"If hair is just beginning to thin, Keranique Hair Regrowth Treatment Spray, $30, is a great first product to try," says fine hair specialist Lucinda Ellery. The product contains 2 percent minoxidil (that's the wonder ingredient in Rogaine), which not only helps stop hair loss, but also promotes regrowth with constant use. But Ellery does warn you need a little patience. Minoxidil-based treatments can take up to three months of use to see results. Plus, the spray is a leave-in treatment, which Dr. Jeannette Graf, M.D., assistant clinical professor of dermatology at The Mount Sinai Medical Center, says could prove a more effective method because it has greater contact time with the area it's treating than other thinning hair products. Sold and sold.

A specially formulated cleansing system can help your mane stay strong and appear fuller. "Shampoos and conditioners work on the appearance of the hair itself and the outer cuticle," says Dr. Graf.

Hairstylist Jon Reyman of Spoke & Weal, a salon with locations including New York and Los Angeles, recommends Aveda Invati Exfoliating Shampoo,$30, and Thickening Conditioner, $30, to prevent sebum buildup on the scalp. "I'm a big proponent of natural solutions," he says, "and I've seen this make a difference on clients."

Looking for a drugstore option? Consider Avalon Organics Biotin B-Complex Shampoo and Conditioner, $9.95 apiece, which build body in fine strands. Or, to protect color-treated hair, try ColorProof BioRepair-8 Anti-Thinning Shampoo and Conditioner, $44 apiece, both of which block DHT, the hormone that damages hair follicles.

A new import to the United States, Danish hair-loss clinic Harklinikken claims success in improving hair growth among 95 percent of its 70,000 users. The hero treatment is the topical Extract, $88, made with ingredients derived from cow's milk and plants. Each formula is customized for the client based on age, gender, family history and hair loss. Applying nightly is key, and the program includes weekly online check-ins with a Harklinikken representative to track progress. Note that it won't work for certain conditions such as scarring or alopecia, but otherwise, expect to see fuller hair beginning in a few months.

If you seek immediately visible results, try hair-building keratin microfibers such as Focus Hair Building Fibers, $24.95, and Toppik Hair Building Fibers, $24.95. WAnd while the secret behind what makes these fibers work is all very scientific (the fibers basically act as a magnet and bond with your hair), we think Toppik's ingenious ad campaigns really show the results best. "These aren't permanent solutions to hair loss," says Ellery, "but rather a short-term camouflaging technique that resists sweat, rain and daily wear, and wash out easily with shampoo." If your scalp is starting to show bare patches, these fibers (which come in eight or nine different shades) are a quick solution with no telltale signs of anything unnatural.

Nioxin Thinning Hair System Kits combine peppermint oil, vitamins and purifying agents to give your strands fullness while protecting against further damage and breakage. Six varieties lets you choose a specific system to match your hair texture, pattern of hair thinning and natural or chemically treated hair. Dr. Graf recommends choosing a kit with Glyco-Shield, a complex that offers protection from daily environmental gunk like smog, pollen and dirt.