How long does my existing hair need to be for Mark Glenn hair extensions?
For the best results, your existing hair should be at least 4 inches (about 10 cm) long all over.
If you're unsure, a good test is to hold up a few strands of hair from the centre of the crown of your head and pull them down across the side of your head - if they reach the top of your ear, you're in the right ballpark.
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