What is the difference between CBD and THC?

  • Marijuana and hemp are two varieties of the Cannabis Sativa plant. The main difference is in their CBD (cannabidiol) and THC (tetrahydrocannabinol or delta-9-tetrahydrocannabinol) content.
  • The average THC level in marijuana (also called cannabis) is about 10%, but its concentration could be as high as 30% in some strains(1). Meanwhile, the hemp plant has a high CBD content but low in THC(2). THC can get a user high, CBD cannot.
  • Aside from pain relief, lessening the effects of muscle control issues, and decreased inflammation, another potential benefit of THC is that it may help stop the growth of cancer cells(3). In a study published in Molecular Cancer Therapeutics, results suggested that purified extracts from whole-plant marijuana can delay the progression of cancer cells in a brain tumor(4).
  • The World Health Organization (WHO) published a 2017 pre-review report, providing a recent summary of the potential and current clinical use of CBD(5). The range of conditions is consistent with CBD’s exciting potential of having neuroprotective, anti-epileptic, anxiolytic (anti-anxiety), anti-psychotic, analgesic (pain-relieving), anti-inflammatory, anti-asthmatic, and anti-tumor properties(6).
  • It is essential to conduct research into the safety and effectiveness of cannabis products and consult with a doctor experienced in cannabis use before consuming or using these products.

The Source

THC products are nearly exclusively sourced from marijuana and may be available in oils, edibles, tinctures, and capsules. These products can be purchased only in states where marijuana is legal for recreational or medicinal use.

Most CBD products, such as gummies, tinctures, lotions, salves, and vape juice, contain CBD sourced from hemp. 

It is possible, however, to extract CBD from marijuana. A CBD-infused oil extracted from marijuana is called ‘cannabis oil’ because of its high THC content.

CBD derived from marijuana plants tend to have high amounts of THC, which can be a concern for individuals who do not want the psychoactive effects of THC or are allergic to THC.

Full-Spectrum, Broad-Spectrum, or Isolate?

Whenever purchasing a CBD product, check the label to see whether the oil is sourced from marijuana or hemp. The label should also indicate whether it contains an isolate, broad-spectrum, or full-spectrum CBD oil.

CBD isolates are pure CBD extracted in isolation from other cannabinoids in the plant. A CBD isolate does not contain THC, which means it is not a psychoactive compound. 

The full-spectrum variety contains a complete range of cannabinoids, terpenes, flavonoids, and other compounds naturally present in cannabis plants, including other compounds and minerals, such as a variety of fatty acids and beneficial fiber. 

Terpenes are cannabis compounds that provide the plant with distinctive aroma and flavors, while flavonoids are responsible for the vivid colors in most plants.

Combining all these components creates a synergy known as “entourage effect,” where all of the constituents working together are more efficient than their isolated elements(7). 

Meanwhile, broad-spectrum CBD is like full-spectrum without the THC. Broad-spectrum CBD oil is ideal for those who want all the health benefits of the cannabinoids, terpenes, and flavonoids but are allergic to THC or do not want the psychoactive effects of THC.

In general, a level of about 1% THC is considered the threshold for cannabis to have an intoxicating effect(8). 

Note that the presence of THC in a full-spectrum CBD oil may be detected in a drug test. To be sure that there would be no trace amounts of THC in the CBD oil, choose a THC-free product that has “broad-spectrum” or “isolate THC-free” on the label(9). 

Is hemp seed oil the same as CBD oil?

Hemp seed oil is not the same as CBD-rich oil extracted from the flowers and leaves of the plant. Oil pressed from hemp seed does not contain CBD, THC, or plant cannabinoids(10)

However, hemp seed oil is excellent as a carrier oil in most CBD oil products. Hemp seed oil is also used in making varnish, paint, soap, and protein-enriched food supplements.

Chemical Composition of CBD and THC

Chemically, the structures of CBD and THC are quite similar. They both share an identical molecular formula: 21 carbon atoms, 30 hydrogen atoms, and two oxygen atoms, or C21H30O2. Furthermore, both CBD and THC have the same molecular weight of 314.5 g/mol(11). 

CBD is essentially a structural isomer of THC, which means although CBD and THC have the same chemical composition, their atoms are arranged a bit differently.  

The molecular structure differences between these compounds differentiate the two, and how the body processes the chemicals gives each their unique medicinal properties.

How CBD and THC Work with the Endocannabinoid System 

The therapeutic effects of CBD and THC are realized by their interaction with the body’s endocannabinoid system (ECS) and its specialized cannabinoid receptors. 

