Stay calm, clear and in control when the pressure is on. L-THEANINE delivers 300 mg per serving to support relaxation, focused attention and a more composed state of mind during demanding workdays, deep-focus sessions or high-pressure situations. Ideal for professionals, entrepreneurs and athletes who want to stay mentally sharp without feeling overstimulated, it fits naturally into a performance-focused routine where calm concentration matters just as much as drive.

L-Theanine is an amino acid that occurs naturally in the leaves of the tea plant, Camellia sinensis. It is a non-protein amino acid, which is why it is taken as an isolated single ingredient rather than obtained in quantity from everyday food. MitoGenix supplies it as the only active in the capsule, so the serving you take is the amount stated on the label, not a share of a blend. Because the active is not diluted down from a standardised extract, the declaration stays simple: L-Theanine, providing 300 mg per capsule, with microcrystalline cellulose and a hypromellose shell as the only other inputs.

This is a product for healthy adults 18 and over who want a single-ingredient amino acid with a flexible timing window — adults with demanding working days, students, shift workers whose routine moves around, and anyone who would rather take one capsule than a stack of them. The label supports use either early in the day or in the evening before bed, so the same jar suits a working day or an evening wind-down. One capsule is the standard serving and a two-capsule enhanced serving is available for high-demand days. Not intended for persons under 18 years, or pregnant or breastfeeding mothers.

The following describes published research on the ingredient. It is not a claim about this specific product.

Studies suggest that a single 200 mg dose, taken 30 to 60 minutes before cognitive testing, improves choice reaction time in healthy adults: a 2026 systematic review and meta-analysis of 31 randomised controlled trials (n = 1168) reported a standardised mean difference of 0.51 for that outcome, and recorded no serious adverse events across the pooled trials. Research indicates the effect may be dose-dependent on some measures. In a four-way crossover trial in 27 healthy young adults comparing 100 mg, 200 mg and 400 mg against placebo, only the 400 mg dose significantly shortened P3b latency, an electrophysiological marker of attentional processing, with each additional 100 mg shortening it by roughly 4 ms; no dose-response effect appeared in reaction time itself. The evidence is mixed, though: a separate meta-analysis of five randomised controlled trials in healthy adults found that short-term supplementation did not clearly improve reaction time or selective attention. Published reviews put the dosage used in clinical studies at 100 to 400 mg per day, so the 300 mg in one capsule sits inside the studied range, while noting that evidence covering use beyond roughly three months is limited.

L-Theanine compared with L-Tyrosine. Both are amino acids sold as single-ingredient supplements, and they are different molecules with different origins. L-Theanine occurs naturally in tea leaves and is supplied here as an isolated ingredient at 300 mg per capsule. L-Tyrosine is obtained from dietary protein, and the body uses it as a precursor in catecholamine synthesis. They are declared and dosed separately, and neither substitutes for the other. If you take both, read each label and account for your total daily intake.

L-Theanine compared with caffeine. These two are often compared because both occur naturally in tea leaves, but they belong to different classes of ingredient: caffeine is a stimulant alkaloid, and L-Theanine is an amino acid. They are not interchangeable and neither substitutes for the other. This product's full declaration is L-Theanine, microcrystalline cellulose and a hypromellose capsule shell. If you take anything else alongside it, read that label too and account for your own total daily intake.

Key Benefits

• Declared 300 mg Dose: Every capsule delivers 300 mg L-Theanine at a one-capsule serving, with the amount printed on the label rather than carried inside a blend.
• One Declared Active: L-Theanine is the only active in the capsule, so the full serving is one amino acid at one declared amount.
• Flexible Timing: Suggested use allows one capsule either early in the day or in the evening before bed, so the timing can follow your own routine.
• Inside the Studied Range: Clinical studies typically use 100 to 400 mg per day; one capsule sits inside that range at 300 mg.
• 60 Servings Per Jar: Sixty capsules at the one-capsule standard serving, a two-month supply.
• Contains L-Theanine — account for total daily intake if combining.

