Hello, I have been taking the product Sinna on and off for nearly a year, and it has worked wonderfully. About a week ago, I started to loose my voice and I am wondering if there is any concern that Sinna may be causing this?

It is not possible for Sinna to have caused your problem, you can safely keep on taking it. It can be combined to any treatment.

Tips
-Drink hot water (ex. Broth and herbal teas), since it help reduce congestion.  
-Eat a lot of raw foods; they contain high levels of antioxidants that help the immune system function better.
-Add a lot of onions and garlic to your diet, they help decongest and boost the immune system.  
-Avoid food that causes congestion (ex. Dairy products, banana, oat…).  
-Eliminate white sugar (reduce efficacy of immune system) and use honey instead.  
-In cases of chronic sinusitis, find your food allergies or any other allergy that can irritate the sinus cavities.