Segals, an 8oz hair scale with a thin appearance, is a good choice.

The Segals Solutions Thin-Looking Hair Scalp Formula is a topical solution that contains a blend of exotic botanical herbs and active hair nutrients, and massages into the scalp to stimulate and restore the ideal scalp and hair roots for thicker, fuller-looking hair. It does not contain sulfates, parabens, animal testing, or harmful chemicals.