runny nose - took synthroid for years and never knew why my nose was always running. Went in for a blood test last year and the lady taking my blood mentioned that she too took synthroid and had a horrible runny nose. She switched to Armour Thyroid and no more nose problems. I then switched to Armour Thyroid and my runny nose went away! There must be something in the filler indgredents that causes the constant runny nose.