A key feature of eggshell membrane's amino acid composition is its high cystine content. In the human body, cystine is converted to L-cysteine, which is thought to work with vitamin C to inhibit melanin production, thus preventing age spots and freckles. In addition, it temporarily binds (chelates) with the anti-oxidant mineral selenium to help protect the body from the effects of ultraviolet and other radiation and remove toxic metals from the body.

As a major component of skin and hair, L-cysteine is believed to promote tissue regeneration, prevent spots, pimples and scabies, and maintain the overall health of skin and nails. It is also reported to be highly effective in stimulating hair growth.

In addition, because L-cysteine contains sulfur, it produces sulfuric acid when metabolized by the body, which helps to rid the body of toxic metals like lead and mercury while preventing excessive buildup of nontoxic metals.