seizures. Two parents said that CBD completely resolved seizures. Parents also reported improved alertness, sleep, and mood. Some side effects were drowsiness and fatigue [54].

In 15 patients with epilepsy who didn’t respond to drugs, 200 – 300 mg of cannabidiol per day over 4.5 months reduced seizures. 7 out of 8 patients who took CBD improved (while only 1 patient in the placebo group did) [55].

7) Reduces Anxiety

A single CBD dose of 400 mg reduced anxiety in a brain imaging study of 10 people with seasonal affective disorder. CBD reduced blood flow to parts of the limbic system that are often overactive in anxiety. It increased blood flow to another region important for cognition and motivation (the posterior cingulate cortex) [56, 57].

In a study of 10 healthy volunteers, CBD reduced anxiety after the stressful task of public speaking [58]. In 24 patients with social anxiety, CBD given before public speaking reduced anxiety and discomfort while improving cognition [59].

In 8 volunteers, CBD prevented anxiety from THC use [60].

With more studies, the benefits of CBD could be expanded to people with various types of anxiety (including panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder) [61].

8) Pain

Many studies suggest that cannabinoids could be a potent new class of “painkillers” for helping millions of people with chronic pain [62, 63].

We have receptors for cannabinoids in the whole body, but the first type (CB1) are very dense in the pain pathways of the brain, spine, and nerves. The second type (CB2) are more important for the immune system but is also involved in inflammation. By gently acting on both pathways, our internal cannabinoids and CBD can balance both pain and inflammation [64].

In a large analysis of 18 clinical trials, cannabinoids strongly and safely reduced various types of chronic pain: neuropathic, arthritis, fibromyalgia, HIV, and multiple sclerosis pain. In another study of almost 2000 people, the benefits of using cannabis-based medicines to combat pain outweighed any risks [63, 65].

A CBD/THC combination reduced pain in several studies of people with MS and chronic pain. It was tolerated well and used regularly for up to 2 years [40, 41, 42, 43].

Cannabidiol/THC combinations show promising results for postoperative pain, chronic pain, cancer pain, rheumatoid arthritis, and neuropathic pain [66, 67, 68, 69, 70].

CBD offers benefits compared to synthetic cannabinoids, and even THC, because it’s not psychoactive. Many people want to avoid the “high”, paranoia, and drowsiness that THC can cause [71].

CBD decreased both chronic inflammation and neuropathic pain in mice without acting on opioid pathways [72, 73].

And importantly, neither CBD not THC seem to cause tolerance long-term (after 2 years), unlike opioids and most other painkillers [40].

Since cannabinoids like CBD don’t mix well with water, they have to be formulated as oils. However, the amount of CBD that’s absorbed from the gut can vary–large amounts may remain unabsorbed. New products like CBD/cannabinoid patches, nose sprays, and lozenges are being developed for better absorption [74].

9) Rheumatoid Arthritis

As natural anti-inflammatories and antioxidants, cannabinoids may provide relief of joint pain and swelling. They could also help decrease joint destruction and disease worsening in inflammatory diseases like rheumatoid arthritis [75, 22].

A CBD/THC combination (Sativex) reduced arthritis symptoms in patients with rheumatoid arthritis. Over 5 weeks, this combination reduced pain on movement and at rest, improved sleep quality and inflammation with no serious adverse effects [67].

CBD protected the joints from damage, reduced inflammation, and improved symptoms in mice with arthritis [76].

10) Nausea and Appetite

THC is an approved drug used to treat nausea and vomiting (dronabinol) in humans, but the clinical evidence for CBD is limited [77]. CBD did reduce nausea and vomiting in rat studies [78].

Typical CBD doses decreased nausea and vomiting produced from toxic drugs in animal studies. But given to the animals in very high doses, CBD could increase nausea or lose its effects [79, 80].

For cancer patients, a balanced THC/CBD combination may be the best option for increasing appetite and reducing nausea. The “high” of THC is usually too strong, and CBD can help reduce these psychotropic effects but doesn’t reduce the appetite stimulation [81].

