All About Cannabinoids: CBD and Understanding WADA’s Stance

Professor Graeme Close is a sports nutrition researcher and practitioner out of the United Kingdom. I have followed his work for years, with a highlight being cannabinoid use and sport. Some of his work has focused on inflammation and pain management stemming from exercise-induced muscle damage in rugby players. The players were reporting chronic pain from rugby and were self-dosing with cannabinoids. Yet there wasn’t any research to support this use.

It’s an important reminder that simply because a gap in research exists, doesn’t necessarily mean the topic, diet, or supplement is irrelevant. Stay curious and open minded about what athletes bring to the table and help guide them with your knowledge of translational research, physiology, and mechanisms (i.e., could it work?).

In this article, we’ll review a summary of what I’ve learned over the years following Graeme’s work:

• Definitions to help clarify the plant and its many cannabinoids (e.g., CBD, THC).

• The endocannabinoid system.

• What CBD might be good for.

• The entourage effect of cannabinoids.

• Supplement third-party certification specific to CBD products, effective dosing, and WADA’s stance.

Definitions

Let’s begin with some definitions that often seem to blend together.

Cannabis sativa L.: This is the chemical name for the plant. (1) It’s often referred to as cannabis, which has a few different species, including sativa and indica. (2-4)

Cannabinoids: Within Cannabis, there are at least 140 known cannabinoids, including THC and CBD. (1)

Cannabidiol: This is the non-intoxicating cannabinoid we refer to as CBD.

Δ9-tetrahydrocannabinol: This is the cannabinoid we refer to as THC—the intoxicating, psychoactive component attributable to feeling high. (1,3)

C. sativa (a.k.a., C. sativa ssp. sativa var. sativa or hemp): Contains 0.2-0.3% THC. (3-5)

C. indica (a.k.a., C. sativa ssp. indica var. indica or marijuana): Is high in THC (~30%) and is specifically grown for this reason. (3-5)

Endocannabinoids: The body produces these to interact with the body’s endocannabinoid system. Two major ones are anandamide (AEA) and 2-arachidonoglycerol (2-AG). (5,6) Even in the absence of CBD, THC, and other external cannabinoids, the human body is equipped to work with cannabinoids.

CBD Isolate product: The product only contains CBD. (7)

Broad-spectrum product: The product contains zero THC, but all other cannabinoids, including CBD. (7)

Full-spectrum product: The product contains THC, CBD, and all other cannabinoids. (7)

What is the Endocannabinoid System?

The endocannabinoid system (ECS) “is a network of receptors that interact with cannabinoids to maintain vital functions throughout our body.” The ECS targets organs essential for life and survival, including relaxation, eating, sleeping, protection, appetite, and pain management, among others. (3,8)

There are two receptors in this system: cannabinoid receptor 1 (CB1) and 2 (CB2). The CB1 receptor is present in the brain and throughout the central nervous system, interacting with THC. (3,8,9) CB2 receptors are present throughout the entire body, including the immune system, gastrointestinal tract, cardiovascular system, liver, reproductive organs, and other organs. CB2 receptors also have an anti-inflammatory role. (1,3,8) I think the explosion of CBD purported as being good for everything throughout the body is due to receptors being present across multiple organs and systems.

Both cannabinoids and endocannabinoids can interact with the ECS.

The Human Endocannabinoid System (Nahtigal et al., 2016)

What is CBD Good For?

In their narrative review on sports performance, McCartney et al. (2020) wrote that “the available evidence [for CBD] is preliminary, at times inconsistent, and largely based on preclinical studies involving laboratory animals.” The researchers noted how there are zero studies on CBD and its effects on sport and exercise performance. Studies do exist that evaluate cannabis, which expands beyond CBD. (1)

However, the lack of agreement and clarity may be due to the doses used across studies, potentially being too low to show any benefit. I’ll address that later.

There seems to be some evidence for effects on skeletal muscle, whether truly mechanistic or placebo. CBD seems to reduce pain and has a productive role in muscle repair and remodeling, although research is limited to animal studies. (3,6) In rodent studies, there seems to be an improvement in mTBI symptoms, with neuronal damage not having been measured. (3,10) CBD does not seem to have a positive impact on sleep, and outcomes may differ depending on if someone who is otherwise healthy is aiming for improved sleep quality or sleep architecture versus someone experiencing a clinical condition, like insomnia. (1,3)

What is the Entourage Effect?

