Can I take L-theanine together with coffee or caffeine? — Suntheanine L-Theanine 100 mg, N60 - Swanson

The product card does not mention combining L-theanine with caffeine, so no conclusions can be drawn about that combination. According to the label, adults take 1 vegetable capsule (100 mg) 1–2 times a day with water before a meal, without exceeding the daily dose.

If you are sensitive to caffeine, or take medicines or other supplements, it is worth consulting a specialist before combining them with coffee. According to the label, consulting a doctor is also needed during pregnancy, breastfeeding and in case of medical problems; the product is intended for adults only.