i use l-lysine. i ordered 5.5kg from america, including shipping it was £40.00. but considering that amount will last me around a year i thought it was fantastic value. i havent had any runny eye's or sneezing since putting my cats on a daily does. my vet supports the use also, i did double check! I found after around a week things started to settle down, but you do need to use it all the time, even after things clear up, if you stop the virus becomes active and your back to square one. if you would like me to send you some, to get you started please feel free to pm me