The ECS, integral to the body’s physiologies, is responsible for regulating a wide range of body functions, including pain sensation, immune response, anxiety, sleep, mood, appetite, metabolism, and memory.

Binding with Cannabinoid Receptors

CB1 and CB2 are the two main types of receptors found in specific parts of the human body. These receptors each have specific roles in the ECS.

CB1 receptors are mostly located in the brain and central nervous system. However, they are also found in the reproductive organs, gastrointestinal and urinary tracts, liver, lungs, and retina(12).  

CB1 receptors play a role in motor regulation, memory processing,  appetite, pain sensation, mood, and sleep(13).

The activation of CB1 receptors has also been associated with potential neuroprotective responses. This activity suggests the cannabinoids with a higher affinity for CB1 receptors could theoretically help in the prevention and treatment of neurodegenerative conditions, such as  Parkinson’s disease, Alzheimer’s disease, and multiple sclerosis.

Meanwhile, CB2 receptors are primarily situated on cells in the immune system and its associated structures.

When CB2 receptors are triggered, they stimulate a response that fights inflammation, reducing pain, and minimizing damage to tissues.

These anti-inflammatory responses have shown promise to be useful for treating inflammation-related conditions, such as Crohn’s disease, arthritis, and inflammatory bowel syndrome.

CB1 and CB2 receptors bind or interact with CBD and THC differently. 

THC binds with CB1, and their interaction causes a user to experience a euphoric high.

However, while THC has the highest affinity for binding with CB1, CBD does not bind directly to either cannabinoid receptors. 

CBD acts indirectly on cannabinoid agonists, which are substances that bind to a receptor and cause the same action as the substances that typically bind to the receptor.

CBD also interacts with several other receptors in the body, such as the 5-HT1A receptor, which is linked to serotonin, a neurotransmitter found to be a contributor to feelings of well-being. It is through this interaction that these cannabinoids promote healing and balance. 

Although THC and CBD interact with the body through different channels, both have proven to have feasibility in modulating the endocannabinoid system and improving health(14). 

Medical Benefits of CBD and THC: Is one superior to the other?

A 2018 study published in Canadian Family Physician looked into how THC and CBD work alone or with the other. Of four randomized controlled trials, one found the THC-CBD combination superior to THC. However, this result was inconsistent within the study and with other studies, highlighting the lack of strong clinical research on the subject(15). 

The same study also showed that unintended effects were prevalent with THC, CBD, and THC-CBD. 

While some early poor-quality research in healthy users suggests that CBD attenuates some psychiatric effects of THC, more longitudinal and comprehensive research is needed to substantiate any benefits of specific components.

Therapeutic Benefits of THC

The term medical marijuana refers to using the entire, unprocessed marijuana plant or its essential derivatives to alleviate symptoms of disorders. The U.S. Food and Drug Administration (FDA) has not explicitly recognized or approved the marijuana plant as medicine(16)

However, the scientific study of cannabinoids, or the chemicals in marijuana, has led to two FDA-approved drugs, dronabinol and nabilone. These medications contain THC in pill form(17).  

Some of the medical benefits of THC include:

  • increased appetite
  • reduced nausea
  • pain relief
  • decreased inflammation (swelling and redness)
  • better muscle control

THC was also shown to help stop the growth of cancer cells in the laboratory and animal models. In a 2014 study with rodents published in Molecular Cancer Therapeutics, results suggested that purified extracts from whole-plant marijuana can delay the progression of cancer cells from one of the most severe types of brain tumors(18).  

Dronabinol and nabilone are both synthetic forms of THC and are used to treat nausea caused by chemotherapy. They also increase appetite in patients with extreme weight loss caused by acquired immunodeficiency syndrome (AIDS).

The United Kingdom, several European countries, and Canada have approved nabiximols (Sativex), a CBD and THC-infused mouth spray. Sativex is used for muscle control problems due to multiple sclerosis (MS), although it is not FDA-approved.

Therapeutic Benefits of CBD

The World Health Organization (WHO) published a 2017 pre-review report, providing a recent summary of the potential and current clinical use of CBD(19).

Evidence showed that CBD could be used in treating some types of epilepsy, such as Dravet’s Syndrome, a complex disorder in children and is associated with a high rate of mortality and high drug-resistant seizures.

Epidiolex (cannabidiol) oral solution was the first drug approved by the FDA for the treatment of seizures in individuals two years of age and older(20). 

