Does anyone use a thickening or volumizing shampoos? The hair at the crown could use maybe use some help, but not all my hair. I tried something once years ago and it made all my hair feel weird and too puffy.
All shampoos do one thing: strip the hair of dirt and oils. It is impossible to add another functionality without diminishing the cleansing effect. If you need to add the old back or give your hair a bit of volume, use a separate product. I highly recommend Kerastase or Oribe products for that. Mousses and spays used on wet hair prior to drying.
I love the Oribe products. The dry texturizing spray is awesome. I bought some Drybar Triple Sec 3-in-1 and it works well but I hate the smell.
Stupid autocorrect. “Add the oils back”
I use “volumizer/moisturizer” shampoos in the winter. My hair is superfine, thick and board straight - not a wave in sight and it is so dry in the winter it’s as if the air sucks every drop of moisture out of my hair and my hair looks even straighter, flatter and finer. The volumizer/moisturizer shampoos do seem to give my hair more lift…
I am using L’Oreal EverStrong Sulfate-Free Thickening Shampoo and Conditioner right now and really like it. It is in a green metallic tube.
If your problem is just your crown, I agree with Bunsen, that a mouse could do the trick. I use that, too.
Ack! No, just…no.
I’ve had good luck with Nioxin products. Also, don’t put conditioner on your scalp; just condition the ends up about half way up the hair shaft.
If you use a conditioner then it is what gives your hair the volume, not the shampoo. 
I use Rusk “Sensories” volumizing shampoo. It really makes a difference. If I use regular shampoo, my thick, fine hair hangs way too flat.
Autocorrect seems to be having a field day today! 
I’ve been using Pantene volumizing shampoo and conditioner and there’s a definite difference. My hair is short, fine and thinning. When we recently traveled and used the hotel products, you could see far more of my scalp than one can at home with the Pantene. I’ve used other more expensive products with less positive results.
I never travel without travel sized bottles of my trusted shampoo and conditioner. The only exception is Hawaii - the water there must be magical so any crappy hotel shampoo works.
Certain conditioners “flatten” my hair badly. My hair is normally very thick and full in appearance, unless I used these particular conditioners.
It took me a lot of experimentation to finally figure out what works for my specific hair. Hair is so individual that what works for one would not work for another. Pantene, for instance, made my hair dull and sticky. 
Ditto many other products, including some very expensive stuff, so I stick with tried and proven.
One thing that works consistently in our family is the Oribe stuff mentioned by sabaray.
My hairdresser says that I should change how I part my hair from time to time. Her theory is that since you start brushing/combing at the part, that area gets more stress. Have no idea if that’s true or not.
If you find a shampoo that volumizes your crown, you could try applying a conditioner only to the sides or ends of your hair to keep the rest under control.
The Irish Setter Adrian at the Westminster dog show was pictured being bathed in Pantene. Seemed to work for him! He had a very full, beautiful coat! He’d be a great advertisement for them.
My hair is very thick, very fine and no lift at the crown. I’ve tried a lot of volumizing shampoos and was a lot happier once I started using product to give lift at the crown. I also stopped washing my hair every day and just freshening it up with product. My hairdresser also uses Olaplex on my hair during color treatments and then I have a bottle for use at home once a week that helps preserve the color and really gives my hair more volume.
Thanks for all the suggestions. I don’t use conditioner above the ears. I do use mousse at the crown and top, and it helps. However, it just seems I need more volume at the top…something to thicken the hairs. Just afraid to use it all over my head. I have medium length hair. I actually have some nioxin. I might try that before looking into the others.
Longer hair length can lead to de-volumizing at the top. Just think of the gravity and the weight of that hair pulling it down from the top.
I borrowed my H’s Jack Black Body-Building Hair Gel and I really liked it.