It is a buyer beware thing..Lugol 5% is, since last July 2007 as per FDA rulings,only sold in 1 oz bottles,this is valid for all sits in the US.
Lugol bottles that are 2 oz and above all contain 2% Lugol even the ones sold for fish tanks.
Some "pet merchants/chemical labs " sell the 2% at inflated prices fooling the customers in hinting that it is the real Lugol(implied 5%)
In Canada Lugol 5%- no restrictions; the 7% solution is only available to professionals
There is a big difference between the 5 and 7% solutions which do give real results..within 1 month or so not 6 months or more with Lugol 5%