California Code, Health and Safety Code - HSC § 106960

It shall be unlawful for any person to implant foreign materials within the scalp of any other person for the purpose of preventing or alleviating baldness. “Foreign materials” shall include, but shall not be limited to, synthetic fibers and strands of human hair from another person. A violation of this section shall be a misdemeanor.

This section shall not be applicable to procedures for the transplantation of a person's own hair or to procedures for the fixation of hairpieces, toupees, or wigs.