My dog has severe anxiety when he is left alone. He tends to destroy things when he is left behind the baby gate during the week while we are at work. He is great when we are around.
I hope this doesn't sound too redundant or trite, but have you tried exercising the dog? I mean, you know, a pretty good amount of exercise. Usually a tired dog is a happy dog!
The anxiety the dog feels will likely override fatigue, but probably not for long if the dog is tired enough. Just a thought :D
I don't believe it's strong enough to do much for separation anxiety. It's meant for milder types of nervousness. I know Clomicalm (clomipramine) is specifically marketed for separation anxiety.
Also, bear in mind that any medication or supplement you use is only to put the dog in a state of mind where it can learn a new behavior i.e. how not to be scared and upset while alone. Behavior modification can be a long process, but it is the on;y way to fix separation anxiety. Stronger medications like acepromazine only make the dog look calmer. He's actually still at his wit's end, he's just too gorked to do anything about it,
Tranquilizers, such as diazepam and lorazepam are a decent middle-ground. As long as the dose isn't real high, the dog is awake, but calmer, so it can learn. However, as controlled drugs, vets are less willing to prescribe them, and there is a high abuse (by people) potential.
So I recommend Clomicalm and desensitization/counterconditioning.
I have a foster dog with me right now that is really nervous and anxious. The guy who runs the rescue had me put him on Valeria. OTC supplement I got at Sprouts. It was inexpensive and helps a little. My guy doesn't destroy anything, though. But, maybe it will help your dog. Good luck.