Common Questions

What does L-Theanine do?
L-Theanine is an amino acid found naturally in tea leaves, taken to support a calm, focused state in healthy adults. MitoGenix L-Theanine provides 300 mg per capsule as a single ingredient, so the whole serving is one amino acid at one declared amount.

How much L-Theanine should I take?
The standard serving is one capsule daily, providing 300 mg, which sits inside the 100 to 400 mg a day used in studies. The enhanced serving is two capsules daily for high-demand days. Do not exceed the recommended dose.

Should I take L-Theanine in the morning or at night?
Either works. The label allows one capsule early in the day or in the evening before bed, so MitoGenix L-Theanine fits a demanding workday or an evening wind-down routine. Choose the time that suits you and take it consistently.

How long does L-Theanine take to work?
In studies on attention, a single 200 mg dose is usually given 30 to 60 minutes before testing. That is a study protocol, not a label instruction: MitoGenix L-Theanine is taken as one 300 mg capsule daily, at the time that suits your routine.

Can L-Theanine support focus?
L-Theanine is chosen to support calm focus. A 2026 review of 31 trials found a single 200 mg dose improved choice reaction time in healthy adults, although a smaller analysis found no clear effect, so results vary. MitoGenix L-Theanine provides 300 mg per capsule.

Can I take L-Theanine with coffee?
The label sets no restriction on coffee. L-Theanine and caffeine both occur naturally in tea leaves but are different ingredients: caffeine is a stimulant and L-Theanine is an amino acid. MitoGenix L-Theanine contains no caffeine, so keep track of your own caffeine intake.

Can I take L-Theanine and Magnesium Glycinate together?
Yes. They share no active ingredient, so there is no overlap to add up, and both fit easily into an evening routine. MitoGenix L-Theanine and MitoGenix Magnesium Glycinate are declared separately, so follow each label's dose and do not exceed either.

Is L-Theanine safe to take every day?
Yes, MitoGenix L-Theanine is directed for daily use at one capsule. Do not exceed the recommended dose. Evidence covering continuous use beyond about three months is limited, so speak to a healthcare professional about longer-term use, especially if you have a known medical condition.

What are the side effects of L-Theanine?
L-Theanine is generally well tolerated: a 2026 review of 31 controlled trials recorded no serious adverse events. Take no more than the recommended dose, and discontinue use if any adverse reactions occur. Anyone with a known medical condition should consult a healthcare professional first.

Can I take L-Theanine with medication or other supplements?
Speak to a healthcare professional or pharmacist before combining L-Theanine with any medication. With other supplements, check the labels: Mito-Focus Xtreme already contains L-Theanine, so account for total daily intake if combining, and do not exceed either product's recommended dose.

Can I take L-Theanine while pregnant or breastfeeding?
MitoGenix L-Theanine is not intended for pregnant or breastfeeding mothers, as stated in the product caution. Anyone who is pregnant, planning a pregnancy or breastfeeding should speak to a healthcare professional rather than using this health supplement.

What makes a good quality L-Theanine supplement?
Look for a declared amount per capsule, a full ingredient list and no proprietary blend. MitoGenix L-Theanine provides 300 mg per capsule, with microcrystalline cellulose and a hypromellose shell as the only other ingredients, and it is independently tested for identity and purity.

CAUTION: Store in a cool, dry place or below 25°C. Keep out of reach of children. Do not exceed the recommended dose. Not intended for children under 18 years, or pregnant or breastfeeding mothers. Individuals with a known medical condition should consult a healthcare professional before using this health supplement. Discontinue use if any adverse reactions occur.

See the full MitoGenix supplement range, or pair L-Theanine with Alpha-GPC as part of a daily stack.

SAHPRA DISCLAIMER: This unregistered medicine has not been evaluated by SAHPRA for its quality, safety or intended use. Health supplements are intended only to complement health or supplement your diet. This product is not intended to diagnose, treat, cure or prevent any disease.