CBD oil helped me greatly reduce my food sensitivities. If you struggle with food sensitivities, SelfHacked recommends experimenting with CBD oil as well as the Lectin Avoidance Diet, a diet specifically designed to help you pinpoint the exact foods that give you a reaction so you can start eating worry free.

11) Diabetes Risk

Although marijuana use is known to increase appetite and calorie intake, it has been linked to lower BMI, less obesity, and reduced chance of diabetes [82].

In one study of almost 5k people, past and current marijuana users had lower fasting glucose and insulin levels (by 16%), lower waist circumference and BMI, lower insulin resistance (by 18%), and higher HDL. Since all these factors are connected to the onset of diabetes, marijuana seems to offer protection [83].

Cannabidiol prevented diabetes in young diabetes-prone mice. Only 30% of the CBD-treated mice got diabetes, compared to 86% in non-treated mice [84, 85].

Cannabidiol could prevent and delay the destruction of insulin-producing cells in the pancreas in a mouse study. It could also reduce inflammatory cytokines in these diabetic mice, shifting the immune response from Th1 (autoimmune) to Th2. This would be especially important for type I diabetes, which has a strong autoimmune basis [85].

CBD is known to be safe in humans. But it may be used to prevent both type 1 and type 2 diabetes, especially at the early disease stages, if more clinical studies confirm these findings [84].

12) Heart Health

So far, some animal and cellular studies suggest that CBD could protect the heart by relaxing blood vessels, reducing inflammation, and combating oxidative stress.

CBD relaxed the arteries and protected blood vessels from damage in animal models of heart disease. It reduced damage to the heart and brain from clogged blood vessels and helped reduce irregular heart rhythms in various animal models. This way, it might protect from heart attacks and stroke [86, 87, 88].

It could also lower the heart rate and blood pressure in response to anxiety or stressful situations in rats [89, 90].

CBD can influence different blood cells. In platelets, it reduced the clumping that can contribute to the clogging of blood vessels. In white blood cells, it reduces inflammatory processes. Both add to its heart-protective effects [91, 92].

However, more studies would need to show if CBD can prevent heart disease in humans.

13) Depression

CBD quickly reduced depression in mice. The effect was maintained over time and as strong as standard antidepressants [93, 94, 95].

14) Inflammatory Bowel Disease

So far, several animal and cellular studies point to CBD as beneficial for inflammatory bowel disease (IBD). This is not surprising, having in mind its proven anti-inflammatory effects that can be extended to the gut. Human studies have yet to confirm these benefits, though.

CBD prevented gut inflammation in animals with IBD [96, 97, 98].

The combination of CBD and THC reduced inflammation and IBD-causing symptoms in tissue models of IBD. It may help with as abdominal pain, diarrhea, and reduced appetite [99].

CBD normalized gut motility and inflammation in mice with IBD [100, 101].

In cells, CBD could reduce gut inflammation by acting on an important inflammation-reducing and metabolic pathway (PPAR-gamma) [102, 103].

15) Bacterial Infections

CBD showed some microbe-killing activity against methicillin-resistant Staphylococcus Aureus (MRSA), which often causes tricky, difficult-to-treat, hospital infections [104].

16) Mad Cow Disease

Studies show cannabidiol inhibits prions, the proteins that cause fatal brain diseases (such as mad cow disease). It increased the survival time of infected mice by almost a week [105].

17) Bone Health

Although much less known, our bones also have little-researched receptors for cannabinoids.

CBD could enhance the healing of broken limbs in mice. Both CBD and THC were tested, but only CBD activated genetic pathways that also increase collagen structure [106].

18) Movement Disorders (Dyskinesia)

Dyskinesia is a type of movement disorder and causes involuntary movements. These movements can become so severe that it makes daily life difficult. It’s most common as a side effect of Parkinson’s disease or schizophrenia therapy.

CBD did not improve movement disorders based on the studies mentioned in the Neurodegenerative Benefits (4th) section of this post. CBD did reduce the symptoms of dyskinesia in mice, though. It might lower enzymes that contribute to this abnormal movement [107].

