If a dose is forgotten once, this is usually not a problem as there will still be enough probiotics present in the intestines to maintain the effect. When for the second time in a row no capsule is taken, there is a big chance that the effect diminishes. As soon as a capsule is taken again the effect will be the same as before, provided that only 1 or 2 days a dose has been missed. When a dose is missed several days in a row then indeed at least 5 days are needed again to build up enough probiotics to have an effect.