Last updated: October 2026
There’s little evidence that CBD improves focus, memory or studying. In placebo-controlled trials in healthy adults, including one in university students, CBD didn’t sharpen attention or memory, and at most doses it didn’t impair thinking either. What reliably helps revision is sleep, short focused blocks with breaks, exercise and well-timed caffeine. CBD is for adults only.
This guide covers what the research shows, CBD and exam nerves, why under-18s shouldn’t use it, how CBD compares with caffeine, L-theanine and lion’s mane, drug tests for students and athletes, ADHD medicines, and what really helps concentration.
If you’re an adult and want to try CBD
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Does CBD help focus? The research
Short answer: not that trials can show. Researchers have given healthy adults single doses of CBD, from 15mg up to 1,500mg, and then tested attention, working memory, reaction time and learning. Here are the human studies that matter most, newest first.
| Study | Who and what dose | What it found |
|---|---|---|
| Learning and memory trial, 2025 | 35 healthy adults analysed, 246mg CBD or placebo | No difference from placebo on any learning or memory measure |
| Review of CBD and cognition trials, 2025 | 36 randomised trials, healthy people and patients | CBD’s effect on cognitive function “remains unclear”; most studies used one-off doses |
| College student trial, 2023 | 40 students aged around 21, 300mg CBD oil or placebo | Most test scores were the same as placebo, but attention lapses on a vigilance test were slightly longer with CBD |
| Systematic review, 2023 | 23 human trials plus animal studies | CBD doesn’t seem to impair thinking in people without a mental health condition; no clear benefit outside one study in heavy cannabis users |
| Driving and thinking skills, 2022 | 17 healthy adults, 15, 300 or 1,500mg | No dose impaired cognition or simulated driving, or made people feel intoxicated |
| CBD, THC and attention, 2020 | 60 healthy volunteers, 800mg CBD | CBD alone had no effect on working memory, processing speed, attention or mood |
| UCL brain scan study, 2020 | 15 healthy adults, 600mg | CBD increased blood flow to the hippocampus, a memory area, but memory test scores didn’t change |
So CBD isn’t a “focus supplement” or a nootropic. Brain imaging studies show CBD changes activity in areas linked to emotion and memory, but that hasn’t translated into better attention or recall on tests. The doses studied were also many times higher than a typical supplement serving. For the wider picture on so-called smart drugs, see nootropics in the UK: which actually work.
The reassuring part is the safety side. Across these trials CBD didn’t make people feel intoxicated. Drowsiness is still a known side effect for some people, and the student trial’s longer attention lapses are a reason not to try CBD for the first time on an exam day.
CBD for studying and exams
Students mainly try CBD for exam stress and sleep, not to concentrate harder. Stress and poor sleep do hurt revision, so those are worth tackling directly. See CBD for anxiety and CBD for sleep for what the research shows on each.
The study people often quote here is a lab test, not an exam. Researchers asked 57 healthy men to give a speech after taking CBD or a placebo. Those given 300mg reported less anxiety during the speech than the placebo group, while 150mg and 600mg made no difference. Nobody has tested CBD in real exams, and CBD isn’t a treatment for anxiety.
Our honest take: if nerves are getting in the way of revision, start with the basics in this guide: sleep, breaks, movement and a breathing exercise. If exam anxiety is stopping you sleeping, eating or getting work done, talk to your university or college wellbeing service or your GP. Our guide on how to deal with anxiety covers what the NHS offers.
The student mental health charity Student Minds also has practical guides on exam stress, motivation and fear of failure.
Under 18? CBD isn’t for you
Many people revising for GCSEs and A levels are under 18, so this matters. All Evopure products are for adults aged 18 and over.
The Food Standards Agency puts children, which it defines as anyone under 18, in its group of people who shouldn’t take CBD unless under medical direction. It suggests CBD products are labelled as not suitable for anyone under 18.
If you’re at school or college and feeling the pressure, the NHS exam tips are a good place to start: plan a few hours of revision each day in manageable chunks, take regular short breaks, practise past papers against the clock, and talk to someone you trust such as a parent, teacher or friend. High-caffeine energy drinks are best avoided too; see are energy drinks bad for you?