CBD along with another drug reduced dyskinesia by activating the cannabinoid system and reducing inflammation [107].

More research is needed to understand its benefits for movement disorders.

19) Insomnia

Research suggests taking CBD before bed improves sleep in people with insomnia. It helped a 10-year-old girl struggling with insomnia, anxiety and PTSD [108].

It could help with sleep due to its relaxing, anxiety-reducing effects [61].

It actually appears to have benefits over THC, which can worsen sleep quality long-term [109].

In fact, cannabis users with insomnia prefer strains much higher in CBD as a sleep aid and are less likely to become dependent–according to a survey of 163 adults purchasing medical cannabis [110].

Can’t fall asleep at night and wake up feeling more tired in the morning than you did the night before? Biohacking Insomnia is the only sleep resource guide that looks at all the possible factors you’re missing out on restorative sleep and works to get you sleeping better from a holistic viewpoint.

20) Substance Use Disorders

In those suffering from chronic pain, cannabis use, in general, reduces the use of opioid painkillers [111].

There is a lack of effective and safe treatments for the growing number of people suffering from opioid use disorder. CBD is a promising, safe alternative [111].

CBD reduced addictive behavior in a rat study. It could interfere with the brain’s reward system in response to the opioids morphine and heroin [112, 113].

21) Quitting Smoking

Research suggests that inhaling CBD may help reduce or quit smoking. In a pilot study of 24 smokers, cannabidiol reduced the number of cigarettes smoked by about 40%, without increasing cravings for nicotine [114].

22) Acne

CBD decreases the production of oils (sebum) by the skin’s oil-producing glands and reduced the number of these glands in a study on human skin (tissue study). It also had anti-inflammatory effects, all of which would be very beneficial for acne. We’re hoping to see more research and more CBD-based skincare products soon [115].

23) Psoriasis

CBD reduces the excessive division of skin cells that contributes to the symptoms of psoriasis [116].

CBD Oil Health Benefits and Mechanisms Infographic

CBD Side Effects & Safety

CBD is generally well tolerated and safe at high doses, even when people use it for a long time [117].
Some people should take additional precautions, including:

  • People with weakened immune systems, who should avoid or use it sparingly. In a cell-based study, CBD decreased the activity of T and B immune cells. This means CBD may increase the risk of infections and worsen HIV, tumor growth, metastases, and asthma [25].
  • People taking medication. CBD may decrease the activity of liver enzymes called cytochrome P450, responsible for metabolizing more than 60% of prescribed drugs. If you take prescription drugs, consult your doctor to rule out any interactions [118, 119].

CBD may mildly lower blood pressure, cause dry mouth, lightheadedness, and drowsiness. Combined with THC, it may interfere with learning and motivation [120, 121, 122].

Megadoses of CBD may trigger or worsen anxiety (via activation of TRPV1 receptors), but this is extremely rare [123].

CBD Dosage & Formulations


CBD dosage can vary anywhere from 100 mg up to even 3 g per day, depending on the health issue being targeted.

For protecting the brain (such as in Alzheimer’s) and reducing inflammation and muscle twitching (MS), doses of 100 to 600 mg of CBD were used in clinical studies. In some studies, patients took as much CBD oil as they needed to feel pain or muscle spasm relief.

Doses up to 800 mg CBD daily were used for psychosis and schizophrenia.

The highest CBD doses used in studies were up to 3.5 g of CBD oil daily for very severe drug-resistant seizures in children and young adults with epilepsy.

300 mg per day was enough to reduce anxiety in clinical studies.

Overall, at higher doses (somewhere over 400 mg), CBD becomes less effective for anxiety but better for pain relief. At higher doses, CBD activates TRPV1, which can cause anxiety and increased body temperature, while also decreasing pain [123, 124].

Sativex is a THC/CBD combination spray approved in Canada. It contains 2.7 mg delta-9-tetrahydrocannabinol (THC) and 2.5 mg cannabidiol (CBD) per spray (100 µL). The typical starting dose is 2 X per day, and the maximum 12 X per day. It’s used to relieve pain, as well as to reduce muscle spasms in MS.