CBD Oil in Australia: What It Is, the Evidence and the Law

What is CBD?

CBD is short for cannabidiol. It is one of the cannabinoids, the family of chemicals found in the cannabis plant, alongside the better-known THC.¹ THC is what makes a person feel high. CBD does not cause a high.²

Cannabinoids act on the body's endocannabinoid system, which helps regulate functions including mood, memory, sleep, appetite and the immune system.¹

Most CBD is extracted from hemp, a type of cannabis plant that is high in CBD and low in THC. CBD oil is CBD in a liquid that is swallowed. CBD also comes in capsules and in products for the skin.^1,3

Is CBD oil legal in Australia?

CBD is legal as a medicine. It is not something you can legally buy off the shelf as a supplement or wellness product.³

• You need a prescription. Patients need a prescription from a doctor, who usually applies to the Therapeutic Goods Administration (TGA) for access on their behalf.¹ A 2020 comparison of nine countries found that Australia and New Zealand were the only two where a prescription was needed for every CBD product.³
• Pharmacist-only CBD exists on paper. In December 2020 the TGA decided that low-dose CBD, up to 150 mg a day, could be sold by pharmacists without a prescription. Only products the TGA has approved and registered qualify, and none had been registered when the decision was made.⁴ At the time of writing, that had not changed.
• One CBD medicine is registered. It is a prescription liquid used with other medicines for rare, severe childhood epilepsies.⁵ Every other CBD product prescribed in Australia is an unapproved medicine, which means the TGA has not assessed it for safety, quality or effectiveness.⁵
• Online sellers are not a legal source. Getting a cannabis medicine from an online store that is not a registered pharmacy is breaking the law, and so is importing it by mail or courier.^2,6

What does the evidence say about CBD?

CBD is promoted for a long list of health problems. The research supports far fewer.

Epilepsy

This is where the evidence is strongest. There is enough trial evidence to support high doses of CBD, 10 to 50 mg for each kilogram of body weight, in childhood epilepsies that have not responded to other treatment.⁷ In a trial in Dravet syndrome, convulsive seizures fell from a median of 12.4 a month to 5.9 with CBD, compared with 14.9 to 14.1 with placebo.⁸ In Lennox-Gastaut syndrome, drop seizures fell by 43.9 per cent with CBD and 21.8 per cent with placebo.⁹

Anxiety

A 2023 review of lower-dose CBD found evidence of reduced anxiety at doses of 300 to 400 mg.⁷ A wider review of cannabinoids for mental health conditions found scarce evidence that they improve anxiety disorders, depression, PTSD or ADHD.¹⁰

Sleep and chronic pain

The same 2023 review described the effects of CBD on insomnia and chronic pain as more marginal and less consistent.⁷

Why dose matters

The benefits of CBD became more clearly evident at doses of 300 mg a day or more, and the reviewers said larger trials are needed to confirm whether lower doses do anything.⁷ That matters because the non-prescription CBD products sold overseas typically recommend well under 150 mg a day, far less than the 300 to 1,500 mg used in trials that found an effect.³

Side effects and safety

A pooled analysis of 12 trials involving 803 people concluded that CBD is well tolerated and has relatively few serious side effects.¹¹ Compared with placebo, people taking CBD were more likely to have:¹¹

• Reduced appetite
• Diarrhoea
• Sleepiness and sedation

Abnormal liver tests showed up in the childhood epilepsy trials, where CBD may have interacted with other medicines the children were taking. Outside those trials, diarrhoea was the only side effect clearly linked to CBD.¹¹

Three practical points:

• Interactions. CBD can interact with other medicines, and the reviewers said this should be monitored carefully.¹¹ Tell your prescriber everything you take.
• Tiredness. CBD does not intoxicate, but it can make you tired, which can affect driving and other risky tasks.¹
• Pregnancy and breastfeeding. CBD passes into breast milk.¹

There is no evidence that people who use CBD regularly become dependent on it, and there have been no recorded deaths from CBD overdose in Australia.¹

The problem with CBD oil bought online

Apart from being illegal, an oil bought online gives you no way of knowing what is in the bottle. Researchers in the United States bought 84 CBD products online from 31 companies and tested them. Only 26 contained the amount of CBD on the label. THC was found in 18.¹²

An unlabelled dose of THC matters. It can cause the side effects CBD does not, and it is the substance roadside and workplace drug tests look for.

