I have had the same problem. I am at the end of my transition. I think the problem is too much deep conditioning and over moisturizing. If you have deep conditioned, blowdrying will make your hair super thin. I am not an expert but you should take a look at Pinkskates regimen. She is 4a natural with strands that look "fine" IMO. She only does a deep DC every three months. She only conditions 30 minutes a week and it isnt a deep condition if I understand correctly. Also make sure the heat is not up too high on your flat iron. I started to turn my temp setting way down and noticed a major difference (duh!) Try easing up on the moisture. Airdrying or hooded dryer may help you with thickness too. My hair is much thicker using these than a blowdryer. Also remember that these new blowdryers have that ionic technology that gets hair straighter than the old school kinds. Things are some things I have noticed about lately.