WHO also stated that CBD might be a useful treatment for several other health conditions. This research, however, is considerably less advanced than for the treatment of epilepsy(21).

The range of medical conditions for which CBD has been assessed is diverse, consistent with its potential as an anti-epileptic, neuroprotective, anxiolytic (anti-anxiety), anti-psychotic, analgesic (pain-relieving), anti-inflammatory, anti-asthmatic, and anti-tumor compound(22).

According to a 2017 study led by Pisanti and published in Pharmacology and Therapeutics, the overview of diseases for which CBD may have therapeutic benefits includes(23):

  • Alzheimer’s disease
  • Parkinson’s disease
  • multiple sclerosis
  • Huntington’s disease
  • hypoxia-ischemia injury
  • depression
  • cancer
  • rheumatoid arthritis
  • inflammatory bowel and Crohn’s diseases
  • cardiovascular diseases
  • diabetic complications 

In addition, a study demonstrated how CBD inhibits inflammatory and neuropathic pain in rodents, two of the most challenging types of chronic pain to treat(24).

Another possible medical application which has been investigated is the use of CBD to treat drug addiction. 

A 2015 systematic review published in the Journal of Substance Abuse Treatment suggests that CBD may have therapeutic characteristics on cocaine, opioid, and psychostimulant addiction(25).

Some preliminary data suggested that CBD might be beneficial in cannabis and tobacco addiction. However, more research is required to assess CBD as a potential treatment(26).

Side Effects of CBD and THC

Consumers are advised to be aware of the risks of using cannabis products with these cannabinoids. Like any natural compound, CBD and THC can also cause some adverse side effects.

Adverse Side Effects of THC

Marijuana contains the mind-altering chemical THC and other related compounds. THC interacts with specific brain cell receptors that typically react to natural THC-like compounds. These natural chemicals are crucial in healthy brain development and function(27).

THC over-activates specific parts of the brain that contain the most number of these receptors. This activity causes the “high” that people feel. 

Other adverse side effects include(28):

  • changes in mood
  • altered senses (for example, seeing brighter colors)
  • altered sense of time
  • impaired memory and learning
  • impaired body movement
  • difficulty with thinking and problem-solving
  • hallucinations and paranoia (when taken in high doses)
  • breathing problems
  • psychosis (risk is highest with regular use of high potency marijuana)
  • possible harm to a fetus’s brain in pregnant women

Marijuana use can result in a substance use disorder, which can develop into an addiction in severe cases; it can also cause gastrointestinal upset and vomiting with chronic, heavy use.

No medications are currently available for the treatment of marijuana use disorder. However, behavioral support can be effective(29).

Adverse Side Effects of CBD

CBD “is generally well tolerated with a good safety profile,” as the World Health Organization (WHO) stated in a critical review(30).

Still, CBD can cause side effects. Mayo Clinic lists down the different effects, such as:

  • dry mouth
  • diarrhea
  • reduced appetite
  • drowsiness
  • fatigue 

CBD can also interact with other medications that one is taking, like blood thinners(31).

Legality Issues 

For decades, federal law did not differentiate hemp from other cannabis plants. However, with its legalization of the cultivation of industrial hemp in the United States, the 2018 Farm Bill also removed hemp derivatives, including CBD, from the purview of the Drug Enforcement Administration (DEA) and the Controlled Substances Act. 

However, FDA views CBD as a pharmaceutical drug. Because it has already approved CBD as a pharmaceutical (Epidiolex), the FDA maintains that it is illegal to sell hemp-derived CBD as a dietary supplement(32).

The DEA, meanwhile, retains jurisdiction over CBD derived from marijuana. CBD cannot contain THC of more than 0.3% to be legal at the federal level(33).  

Many states and Washington, D.C., have passed cannabis-related laws, making medical marijuana with high levels of THC legal. Still, marijuana may require a prescription from a licensed physician(34).

Also, several states have made recreational use of marijuana and THC legal. One should be able to buy CBD in states where marijuana is legal for recreational or medical purposes.

The average marijuana strain today contains about 12% THC, according to a 2017 study published in Biological Psychiatry(35).

To get more information on state laws and penalties, click here(36).

Individuals who possess cannabis-related products in a state where they are illegal or do not have a medical prescription in states where the products are legal for medical treatment could face legal penalties.

For a complete list of legal medical marijuana states and D.C., including the corresponding laws, fees, and possession limits, click here(37).

