I would never correct any other member's spelling, but I have noticed that many people confuse these two words. 'Loose' is the opposite of 'tight' - the verb is 'to loosen', as in 'I had to loosen my waist band'.
'Lose' is the opposite of 'gain' or 'find', so you 'lose weight'.
I don't know why the confusion has arisen as the two words are pronounced quite differently - 'loose' rhymes with 'moose' and 'lose' rhymes with 'muse'.
I trust nobody will take offence at my pointing out this common error.