Hair loss isn’t always dramatic. It can be incremental. You start noticing a bit more scalp in harsh bathroom lighting; a tiny bald spot when you tie your hair up in a ponytail. The shower drain is more clogged than usual. Not long ago, hair loss treatments meant topical remedies, supplements, or a flight to Turkey. Luckily, red light therapy brings the potential for hair regrowth into your home—no clinical appointment required. Beyond skin rejuvenation, research suggests red light therapy can help energize hair follicles, increase blood circulation in the scalp, reduce inflammation, and lower dihydrotestosterone levels—a hormone that causes hair loss and thinning. Red light therapy also supports adenosine triphosphate (ATP) production, which helps provide oxygen and blood flow to the scalp and triggers follicles to remain in the hair growth phase. To determine the best red light therapy for hair growth, I tapped three WIRED tech reviewers who’ve dealt with hair loss themselves. We assessed red light therapy caps, hands-free helmets with full scalp coverage, and low-level laser therapy or photobiomodulation devices for …