My horse has a severe pollen allergy and I looked into Nostrilvet (as it were) last year. My equine vets advised me to save my money as it just won't work. First Defence for humans (similar concept) works for humans because humans have teensy noses and the air they breathe in at each breath stands a good chance of brushing up against the side of the the narrow airways in the nostrils, to be trapped by the sticky First Defence. With horses, it's different. They have humungus noses with W-I-D-E nostrils and they take in a vast amount of air at each breath. The likelihood of 100% (or even 5%) brushing against the nostril walls so the sticky Nostrilvet can trap particles is about nil.
Well, I can say that Nostrilvet works 100% for some horses. My youngster had an allergy to some unspecified thing in the summer of 2010, we never did find out what it was even though we went through a long process of elimination. Anyway, I digress... When he was suffering with the allergy, he was headshaking and was uncomfortable to such an extent that he was dangerous, throwing his front legs around, twitching violently, throwing himself around bodily to try and relieve the irritation, etc etc. I was very sceptical about Nostrilvet, but it wasn't hugely expensive and was worth a punt, so I got some, and was absolutely AMAZED at the difference it made. Every morning, I would squirt the product up his nostrils before turning him out, and it instantly stopped the behaviour. I was so sceptical, I even conducted an experiment, whereby I didn't use the product on random days. Without it, he returned to the violent behaviour. Then the winter came, and whatever the allergy was disappeared. He has, touch wood, subsequently grown out of the allergy, my vet thinks the horse has now developed an immunity to whatever it was that was causing him a problem.
If you have a problem with your horse, the Nostrilvet is cheap enough to take a gamble on. It definitely worked for me, and I subsequently gave the remainder of the bottle to another lady on my yard who's horse has suffered from bad head shaking for 14 years. Whilst the NV didn't cure the horse, it radically reduced the symptoms displayed, and this was a horse who the owner had tried absolutely EVERYTHING on over the years to try and alleviate the issues.
OP, I would try it for yourself and see how you get on.
My five year old seemed to headshake from March to August last year. I tried Nostrilvet but had battle to get even some of it up her nose each time was a nightmare and whatever actually did go up there didn't make any difference. Nosenet worked 80% and it seemed to stop around August. Will be interesting to see if it starts again this year.
I really don't know, but it's not hugely expensive and is definitely worth a go. If you shop around on the internet you can get it fairly cheaply.
I wish you all the best with whatever problems you are having, it is no fun having a horse that head shakes and has allergies, I am so glad that my boy appears to have grown out of his.
I tried it for my gelding who has pollen allergy, dust allergy etc.
IT WAS USELESS!
The bottle blocks up, you are never sure you've squirted enough and it didn't make any different to his head shaking. In my experience don't waste your money.