L-theanine

L-theanine is a naturally occurring amino acid primarily found in green and black tea that’s known for its calming effects on the brain. It is often used as an oral supplement to reduce stress or anxiety and promote relaxation without causing drowsiness. 

L-theanine is thought to work by increasing levels of neurotransmitters such as gamma-aminobutyric acid (GABA), serotonin, and dopamine, which help regulate mood and improve cognitive function. Many women take l-theanine to manage stress, improve focus, and support better sleep quality, particularly during timeframes marked by hormonal fluctuations such as premenstrual syndrome or menopause. 

While the United States Food and Drug Administration hasn’t approved it for medical treatment, studies suggest l-theanine may also aid in blood pressure regulation and enhance the body's ability to manage stress-related cortisol levels.

Overall, l-theanine is a well-tolerated option for stress relief and cognitive support, but it should be used cautiously in combination with other medications or supplements. Make sure to talk to your healthcare provider before starting any supplements.

L-theanine is not approved as a drug in the United States. It is sometimes taken to improve sleep and reduce anxiety, but research is limited on its true effects

L-theanine is not a drug; it is an amino acid commonly found in teas and certain mushrooms

Information about the potential side effects of l-theanine is limited

The cost of l-theanine may vary depending on the quantity, brand, and where you buy it. Online prices for l-theanine range from about $16 to $60 for a two-month supply of 200-milligram (mg) capsules.

L-theanine is available over-the-counter at many pharmacies and online retailers.

• Information about l-theanine is limited

• Talk with your healthcare provider if you’re taking medications that help you sleep such as lorazepam, diazepam, or zolpidem. Taking these medications and L-theanine may increase drowsiness

• Information about l-theanine is limited

• Pregnancy/Breastfeeding: Talk with your healthcare provider if you’re pregnant or breastfeeding. L-theanine may not be safe for you

There are other supplements that may help manage stress or anxiety and promote relaxation, although some have more research-backed evidence for this purpose than others. They include:

• Ashwagandha 

• Lemon balm

• Magnesium

• Melatonin

• Rhodiola 

• Valerian

There are also prescription medications available that may help manage anxiety. These include:

• Selective serotonin reuptake inhibitors (SSRIs) such as sertraline (Zoloft^®) and fluoxetine (Prozac^®)

• Serotonin-norepinephrine reuptake inhibitors (SNRIs) such as duloxetine (Cymbalta^®)

• Monoamine oxidase inhibitors (MAOIs) such as isocarboxazid (Marplan^®)

• Tricyclic antidepressants (TCAs) such as clomipramine (Anafranil^®)

• Atypical antidepressants such as bupropion (Wellbutrin^®)

• Benzodiazepines such as alprazolam (Xanax^®) and diazepam (Valium^®)

*Information about l-theanine is limited. This information was taken, in part, from Memorial Sloan Kettering Cancer Center's website on L-theanine.