L-theanine lattes are the new mushroom coffee—and, fortunately, a lot better tasting. In LA, you’ll find the amino acid on the menu at influencer hot spot Alfred Coffee in its Bolt Energy drink, paired with biotin and B vitamins. Beyond Juicery+Eatery (which has locations in 48 states) has it in their Iced Functional Lattes.
And it’s not just popping up in lattes. L-theanine is a core ingredient in NA drinks like Trip (which has taken over Whole Foods everywhere), Recess’s adaptogenic Mood beverages, and Hiyo social tonics.
Why the sudden obsession and, more importantly, is it worth the hype? We talked to functional-medicine doctors to find out.
What is l-theanine?
L-theanine is a non-protein amino acid that can be found naturally in green, black, and oolong teas, says Yoshua Quinones, MD, an internal medicine doctor with Medical Offices of Manhattan and a contributor to LabFinder. It works as an antioxidant in the body, helping to reduce inflammation. “It’s well-known for its effect of feeling calm yet alert,” Dr. Quinones says.
If you’re a matcha drinker, you’ve experienced this firsthand. The caffeine in the green tea leads to a feeling of alertness, but it’s the l-theanine that prevents the jittery effect that espresso or coffee can have. Sunjya Schweig, MD, founder of the California Center for Functional Medicine, says that’s exactly why it’s being added to coffee drinks; you can stick with coffee instead of ordering matcha but experience a similar feeling.
“It’s become increasingly popular as a way for people to feel calmer and more focused without feeling sedated,” says Jennifer Timmons, MD, a functional medicine doctor and the medical director of Timmons Wellness. L-theanine does this by influencing several neurotransmitter systems in the brain, including the GABA, dopamine, and serotonin systems. “It also increases what’s called alpha brainwave activity, which is associated with a mental state of alert relaxation,” says Dr. Timmons. “So instead of feeling drowsy and relaxed, you’re actually alert and relaxed. It also directly affects cortisol and lowers cortisol levels, which can help you feel more relaxed as well.”
The calming effect is why l-theanine has become a go-to ingredient in nonalcoholic drinks, too, according to the doctors we talked to. If you have trouble sleeping due to anxiety or racing thoughts, popping a l-theanine supplement could help due to its cortisol-lowering effects.
Jeffrey Bland, PhD, a biochemist and longevity expert at Big Bold Health, says that some clinical studies have shown that l-theanine can lead to falling asleep faster when it’s taken 30 to 60 minutes before bed, even though it’s not considered a sedative. Additionally, a 2022 study published in Frontiers in Nutrition found that supplementing with l-theanine can lead to better sleep quality. Researchers explain that it does this by dampening overstimulation in the brain, which can otherwise interfere with sleep.
Why is l-theanine popular right now? After all, anxiety and sleep problems are nothing new. Functional medicine doctor and Anderson Longevity Clinic founder Brian Anderson, DO, says it stems from the rising interest in brain health. “Optimized brain health is one of the hottest trends in longevity-based health care right now. L-theanine taps into this trend and is readily available,” he says.
Dr. Schweig adds that the search for a better night’s sleep plays a big part in the supplement’s popularity as well. “People are just really stressed and can’t sleep well, and if they ask ChatGPT or other AI tools what can help, it’s a likely solution that they’ll come across,” he says.
The best ways to reap the benefits of l-theanine
For what it’s worth, all five doctors we talked to do think l-theanine is more than just a trend. “The hype is real—and it reflects what many people are looking for right now,” Dr. Quinones says. “The pressures of work, family, chores, and everyday responsibilities can be overwhelming. Many people want something that helps reduce stress without making them feel sleepy.”
Unlike adaptogenic herbs like ashwagandha and reishi mushrooms, Dr. Schweig and Dr. Anderson both say that the effects of l-theanine work shortly after consuming it. This means you don’t have to consume it every day to benefit from it. Experiencing a bout of the Sunday scaries? That’s when an l-theanine supplement can help. Want to feel chill yet focused before an important meeting at work? Dr. Quinones says that consuming an l-theanine beverage (with or without caffeine) an hour or so ahead of the event can get you there.
When it comes to dosage, Dr. Anderson says that beneficial effects start with as little as a 100-milligram dose, but many of the larger studies on brain-boosting effects use a 400-milligram dose. Anywhere within that range is a good way to go. “A lower dose might be used during the day for focus and calmness, while a higher dose could be used in the evening to support relaxation and deep sleep quality,” Dr. Timmons says.
Even though l-theanine can lead to feeling calmer and support good sleep, Dr. Quinones emphasizes that it isn’t a replacement for treatment for anxiety, depression, or insomnia. You still have to get to the root problem of what’s going on and deal with it. If you’re taking any other medications or have any underlying health conditions, he adds that it’s best to talk to your doctor before consuming l-theanine regularly. That said, all of the doctors say there is little risk to consuming it.
Not all trends are worth experimenting with. We can cool it with cooking with beef tallow, for example. But the experts agree: paying extra at the café for an l-theanine add-in or stocking your bar cart with l-theanine NA drinks is actually beneficial, especially when you’re feeling jittery or tense.