L-Theanine For Sleep: Benefits, Dosage, Side Effects

You’re not alone if you’re tired of tossing and turning throughout the night.

Statistics show that 50 to 70 million Americans struggle with an ongoing sleep disorder. (Source)

Skimping on shut-eye is often brushed off as no big deal, but it has serious consequences. Insufficient sleep has been linked to mental health conditions, physical illness, reduced productivity, and injury. In some cases, it can even shorten your lifespan. (Source)

There are ways to improve your sleep. Lifestyle changes like exercising regularly, eating a healthy diet, reducing stress, and minimizing screen time can all help regulate your sleep cycle. Over-the-counter sleep aids are also an option, but they might make you groggy the next day.

More recently, research has suggested that the amino acid L-theanine may be an effective sleep aid.

This article dives into the relationship between L-theanine and sleep and how to incorporate L-theanine into your daily routine. 

What Is L-theanine?

L-theanine is an amino acid. It is naturally found in black, green, white, and oolong teas as well as some mushrooms in small doses.

L-theanine has a range of supposed brain benefits.

It is believed to regulate neurotransmitters which can reduce cortisol levels, promote feelings of calmness, and regulate blood pressure when consumed. These effects can also happen quickly, sometimes within a span of 30 minutes. (Source) 

Health Benefits Of L-theanine

L-theanine may reduce anxiety, enhance focus, manage blood pressure, and improve sleep. (Source) 

1. It May Help Anxiety

Research suggests that L-theanine can potentially alleviate anxiety. It is believed to do so by encouraging restful brain waves, regulating neurotransmitters, and lowering blood pressure, all of which can calm the body.

One study showed, for example, that adults who took 200 mg of L-theanine every day reported improved anxiety and stress levels. (Source) 

If you’re wondering about the best l-theanine dose for anxiety, most clinical studies found L-theanine to be effective in doses of 200 to 400 mg daily.

2. It Potentially Improves Focus

Research shows that L-theanine might enhance concentration when combined with caffeine.

For example, a study showed that young adults who took L-theanine with a small dose of caffeine exhibited improved focus during a mentally demanding task. They also reported feeling more energized and alert. (Source)

More research is needed to confirm the link between L-theanine and focus.

3. It May Help Manage Blood Pressure

L-theanine may help control elevated blood pressure levels, particularly during mentally demanding tasks.

One study found that participants who took an L-theanine supplement before a mental task experienced fewer blood pressure spikes than when completing the mental task without L-theanine. (Source) 

These findings suggest that by inhibiting blood pressure spikes, L-theanine can help keep the body calm during stress and help the body relax after the event.

4. It May Improve Sleep

There is research that suggests L-theanine may improve sleep.

One study discovered, for example, that both humans and animals experienced improved sleep after L-theanine consumption. (Source)

However, the answer to “How does L-theanine help sleep” is a bit more nuanced.

We’ll look into the relationship between sleep and L-theanine in the next section.

Does L-theanine Help Sleep?

It may sound counterproductive to use L-theanine as a sleep aid, considering it contains cognitive-boosting qualities and has been used alongside caffeine in trials. Some alternative energy drinks may even feature L-theanine as an ingredient.

However, research suggests that L-theanine can help sleep, albeit indirectly.

So what exactly does L-theanine do for sleep?

According to the National Institutes of Health, our internal clock, age, and hormones impact our quality of sleep the most. (Source) 

The hormone cortisol is especially influential to the sleep cycle, as the body releases it in the morning to alert the body to wake up. (Source)

However, your body also releases cortisol when stressed. Elevated cortisol levels caused by chronic stress can disrupt your sleep cycle, making it difficult to fall and stay asleep.

This is where L-theanine comes in handy. Just as ashwagandha can make you sleepy, L-theanine can prime the body for sleep by helping the body relax and produce a calming effect when consumed.

Research supports this, with one 2016 study showing that L-theanine relaxed and reduced the resting heart rate of participants. (Source) 

While this link is promising, more research is needed to confirm the benefits of L-theanine for sleep.

The Relationship Between L-theanine And GABA

L-theanine’s effect on glutamate levels in the brain may also influence your quality of sleep.

