From Consumer Wiki
The title of "consultant" can be misleading, but it generally indicates the person being consulted is an expert or professional in a particular field who offers advice. Consultants may act in the interest of private business, state business, or advise consumers in the private sector. Consultants may or may not be licensed; however, licensure will be required if there is agency jurisdiction. The determining factor is the extent of their advice and the consultant's area of expertise.
It is the consumer's responsibility to verify the credentials (education, technical training, or expertise) of a consultant before accepting such advice.
Consultants in the following categories may or may not be licensed and may or may not charge a fee. Again, the consumer must evaluate the extent of advice because the need for a license may exist (based on some agency requirement) or it may not.
Palm reader or spiritualist: Unlicensed
Fashion consultant (Nordstrom's): Unlicensed
Interior decorating consultant: Unlicensed
Skin care consultant (Mary Kay): Unlicensed if just selling products
Esthetician (skin care--waxing, chemicals): Licensed (Barbering and Cosmetology)
Diet consultant (Jenny Craig): Unlicensed
Diet consultant (health evaluation): Registered nurse (licensed)
Headhunter (business field): Unlicensed or licensed
Employment consulting services: Bonded (see entry for Bonds and filing)
Investment consultant or Advisor: Licensed (California Dept. of Corporations)
Financial planner: if the client funds under management are $25 million or less; the United States Securities and Exchange Commission registers all other investment advisors)
Tax consultant: Licensed by Board of Accountancy or the Internal Revenue Service)
Wine Consultant: Unlicensed