Policosanol is a term used to refer to a mixture of lipophilic (fat-soluble) compounds derived from the waxy coating of Cuban Cane Sugar. It has been used frequently to treat high cholesterol levels, and several studies claim that it does so with a potency rivaling statin therapy. The studies in question all appear to originate from Cuba, and when all studies are looked at collectively yet exclude Cuba the 100% success rate in Cuba declines to approximately 14% success rates in human trials. Due to this significant schism in the literature coupled with Policosanol being derived from a Cuban export, it is plausible that the scientific literature is suffering from publication bias.
The studies conducted outside of Cuba and those conducted in Cuba use similar participant pools, similar dosing, and at times have used the same sources of Cuban Cane Sugar specifically. The only difference is in the dietary protocol given, but some evidence suggests that this is a plausible explanation for the differences seen.
At this moment in time, publication bias and dietary intervention lead-in period are both plausible explanations for the observed differences. Which is disconcerting, as the latter would mean that policosanol can be as effective as statin therapy whereas the former means it is merely a placebo; a black and white issue with little grey area.
Regardless of source of the study or context, however, policosanol usage appears to be very safe; no side-effects have been reported in human interventions from Cuba or elsewhere and blatant overdoses in research animals fail to exert toxicity.