Using your regular shampoo and conditioner regimen, wash your hair as you normally would. Rinse your hair clean of shampoo and conditioner. Choose a time when you will not be exercising or creating a lot of extra sweat in your hair, which can alter your results. Using a hair dryer might change the way your hair reacts in a certain amount of time, so using a towel and air to dry your hair is the best method. Choose regular thread instead of a thicker thread intended for sewing heavy-duty fabrics. Try to get the full strand, rather than having it break in the middle. You want to see how thick your hair is, so choose a strand of hair that is most representative of your entire head of hair. The crown of your head is the best area to get the strand from.  Your hair should be dry, and have no styling products in it. It is best to leave styling products out of your hair while you’re testing it to get the most authentic results. Use a sheet of white paper to help you clearly see the hair strand and the thread so that you can compare them more easily. Take a close look at your hair, such as by using a magnifying glass or magnifying mirror. If it is really curly, stretch it out a bit before you compare it to the thread. It might help to tape down the strand and thread ends so they stay put.   Thin hair: If the hair strand’s thickness is thinner than the thread piece, you have thin hair.  Medium hair: If your hair strand is about the same thickness as the thread, you have medium hair texture.  Thick hair: If the hair strand is thicker than the piece of thread, you have thick hair.

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Write a summary of the previous text in Vietnamese:
Gội đầu. Để tóc khô tự nhiên. Cắt một sợi chỉ may dài khoảng 15-20 cm. Nhổ một sợi tóc. Đặt sợi tóc cạnh sợi chỉ trên giấy trắng. So sánh sợi tóc với sợi chỉ.