Choose the Right Wavelengths
The appropriate wavelength is crucial for red light therapy. Multiple studies have shown that 630, 650, and 660 nm wavelengths can provide effective results for hair growth.
Additionally, although early research primarily used red light (600-700 nm), it was later discovered that near-infrared (NIR) light (760-1000+ nm) is equally (if not more) effective.
We don't have to be too concerned about the most effective wavelength. If possible, more wavelengths would be better. Therefore, choosing a device with both red light (630-660nm) and near-infrared light (760-1000+ nm) can give you the best and most comprehensive hair growth results.