I have been looking all over the place for the best volumizing products I can find. I have a ton of hair, but it's very fine, and I flat iron it almost everyday. A hair dryer, a round brush, and some huge curlers pump up the volume a bit, but my hair would be nothing close to what it is everyday without the products I have finally found.
Catwalk by Tigi Your Highness Root Boost Spray review: This is hands down the best root spray I've ever used for volume. It works best when used right before blow drying with a round brush (I also put curlers in immediately after drying each section to set the volume. It sprays on easily and evenly, and the consistency allows for easy distribution through the hair. It smells great, too! Definitely an essential part of my hair regime for huge volume.
Kenra Volume Spray review: Also, hands down the best hair spray I've ever used. I bought this several months ago and fell in love with it. I used it a lot when I was living on the east coast, which was a good test for its ability to fight humidity - it held up the volume without a problem! It also doesn't leaving your hair feeling hard as rock, the hold is flexible but SUPER strong. I can brush through my hair quite a bit to clean up after back-combing, and the volume still holds. It even holds through sleeping; seriously, I wake up with more volume than I had going out. I noticed that Sally's recently came out with a version of this through their Generic line... I used it for the last month, after trying a few other hair sprays as well. After some of the other hairsprays I tried, it seemed to work better, but not significantly. Right after using the Generic version, I switched back to Kenra and noticed a huge difference. Love this stuff!
Paul Mitchell Thicken Up review: The Root Boost Spray works as an anti-gravity for the roots, but this serum is what's responsible for the overall body. I bought this after reading a review somewhere that said it produced super-model like volume (that's pretty much exactly what I'm looking for). I can tell you, that's absolutely true. Again, this is based on use with a hair dryer; I've never used volumizing products when air-drying. Smells great, goes on easy, doesn't weigh the hair down, and adds tremendous volume through to the ends.
Mane Boost Products review: I use their shampoo, mousse, and Amplifying Cream. I tried their spray for roots, but I wasn't super impressed. The shampoo provides great volume all on its own, and doesn't require conditioning afterwards! It cleans gently and, from what I've noticed, doesn't cause issues with any sort of build-up. The mousse and Amplifying cream add a bit of texture and extra volume, additional to what Thicken Up adds. The texture both products add helps with teasing (I find that sometimes if my hair is TOO soft, even hairspray won't hold any back-combing). The Amplifying Cream also adds heat protection, which is critical (although I use other products for this generally).
All together: Soft, manageable, heat-protected, HUGE hair. Quick drying, with tons of shine. Hair looks extremely healthy, and has tons of bounce. The style lasts all day, even if you play with your hair and run your fingers through it all the time like I do! I would absolutely recommend this team of hair products to anyone looking for volume.