My hair is baby fine too. It gets a little frizzy and puffy shortly after straightening it, but worst of all, it LOOKS dried out and fried. If I got extensions they'd be too shiny against my hair's dry texture. I so badly want silky, shiny hair. And the problem with fine hair is, in my experience, you have to use a lightweight serum, not a heavy cream or pomade, when straightening it since it weighs down and gets greasy easily. On the flip-side, a lightweight serum, at least the ones I've tried, don't really help straighten my hair nor create shine. The 'product' that works best at creating shine for me, and I know this is awful, is olive oil.
I've noticed the ingredients in all straightening serums/heat protectants, are pretty much the same. It doesn't seem worth spending a lot on these products because whether you pay $4 or $40, many of them contain at least some kind of combo of the following ingredients:
-Cyclomethicone or Cyclopenthasiloxane
-A protein such as Wheat Protein or silk protein.
-Vitamin E, B5, and/or A.
-some contain polyquats or PVP.
I've heard good things about Sedu and Solia straighteners, though I've never tried one myself. And is the Aveda product you're talking about called Aveda Brilliant Anti-Humectant Pomade? Or is it the Spray-On Shine or Emollient Finishing Gloss? If it's the pomade, the key ingredients are aloe and castor oil.
I'd love to see straight hair photos of everyone who's made a suggestion in this post.