Another treatment Youn loves for thinning hair? Low-light laser therapy. While we need more research, the current data seems encouraging: Specifically, one study found that women who received red light therapy at 650 nm every other day for 17 weeks experienced a 51% increase in hair density, and another research review touted red light therapy as safe and effective for promoting hair growth in both men and women. 

“Low-light laser therapy is basically like the laser of a laser pointer,” Youn explains. “It doesn’t create any heat. You can have it pointing at your skin for hours, and you’re not going to get a burn.” The theory, he continues, is that these low-light lasers can create changes in your follicle’s growth phase, which can help to thicken and grow hair. 

“There are baseball caps you can wear—on the undersurface of the cap, there are dozens or so low-light lasers that can affect the scalp and cause the hair to go into its growth phase,” he adds. Check out this FDA-cleared option—it costs a pretty penny, but most high-quality options hover around this price point.