CBD vs caffeine vs L-theanine vs lion’s mane
If what you want is sharper focus for a study session, here’s how CBD compares with the other options people search for. The research summaries are for healthy adults.
| What the research shows for focus | Good to know | |
|---|---|---|
| CBD | No improvement in attention or memory in healthy adults | Some people feel drowsy; adults only; FSA advice is 10mg a day |
| Caffeine | The best studied. In one trial, 50mg improved alertness at 60 minutes and accuracy on an attention-switching task at 90 minutes | Too much, or too late in the day, can cause jitters and poor sleep |
| L-theanine with caffeine | A 2025 meta-analysis found small to moderate improvements on some attention and reaction time tasks in the first two hours, with a lot of uncertainty | The tea industry funded part of that review |
| Lion’s mane | Two small UK trials: one found faster performance on a single task an hour after a dose; the other found no overall improvement | Early, small studies; not a proven focus aid |
For timing your coffee around study and sleep, see how long caffeine lasts. You’ll find more on the amino acid from tea in L-theanine benefits, and on the mushroom in our lion’s mane guide. If you already drink coffee and are curious about combining the two, read CBD coffee: can you mix CBD and caffeine?
CBD, drug tests and student sport
If you play sport for your university or club, or could be tested on a placement or at work, the type of CBD matters. CBD itself isn’t on the World Anti-Doping Agency’s prohibited list, but THC is prohibited in competition. UK Anti-Doping says any CBD product is used at the athlete’s own risk, because products can contain THC or other cannabinoids that aren’t on the label.
- Full spectrum CBD contains trace THC, which can build up with regular use.
- Broad spectrum CBD keeps other hemp compounds but has the THC removed.
- CBD isolate is CBD on its own.
iAll Evopure CBD is broad spectrum with 0% THC, and you can read the batch reports before you buy. If you’re a tested athlete, speak to your team doctor first. Our guides to CBD and drug tests and full spectrum vs broad spectrum vs isolate go into the detail.
CBD and ADHD medicines
Lots of students search for CBD because they have ADHD or think they might. CBD isn’t a treatment for ADHD, and our CBD and ADHD guide covers what the research does and doesn’t show.
If you take an ADHD medicine, ask your pharmacist or ADHD specialist before adding CBD. CBD can change levels of some medicines. One small trial in 12 healthy adults found that high-dose CBD (750mg twice a day) changed blood levels of methylphenidate only slightly, an amount the researchers thought unlikely to matter. That was one study, at one dose, of one medicine, so it doesn’t rule out interactions for you. The NHS notes ADHD medicines are started and monitored by a specialist, who is the right person to ask.
See also can CBD interact with medication? and ADHD and sleep.
What actually helps focus
| Habit | Why it helps |
|---|---|
| Sleep 7 to 9 hours | Memory consolidation happens during sleep; all-nighters backfire |
| Short, focused blocks with breaks | For example, 25 to 50 minutes on, 5 to 10 off. The NHS recommends regular short breaks to keep concentration up |
| A few hours a day, in chunks | The NHS suggests a few hours of revision each day rather than leaving it all to the end |
| Past papers against the clock | The NHS says practising under the time limit improves your technique |
| Phone out of the room | Notifications break concentration |
| Regular exercise, even a walk | The NHS says it helps with stress and sleep |
| Regular meals and water | Steady energy; eat a good breakfast on exam day |
| Caffeine in moderation, early in the day | Helps alertness, but too much causes jitters and poor sleep |
| A breathing exercise when overwhelmed | The NHS suggests in for 4, hold for 2, out for 7 |
Some people pair caffeine with L-theanine; the comparison table above shows how modest the evidence is. Magnesium contributes to normal psychological function and the reduction of tiredness and fatigue. Our guide to magnesium for focus and brain fog explains the forms and doses. If your concentration has been poor for weeks, our guide to brain fog covers causes worth checking with a GP.
For a full plan, see how to focus better: 12 science-backed tips, and for better nights before exams, our sleep hygiene habits.
If you want to try CBD
If you’re an adult and want to see whether CBD suits your routine, go in with realistic expectations: it isn’t a study aid.
