I took primal defense for like 3 mnths and i took the max dose - it didnt work at all and cost me a fortune!!. Something that worked was oxygen elements plus and it was brilliant, i felt great my sinusis were cleard and i had energy for the first time in years while i was on it - but then my nutritionist tole me oxygen can cause free radicals so ive stopped it and all my symtomps have returned. Maybe nutritionists have got it wrong??? cos its the only thing that worked for me!!