Drowsiness without sedation is characteristic of hyperthyroidism (which we might expect to have the same symptoms as bacopa-induced T4-elevation. Bacopa was reported to boost T4 by 41%: [http://www.greenphar...=9;aulast=Gohil]). Re-read this which I quoted: "Patients with hyperthyroidism usually experience fatigue at the end of the day, but have trouble sleeping [properly]".
You're probably taking less bacopa, have developed a tolerance to the thyroid-effects, or are living an otherwise healthier lifestyle. Taking it in the early or late morning, as opposed to the evening, will also make the pro-fatigue anti-sleep properties less noticeable, since it's more difficult to become fatigued/drowsy in the morning, and you're less likely to have issues sleeping after the drug has partially (or largely) worn off (which it probably does as the day drags on, peaking after 3-5 hours, and then returning to baseline within 24-48 hours). Bacopa is NOT sedative, or at least I don't know of any mechanism through which it decreases sleep latency or enhances sleep quality. If anything, the increased T4 will interfere with proper sleep until you develop a tolerance. It returns 5-HT2C receptors to near baseline in epileptic rats, but I don't see why this mild serotonergic activity should correlate to enhanced sleep. Even if it happens to raise healthy people above the baseline 5-HT2C receptor density, it's not at all clear how this would affect sleep quality.
Edited by dasheenster, 31 July 2012 - 01:08 AM.