Does L-Cystine Help With L-Cystine is a naturally occurring amino acid formed when...?

Evidence Summary

L-Cystine is a naturally occurring amino acid formed when two cysteine molecules bond together. It is a building block for glutathione, the body's main antioxidant, and is found in hair, skin, and nails. In clinical studies, it has been tested — almost always in combination with other ingredients — for skin lightening (paired with glutathione), hair loss support (paired with plant extracts), and immune response in elderly people (paired with L-theanine). No study in the provided data tested L-Cystine alone as the sole active ingredient for any of these outcomes.

Source: auto-research

Effective Dose

500 mg/day (skin lightening, combined with glutathione); 200 mg/day (fertility blend); No established dose for standalone use