All the cheap hair have been chemically and mechanically processed. Before being sold on the market and this is not only in London. Most of the suppliers collect the raw hair from donors and pack it in bulks. Those bulks are then “improved” to look like natural virgin Remy.
Most of this processed hair have been passed through the skimming machine. This process removes the cuticle and makes the hair thinner. It was bleached in strong chemicals and dyed to the desired colour. Is this right or wrong for your Extensions? There is not a simple answer to this question. If the client wants to buy a cheap and knows the hair will serve just a couple of week, why not?
The problems come when the customer pay few hundred pounds for extensions. But those get tangled, faded and look awful after just a few shampoos.
Here is why the Russian Hair is the best in the world. A professionally fitted set of Russian Hair could last for more than one year with a proper After Care. The maintenance must be done every three or four months. If the extensions are looked after, they will serve several refittings. They will still look gorgeous for longtime.