Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
I've done a research on the internet before deciding to buy this. Easy to swallow and no offensive taste. I have just taken this for the past 2 weeks ..so its too early to expect any result. So far I feel less tired and no adverse reaction.