Want stronger hair, nails, and brows? Here's your guide to the best vitamins, serums, shampoos, and other treatments that live up to their claims and can actually make a noticeable difference.

Vitamins for hair growth

As we age, hair becomes finer and duller, thanks to hormonal changes and styling damage. The good news: There are ways to make your hair happy again. Shereene Idriss, MD, a dermatologist in N.Y.C., recommends an insideout approach, starting with a protein-rich diet and a hair vitamin, like Nutrafol ($88 for a 30-day supply; amazon.com), which helps increase blood flow to the scalp.

Pair that with a moisturizing shampoo, like Nioxin System #3 Cleanser ($20; ulta.com). Then, similar to skin care, exfoliation is key for healthy hair, says Anabel Kingsley, a trichologist (hair and scalp specialist) in N.Y.C. Use IGK Low Key Scalp Scrub ($36; sephora.com) once a week to create a clean slate for follicles to grow.

Vitamins for nail growth

Regardless of how many manis you get, your nails are often neglected beneath that pretty polish. Whether they’re ridge-filled or peeling, a few swaps can get you back to a perfect 10. First, use an acetone-free remover—it’s less drying—to take off polish, advises Dana Stern, MD, a dermatologist and nail specialist in N.Y.C. Try Cutex Non-Acetone ($3, amazon.com). Apply cuticle oil, and paint nails with polishes that are at least five-free (they don't contain harmful chemicals like formaldehyde).

Ingesting a biotin supplement can also help strengthen nails, says S. Manjula Jegasothy, MD, a dermatologist in Miami. Try Vital Proteins Beauty Boost capsules with biotin ($49; neimanmarcus.com).

Serums for brow growth

Ah, the coveted brows—full, fluffy, and symmetrical. If you weren’t blessed with them, try these tricks: To help promote new hair growth, brush brows with a spoolie to stimulate circulation, then massage on Streicher’s Aforé, which is made with organic argan oil. Also helpful: swiping on RevitaBrow Advanced Conditioner ($110; amazon.com or nordstrom.com) daily, which improves flexibility and shine. Finally, fill in patches with WunderBrow Dual Brow Precision Liner ($16; amazon.com).

Brow gurus Kristie Streicher, creator of the feathered brow, at Striiike Salon in Beverly Hills, California, and Venice Beach-based celebrity brow expert Kelley Baker of Kelley Baker Brows also agree on ditching tweezers and pomades. "If the product is too sticky, it can pull hairs out," warns Baker.