Low-level light therapy is one of the better-studied RLT uses — there's reasonable evidence for pattern hair loss (androgenetic alopecia), and FDA-cleared caps and combs exist for it.

Realistic timeline: think in months, not weeks — most people evaluate around the 3–6 month mark, and results vary. It tends to work best on early-stage thinning and alongside other treatments (like minoxidil) rather than as a standalone fix. Consistency is everything. What device are you considering or using, and how long have you been at it?