vitamins and supplements background

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Anxiety is normal, and something most people have likely experienced before. When it becomes part of daily life, however, it can be disruptive and bothersome. There’s no single supplement or food that has been shown to eradicate all forms of anxiety, but L-theanine is one receiving a lot of praise for its anti-anxiety properties. But why?

What is L-theanine?

There’s a reason that a nice cup of tea is peak relaxation. L-theanine is an amino acid commonly found in a variety of teas, as well as some mushrooms. The content within tea can vary, so you may not always get the same amount in each cup. For more consistency, the amino acid is widely available in supplement form. It isn’t an essential amino acid, but that doesn’t mean it doesn’t confer benefits.

Nature Made L-Theanine
Nature Made L-Theanine

How does L-theanine help reduce anxiety?

In your brain, there is a neurotransmitter called GABA (gamma-aminobutyric acid). It is the primary inhibitory neurotransmitter, meaning that it reduces excitability in your neurons. GABA is critical for keeping anxiety, stress, and fear under control. It works in tandem with glutamate, the primary excitatory neurotransmitter. Glutamate has the opposite effect and stimulates neurons to fire. It’s important for learning and memory. In a way, these two neurotransmitters dance the tango together, so if one is off-beat, it can throw everything off balance. Heightened anxiety is linked to excess glutamate and reduced GABA. L-theanine can effectively raise GABA levels while blocking glutamate, helping you to calm down. This is why studies have shown that it can reduce anxiety and relieve stress.

Can you just get it from food?

While it’s present in tea and mushrooms, it is only in small and inconsistent amounts. You’d likely have to drink lots of tea and eat plenty of mushrooms in order to produce any noticeable benefit.

Mixed mushrooms in a pot
(© fedorovacz –

Risks and side-effects of taking L-theanine

L-theanine is one of the least concerning supplements out there and yields fantastic results for many. So far, there are no definitive side-effects of consuming it. However, as with all supplements, the Food and Drug Administration (FDA) doesn’t approve the safety nor efficacy of them. It’s up to the manufacturers to be honest in their claims. Additionally, l-theanine has been shown to impact chemotherapy either by enhancing its efficacy or reducing it. Before taking this, it’s important to speak with a medical professional, and especially if you are a cancer patient.

Bottom Line

L-theanine is an affordable amino acid commonly found in supplement form. Research so far has been largely consistent on the benefits it has on anxiety, stress relief, and even focus. With no confirmed side-effects, it could be a great addition to your supplement cabinet. As always, this is not medical advice, and you should contact your medical professional prior to the use of supplements.

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About Shyla Cadogan, RD

Shyla Cadogan is a DMV-Based acute care Registered Dietitian. She holds specialized interests in integrative nutrition and communicating nutrition concepts in a nuanced, approachable way.

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