Natural hair is defined as virgin hair, free of chemicals and abuse. In essence, natural hair is hair the way it grows from the scalp before it is altered by chemicals or damaged by mechanical tools, products, mis-handling, etc. The term "natural hair" applies to every hair type: kinky, coily, curly, wavy and straight. Although, you may find that many people only apply the term to those with highly textured hair.
Most of us are familiar with common chemical services such as relaxers, haircoloring, and texturizers. Even though, many people with haircolor still consider themselves as having natural hair. You will have to make a personal decision as to whether or not you are willing to have one of these permanent chemical processes applied to your virgin hair and whether or not you wish to take on any risks associated with them. We each know at least one person with a fierce relaxer, but we also know someone with a horrible one. Best recommendation is to find a Licensed Cosmetologist to perform these critical services, preferably one that can explain some of the risks involved and also knows how to keep the hair at its healthiest state.
In addition to chemical services, there are chemicals that are directly listed in our every day products as well. Some of these chemicals alter the hair and some are just downright toxic to the body (i.e. formaldehyde forming ingredients in smoothing products, formaldehyde releasing DMDM-Hydantoin found in many shampoos and the hormone-disrupting combination of MEA, TEA, DEA). Furthermore, there are chemicals in our everyday products that are just bad for our hair and scalp such as Isopropyl Alcohol, Butane, Propane (all drying alcohols) and Petroleum, Mineral Oil (by products of crude oil). Best recommendation is to conduct your own research and study what you put on your hair and into your body. Find a basic list of good and bad ingredients, check the products you are currently using and then begin to look for and buy less harmful products that give you the results you want. Check out: http://www.naturallycurly.com/curlreading/kinky-hair-type-4a/top-ten-natural-ingredients-for-your-hair/ or http://www.blackhairinformation.com/products-2/top-15-important-ingredients-natural-hair-products/ or http://trialsntresses.com/natural-hair/product-reviews/worst-ingredients-in-natural-hair-products or http://www.healthychild.org/chemicals-to-avoid-in-your-personal-care-products/ and http://naturalhaireverything.tumblr.com/post/3253973196/10-ingredients-to-avoid-putting-on-your-hair.
Abused hair does not feel, look or act like it would if it were healthy. Abuse can come from many causes such as incorrect handling, heat damage, incorrect product usage, tight styling, mechanical tools, etc. It is very rare that I need to advise a client to cut off all of his/her hair because it is entirely damaged from root to tip. However, I have seen many clients that needed several inches of split/damaged ends cut off, repairative treatments for damage to cuticle layer, strengthening treatments for broken and shedding hair, deep conditioning treatments to soften dry damaged hair, loc repairs from rubber bands and improper interlocking, etc. Best recommendations include (not limited to) proper use of healthy products, proper detangling, less manipulation, less heat, higher moisture, and healthy protective styles.
If you have done some research and are still not able to figure out what may work for your hair, you may want to do a consultation with a seasoned professional that can help you navigate your hair journey. A good stylist will not only tell you what is healthy or not so healthy about your hair, but they will also tell you what it will take to change it (if not healthy). Note: bring your current products to the consultation.
In the end, I don't choose to debate the natural versus not natural point with clients. I prefer to work with them where they are and help them move to where ever they need to be to keep their hair as "healthy" as possible. Remember, many of us had previously relaxed, chemically treated and damaged hair before we decided to return to our virgin textures. So, let's be kinder and gentler in our language and treatment of each other as each of our hair journeys may be totally unique.