L-Theanine Supplements

Theanine is part of why a cup of green tea can leave you feeling settled and alert at the same time, but a cup holds only a small amount, so supplements give you a measured 200 mg instead.

L-theanine in our range can help maintain mental concentration, focus and clarity. It can also aid mind relaxation, help calm the mind and support a healthy stress response. In trials, a single 200 mg dose was studied for reaction time 30 to 60 minutes later.^[2]

L-theanine may suit you if:

• you want help staying focused and clear-headed through work or study
• a busy stretch has you wound up, and you want support for a healthy stress response
• you drink coffee and like the idea of pairing it with theanine, a combination studied for attention^[5]
• you prefer one simple capsule a day with a single ingredient

Listed theanine medicines are for adults and are not recommended in pregnancy or breastfeeding.^[1] Our other theanine products are not for anyone under 15.

Shop by type: Amino Acids, Magnesium Tablets & Supplements, Stress Relief Vitamins and Cognition & Focus Support.

Prices change, so check the pack. The powders cost the least a serve because you measure them yourself. Capsules and tablets cost a little more for the convenience, and two of them are listed medicines.

1. Focus: L-theanine can help maintain mental concentration, focus and clarity, and supports healthy cognitive function.
2. A calm mind: L-theanine can aid mind relaxation and help calm the mind.
3. Stress: it supports a healthy stress response in the body and can help relieve the everyday symptoms of stress.
4. Nervous system: it can help maintain and support healthy nervous system function, which matters on demanding days.
5. One a day: the standard capsule is a single, convenient 200 mg dose that you take once daily with food.
6. Value: the pure powders work out at only a few cents a serve, which makes them the most economical option available.
7. No capsules needed: the chewable tablet is a good alternative if you dislike swallowing capsules.
8. Single ingredient: several of our products contain nothing but L-theanine, with no unnecessary additives.

Always read the label and follow the directions for use. If symptoms persist, talk to your health professional.

Focus and attention. A 2026 review of 31 randomised trials in 1,168 people found its clearest result was faster choice reaction time. That came from a single 200 mg dose taken 30 to 60 minutes before testing. Effects on stress in healthy adults were modest, and much of that evidence came from studies at high risk of bias. There was no significant effect on fatigue. The senior author founded a company that sells supplements.^[2]

With coffee. A 2025 review funded by Lipton Teas and Infusions and the Scottish Government found theanine alone improved reaction time at one hour. Several results for theanine with caffeine were too uncertain to call.^[5] An earlier analysis of 11 trials put most of the first-hour effect down to the caffeine.^[6]

Stress. In 30 adults with moderate stress, 400 mg a day for 28 days lowered perceived stress by about 18 per cent. The placebo group, who took a dummy capsule, improved by about as much. The authors work for the ingredient supplier and the company that ran the trial.^[4]

Sleep. A 2025 review of 19 studies in 897 people found small gains in sleep quality scores. All of them came from questionnaires, not sleep recordings, and several products tested were blends.^[3] If you cannot sleep most nights, see your doctor.

Follow the label on your pack. Most serves in our range are 200 mg once a day, and the chewable tablet allows up to two a day. In Australia, a listed theanine medicine cannot recommend more than 450 mg a day.^[1]

For focus, the trials gave a single dose 30 to 60 minutes before the task.^[2] For everyday use, pick a time you will remember. With a powder, check the scoop size first. Our powder scoops hold anything from 50 mg to 400 mg, and one pack is dosed at half a scoop.

• Adults. Listed theanine medicines are for adults only, and our other theanine products say they are not for anyone under 15.^[1]
• Pregnancy and breastfeeding. Not recommended, and the label must say so.^[1]
• Medicines. Check with your doctor or pharmacist first if you take any medication for blood pressure, sleep or attention.
• Headache. Some people notice a mild headache, which a lower dose usually settles quite quickly.
• Time limit. One practitioner-only label says not to use it for more than eight weeks without medical advice.

1. Single ingredient or blend. One ingredient shows you what theanine does for you. A magnesium blend suits you if you were buying magnesium anyway.
2. Pick your format. Choose a capsule for ease, a powder for cost, or the chewable if you dislike swallowing tablets.
3. Check the milligrams a serve. 200 mg is usual. Some blends hold less, so check the label.
4. Look for an AUST L number. A listed medicine can only contain TGA-approved low-risk ingredients, and its maker must hold evidence for what it says the product helps with.
5. Work out the cost a day. Across our range it runs from about 6 cents to about $1.90.
6. Ask first. Book a Free 10-minute consultation and we will help you choose.

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• More than 800 brands and over 10,000 products, chosen by practitioners.

Explore more: read our guide to the best supplements for focus and concentration. You can also browse Cognition & Focus Support and Memory & Focus Supplements.

1. Therapeutic Goods (Permissible Ingredients) Determination (No. 3) 2026 (F2026L01382), item for theanine: oral route only, maximum recommended daily dose 450 mg, with required label warnings 'Adults only' and 'Not recommended for use by pregnant and lactating women'. Available at: https://www.legislation.gov.au/F2026L01382 (Accessed: 4 November 2026).
2. Gerolymos, C., Saddier, E., Boyer, L. and Fond, G. (2026) 'Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trials', Molecular Psychiatry, 31(11), pp. 6592 to 6602. doi: 10.1038/s41380-026-03727-9. Competing interests: the senior author founded a company selling dietary supplements; the other authors report none.
3. Bulman, A., D'Cunha, N.M., Marx, W., Turner, M., McKune, A. and Naumovski, N. (2025) 'The effects of L-theanine consumption on sleep outcomes: a systematic review and meta-analysis', Sleep Medicine Reviews, 81, 102076. doi: 10.1016/j.smrv.2025.102076. Three authors received funding from a University of Canberra Discovery Translation Grant; the others declare no conflict of interest.
4. Moulin, M., Crowley, D.C., Xiong, L., Guthrie, N. and Lewis, E.D. (2024) 'Safety and efficacy of AlphaWave L-Theanine supplementation for 28 days in healthy adults with moderate stress: a randomized, double-blind, placebo-controlled trial', Neurology and Therapy, 13(4), pp. 1135 to 1153. doi: 10.1007/s40120-024-00624-7. Competing interests: one author is an employee of Ethical Naturals Inc. and four are employees of KGK Science Inc.
5. Payne, E.R., Aceves-Martins, M., Dubost, J., Greyling, A. and de Roos, B. (2025) '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', Nutrition Reviews, 83(10), pp. 1873 to 1891. doi: 10.1093/nutrit/nuaf054. Funded by Lipton Teas and Infusions and the Scottish Government; one author is an employee of Lipton Teas and Infusions and one of Unilever.
6. Camfield, D.A., Stough, C., Farrimond, J. and Scholey, A.B. (2014) 'Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis', Nutrition Reviews, 72(8), pp. 507 to 522. doi: 10.1111/nure.12120. No competing-interest statement appears in the bibliographic record.