There comes a time in every man’s life when his once-glorious mane begins to look, well, kind of sparse. No matter—it’s about making the most of what you’ve got and using the right kind of products. On the latter front, we’re fans of this professional-grade treatment, which thickens hair and keeps it healthier over time. The high-tech formula is designed to strengthen existing hair follicles and protect them against the enzymes that cause hair loss.