Natural supplements in the market today are gaining attention because of their benefits when taken together. Most often, it is due to their benefits in improving better sleep. These two supplements are Melatonin and L-Theanine.

These two natural supplements complement one another effectively because L-Theanine improves cognitive performance during the day while Melatonin promotes sleep at night. Because of these health benefits, these two supplements are becoming popular among people whose having issues are getting a good night’s sleep.

Let’s explore the similarities and differences between Melatonin and L-Theanine. In this article, we’ll also look at what happens when Melatonin and L-Theanine are mixed in to promote better sleep.

What are Melatonin and L-theanine?

To help in restoring normal sleep patterns, many people are turning to melatonin supplements. We are always learning more about the value of getting enough rest to keep our bodies and minds working at their best. 

Many people have tried using L-Theanine for sleep because insomnia is a very common yet especially harmful condition. Let’s look at what Melatonin and L-theanine are and what are their similarities and differences.

What is Melatonin?

Part of our brain, called the pineal gland, produces the hormone Melatonin. What Melatonin does is helps in regulating other hormones and keeping the body’s normal circadian rhythm. This is the “clock” we have inside of us, and it is what determines when we wake up and when we go to bed. The regular cycles of Melatonin release and production might be disturbed by external events. For instance, disturbances in Melatonin production and release may be due to things like stress, aging, some medications, supplements, and even exposure to light at night.

What is L-theanine?

L-theanine is a naturally occurring amino acid that was first found in green tea in 1949. It is a popular supplement for reducing stress and promoting relaxation. As a psychoactive substance, L-theanine can affect the chemical processes underlying our thoughts and neurological system by crossing the blood-brain barrier. 

When L-Theanine enters the body, it immediately starts to operate by promoting the synthesis of GABA. GABA, or Gamma-aminobutyric acid, is an amino acid that serves as the chemical neurotransmitter in the brain. As a chemical messenger, GABA can help block or slow down some brain signals and reduce brain activity in the nervous system. 

GABA produces a calming impact when connected to the GABA receptor protein in your brain. The result leads to reducing feelings of worry, stress, and fear. Additionally, this can help to prevent seizures. 

Melatonin and L-Theanine Similarities

Combining L-Theanine and Melatonin may support the quality of sleep and nighttime sleepiness. They might complement one another to simultaneously calm the body and mind and regulate sleep cycles.

It is commonly known that Melatonin can help with sleeping problems. According to the Natural Medicines Comprehensive Database that under some conditions, it can shorten the amount of time it takes to fall asleep and relieve the signs of insomnia [1].

In adults with impaired REM (rapid eye movement) sleep, taking 3 mg of melatonin daily for four weeks tends to enhance the percentage of REM sleep, according to their findings [1]. Furthermore, elderly people with dementia and sleep-wake cycle disorder appear to require less time to fall asleep and wake up after taking 6 mg of melatonin every day for 10 days.

Interestingly, the benefits of taking L-Theanine were found to increase sleep efficiency in a study for sleep disruption in kids with ADHD [2]. Compared to the boys taking the placebo, those taking L-Theanine had considerably greater sleep efficiency and percentage scores throughout the treatment period. Even though sleep latency, or the amount of time it takes to fall asleep, remained unchanged, sleep quality improved, and there were no discernible negative effects.

Melatonin and L-Theanine Differences

L-Theanine and Melatonin are two well-known supplements used to treat insomnia and stimulate relaxation.

Both of them have a relaxing impact on the mind, but they do it in different ways. L-Theanine is known to combat stress-related sleep issues [3]. This is why people tend to use L-Theanine in their morning coffee to keep them awake while at school, at work, or while driving. Meanwhile, the main hormone that the body uses to regulate sleep is Melatonin, which is produced internally from the neurotransmitter serotonin. So when a person needs to fall asleep, Melatonin is their go-to supplement. This is because Melatonin is generally a more efficient sleep stimulant than L-theanine. 