Given CBD is one of at least 140 cannabinoids, there seems to be a synergistic effect when present with other cannabinoids. Russo (2019) summarized a few of these studies: (2)

• Johnson et al. (2010): Patients with intractable pain were provided with oromucosal cannabis-based extracts. Those receiving an extract with a mix of THC and CBD experienced a statistically significant improvement compared to a THC-predominant extract. (15)

• Gallily et al. (2014): Pain research in animals showed that CBD on its own was helpful, until a certain dose limit was met. However, a full spectrum cannabis extract (identical dose of CBD within the extract, plus other cannabinoids) lacked a dose ceiling, meaning higher doses continued to provide additional pain management. (16)

Regarding epilepsy management, the U.S. Food & Drug Administration has approved Sativex® and Epidiolex®. The latter is 97% pure CBD. Studies in those with severe epilepsy have found that a high-CBD extract may result in using a lower total dose when compared to an isolate. (2) Across medicine and nutritional supplementation, the lowest effective dose is always useful to be aware of. Unnecessarily high doses can result in a financial burden or side effects.

When thinking about synergism and the entourage effect, consider fibre. Yes, you can in theory eat a diet comprised of only deep-fried foods and supplement with Metamucil or psyllium husk for an isolated source of fibre. But it’s not only the fibre that has health benefits. For instance, oats contain a type of soluble fibre called beta-glucan that helps reduce LDL cholesterol (whereas deep-fried foods will increase LDL). Oranges contain fibre, but also vitamin C that’s beneficial for your immune system. When fibre is consumed within its original, whole form, there are additional benefits.

The collaborative effect of all nutrients and components often work better. That’s synergy.

Third-Party Certification: Why it’s Important and Why with CBD it's Concerning for WADA

The Dose

I will always harp the importance of using third-party certified supplements, in part because of verifying the dose of the active ingredient(s) (i.e., the whole reason you’re taking a supplement).

Non-certified supplements have been shown to have varying degrees of CBD compared to what their labels described. Bonn-Miller et al. (2017) discovered that ~31% of CBD products sold online were accurately labeled (defined as being within 10% of what was listed on the label), nearly half contained underestimated values, and a quarter overestimated their CBD content. Additionally, 20% of samples contained detectable levels of THC. (1,11) So if you’re participating in a sport where THC is banned, third-party certification matters.

McCartney et al. (2020) wrote about the available evidence not being stellar regarding sport performance. (1) However, it wasn’t until the 2018 Farm Bill in the USA where hemp was removed from the Schedule 1 Drug criminalization definition for marijuana. The Farm Bill was specific to hemp products containing less than 0.3% THC on a dry weight basis. (12) Collectively and prior to 2018, an illegal drug wasn’t going to receive research grants to study any benefits to human health and performance. (8) So, a lack of past research is a culprit in our collective knowledge gap on cannabinoids in humans, their possible benefits, and required dosing.

There are a variety of NSF Certified for Sport CBD supplements available. Regarding oral options, the doses range from 15-51 mg, with some being isolates and others broad spectrum, and are derived mainly from hemp extract.

For context, McCartney et al. (2020) reported various doses used across studies and conditions: 10-250 mg/day for inflammatory bowel diseases, 100-1,200 mg/day for cardiovascular and metabolic functioning, 300-600 mg/day for anxiety related to sport, 160 mg for insomnia, 10-60 mg/kg body weight for acute or skeletal muscle inflammation, and that pain relief was inconsistent in doses <1 mg/kg (i.e., ~80 mg for a 180-lb. person).* (1) Epidiolex®, which is an FDA drug used for intractable epilepsy, has a daily dose beginning at 5 mg/kg, or ~410 mg. (13)

Ultimately, the clinical doses for pain management, inflammation, and possibly mTBI symptom management in athletes are not currently known. Future research would need to consider higher doses, plus isolated versus broad-spectrum CBD products.

*These doses weren’t necessarily found to be productive in management/prevention. I encourage you to read the review for further details.

Isolate versus Broad-spectrum CBD

The effectiveness (or ineffectiveness) and dosing for CBD and cannabinoids in healthy adults remains unknown. That’s why I’m not at the point where I’m actively encouraging the athletes I work with to use CBD, outside of anxiety related to sport. However, if an athlete is set on CBD supplementation, I recommend broad spectrum due to entourage effect—unless the athlete is participating in a WADA-sanctioned event (or has a desire to do so in the near future).

WADA-Sanctioned Sport Participation

Under the World Anti-Doping Agency’s (WADA) Prohibited List section S8 Cannabinoids, CBD is not prohibited—but all other cannabinoids while in competition, including THC, natural, and synthetic non-CBD cannabinoids continue to be banned. (14)

Given the entourage effect, broad-spectrum CBD products are preferred, yet if the athlete you’re working with opts to compete for a WADA-sanctioned team on the side (e.g., Olympics, World Baseball Classic), the athlete is now at risk of failing a drug test.

