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High Strength L-Theanine Capsules - 400mg

UK's strongest L-Theanine - Pure & potent double-strength capsules

(58 reviews)9410020
Buy High Strength L-Theanine Capsules - 400mg
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  • Double-strength capsules
  • Purest form available
  • Strongest form available in the UK
  • Increases brain alpha waves

Supplement Description

Introducing our new double-strength L-Theanine capsules. L-Theanine supports a sense of calm, contentment and well-being. It crosses the blood brain barrier and has been shown to increase brain alpha waves in less than 40 minutes. Alpha brain waves are an indication of a state of relaxation and mental alertness similar to that achieved through meditation, this promotes a feeling of relaxation but with an alert state of mind.

Theanine is an amino acid found predominantly in tea.  When you have a stressful moment or a shock a 'cup of tea' one of the first things that come to mind but why? The reason is thought to be L-Theanine which is believed to be responsible for the calming and relaxing effect of a cup of tea.

If you are a coffee drinker it's likely that at some point you will have drunk too much and experienced a 'hyper' effect.  It is very doubtful that you have ever experienced the same thing with tea even though it contains a lot of caffeine and the reason why is thought to be theanine. It is also a supplement which is not known to be addictive.

Purest form available, strong and high grade material

A single capsule provides 400mg of this high-grade amino acid in a vegetarian capsule - currently the strongest form available in the UK.

Nutritional Information

Each capsule typically provides:
L-Theanine 400mg

Allergen Advice

Any allergens are highlighted in bold in the ingredients list.

List of Ingredients

L-Theanine, Hydroxypropylmethyl Cellulose, Maltodextrin, Silicon Dioxide.

Suitable for vegetarian and vegan diets.

Dosage / Suggested Intake

Swallow one capsule per day with food, or as directed by your health professional.

Capsule Size

23mm x 8mm Oblong capsule

Legal Category

Food Supplement

Customer Reviews for High Strength L-Theanine 400mg

The views expressed below are the personal opinion of Just Vitamins customers. Just Vitamins does not endorse these views, nor should they be regarded as health claims or medical advice. All reviews are collected and verified as genuine by a 3rd party called Feefo.

Overall product rating 9.4 / 10 - 58 customers have independently reviewed and recommend High Strength L-Theanine from 58 reviews (showing latest 50 reviews)
Review Date
Review Details
Service Rating: Prompt delivery
Product: Not sure if it is helping yet as I haven’t taken it for long enough
Great as always
Prompt delivery as always. I’m very pleased to see 400mg L Theanine back in stock. I had to buy from a different company last time as only 200mg were available. I don’t want to have to take two capsules when I can take one so it’s good to be back with Just Vitamins!
Quick delivery and quality products. Trusted them for years and never had a problem.
Service Rating: Very prompt service, would definitely recommend
Product: Very effective, works quickly for me.
There was a glitch in my order and they fixed it, no quibbles.
shipped quickly without hassle the items i purchased.
Brilliant. Helped me sleep. Warm fuzzy feeling is both relaxing and enjoyable.

A must have !
Service Rating: The site works as it should do with a dedicated page for re-ordering items you've bought before.
They could improve this re-order page by allowing you to delete items that you have had problems with and have no intention of buying again, especially when they have refunded the cost of the item(s) complained about.
Product: I find they have the calming effect claimed for this product.
Service Rating: Quickly dispatched and delivered only negative is the tablets don’t work for me
Product: No side effects but no good effects either. I take these to help with anxiety induced tremors.
Feedback Response: Hi, sorry to hear that you did not find this supplement to be effective for you. Perhaps you might get better results with 5-HTP?
Let us know how you get on.
Ian - Just Vitamins Customer Team
Service Rating: Fast delivery, great prices.
Product: L-theanine is subtle but very effective. I have found that it's great for a) a calm focus, b) reducing stress and c) helping you achieve a deep long sleep without any drowsiness in the morning.
Service Rating: Quick delivery good website cheap prices.
Product: Why three stars because the vitamens placed in plastic bag instead of can or box so when i picked it from my mail box it was very warm.
Very quick service. Great vitamins
Service Rating: Very fast delivery and good communication
Product: Good but not massive results.
Ordering has been a bit confusing but delivery has been good.
I hope that the quality is good , no way of knowing that.
Service Rating: Very prompt service
Product: Helps reduce anxiety quickly
Service Rating: The vitamins are reasonably priced, the service prompt and efficient. I love how the vitamins are packaged as they can be posted through my letterbox.
Product: They definitely help with my sleep and lessen my anxiety
Service Rating: Easy to order, fair pricing and fast delivery.
Product: Calming effects - very good
Service Rating: Great products, good price and fast delivery.
Product: Helps calm my mind, relax and focus.
Service Rating: Because their vits are excellent quality and their service is very good too.
Product: high strength so I don't need to take twice daily so saving money
Service Rating: Would recommend they do just what they say very good
Product: The service is very good as is the product
Service Rating: Everything is high quality and well thought from product to delivery. I will use again. Thanks
Product: I cannot live without it now it makes a real difference.
Very good
Service Rating: Just ordered one type of product, which was very good.Overall experience was pleasant and delivery was very fast.
Product: Did not try similliar products from competition but it does what it's supposed to with a very good price!
Service Rating: Great Products, prompt delivery, thanks!
Product: Great Quality, affordable prices, nice packaging
Good service
Wish you had thenine in smaller portions
Service Rating: Product has yet to arrive and its been 3 likes, will update review if it arrives.