- Start low, around 10mg a day. The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.
- Try it on a normal day first, not before an exam, to see how it affects you; some people feel drowsy.
- Evenings suit many people, as part of a wind-down after study.
- Choose THC-free, lab-tested CBD, especially if you might be drug tested.
Our Broad Spectrum CBD Oil is just CBD in organic MCT oil, in 500mg, 1,000mg or 2,000mg bottles (about 2.5mg, 5mg or 10mg a drop), so it’s easy to adjust. Flow CBD Oil blends broad spectrum CBD with ashwagandha and maca in MCT oil, in 500mg or 1,000mg. If you prefer a fixed amount, our Broad Spectrum CBD Capsules come in 10mg or 25mg. Our CBD dosage guide has a drops chart for each oil.
Safety
- Adults (18+) only. We don’t recommend our products during pregnancy or breastfeeding.
- CBD can interact with some medicines, including some ADHD and anxiety medicines. Ask a pharmacist. See can CBD interact with medication?
- Possible side effects include tiredness, dry mouth and an upset stomach.
- Don’t drive or do anything safety-critical until you know how CBD affects you.
For the food side of concentration, including exam snacks, see our guide to brain foods. New to CBD? Start with what is CBD?
For the supplements with the strongest evidence for concentration, see our guide to the best supplements for focus.
Taking CBD in the daytime? Our guide to CBD oil morning or night covers food, coffee and splitting the dose.
Sources 19
- Gebregzi HH et al. Oral cannabidiol did not impair learning and memory in healthy adults. J Cannabis Res, 2025.
- Singh J et al. Cannabidiol and cognition: a literature review of human randomized controlled trials. Behav Pharmacol, 2025.
- Rudisill TM et al. The effects of cannabidiol on subjective states, cognition, and psychomotor function in healthy adults: a randomized clinical trial. Fundam Clin Pharmacol, 2023.
- Bomfim AJL et al. Effects of the acute and chronic administration of cannabidiol on cognition in humans and animals: a systematic review. Cannabis Cannabinoid Res, 2023.
- McCartney D et al. Effects of cannabidiol on simulated driving and cognitive performance: a dose-ranging randomised controlled trial. J Psychopharmacol, 2022.
- Woelfl T et al. Effects of cannabidiol and delta-9-tetrahydrocannabinol on emotion, cognition, and attention: a double-blind, placebo-controlled, randomized experimental trial in healthy volunteers. Front Psychiatry, 2020.
- Bloomfield MAP et al. The effects of acute cannabidiol on cerebral blood flow and its relationship to memory: an arterial spin labelling magnetic resonance imaging study. J Psychopharmacol, 2020.
- Batalla A et al. The impact of cannabidiol on human brain function: a systematic review. Front Pharmacol, 2021.
- Linares IM et al. Cannabidiol presents an inverted U-shaped dose-response curve in a simulated public speaking test. Braz J Psychiatry, 2019.
- Owen GN et al. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci, 2008.
- Payne ER et al. Effects of tea (Camellia sinensis) or its bioactive compounds l-theanine or l-theanine plus caffeine on cognition, sleep, and mood in healthy participants: a systematic review and meta-analysis of randomized controlled trials. Nutr Rev, 2025.
- Docherty S et al. The acute and chronic effects of lion’s mane mushroom supplementation on cognitive function, stress and mood in young adults: a double-blind, parallel groups, pilot study. Nutrients, 2023.
- Surendran G et al. Acute effects of a standardised extract of Hericium erinaceus (lion’s mane mushroom) on cognition and mood in healthy younger adults: a double-blind randomised placebo-controlled study. Front Nutr, 2025.
- Markowitz JS et al. The influence of cannabidiol on the pharmacokinetics of methylphenidate in healthy subjects. Med Cannabis Cannabinoids, 2022.
- Food Standards Agency. Cannabidiol (CBD) guidance. GOV.UK.
- NHS. Tips on preparing for exams.
- NHS. ADHD in children and young people.
- UK Anti-Doping. CBD (cannabidiol).
- Student Minds. Studying and exams.