Benefits of Melatonin and L-Theanine

Melatonin and L-theanine together can promote deeper, more restful sleep. Some discover that using these two together makes it easier for them to fall asleep and stay asleep all night. L-Theanine and Melatonin can also contribute to reducing anxiety and stress levels.

By enhancing sleep efficiency and the amount of time you spend in REM (rapid eye movement) sleep, L-Theanine can help people feel less anxious and have better quality sleep. Taking L-Theanine can relieve anxiety and improve sleep quality as this supplement may enhance sleep efficiency and the amount of time the body spends in REM (rapid eye movement) sleep. This sleep stage plays a crucial role in learning, memory, and healthy brain development.

Melatonin production will be stopped or reduced by light. The body uses the hormone to control the sleep-wake cycle. More Melatonin in the body means the quicker you fall asleep and stay asleep all night as it supports the body’s normal functions and the sleep cycle.

The benefits of L-Theanine for sleep are increased because it may raise serotonin levels in the body, which facilitates easier Melatonin production. This is because serotonin is converted into Melatonin in the pineal gland.

What are the Side Effects of Melatonin and L-Theanine?

Although they are uncommon when taken at the prescribed dosage, minor headaches and dizziness are possible side effects of L-Theanine.

When used at the proper dosage, melatonin side effects are also uncommon. However, they can include headaches, irritability, dizziness, nausea, and rashes.

Safety Dosage

Your daily Melatonin dosage should remain reasonably constant. However, the amount of L-Theanine you consume may vary depending on your cognitive needs. The dosages of Melatonin and L-Theanine are as follows:

  • L-Theanine dosage varies between 100 and 400 mg per serving.
  • Melatonin dosage is 3 mg per serving

It is typically advised to combine L-Theanine and caffeine at a 2:1 ratio. For example, when taking the supplement, the ratio should be 50 mg of caffeine and 100 mg of L-Theanine.

To help you sleep better at night, it’s safe to take up to 400 mg of L-Theanine even when combined with Melatonin [2].

Bottomline: Melatonin and L-Theanine

Melatonin and L-Theanine are two natural health supplements that are becoming more popular among sleep-deprived people. Although it is Melatonin that promotes sleep because it serves as the hormone to maintain the body’s normal circadian rhythm, L-Theanine can also be beneficial to promote a better quality of sleep because of what it does in the brain. 

While it is uncommon to experience adverse effects when taking Melatonin and L-Theanine, some users may still experience minor headaches, dizziness, rashes, and irritability. Although taking these two supplements can be beneficial for a good night’s sleep, remember that it is still best to have a consistent night and morning routine to keep you awake in the morning and asleep at night time.

Disclaimer: This article is only a guide. It does not substitute the advice given by your healthcare professional. Before making any health-related decision, consult your healthcare professional.

Editorial References And Fact-Checking

  • Melatonin: What You Need To Know. (n.d.). NCCIH.
  • Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. 2011 Dec;16(4):348-54. PMID: 22214254.
  • Hidese S, Ogawa S, Ota M, Ishida I, Yasukawa Z, Ozeki M, Kunugi H. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019 Oct 3;11(10):2362. doi: 10.3390/nu11102362. PMID: 31623400; PMCID: PMC6836118.


  • Charish Luzuriaga, RDN

    Charish is a Registered Nutritionist-Dietitian (RDN) who really enjoys helping her readers understand their dietary habits better. She has impressive experience and knowledge about the nutritional values of various foods and ingredients and enjoys informing her readers about popular diets, supplements, and herbs. Charish harnesses her nutritional expertise to inspire and empower people to make positive, healthy changes through what they eat (and drink!). LinkedIn


Charish is a Registered Nutritionist-Dietitian (RDN) who really enjoys helping her readers understand their dietary habits better. She has impressive experience and knowledge about the nutritional values of various foods and ingredients and enjoys informing her readers about popular diets, supplements, and herbs. Charish harnesses her nutritional expertise to inspire and empower people to make positive, healthy changes through what they eat (and drink!). LinkedIn