Conclusion

Cannabidiol and tetrahydrocannabinol are two natural phytocannabinoids that interact with the body’s endocannabinoid system (ECS), which one day may show true therapeutic effects.

The ECS regulates many of the body’s processes and works to maintain homeostasis or balance.

Although the human body naturally produces cannabinoids, most people do not generate enough. These deficiencies may disrupt homeostasis, leading to the development of diseases and disorders(38).  

Supplementing diets with active cannabinoids like CBD and THC may help prevent this deficiency and even encourage the body to create more naturally-occurring endocannabinoids.

However, it is essential to conduct more research into the safety and effectiveness of cannabis products and to consult with a doctor experienced in cannabis use before consuming or using these products.

Like all cannabinoid products, choosing the ideal one depends on personal health concerns, preferences, and lifestyle.


  1. Based on sample tests of illegal cannabis seizures from December 2007 through March 2008. National Institute of Drug Abuse, “Quarterly Report, Potency Monitoring Project,” University of Mississippi, 2008.
  2. R. C. Clarke and M. D. Merlin, Cannabis: Evolution and Ethnobotany (University of California Press, 2013), p. 255. A psychotrophic drug is capable of affecting mental activity, behavior, or perception and may be mood-altering; U. R. Avico et al., “Variations of Tetrahydrocannabinol Content in Cannabis Plants to Distinguish the Fibre-Type from Drug-Type Plants,” UNODC Bulletin on Narcotics, January 1985; C. W. Waller, “Chemistry of Marihuana,” Pharmacological Reviews, vol. 23 (December 1971); K. W. Hillig and P. G. Mahlberg, “A Chemotaxonomic Analysis of Cannabinoid Variation in Cannabis (Cannabaceae),” American Journal of Botany, vol. 91, no. 6 (June 2004); and A. W. Zuardi et al., “Cannabidiol, a Cannabis sativa Constituent, as an Antipsychotic Drug,” Brazilian Journal of Medical and Biological Research, vol. 39 (2006).
  3. NIH Drug Facts. (2019, July). Marijuana as Medicine. Retrieved from https://www.drugabuse.gov/publications/drugfacts/marijuana-medicine
  4. Scott KA, Dalgleish AG, Liu WM. The combination of cannabidiol and Δ9-tetrahydrocannabinol enhances the anticancer effects of radiation in an orthotopic murine glioma model. Mol Cancer Ther. 2014;13(12):2955-2967. doi:10.1158/1535-7163.MCT-14-0402.
  5. WHO. Expert Committee on Drug Dependence. (2017, Nov 6-10). Cannabidiol (CBD). Retrieved from https://www.who.int/medicines/access/controlled-substances/5.2_CBD.pdf
  6. Fasinu, P.S., et al., Current Status and Prospects for Cannabidiol Preparations as New Therapeutic Agents. Pharmacotherapy, 2016. 36(7): p. 781-96; Iffland, K. and F. Grotenhermen, An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies. Cannabis and Cannabinoid Research, 2017. 2(1): p. 139-154; Devinsky, O., et al., Cannabidiol: Pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders. Epilepsia, 2014. 55(6): p. 791-802. 
  7. Russo EB. The Case for the Entourage Effect and Conventional Breeding of Clinical Cannabis: No “Strain,” No Gain. Front Plant Sci. 2019;9:1969. Published 2019 Jan 9. doi:10.3389/fpls.2018.01969.
  8. See, for example, E. Small and D. Marcus, “Hemp: A New Crop with New Uses for North America,” in Trends in New Crops and New Uses, ed. J. Janick and A. Whipkey (Alexandria, VA: American Society for Horticultural Science Press, 2002).
  9. Gill, L. (2019, May 15). Can You Take CBD and Pass a Drug Test? Retrieved from https://www.consumerreports.org/cbd/can-you-take-cbd-and-pass-a-drug-test/.
  10. Lee M. Cannabis Oil vs Hemp Oil. Retrieved from https://www.projectcbd.org/cbd-101/cannabis-oil-vs-hemp-oil.
  11. PubChem-NCBI. Cannabidiol. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Cannabidiol; PubChem-NCBI. Delta9-Tetrahydrocannabinol. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/delta9-Tetrahydrocannabinol.
