这个在item 下面Costco没有说自己不是 authorized" dealer ， 所以应该是costco 卖的。 主要是要看产品下面有没有下面的，有的话就不是Costco自己卖的，而是第三方seller This item is covered by Costco's guarantee to refund your purchase price if you are not completely satisfied. Costco's guarantee applies, even though this item may not be covered by the manufacturer's warranty, because Costco is not an "authorized" dealer of the merchandise.
SK-II肯定不会有假，因为进货渠道和其他的牌子不一样。Costco的财报提过SK-II产品是他家和P&G的strategic partnership的一部分，也就是P&G直接供应的货。（前情提要一下SK-II虽然是日系，但是现在是P&G的牌子）
其他牌子有的是gray market product,可能是供应商出了问题，但是Costco是不会主动卖假货的，public company主动卖counterfeit简直是自杀。
像护肤品这种东西 如果有concern 还是从更可靠的渠道买好
这个在item 下面Costco没有说自己不是 authorized" dealer ， 所以应该是costco 卖的。
主要是要看产品下面有没有下面的，有的话就不是Costco自己卖的，而是第三方seller
This item is covered by Costco's guarantee to refund your purchase price if you are not completely satisfied. Costco's guarantee applies, even though this item may not be covered by the manufacturer's warranty, because Costco is not an "authorized" dealer of the merchandise.
tongwen