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  • Hartley


Updated: May 5

l-theanine pills in a black plate, on a white sheet with the text "l-theanine sleep aid or nah? an insomniac's review"

When Taylor Swift, a woman who has stepped in front of 3.5 million concert-goers this year, names the supplement she takes to manage stress….my ears perk up.

In candid interviews about her struggles with anxiety, she says that she turns to L-theanine as a natural chill pill.

Ever feel calm and relaxed after an afternoon cup of tea? It may just be because of l-theanine, a rare amino acid found primarily in green or black tea, and certain mushrooms.

So let’s get into how it eases anxiety, stress and insomnia and what it did for me in my battle with sleep…

How does taking l-theanine help you sleep?

Some anxiolytic herbs, such as valerian root, have sedative side-effects. What’s unusual about L-theanine is that it promotes relaxation without sedation…and as we learned in the last post, sedation is not sleep!

It gets to work in the brain by increasing GABA, serotonin and dopamine–all of which regulate mood, concentration, alertness and sleep.

It may also enhance alpha brain waves which helps promote “wakeful relaxation.”

These are the brain waves we see in activities like meditation, but also REM sleep. Enhancing these alpha waves improves focus, learning and creativity.

We don’t create L-theanine naturally, but we do create something called glutamate–a naturally-occurring neurotransmitter– which is precisely why l-theanine has caught scientists’ attention. Its effects appear to be similar to glutamate, which is involved with initiation and maintenance of sleep-wake cycles.

In fact, people with low glutamate tend to suffer from insomnia, low energy, mental exhaustion and trouble concentrating.

What's the evidence that l-theanine helps with sleep?

In one study, participants taking theanine took less time to fall asleep, had fewer sleep disturbances, and took fewer sleep medications, compared to the placebo group.

Another study showed that those who took L-theanine t experienced improved sleep latency and duration, increasing their total sleeping time by 45 minutes compared to the placebo group.

How much l-theanine should you take for sleep?

Even small amounts of L‑theanine may help you sleep better but to experience L-theanine’s full benefits, you may want to take the clinically-recommended dose of 200 mg before bedtime.

When to take l-theanine for sleep?

The calming effects usually last 8-10 hours and kick in about 30 minutes after taking it (at doses of at least 50-200mg), peaking at 5 hours in the body.

What are the negative side effects of l-theanine?

People like l-theanine because it has few, if any, side effects. Because it's not sedative, some people use it in the day to take the edge off of caffeine jitters (same reason why matcha is a good alternative to coffee–it naturally combines both).

However, in high doses it can cause possible GI issues, dizziness, headaches and other symptoms.

My experience with L-theanine

My battle with insomnia is typically focused on an inability to fall asleep easily. While sedation is always tempting to me, my hope was that l-theanine may help me in a roundabout way with the reasons I likely can’t wind-down: rumination, anxiety and future-anticipation.

Can you get l-theanine from food instead of a supplement? You can but the concentration will be low. Even matcha, with one of the highest natural concentrations of l-theanine, only contains 20mg (for reference, 100-400mg is typically recommended). Not to mention I’m avoiding caffeine after 12pm.

I experimented with upping my dosage over three nights, starting with 250mg.

So…what did it do for my insomnia?

The verdict

I loved it. But if you have trouble falling asleep, manage your expectations. It did what it promised: got me into a state for a quality wind-down. I certainly noticed feeling more relaxed, without being drowsy.

While I still wish I could fall asleep faster, once I was out, I stayed out. And I woke up feeling rested…which tells me it enhanced my REM sleep or perhaps led me to experience fewer sleep disturbances.

Instead of reaching for a nightcap to relax, this is a much healthier (non-habit forming!) sleep aid. I’m keeping this one in my repertoire.

Have you tried l-theanine or had a similar experience with another supplement?

Drop a comment.

Psst. Does tryptophan do anything for your sleep? My review here.


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