CBD, driving and drug tests

In an on-road driving study of 26 people, cannabis that was mostly CBD did not affect driving compared with placebo, while cannabis containing THC did.¹³ The authors cautioned that their results could not rule out an important effect. CBD can also cause drowsiness.²

Drug tests look for THC, not CBD. In a study of 18 adults given 100 mg of pure CBD, there was no sign of it turning into THC in the body.¹⁴ The risk comes from THC in the product. Some prescribed products that do not list THC still contain traces of it, and you can be charged if THC is found in your system while driving, whether or not you have a prescription.⁶

CBD compared with THC

CBD and THC come from the same plant and do different things. Our guide to THC and CBD sets out the differences, and medicinal cannabis in Australia explains how prescribing works.

When to talk to a doctor

• You have a health problem that is not settling and you are wondering about your options
• You are already taking CBD you bought online. A doctor needs to know, because of the possible interactions with other medicines
• You take CBD and notice side effects

For most of the conditions CBD is marketed for, other treatments have stronger evidence. A doctor can go through them with you.

References

1. Alcohol and Drug Foundation. CBD (Cannabidiol).
2. healthdirect. Medicinal cannabis.
3. McGregor IS, Cairns EA, Abelev S, et al. Access to cannabidiol without a prescription: A cross-country comparison and analysis. Int J Drug Policy. 2020;85:102935.
4. Therapeutic Goods Administration. Over-the-counter access to low dose cannabidiol.
5. Alcohol and Drug Foundation. Medicinal cannabis products.
6. Therapeutic Goods Administration. Medicinal cannabis: information for consumers.
7. Arnold JC, McCartney D, Suraev A, et al. The safety and efficacy of low oral doses of cannabidiol: An evaluation of the evidence. Clin Transl Sci. 2023;16(1):10-30.
8. Devinsky O, Cross JH, Laux L, et al. Trial of Cannabidiol for Drug-Resistant Seizures in the Dravet Syndrome. N Engl J Med. 2017;376(21):2011-2020.
9. Thiele EA, Marsh ED, French JA, et al. Cannabidiol in patients with seizures associated with Lennox-Gastaut syndrome (GWPCARE4): a randomised, double-blind, placebo-controlled phase 3 trial. Lancet. 2018;391(10125):1085-1096.
10. Black N, Stockings E, Campbell G, et al. Cannabinoids for the treatment of mental disorders and symptoms of mental disorders: a systematic review and meta-analysis. Lancet Psychiatry. 2019;6(12):995-1010.
11. Chesney E, Oliver D, Green A, et al. Adverse effects of cannabidiol: a systematic review and meta-analysis of randomized clinical trials. Neuropsychopharmacology. 2020;45(11):1799-1806.
12. Bonn-Miller MO, Loflin MJE, Thomas BF, et al. Labeling Accuracy of Cannabidiol Extracts Sold Online. JAMA. 2017;318(17):1708-1709.
13. Arkell TR, Vinckenbosch F, Kevin RC, et al. Effect of Cannabidiol and Δ9-Tetrahydrocannabinol on Driving Performance: A Randomized Clinical Trial. JAMA. 2020;324(21):2177-2186.
14. Sholler DJ, Spindle TR, Cone EJ, et al. Urinary Pharmacokinetic Profile of Cannabidiol (CBD), Δ9-Tetrahydrocannabinol (THC) and Their Metabolites following Oral and Vaporized CBD and Vaporized CBD-Dominant Cannabis Administration. J Anal Toxicol. 2022;46(5):494-503.