In NY:
http://www.dos.state.ny.us/licensing/cosmetology/cosmetology_faq.html#4
What does the practice of Cosmetology cover?
The practice of Cosmetology includes providing the services of natural hair styling, esthetics, nail specialty and waxing and also includes providing services to the hair, head, face, neck or scalp of a human being, including but not limited to shaving, trimming, and cutting the hair or beard either by hand or mechanical appliances and the application of antiseptics, powders, oils, clays, lotions or applying tonics to the hair, head, or scalp, and in addition includes providing, for a fee or any consideration or exchange, whether direct or indirect, services for the application of dyes, reactive chemicals, or other preparations to alter the color or to straighten, curl, or alter the structure of the hair of a human being.
Who must apply for a Cosmetology license?
Any person practicing Cosmetology as described above is required by law to have a Cosmetology license. A Cosmetology license will not permit you to operate a business; a separate business application must be completed and a separate business license obtained.