Can I take Escitalopram and L-theanine together?
Drug interaction guide
Originally published 14 Mar 2026
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Taking escitalopram and L-theanine together may increase the risk of feeling very drowsy, dizzy, or relaxed. There is also a theoretical risk of blood pressure becoming too low.
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Why this happens
Both substances affect brain chemicals. Escitalopram increases serotonin, while L-theanine is thought to influence GABA and glutamate levels. Together, they can have an 'additive' effect, meaning their calming or sedative properties are strengthened. L-theanine may also have a mild blood-pressure-lowering effect which could add to the effects of escitalopram.
What you should do
Back to contentsYou should speak to your doctor or pharmacist before combining these. If you do take them together, start with a low dose of L-theanine and monitor how you feel. Avoid driving or using heavy machinery until you know how the combination affects you. If you feel excessively sleepy or faint, stop taking the L-theanine and consult your GP.
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Important precautions
Back to contentsSerotonin Syndrome
Combining escitalopram with other serotonergic substances (including certain antidepressants, St John's Wort, or high-dose L-theanine) can cause a life-threatening build-up of serotonin. Seek urgent medical help if you experience shivering, severe sweating, or muscle twitching.
Heart Rhythm Disorders (QT Prolongation)
Escitalopram can affect your heart rhythm. You must not take it if you have a known heart rhythm abnormality or are taking other medicines that affect the heart's electrical activity.
Suicidal Ideation (Under 25s)
In young adults, there is an increased risk of suicidal thoughts and self-harm during the first few weeks of treatment. Family or carers should monitor for any sudden changes in mood or behaviour.
Food and drink warnings
Back to contentsAlcohol
It is best to avoid drinking alcohol while taking escitalopram. Alcohol can increase the sedative effects of the medicine, making you feel more sleepy or dizzy, and may worsen your underlying symptoms.
Caffeine (Coffee, Tea, Energy Drinks)
Escitalopram can sometimes cause jitteriness or anxiety when you first start taking it; caffeine may worsen these side effects. Additionally, l-theanine is often used to counteract the 'jitters' from caffeine, but high caffeine intake may simply override the calming effects of the supplement.
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Using other medicines
Back to contentsTaking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
14 Mar 2026 | Originally published

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