Make sure the hair has no chemicals left in it. If it is true virgin hair, it should have no chemicals at all. You can do a sniff test to see if you can pick up any odors from a perm or relaxing. Another method is to apply a dime sized amount of neutralizing shampoo and massage into the hair. If it turns pink, it means the hair has been chemically treated.
100% virgin hair should have cuticles. If it does not, the cuticles have been stripped, usually with an acid bath. You can check for cuticles by running your finger down the length of the hair. The hair should feel smooth going down, but you should experience some resistance as you move your hand up the shaft.
Take a match or lighter and light the ends of the hair. Human hair should burn with white smoke and turn to ash. Synthetic hair will burn with black smoke and have a sticky texture.
The “too-perfect” check:
Virgin hair is taken straight from the scalp of donors and should have some irregularities in it. If the hair seems “too perfect” then it probably is.
Tip: Sample the hair first. Order a sample-size hair from the virgin hair company and perform the above tests on it. If the company is not forthcoming with their product, then it makes sense to wonder if they have something to hide.