L-Theanine and Alcohol: Is It OK to Take Them Together?

There is no known harmful interaction between L-theanine and alcohol, and L-theanine does not make people drowsy at the amounts studied. The two have not been tested together in people, though, so the sensible approach is simple: keep drinking moderate, do not use L-theanine to offset alcohol, and space them apart where you can. If you take prescription medicine, check with your clinician before mixing alcohol with anything new.

Key Takeaways

• L-theanine is an amino acid from tea leaves. In healthy young adults, 50 mg raised alpha brain wave activity, a pattern linked with relaxed alertness rather than drowsiness (Nobre et al., 2008).
• In a 4-week trial in 30 healthy adults, 200 mg of L-theanine a night was taken with no adverse events apparent (Hidese et al., 2019).
• No human study has looked at L-theanine and alcohol together, and no harmful interaction has been reported.
• Alcohol is the bigger factor: it can make you sleepy, drowsy or lightheaded on its own, and even some herbal remedies can have harmful effects when combined with it (NIAAA).
• Alcohol helps you fall asleep but disrupts the second half of the night (Ebrahim et al., 2013), and L-theanine is not a way around that.

Can You Take L-Theanine and Alcohol Together?

For most healthy adults, an L-theanine serving and a moderate drink are not known to clash. L-theanine is an amino acid found naturally in tea, and a cup of black tea holds about 20 mg of it (Nobre et al., 2008).

What we do not have is a human study that gave L-theanine and alcohol together and measured the result. So the honest answer is that it looks fine in moderation, and that the caution comes mostly from the alcohol side. Alcohol can make you sleepy, drowsy or lightheaded, and the US National Institute on Alcohol Abuse and Alcoholism (NIAAA) notes that even some herbal remedies can have harmful effects when combined with alcohol (NIAAA). L-theanine is not on its list, but the general rule holds: keep it simple on nights you drink.

L-Theanine vs Alcohol: How Each Affects You

	L-theanine	Alcohol
What it is	An amino acid from tea leaves	Ethanol; one US standard drink holds about 14 grams
Alertness	50 mg raised alpha activity, linked with a relaxed but alert state	Can make you sleepy, drowsy or lightheaded
Sleep	200 mg nightly for 4 weeks improved sleep scores for falling asleep and sleep disturbance compared with placebo	Helps you fall asleep, then disrupts the second half of the night; delays the first REM period
Tolerability	No adverse events apparent in the 4-week trial	Blood alcohol can keep rising after you stop drinking

Sources for the table: Nobre et al., 2008; Hidese et al., 2019; Ebrahim et al., 2013; NIAAA standard drink; NIAAA overdose. The trial behind the sleep row was in 30 healthy adults aged 20 to 69, who took 200 mg before sleep for 4 weeks in a crossover design (Hidese et al., 2019). Our L-theanine benefits guide covers the wider research.

Do L-Theanine and Alcohol Interact?

No interaction has been reported in people. The closest research is an early animal study: in mice given L-theanine by injection along with alcohol, blood alcohol was lower one hour later than in mice given alcohol alone (Sadzuka et al., 2005). That was an injected dose in mice, so it tells us nothing about how a drink will affect you, and it is not a reason to drink more.

The more useful point is the difference in how they feel. L-theanine is studied for calm with a clear head, while alcohol brings drowsiness and slower reactions. Taking L-theanine does not cancel any of alcohol's effects, so the usual rules about driving, judgment and pacing your drinks apply exactly as they would without it. For the full safety picture on L-theanine itself, see our guide to L-theanine side effects.

Timing: Before, During or After Drinking

• Earlier in the day is the easy choice. L-theanine pairs well with morning coffee or tea, or a busy afternoon. Using it then keeps it well apart from an evening drink. Our guide to L-theanine and caffeine covers that pairing.
• Before a drink: one serving is unlikely to cause problems, but there is no need to take it to "prepare" for drinking.
• After drinking: skip it that night. Blood alcohol can keep rising even after you stop drinking (NIAAA), and adding anything relaxing on top is not worth it.
• Count your drinks. One US standard drink holds about 14 grams of pure alcohol: a 12-ounce beer at 5%, a 5-ounce glass of wine at 12%, or a 1.5-ounce shot of spirits at 40% (NIAAA).
• Never mix alcohol with sleep medicines or other sedating prescriptions. The NIAAA warns that this can raise the risk of overdose (NIAAA).

If your aim is better sleep, the bigger lever is a cutoff for your last drink. Alcohol shortens the time to fall asleep at every dose studied, but sleep becomes more disrupted in the second half of the night, and the first REM period is delayed at all doses (Ebrahim et al., 2013). On alcohol-free nights, our guide to L-theanine for sleep explains how to use it at bedtime.

