I want to offer a counterpoint to the glowing reviews. I tried Holy Basil at the commonly recommended 300mg once daily for a full month and noticed essentially nothing. No change in anxiety, no change in sleep, no change in stress tolerance. I was ready to write it off.
Before giving up, I increased to 300mg three times daily (900mg total) based on the clinical trial dosages I found in the literature, which often used 500-1,000mg twice daily. The higher dose made a noticeable difference within about two weeks.
At 900mg daily, I experienced a definite reduction in my baseline anxiety -- not dramatic, but real. The constant low-level worry that characterizes my days softened. I was less reactive to minor stressors. My sleep improved modestly.
The lesson: dose matters enormously with Holy Basil, and the "standard" dose on most supplement bottles (300mg once daily) may be subtherapeutic for many people. The clinical trials that showed significant effects typically used 600-1,200mg daily. If you try Holy Basil at a low dose and feel nothing, try increasing before dismissing it entirely.
The only downside at the higher dose was mild stomach upset for the first few days, which resolved after I started taking it with meals consistently. No other side effects.