It never spoils. There's no chance of "spoilage spooking"

When you open a bottle of deer scent made from real deer pee you are likely to smell an ammonia-like odor. This is the smell of bacterial breakdown or spoiling. This process begins as soon as the urine leaves the deer and, many think, it is one way deer can determine how recently other deer have been in the area. In other words, odds are a real deer knows your real deer pee scent is old because it smells old! And that means it probably won’t work!

Buck Fever lasts for months and is refreshed by moisture.

Real deer pee, because it spoils, will last for a matter of hours before it is gone. Buck Fever Synthetic Scents, on the other hand, lasts for months because there is no bacterial breakdown. And, Buck Fever Scent crystallizes only to revert back to its liquid state with rain or other moisture.