Natural bodybuilding is a bodybuilding movement with various competitions that take place for bodybuilders who abstain from performance-enhancing drugs. This categorically excludes the use of substances like anabolic steroids, insulin, diuretics and human growth hormone. If a bodybuilder meets the requirements of the sanctioning body (the recognized group or authority that sanctions and validates competitions) that they are competing in, then they are considered to be "natural". There are numerous sanctioning bodies who provide their own rules and regulations that govern the competition procedures, event qualifications, banned substance lists, and drug testing methods. Doping detection methods include urinalysis and polygraph testing, and federations typically conduct these tests on the day of competition, or shortly before. Out-of-season testing, although less common, may also be used. Each organization will specify within its rules the length of time that its athletes should be drug-free, which may vary from testing clean on the day of the event, to being drug-free for a number of years, right up to a lifetime natural requirement.
Since natural bodybuilders avoid using steroids and other performance-enhancing drugs, they seek to optimize their training, diet and rest regimes to maximize natural anabolic hormone production, thereby accelerating recovery and increasing hypertrophy and strength. Certain legal supplements may also be used to aid recovery and promote muscle growth, although diligence is needed as some over-the-counter products contain ingredients that are banned by natural bodybuilding organizations.
- OCB - Organization of Competition Bodies www.ocbonline.com
- INBA - International Natural Bodybuilding Association
- NANBF - North American Natural Bodybuilding Federations 
- IPE - International Pro Elite