  12. Reggio PH. Endocannabinoid binding to the cannabinoid receptors: what is known and what remains unknown. Curr Med Chem. 2010;17(14):1468–1486. doi:10.2174/092986710790980005.
  13. ECHO. (2017, April 18). Retrieved from https://echoconnection.org/look-endocannabinoid-systems-cb1-cb2-receptors/.
  14. ECHO. (2017, March 29). Retrieved from https://echoconnection.org/differences-cbd-thc/.
  15. Perry D, Ton J, Allan GM. Evidence for THC versus CBD in cannabinoids. Can Fam Physician. 2018;64(7):519.
  16. NIDA. (2019, July 5). Marijuana as Medicine. Retrieved from https://www.drugabuse.gov/publications/drugfacts/marijuana-medicine on 2020, March 13.
  17. NIH Drug Facts. (2019, July). Marijuana as Medicine. Retrieved from https://www.drugabuse.gov/publications/drugfacts/marijuana-medicine.
  18. Scott KA, Dalgleish AG, Liu WM. The combination of cannabidiol and Δ9-tetrahydrocannabinol enhances the anticancer effects of radiation in an orthotopic murine glioma model. Mol Cancer Ther. 2014;13(12):2955-2967. doi:10.1158/1535-7163.MCT-14-0402.
  19. .WHO. Expert Committee on Drug Dependence. (2017, Nov 6-10). Cannabidiol (CBD). Retrieved from https://www.who.int/medicines/access/controlled-substances/5.2_CBD.pdf.
  20. USFDA. (2018, June 25). FDA approves first drug comprised of an active ingredient derived from marijuana to treat rare, severe forms of epilepsy. Retrieved from https://www.fda.gov/news-events/press-announcements/fda-approves-first-drug-comprised-active-ingredient-derived-marijuana-treat-rare-severe-forms.
  21. WHO. Expert Committee on Drug Dependence. (2017, Nov 6-10). Cannabidiol (CBD). Retrieved from https://www.who.int/medicines/access/controlled-substances/5.2_CBD.pdf.
  22. Fasinu, P.S., et al. op. cit.
  23. Pisanti, S., et al., Cannabidiol: State of the art and new challenges for therapeutic applications. Pharmacol Ther, 2017. 175: p. 133-150.
  24. Xiong W, Cui T, Cheng K, et al. Cannabinoids suppress inflammatory and neuropathic pain by targeting α3 glycine receptors. J Exp Med. 2012;209(6):1121–1134. doi:10.1084/jem.20120242.
  25. Prud’homme M, Cata R, Jutras-Aswad D. Cannabidiol as an Intervention for Addictive Behaviors: A Systematic Review of the Evidence. Subst Abuse. 2015;9:33–38. Published 2015 May 21. doi:10.4137/SART.S25081.
  26. ibid.
  27. NIH Drug Facts. (2019, Dec). Marijuana. Retrieved from https://www.drugabuse.gov/publications/drugfacts/marijuana.
  28. ibid.
  29. ibid.
  30. Expert Committee on Drug Dependence Fortieth Meeting. Cannabidiol (CBD) Critical Review Report. June 2018.
  31. Bauer B. (2018, Dec 20). What are the benefits of CBD — and is it safe to use? Retrieved from https://www.mayoclinic.org/healthy-lifestyle/consumer-health/expert-answers/is-cbd-safe-and-effective/faq-20446700.
  32. USFDA. (2020, March 11). FDA Regulation of Cannabis and Cannabis-Derived Products, Including Cannabidiol (CBD). Retrieved from https://www.fda.gov/news-events/public-health-focus/fda-regulation-cannabis-and-cannabis-derived-products-including-cannabidiol-cbd.
  33. Lee, M. (2019, Feb 2). CBD and  THC: Myths and Misconceptions. Retrieved from https://www.projectcbd.org/cbd-101/cbd-misconceptions.
  34. ProCon.org. (2019, July 24). Legal Medical Marijuana States and DC Laws, Fees, and Possession Limits. Retrieved from https://medicalmarijuana.procon.org/legal-medical-marijuana-states-and-dc/.
  35. ElSohly MA, Mehmedic Z, Foster S, Gon C, Chandra S, Church JC. Changes in Cannabis Potency Over the Last 2 Decades (1995-2014): Analysis of Current Data in the United States. Biol Psychiatry. 2016;79(7):613–619. doi:10.1016/j.biopsych.2016.01.004. 
  36. State Laws. Retrieved from https://norml.org/laws.
  37. ProCon.org. op.cit.
  38. ECHO. (2017, March 29). What Are the Differences Between CBD and THC? Retrieved from https://echoconnection.org/differences-cbd-thc/.
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