L theanine and magnesium are individual supplements that are growing in popularity.
L theanine (or l-theanine) is commonly used for sleep issues and stress, while magnesium has a wide range of uses, including mood disorders and heart conditions.
These two supplements may complement each other's effects on anxiety and other indications in a process called synergy. Synergy means that the effect of taking both products together is greater than the effect of taking them separately.
This article explains the effects of these supplements on anxiety symptoms, whether combining them is beneficial, and safety precautions to consider.
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What Is L Theanine?
L-theanine is the primary amino acid found in tea leaves. It helps give tea its distinct caramel flavor and counteracts its caffeine's bitterness. L-theanine is also found in some mushrooms.
L-theanine can be formulated as a supplement either by extracting it from tea leaves or using bacterial enzymes in a lab.
How L Theanine Works
L-theanine interacts with neurotransmitters (chemical messengers) to produce a relaxed but focused state. Specifically, it helps release gamma-aminobutyric acid (GABA), an amino acid that regulates the body's dopamine and serotonin levels.
L Theanine Health Benefits
It's been studied for various health benefits. Some of these include the following:
- Stress reduction. A review of nine published articles showed that taking 200 to 400 mg of L-theanine a day can help reduce anxiety in people exposed to stressful environments.
- Improved focus. A small clinical trial of people between 50 and 70 showed that L-theanine supplements improved attention.
- Sleep quality. According to a small clinical trial of healthy adults, taking L-theanine shortened the time it took to fall asleep and reduced the number of sleep disturbances. However, more research is necessary to determine if L-theanine can improve sleep.
- Immune system booster. When taken with another supplement, L-cystine, L-theanine has been shown to help with recovery after exercise. Some research also suggests that this combo can help prevent colds and flu.
- Blood pressure control.
Before you stock up on L-theanine, remember that larger, long-term studies into these effects are still necessary.
What Is Magnesium?
Magnesium is an important mineral for overall health. It's involved in more than 300 reactions in the body, and plays a role in processes like the following:
- Heart rhythm
- Muscle contraction
- Making protein
- Blood sugar control
- Blood pressure regulation
- Nerve impulse conduction
Where Can I Get Magnesium?
Magnesium can be consumed in the diet or taken as a dietary supplement. Magnesium-rich foods are also generally high in fiber. These include:
- Seeds (pumpkin, chia)
- Nuts (almonds, peanuts, cashews)
- Spinach
- Soy milk
- Black beans
Of note, more than two out of three people in the U.S. do not get the recommended daily amount of magnesium from their diet. Low levels of magnesium have been linked to conditions like depression, anxiety, and type 2 diabetes.
Magnesium is available as a supplement in various forms, including:
- Magnesium citrate
- Magnesium glycinate
- Magnesium oxide
- Magnesium chloride
- Magnesium taurate
How Magnesium Works
Magnesium works by blocking glutamate receptors in the brain. This increases levels of GABA, a chemical messenger that helps promote sleep and reduce stress.
Potential health benefits of magnesium include, but are not limited to:
- Stress management. A review of 18 clinical trials concluded that magnesium may help alleviate symptoms of anxiety in people who struggle with mild anxiety, but more research is necessary.
- Muscle relaxation. Magnesium may help relieve muscle cramps associated with pregnancy, but it hasn't proved helpful for older people with muscle cramps.
- Sleep regulation. A small study of 60 adults recovering from open-heart surgery concluded that magnesium improved sleep quality.
- Cardiovascular health. Diets high in magnesium are associated with a lower risk of stroke and heart disease. But taking magnesium supplements hasn't proved helpful and could cause side effects. If you have risk factors for heart disease, talk to your healthcare provider about whether magnesium is right for you.
Magnesium is primarily absorbed in the small intestine. For this reason, some conditions that affect the gastrointestinal tract interfere with magnesium absorption. Some examples of these conditions are:
- Chronic diarrhea
- Pancreatic insufficiency
- Celiac disease
- Alcoholism
- Inflammatory bowel disease
Magnesium Nutrient Interactions
Magnesium can interact with some other nutrients. Taking very large doses of calcium can cause magnesium levels to decrease. Taking specific forms of vitamin D can increase magnesium abosprtion. Taking high doses of zinc can keep magnesium from getting absorbed into the body.