With CBD supplements, the dietitian must complement third-party certified supplement education with WADA’s stance. Dietitians cannot simply check off that a supplement is certified. They must understand the athlete’s current and future intentions for sport participation.

Key Takeaways

• The CBD doses used by athletes and that exist in supplements are likely too low to reap any benefit (if one exists).

• It remains unclear the true benefit of supplementation on sport and performance.

• The combination of cannabinoids (broad spectrum) seems to be better than a highly-isolated CBD product due to the entourage effect.

• Even though broad-spectrum products are likely better, athletes consuming these products while preparing for or participating in a WADA-sanctioned sport or event are at risk of failing a drug test.

References

1) McCartney, D., Benson, M.J., Desbrow, B., Irwin, C., Suraev, A., & McGregor, I.S. (2020). Cannabidiol and sports performance: a narrative review of relevant evidence and recommendations for future research. Sports Med Open,6(1):27. https://pubmed.ncbi.nlm.nih.gov/32632671/

2) Russo, E.B. (2019). The case for the entourage effect and conventional breeding of clinical cannabis: no “strain,” no gain. Front Plant Sci(9):1969. https://pmc.ncbi.nlm.nih.gov/articles/PMC6334252/

3) Close, G. Cannabidiol (CBD) [lecture]. mysportscience Academy, online. https://www.mysportscienceacademy.com/courses

4) Piomelli, D., & Russo, E.B. (2016). The Cannabis sativa versus Cannabis indica debate: an interview with Ethan Russo, MD. Cannabis Cannabinoid Res,1(1):44-46. https://pmc.ncbi.nlm.nih.gov/articles/PMC5576603/

5) Bannock, L. (Host). (2020, July 17). CBD for athletes: efficacious or risky business? With Professor Graeme Close (No. 146) [Audio podcast episode]. In We Do Science. Institute of Performance Nutrition. https://theiopn.com/podcast/episode-146-should-athletes-use-cbd/

6) Close, G.L., Gillham, S.H., & Kasper, A.M. (2021). Cannabidiol (CBD) and the athlete: claims, evidence, prevalence and safety concerns. SSE,34(213):1-7. https://www.gssiweb.org/docs/default-source/sse-docs/close-gillham-kasper_sse_213.pdf?sfvrsn=2

7) Close, G. (2025, May 15). Research updates [Conference session]. 2025 Annual ASPDA Conference, Scottsdale, AZ, United States.

8) Flanagan, A., & Lennon, D. (Hosts). (2022, January 4). Cannabis – Kevin Boehnke, PhD & Carrie Cuttler, PhD (No. 420) [Audio podcast episode]. In Sigma Nutrition Radio. Sigma Nutrition. https://sigmanutrition.com/episode420/

9) Close, G. (2020, December 5-6). CBD oil [Conference Session]. WorldwidE Nutrition Conference, online.

10) Belardo, C., Iannotta, M., Boccella, S., Rubino, R.C., Ricciardi, F., … & Guida, F. (2019). Oral cannabidiol prevents allodynia and neurological dysfunctions in a mouse model of mild traumatic brain injury. Fron Pharmacol,10:352. https://pubmed.ncbi.nlm.nih.gov/31040777/

11) Bonn-Miller, M.O., Loflin, M.J.E., Thomas, B.F., Marcu, J.P., Hyke, T., & Vandrey, R. (2017). Labeling accuracy of cannabidiol extracts sold online. JAMA,318(17):1708-9. https://pubmed.ncbi.nlm.nih.gov/29114823/

12) Abernethy, A. (2019, July 25). Testimony I in person: hemp production and the 2018 Farm Bill. U.S. Food & Drug Administration. https://www.fda.gov/news-events/congressional-testimony/hemp-production-and-2018-farm-bill-07252019

13) Drugs.com (2024, March 13). Epidiolex oral solution dosage.

https://www.drugs.com/dosage/epidiolex-oral-solution.html

14) World Anti-Doping Agency. (n.d.). The prohibited list. https://www.wada-ama.org/en/prohibited-list

15) Johnson, J.R., Burnell-Nugent, M., Lossignol, D., Ganae-Motan, E.D., Potts, R., & Fallon, M.T. (2010). Multicenter, double-blind, randomized, placebo- controlled, parallel-group study of the efficacy, safety, and tolerability of THC:CBD extract and THC extract in patients with intractable cancer-related pain. J. Pain Symptom Manage,39(2):167-179. https://pubmed.ncbi.nlm.nih.gov/19896326/

16) Gallily, R., Yekhtin, Z., & Hanus, L. (2014). Overcoming the bell-shaped dose-response of cannabidiol by using Cannabis extract enriched in cannabidiol. Pharmacol Pharm,6(2):75-85. https://www.scirp.org/journal/paperinformation?paperid=53912