Magnesium, L-Theanine and Alcohol

Many evening routines pair L-theanine with magnesium. The same advice applies to the trio: no study has tested them together with alcohol, so keep drinking moderate and save the routine for nights you are not drinking. On magnesium itself, adults should keep supplemental magnesium at or under the upper limit of 350 mg a day, because high intakes from supplements can cause diarrhea, nausea and cramping (NIH Office of Dietary Supplements).

If your evening product also contains melatonin, the advice is stricter: skip it on nights you drink. Our guide to melatonin and alcohol explains why, and NAC and alcohol covers another common question.

Who Should Check With a Clinician First

Most people tolerate L-theanine well. Talk with your clinician before combining L-theanine and alcohol if you take any prescription medicine, if you are pregnant or breastfeeding, or if you are an older adult, since the NIAAA notes that older people are at particularly high risk for harmful alcohol and medication interactions (NIAAA).

Where Our Theanine Nasal Spray Fits

Our Theanine Nasal Spray gives 36 mg of L-theanine in every 2-spray serving, with alkaline water as the only other ingredient, made with third-party tested ingredients. It is caffeine-free and absorbed through the lining of the nose, so some of each dose skips digestion. Use 2 sprays as needed, breathe in gently, tilt your head back slightly and leave it for at least 60 seconds before blowing your nose. It is made to pair with coffee or tea or to use for calm focus during the day, which keeps it naturally apart from an evening drink. It is part of our Focus Stack and Sleep Stack. For bedtime on alcohol-free nights, our Melatonin Nasal Spray pairs 200 mcg of melatonin with 17 mg of L-theanine per 2-spray serving. Learn more on our L-theanine ingredient page and our stress, mood and nervous system hub.

Frequently Asked Questions

Do L-theanine and alcohol interact?

No harmful interaction has been reported in people. They have not been studied together, so keep drinking moderate and space them apart where you can.

Is it OK to take L-theanine and alcohol together?

For most healthy adults, a single serving and a moderate drink are not known to clash. Check with your clinician first if you take prescription medicine.

Can I take L-theanine before drinking?

One serving earlier in the day is unlikely to cause problems, but there is no reason to take it to prepare for drinking. It does not cancel any of alcohol's effects.

Can I take L-theanine after drinking?

It is best to skip it that night. Blood alcohol can keep rising after your last drink, so wait for an alcohol-free day.

What are the side effects of L-theanine with alcohol?

None specific to the combination have been reported. Most people tolerate L-theanine well; the drowsiness, lightheadedness and poor sleep people notice on drinking nights come from the alcohol.

Does L-theanine make you drowsy like alcohol?

No. In studies, L-theanine raised alpha brain wave activity, a pattern linked with relaxed alertness, while alcohol can make you sleepy and lightheaded.

Can I take magnesium and L-theanine with alcohol?

The combination has not been studied, so save the routine for alcohol-free nights. Keep supplemental magnesium at or under 350 mg a day.

Can I use L-theanine the day after drinking?

Yes, once you are no longer drinking. You can use it with your morning coffee or tea as usual.

Sources

• Nobre AC, Rao A, Owen GN. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition, 2008. https://pubmed.ncbi.nlm.nih.gov/18296328/
• Hidese S, et al. Effects of L-theanine administration on stress-related symptoms and cognitive functions in healthy adults: a randomized controlled trial. Nutrients, 2019. https://pubmed.ncbi.nlm.nih.gov/31623400/
• Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB. Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical and Experimental Research, 2013. https://pubmed.ncbi.nlm.nih.gov/23347102/
• Sadzuka Y, Inoue C, Hirooka S, et al. Effects of theanine on alcohol metabolism and hepatic toxicity. Biological and Pharmaceutical Bulletin, 2005. https://doi.org/10.1248/bpb.28.1702
• National Institute on Alcohol Abuse and Alcoholism. Harmful Interactions: Mixing Alcohol With Medicines. https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/harmful-interactions-mixing-alcohol-with-medicines
• National Institute on Alcohol Abuse and Alcoholism. Understanding the Dangers of Alcohol Overdose. https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/understanding-dangers-of-alcohol-overdose
• National Institute on Alcohol Abuse and Alcoholism. What Is a Standard Drink? https://www.niaaa.nih.gov/alcohols-effects-health/what-standard-drink
• NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Consumers. https://ods.od.nih.gov/factsheets/Magnesium-Consumer/

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.