L-Theanine Guide (2026): Calm Focus, Dose & Caffeine Stacking
L-theanine is an amino acid found in tea that promotes calm alertness without sedation. Human trials at 100–200 mg show modest reductions in acute stress and improved subjective relaxation, and it measurably raises alpha brain-wave activity. Its most reliable use is stacked with caffeine: theanine blunts the jitters and anxiety spike while keeping the focus. It's one of the better-tolerated calming supplements — no dependence, no next-day grogginess. Below: the evidence, dose, and how to stack it.
Dosage Guide (focus, anxiety, sleep)
Does It Actually Work?
How Long Does It Take to Work?
Best L-Theanine Supplement
L-Theanine for Anxiety & Stress
L-Theanine + Caffeine (Calm Focus)
Compare L-Theanine Products by Cost per Dose
Compare L-Theanine Products by Cost Per Day
If you're ready to buy, here's how the l-theanine products we track and verify compare on cost per day.
| Product | Dose/Serving | Servings | Price | Cost/Day | Certification | Buy |
|---|---|---|---|---|---|---|
| NOW Foods L-Theanine 200mg with Inositol (120ct) Best Value | 200mg | 120 | $20.76 | $0.18 | None | Buy on Amazon |
| Sports Research Suntheanine L-Theanine (200mg, 60ct) Budget Pick | 200mg | 60 | $19.95 | $0.34 | Non-GMO Verified | Buy on Amazon |
| Thorne Theanine (200mg, 90ct) Quality Pick | 200mg | 90 | $68.00 | $0.77 | NSF Certified for Sport | Buy on Amazon |
About our data
Every comparison uses clinical evidence from PubMed systematic reviews, product label data from the NIH Dietary Supplement Label Database, and third-party certifications (USP, NSF). Products are ranked by cost per clinically-effective dose. See our methodology and editorial standards.