Yes. My ferritin was low, iron in normal range and I was told to supplement. Even part of CBC had dropped, but I believe iron was still in normal range. I was having symptoms of iron deficiency- extremely fatigued and worse tachycardia with my P.O.T.S.. My doctor said ferritin is the best indicator for iron in the body. It is your iron stores. You need to take ester-C vitamin or regular vitamin C if you don't have a problem with it- at least 250 mg for best absorption of the iron and take it separate from calcium as well.
I also have borderline normal iron and low ferritin. And I have noticed more hair in the shower too. Hair feels really dry and week:( Im going to go on an iron supplement for a while to see if it helps. I also ake spirallina everyday.