No. Hair extensions should never be bleached or lightened, you should only ever dye or tone extensions to go darker or change tone. Lifting or lightening the hair will cause severe damage to the quality and decrease the life span.
During manufacturing of almost all hair extensions they will go through a bleaching process, especially very light shades. This means 95% of human hair extensions have already been bleached, adding another layer of bleach to the hair could cause the hair to break.
Hair extensions have been removed from their natural roots therefore they are missing all of the natural nutrients and oils from the scalp they need to thrive. For this reason, even thought the hair is human it is weaker and more prone to breakage than hair that is still attached which is why we strongly advise against bleach and lighteners.