Synthetic Hair BraidingQ: Does synthetic braiding hair damage your real hair or does it help your hair grow?
A: As with most questions of this type (as well as most questions about hair in general) the answer isn't really a simple one. As for the type of hair used in braiding (and I am assuming you mean synthetic extension hair being braided into the natural hair) synthetic hair is typically no more harmful or beneficial for an individual than quality human hair. Usually, the choice between using human hair and synthetic hair is made based solely on financial considerations.
However, I think you are likely asking whether the braiding process (using synthetic hair) is damaging or helps the hair grow, because you've heard conflicting stories from people saying that they either A) wore their hair braided and when they took it down, their hair was longer and had grown in well, or B) had their hair in braids and had dramatic hair loss as a result.
In this case, the fact is that it really depends on the stylist doing the braiding. A person who has been unhappy with the length of his or her hair, might opt for a braided style with extensions and it allows him or her to get his hair beyond a certain length since a well-performed braid style can be protective for the hair. This is especially true in cases where the hair is being damaged by heat styling and the person is experiencing a lot of breakage and loss in this manner.
However, when improperly done (too tight, uneven tension, etc.) and improperly maintained (not retouched/retightened) the braids can cause hair loss called traction alopecia. You need to always choose a stylist who specializes in braided styles, and speak up when the hair feels as though it's being pulled tight. If the stylist tells you that the tightness will relax in a day or so, remember that the relaxing is probably because the hairs that were being pulled on have come loose.
How to braid hair
Braiding and hair damage