Doctor's Best L-Theanine with Suntheanine provides calm focus and lowered tension, helping you stay productive and alert without the groggy aftertaste of stress. Each capsule provides 150 mg of L-Theanine, using the branded Suntheanine form known for purity and consistency. Doctor's Best is trusted for science based nutrition and quality, with vegan, non GMO, gluten free, and soy free ingredients.

Available Sizes & Variants:

90 vcaps - Convenient daily supply for ongoing calm focus.

Benefits & Features:

• Promotes tension and stress support for calm focus and steadiness.
• Relaxed alertness without drowsiness helps daytime productivity and steady performance throughout busy days.
• Star ingredient Suntheanine offers a patented, high-purity form that delivers purity and consistency in every capsule, for reliable calm focus throughout the day, consistently.
• Fits into wellness routines easily.
• Each capsule's easy swallow design makes it simple to fit into a routine, supporting steady intake and mood without interfering with daytime tasks.

Doctor's Best has earned trust with science based nutrition, and this L-Theanine with Suntheanine keeps that promise. Suntheanine is a patented, high-purity form of the amino acid, and the brand uses vegan ingredients for a clean, straightforward supplement. This is one of the leading L-Theanine supplements, designed for calm focus without sedation. It fits easily into a broader wellness routine, whether paired with a Vitamin D supplement or probiotics.

L-Theanine (as Suntheanine), L-Theanine (as Suntheanine)

• GTIN: 753950001978
• Manufacturer: Doctor's Best
• Categories: Doctor's BestL-TheanineNootropicsSleep & Relaxation SupplementsStress Relief & Calming SupplementsSupplements for Anxiety
• Best buy: 6 - 24 months+

United Kingdom Shipping:

Orders placed by 2pm (Monday to Friday) are dispatched the same day. Orders placed after 2pm will be dispatched the next working day.

Free shipping on orders over £50 to the UK.

Returns: Our products are meant to make you feel healthy and at your best. If you need to return your item, you can do so free of charge within 30 days in the same original and unopened packaging. Subject to T&C's.

Take 1 capsule daily without food, or as recommended by a nutritionally informed physician. Store in a cool, dry place. Not recommended for individuals who are pregnant or lactating.

Please consult the product packaging for accurate instructions on how to use the product.

*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

The Active Ingredient Is: L-Theanine (Suntheanine Form)

L-Theanine is basically an amino acid analogue that crosses the blood-brain barrier and modulates neurotransmitter levels, helping a state of relaxed focus. This formulation uses Suntheanine, a purified, branded form of L-Theanine, commonly recognised for purity and consistency.

In this product, L-Theanine is provided as the active ingredient, with excipients making up the vegan capsule. Suntheanine delivers the intended active nutrient while keeping vegan suitability and product stability.

What Does L-Theanine Do?

L-Theanine helps promote relaxation without sedation and supports a state of calm focus, which can be handy in everyday stress scenarios. The mechanism includes modulation of brain activity linked to relaxed alertness, which aligns with guidance from health information sources.

Dr. Zumpano at the Cleveland Clinic found that L-Theanine promotes relaxation without drowsiness and can sharpen mental focus, supporting its role in daytime cognitive balance.

Doctor's Best stands out for quality standards with a science-led approach that prioritises purity and consistency. This brand teams up with Suntheanine®, a patented L-theanine ingredient recognised for its high purity, helping reliable formulation across their ranges. The emphasis on science-based nutrition and vegan, Non-GMO, gluten-free and soy-free labelling shows a rigorous, consumer-friendly quality mindset that lines up with Welzo's commitment to transparent sourcing. For credibility, Doctor's Best has established itself as a major supplement manufacturer in the space, with a reputation for delivering well-documented formulations that travellers through the supply chain can trust. This is reinforced by their use of Suntheanine® as a trusted branded ingredient known for quality control in production, a factor we value highly when choosing a partner.

Our choice is rooted in the brand's clear quality language and manufacturing philosophy, which positions Doctor's Best as a dependable supplier for L‑theanine. This product pairs well with the brand’s focus on targeted, science-backed nutrients and our vetting process, supported by our expert team of doctors, nurses, and nutritionists and the framework detailed at the certifications we require.