What Does L-theanine Do For Sleep?
A cup of tea is linked to relaxation, unwinding, and (if non caffeinated) a good night’s sleep. The warmth and comfort tea brings is like a cosy pair of socks or a hug from a close friend. Some even say the first whiff of tea signifies it’s time to wind down before slumber.
And perhaps we have L-theanine to thank — an amino acid commonly found in a whole range of tea believed to be a powerful agent in reducing stress and insomnia.
So, what are the benefits of L-theanine?
What does L-theanine do for sleep?
And when should you consume it?
What Is L-theanine?
L-theanine is a non-protein amino acid most commonly found in green and black tea. Amino acids play an important role in your body’s everyday functioning and processes.
L-theanine isn’t naturally produced by the body, nor is it an essential amino acid (AKA something we humans need to ingest).
But in saying that, if you choose to ingest L-theanine, it’s believed to have an array of health benefits, including increasing the alpha brain wave activity which works to relax the mind without inducing drowsiness. This is great news when it’s paired with caffeine (like in green and black tea), as it’s believed to control the excitement that caffeine induces.
What Is L-theanine Good For?
L-theanine’s most renowned benefit is relaxation and sleep.
But turns out, it could also help with the chemicals serotonin and dopamine. These chemicals can increase happiness, keep us calm and increase our focus.
Let’s turn to some recent studies into L-theanine…
L-theanine may improve sleep
L-theanine promotes deeper, higher-quality sleep by influencing the chemicals in the brain (like dopamine and serotonin).
In 2018, researchers conducted a 10-week double-blind, placebo-controlled study into l-theanine.  It involved 46 participants with generalised anxiety disorder. The study found that those who were taking 450 – 900mg of L-theanine per day reported greater sleep satisfaction than the placebo group.
L-theanine may reduce stress
For most of us, sipping a warm cup of tea is like a permission slip to unwind.
In 2019, a random, placebo-controlled, double-blind trial put l-theanine to the test, assessing the role it plays in stress-related symptoms and cognitive functions. The study involved 30 individuals split into two groups, either receiving 200mg per day of L-theanine or a placebo tablet.
It was found that sleep disturbance was reduced with L-theanine consumption, whilst cognitive functions (like verbal fluency) increased. Exciting findings for tea lovers around the world.
L-theanine may boost immunity
Early research suggests that L-theanine may boost immunity, allowing your body to better respond to illness.
A 2011 randomised, double-blind, placebo-controlled trial looked at the impact of green tea catechins and L-theanine on the prevention of the flu.  The study found that among healthcare workers for the elderly, catechins and L-theanine show the potential to prevent the influenza virus. Although, it’s necessary to do further research before making any final conclusions (but the early signs are looking promising).
L-theanine may increase your focus
Now we know that L-theanine may reduce stress and relax the mind. But what’s more exciting, it can do this without inducing drowsiness. So much so, it could even increase your focus.
A study found that the combination of L-theanine and caffeine (like in green and black tea) can increase cognitive awareness. The study involved a group of 44 young adults consuming a combination of 97mg of L-theanine and 40mg of caffeine. The participants reported feelings of alertness and demonstrated increased focus during demanding cognitive tasks.
L-theanine In Tea
L-theanine is most commonly found in the Camellia Sinensis plant (green and black tea). But that’s not the only way you can get a dose of L-theanine.
What’s a little less known is the L-theanine in Guayusa.
Pronounced why-you-sa, Guayusa is an ancient herb from a type of Holly tree (Ilex Guayusa). Guayusa thrives where the Ecuadorian Amazon meets the Andes – and the leaves are picked, dried and brewed to make a nourishing herbal tea.
The impressive L-theanine and theobromine content in Guayusa tea contribute to long-lasting energy, while also acting as a relaxant for the mind.
How Much L-theanine Do You Need For Sleep?
This is a broad question with no definitive answer, because everyone’s body works a little differently. In the 2018 study above, the 46 participants received 450 – 900mg of L-theanine per day and reported greater sleep satisfaction.
Other studies suggest as little as 200mg of L-theanine can improve sleep quality (without inducing daytime drowsiness). Guayusa contains 1.3mg of l-theanine per 1 gram. 
Therefore, a warm cup of Guayusa tea per day may be enough to boost sleep satisfaction.
When Should You Take L-theanine For Sleep?
If you choose to take L-theanine supplements before sleep, many suggest you take it 30 minutes to 1 hour before bed. However, if you plan on increasing your L-theanine intake through green tea, black tea or Guayusa tea, it’s important to also consider the caffeine content in these leaves.
While L-theanine may work to counteract caffeine (calming the mind while increasing awareness) — we wouldn’t recommend it for those who are particularly sensitive to caffeine.
Some of our community say that sipping Guayusa tea throughout the day (not necessarily before bed) can enhance their sleep quality.
Finally, the research into L-theanine and Guayusa is still in its early stages, but the early signs are looking promising.
We invite you to try it for yourself and see if Guayusa enhances your sleep.
At Ayusa tea, we have three incredible Guayusa blends for you to try:
- Pure Guayusa for a subtle, smooth and full-bodied flavour
- Guayusa and Cinnamon Myrtle for an added cinnamon aroma
- Guayusa and Anise Myrtle for a subtle liquorice flavour
With every purchase, we donate $1 to the Ecuadorian Foundation Conciencia Amazonica so they can continue sharing Guayusa with the world.