Synergy and Combined Benefits
In medicine, synergy is a term for what can happen when two drugs that act similarly in the body produce a much greater effect than expected. For example, some cancer medications and antibiotics act synergistically when taken together. Drugs with synergy produce a super effect that may allow for smaller doses.
In theory, L-theanine and magnesium have potential synergistic effects when taken together. But so far, there's not much high quality evidence to prove it.
A combination study compared the effects of L-theanine alone to a combination of L-theanine plus magnesium in mice. It showed that taking the combination product significantly benefited sleep quality. L-theanine plus magnesium reduced the time it took to fall asleep and increased the length of sleep more than either supplement alone. The combination produced more delta waves in the brain, which are associated with deep sleep.
Importantly, this study has a big caveat. Effects seen in animals may or may not translate into benefits for humans, so trials in people are certainly necessary.
Another combination study explored the effects of a product containing L-theanine, magnesium, B vitamins, and rhodiola. This combination was given to chronically stressed but otherwise healthy people. Their anxiety symptoms were modestly reduced within two weeks. More research is necessary before this product or its individual components can be routinely recommended.
Dosage
Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.
L-Theanine Dosage
L-theanine has been studied in clinical trials at the following dosages:
- 100.6 milligrams (mg) daily for 12 weeks for cognition and attention
- 200 mg daily for four weeks for stress
For comparison, one cup of green tea contains 8 to 30 mg of L-theanine.
There's little evidence of drug interactions with l-theanine. However, because it acts on the GABA receptors, it could enhance the effects of other medicines with similar actions. Some examples include other sedating medicines like barbiturates and benzodiazepines.
Magnesium Dosage
The Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies recommends a daily intake of magnesium for adults and children. For adults, the recommended intake is between 310 and 420 mg of elemental magnesium daily, depending on gender and pregnancy status.
Remember that any combination of diet and supplements can meet this magnesium goal. If you take a magnesium supplement, keep in mind that the maximum dose for adults is 350 mg per day.
Magnesium Medication Interactions
Other medicines can affect magnesium levels. Some that can increase magnesium levels include:
- Lithium
- Antidepressants such as Zoloft (sertraline) and Elavil (amitriptyline)
- Diuretics like spironolactone
Many medications decrease levels of magnesium. Some examples include the following:
- Acid reflux medicines like Prilosec (omeprazole) and Nexium (esomeprazole)
- Antacids like aluminum and sodium bicarbonate
- Antibiotics like Amoxil (amoxicillin), Zithromax (azithromycin), and Cipro (ciprofloxacin)
- Seizure medicines like Dilantin (phenytoin) and phenobarbital
- Heart medicines like Lasix (furosemide), digoxin, and sotalol
Side Effects and Precautions
The U.S. Food and Drug Administration (FDA) has classified L-theanine as generally recognized as safe (GRAS). At normal doses, it's not associated with side effects.
That said, side effects are always possible when taking a medication or supplement. If you notice anything unusual, be sure to keep your healthcare provider informed.
Though magnesium from the diet is unlikely to cause side effects, avoid taking high doses of magnesium supplements.
Potential side effects that may occur with very high doses of magnesium include:
- Diarrhea
- Nausea
- Stomach cramps
- Low blood pressure (hypotension)
- Urine retention
- Depression
- Muscle weakness
- Irregular heartbeat
Consult your healthcare provider, pharmacist, or registered dietitian nutritionist before starting any new supplement regimen.
The best time of day to take an L-theanine or magnesium supplement may depend on why you're taking it. Try taking L-theanine at bedtime to promote quality sleep or during the day for anxiety symptoms. It's not known to cause daytime drowsiness.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements like prescription drugs. This means some supplement products may not contain what the label says. When choosing a supplement, look for third-party tested products and consult a healthcare provider, registered dietitian nutritionist (RDN or RD), or pharmacist.
Summary
There's some evidence that both L-theanine and magnesium supplements can help regulate sleep and anxiety symptoms.
Some people take them together to enhance the effects, but there is no evidence from human trials to validate this.
If you are struggling with sleep issues or stress symptoms, discuss your goals with your healthcare provider for individualized recommendations that can help.