Product arrived later than expected but due to a 3rd party postal service, so no complaints about Just Vitamins service.
Product: Cant review as not arrived
Feedback Response: Thank you for your feedback.We dispatch all orders (including yours) on the next working day of receipt, but unfortunately we are at the mercy of the local postal service once it leaves us.  Our customer services team will be contacting you.
Really fast delivery!! Good prices,what I wanted was cheaper with JustVits than anywhere else. Excellent product. Will definitely use again and would recommend!
Service Rating: Order arrived very quickly and always does.
Product: I believe L-Theanine to be a derivative of green tea and so helps against depression.
Top product
Great product and service
I have only recently become a customer so am hoping that I will eventually be a regular customer. The price of vitamins appears decent. Only downside so far my last order was slow in delivery.
Service Rating: Never any problems and products are good
Product: A calming supplement instead of taking addictive medicine
It took 10 days to arrive not 5. Not waiting that long again I’m afraid. I can have stuff from the other side of the world in half that.
Feedback Response: Thank you for your feedback

We dispatch all orders (including yours) within 24 hours of receipt, but unfortunately we are at the mercy of the local postal service once it leaves us.  We do offer additional postage methods to guarantee a faster delivery.
Service Rating: First class service from start to finish, products as described and prices are hard to beat, delivered in time too.
Product: Quality is as expected. Great product.
Service Rating: Fast delivery, excellent packaging of product and delivery package (cardboard). The discount details were relayed to me quickly by support when I wrote to them. Regular updates on status of my order.
Product: Excellent and does what it says on the label. Keeps me calm and relaxed.
Service Rating: I ordered L-Theanine from Just Vitamins which are recommended for helping to reduce the symptoms of stress. I found the website easy to navigate and the capsules arrived promptly. I feel the capsules are definitely helping and will be re-ordering when I need more. Thank you.
Product: I take one capsule daily and I personally feel an improvement in my stress levels. I will buy this product again.
Great Service
Service Rating: Good.
Product: Its not effective. I was getting more benefit from green tea.
Feedback Response: Hi,
Sorry you feel this supplement is not effective for you yet, but please persevere - it may take up to 3 months for you to recognise the benefits.
Kind regards,
Just Vitamins Customer Team
Glad to be able to get hold of L-Theanine for supplementary treatment of epilepsy.
Always excellent, prompt service and good communication. Recommended.
Service Rating: Always a. 5 star service that's why I keep coming back
Product: Great supplement.I take this on regular basis and you provide capsules with the highest strenght.
Delighted with service & product will be using just vitamins again
Service Rating: Great service fast deliveey
Product: Always A* service.Speedy delivery and great communication.
Service Rating: Excellent service and very keen prices
Product: Excellent products at very keen prices!
Service Rating: responded really quickly to my enquiry. packages fit through the letterbox which is great. very pleased, will purchase again.
Product: good value for money, pleased with the product.
Service Rating: As usual, excellent service from Just Vitamins. Good price, rapid delivery.
Product: good to have double strength available. Helps with my SADs
Service Rating: Good service, delivered on time as promised.
Product: Great product, eases the nerve pain in my fingers.
Service Rating: Quick service and good product. I have ordered several times and never had any issues.
Product: I find L-theanine a very effective product