CBD for anxiety and stress: what the studies really show

Research on CBD for anxiety is promising and still developing. In small placebo-controlled trials, a single 300–600 mg dose taken by mouth lowered anxiety during a public-speaking test, and four weeks of CBD reduced social anxiety scores in 18- and 19-year-olds. These were research doses, not product advice. If anxiety affects your daily life, talk to a doctor.

Can CBD help with anxiety?

The research so far is encouraging. Since the 1990s, researchers have tested CBD in people facing a stressful task, in people diagnosed with social anxiety disorder and, more recently, over several weeks of daily use. Most of these studies found lower anxiety with CBD than with placebo or than at the start of the study. A review from New York University concluded that the human evidence supports a calming role for CBD, but that most studies tested a single dose and few involved people with an anxiety disorder (Blessing 2015).

That is where the field still stands. The trials are small, many come from one pioneering research group at the University of São Paulo in Ribeirão Preto, and larger placebo-controlled trials over longer periods are still needed. CBD is not an approved treatment for anxiety in Europe or the UK.

What did the key human studies find?

The table lists the main human studies, with their design and size. "Double-blind" means neither the participants nor the researchers knew who received CBD. All studies gave CBD by mouth.

Public-speaking studies

Speaking in front of others is one of the most reliable ways to make people anxious in a controlled setting, which is why so many CBD studies use it. The best-known example is the 2011 trial by Bergamaschi and colleagues. Twenty-four people with social anxiety disorder, none of whom had been treated before, received either 600 mg of CBD or a placebo about 90 minutes before a simulated public-speaking test. The placebo group became clearly more anxious and uncomfortable than a comparison group of 12 healthy volunteers. In the CBD group, anxiety, discomfort and negative thoughts about their own performance stayed much closer to the healthy group (Bergamaschi 2011).

Earlier studies from the same group had found less anxiety after 300 mg in healthy volunteers (Zuardi 1993) and after 400 mg in 10 people with social anxiety disorder, along with changes in the activity of brain areas involved in emotion (Crippa 2011).

Several weeks of use

In Japan, 37 young people aged 18 and 19 with social anxiety disorder took either an oil containing 300 mg of CBD or a placebo every day for four weeks. Both social anxiety scales used in the study showed a significant fall in the CBD group (Masataka 2019).

In Australia, 31 young people whose anxiety had not improved with talking therapy or antidepressants added CBD, up to 800 mg a day, for 12 weeks. Their anxiety severity fell by 42.6% on average, and mood and daily functioning also improved. There was no placebo group, so the authors call for randomised trials (Berger 2022).

At a psychiatric clinic in Colorado, doctors added CBD, mostly 25 mg a day in capsules, to usual care. In the chart review of 72 adults, anxiety scores fell within the first month in 79% of patients and stayed lower. This was a review of patient records without a control group, so it can suggest but not prove an effect (Shannon 2019). The same paper looked at sleep, which we cover in our guide to CBD oil and sleep.

Not every trial found an effect

As in any young field, results vary. In a Dutch trial, adding 300 mg of CBD to eight sessions of exposure therapy brought no extra benefit compared with placebo (Kwee 2022). In a UK study, a single 600 mg dose did not change anxiety induced in the lab in 24 healthy volunteers (Bloomfield 2022). Differences in dose, timing and the people studied may explain part of this, which is why larger trials are the next step.

Is there an ideal amount of CBD for anxiety?

Two studies from the São Paulo group tested several single doses against placebo before a public-speaking task. In both, the middle dose of 300 mg lowered anxiety, while the lower and higher doses did not differ from placebo. Researchers call this an inverted-U curve: the effect rises and then falls again as the dose goes up (Zuardi 2017; Linares 2019).

Other studies found an effect at 400 and 600 mg, so 300 mg is not a fixed rule. What these studies do show is that a higher amount does not automatically mean a stronger effect.

Is everyday stress the same as an anxiety disorder?

No. The NHS points out that most people feel anxious or stressed sometimes, and that stress can even be helpful or motivating. An anxiety disorder is more likely when you feel anxious most of the time and it affects your everyday life (NHS, generalised anxiety disorder; NHS, stress).

Anxiety disorders are common. The World Health Organization estimates that 470 million people had one in 2023, which makes them the world's most common mental health condition. The WHO also stresses that highly effective treatments exist, yet only about 1 in 4 people with an anxiety disorder receive treatment (WHO).

For stress, the closest evidence comes from two kinds of study:

• Short-term stress in the lab. The public-speaking studies above were run mainly in healthy volunteers, so they say most about a stressful moment rather than a disorder.
• Work stress and burnout. In a Brazilian trial with 120 frontline health workers during the COVID-19 pandemic, those who took 300 mg of CBD a day for four weeks alongside standard care reported less emotional exhaustion than those who received standard care alone. Five people in the CBD group had serious side effects: four had raised liver enzymes and one had a severe skin reaction. Two stopped CBD, and both recovered fully (Crippa 2021).

The WHO's self-care advice for anxiety applies to stress too: regular exercise, regular sleep and meals, less alcohol, and relaxation or mindfulness techniques (WHO). CBD research sits alongside these habits and alongside professional care, not in place of them.

How do study doses compare with CBD cosmetics?

The anxiety trials gave CBD by mouth, in capsules or oil, at 300–600 mg as a single dose or 25–800 mg a day over several weeks. Researchers chose these amounts to measure an effect under study conditions, and participants were monitored. The doses are not recommendations for anyone to copy.

Our human CBD oils and creams are cosmetics, notified for use on the skin (CPNP in the EU, SCPN in the UK). Amounts applied to the skin cannot be compared with doses swallowed in a trial, so we do not translate study doses into drops. For how strengths and drops work on our labels, see our CBD oil dosage guide.

Is CBD safe with antidepressants and anti-anxiety medicines?

CBD is generally well tolerated with a good safety profile, and in people it shows no signs of abuse or dependence potential, according to the World Health Organization's expert committee (WHO ECDD 2018). The WHO adds that reported side effects may come from interactions with medicines people already take. That matters for anxiety, because many people with anxiety take medicine for it.

In the 12-week Australian study, reported side effects included tiredness, low mood and hot flushes or chills, with none serious (Berger 2022), and two people in the Colorado case series stopped in the first week because of tiredness (Shannon 2019). For a full overview, including who should avoid CBD, see CBD side effects.

When should you see a doctor about anxiety or stress?

See a doctor if:

• you feel anxious or worried most of the time, and it affects your work, relationships or daily life;
• you are struggling to cope with stress, or the things you are trying yourself are not helping;
• you have sudden panic attacks or overwhelming fears;
• you have been diagnosed with an anxiety disorder and your treatment is not helping;
• you take any regular medicine, are pregnant or breastfeeding, or are under 18, and are thinking about using CBD.

The first points follow NHS advice on anxiety and stress. Talking therapies based on cognitive behavioural therapy have the most evidence for anxiety disorders, and antidepressants such as SSRIs can also help adults, according to the WHO. In many countries you can ask your doctor for a referral, and in some you can refer yourself.

Why doesn't Formula Swiss promise results for anxiety?

Because the evidence comes from oral CBD at research doses, and because our human oils and creams are cosmetics for use on the skin, we make no claims that they relieve anxiety or stress. We would rather give you the studies as they are, and let your doctor help with the medical side.

What we can speak for is what is in the bottle: every production batch is tested, and we publish the certificates of analysis.

Our CBD oils are cosmetics for use on the skin and are not intended to treat any condition. See our CBD oils.