Numerous people reported piracetam was the only thing that brought back clarity, lack of tolerance, and most noted "magic" from rolling. After reading many trip reports, I gave it a try, and was really delighted with the results. It's a legal supplement, it's not designed for pre-rolling, but it seems to work for many.
From the piracetam wikipedia page:
# 4 Approval and usage
* 4.1 Aging
* 4.2 Alcoholism
* 4.3 Alzheimer's and senile dementia
* 4.4 Clotting, coagulation, vasospastic disorders
* 4.5 Stroke, ischemia and symptoms
* 4.6 Dyspraxia and dysgraphia
* 4.7 Schizophrenia
* 4.8 Preventive for Breath-Holding Spells
* 4.9 Closed craniocerebral trauma
Piracetam appears to increase communication between the two hemispheres of the brain, and increases activity of the corpus callosum
Piracetam appears to reverse the effects of aging in the brains of mice.[22][23]
Piracetam appears to reduce levels of lipofuscin in the rat brain.[24] (Lipofuscin accumulation is a common symptom of aging and alcoholism).