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.

Don't underestimate the lifestyle factor. "When you're worried and stressed, your cortisol levels go up, and your body attacks itself," Reyman says. Indeed, a 2016 article in the Journal of Drugs in Dermatology found that high levels of cortisol are related to certain hair growth disorders. Poor nutrition can also lead to hair loss, especially when levels of iron, zinc and omega-3 fatty acids are low. Taking part in stress-reducing activities such as yoga can help reduce cortisol over time, and eating foods such as salmon, spinach and lentils should help new hair grow in strong. The jury is out on whether hair-growth supplements are effective; relatively little academic research has been done on them, but anecdotal evidence suggests they can help. Ouai Thinning Hair Supplements, $84, created by celebrity hairstylist Jen Atkin in conjunction with Dubai-based physician Lamees Hamdan, include essential fatty acids and biotin to bolster sparse strands. Another supplement, Nutrafol, $88, features biotin as well as anti-inflammatory ingredients and a highly bioavailable version of keratin to strengthen hair.