As the language of longevity shifts from anti-aging to optimization, the way men think about hair is evolving alongside it. And nothing demonstrates this change quite as well as the preponderance of supplements on the market designed to help your hair look thicker, shinier, and in some cases, less gray. But the best hair growth supplements for men aren’t just well-marketed snake oil. As part of an overall hair retention strategy, these formulas can do everything from reducing the amount of dihydrotestosterone, or DHT, the hormone that leads to male pattern baldness and prostate enlargement, to helping your body handle the challenges of modern life. “Hair ages just like skin,” says Greg Ruggieri, a trichologist and hair stylist who owns New York City’s Salon Ruggieri. He notes that oxidative stress (basically, everyday exposure to the elements) can do real damage to your hair over time. “Antioxidants help slow that process at..