I've been taking antihistamines my whole life. My hay-fever symptoms come on unannounced randomly all year round. I'm allergic to mold, pollen, pet dander, etc. The once-daily pills would help prevent allergy attacks for a while, but would decline in efficacy with time. So, I would switch to another, and it would work for a time. Now that I'm in my 50's, they seemed like they worked more poorly than ever.
Then, I tried Banyan Pollen Protect and found my allergies to be better managed than they have in a long time. I dropped the antihistamine dujour, and my allergies were still managed well. I've been taking this for nearly a year, and my allergies have not gotten worse with time. I'm impressed!
I have observed no side effects with the use of this product. I should have but have never looked up what side effects might be listed for it. Antihistamines that make others drowsy now barely have that effect on me. If that is a side effect of Banyan Pollen Protect, I've never noticed it. (I recommend that you research any supplement or medicine better than I have.)
My only complaint is that this product is bitter. But medicine isn't candy. And it isn't horrible.
I highly recommend that you give it a try if your fight with allergies is similar to mine.