Glutamate is an excitatory neurotransmitter that influences cognitive function. People with low glutamate levels might experience brain fog, poor memory, and tiredness, while excess levels might cause restlessness, insomnia, anxiety, and difficulty concentrating.

The body naturally balances glutamate levels with GABA (gamma-aminobutyric acid), an inhibitory neurotransmitter that produces a calming effect.

So where does L-theanine come in?

Research shows that L-theanine may increase levels of GABA in the body, which would naturally encourage glutamate levels to decrease. As a result, the body becomes more calm and restful, both of which are prerequisites for a full night’s sleep. (Source)

However, more research on the relationship between L-theanine and gamma-aminobutyric acid is needed before making any conclusive claims.

Safety And Side Effects Of L-theanine

L-theanine is generally considered a safe supplement. (Source)

Existing research on L-theanine indicates that it has very low toxicity levels and is unlikely to cause side effects.

That being said, L-theanine is not for everyone. Women who are pregnant and breastfeeding are not advised to take an L-theanine supplement. (Source) 

In addition, L-theanine may also have an antihypertensive effect, which means it can lower blood pressure. Due to this, people who take blood pressure medication or any medication that might lower blood pressure should consult a health professional before trying an L-theanine supplement. (Source)  

Lastly, L-theanine has a slightly stimulating effect. People with caffeine sensitivities should avoid taking L-theanine and caffeine together.

L-theanine Dosage For Sleep

There is no set recommended dosage of L-theanine for sleep. The best L-theanine sleep dosage may differ for each person.

That being said, research has found L-theanine to be safe and effective in doses of 200 mg to 400 mg. Looking for a supplement within that range will ensure you get the benefits of L-theanine without experiencing any adverse side effects.

A greens powder like Supergreen Tonik is a good option for your L-theanine fix. It contains 250 mg of L-theanine alongside a range of beneficial ingredients.

How To Incorporate L-theanine Into Your Diet

There are two ways to incorporate L-theanine into your diet: natural sources or supplementation.

1. Tea

Tea is one of the only ways you can naturally get L-theanine in your diet. The amount of L-theanine you get in each serving depends on the type of tea you consume.

For example, black tea contains about 5.13 mg of L-theanine per cup while oolong, green, and white tea all contain about 6 mg of L-theanine per cup. (Source)  

When compared to L-theanine supplements, tea contains a small amount of L-theanine. You would have to consume an exorbitant amount of tea to meet your daily 200 mg of L-theanine from diet alone.

This is why an L-theanine supplement can be a more effective way of meeting your L-theanine needs.

2. Supplements

You can find a variety of L-theanine supplements on the market.

L-theanine supplements come in tablet, capsule, or powder form and contain up to 400 mg in each serving. There are also green powder supplements that contain L-theanine.

Supergreen Tonik offers 250 mg of L-theanine alongside a blend of 38 nutritious superfoods in every scoop.

It also includes adaptogenic herbs like Rhodiola rosea that reduce cortisol levels. Combined, Supergreen Tonik can reduce anxiety and promote healthy sleeping habits.

Supergreen Tonik is also free of proprietary blends and third-party tested. This means you are guaranteed a high-quality L-theanine supplement with full ingredient transparency.

Conclusion

L-theanine, an amino acid naturally found in tea, offers a wide range of potential health benefits. Research shows it may reduce anxiety, enhance focus, lower blood pressure, and improve sleep quality and duration.

These benefits are largely in part due to L-theanine’s ability to regulate neurotransmitters, promote restful brain waves, and calm the body.

L-theanine can be found naturally in tea and some mushrooms, but it is also available in supplement form. It is considered a safe supplement with low toxicity levels and few side effects.

Taking a greens powder supplement with L-theanine is a great way to meet your L-theanine needs while increasing your overall nutrient intake.

Kelly McGeehan, MSc

Kelly McGeehan is a freelance health and wellness writer based in Oahu, Hawaii. She’s a proud former Owl, graduating with her Master’s degree in English from Temple University. She is also a competitive runner with 15 years of mileage under her spikes. Kelly combines her background in healthcare, wellness, and fitness with her writing background to create content for various health-related businesses.

She brings a passion for holistic health to the keyboard and writes to inspire others to live happier, healthier lives. In her free time, you’ll find her reading on the beach or training for her next half marathon.