It is recommended for nasal conditions with mucus buildup that requires thinning, such as the persistent common cold, allergic rhinitis, and sinusitis. Preservative-free product. Opti-Ionoc Marine Solution is a slightly hypertonic solution (more concentrated in salt than blood plasma). Due to its osmotic effect, it drains excess water retained in the nasal passages, helping to thin mucus and producing a decongestant effect without irritation. It allows the passage of water from a less concentrated solution to a more concentrated solution, causing water to flow into the nasal passages. It helps thin mucus, producing a decongestant effect without irritation.