Hair straightening is safe for health only when it does not contain formaldehyde in its composition, such as a progressive brush without formaldehyde, laser hair straightening or hair lift, for example. Anvisa classifies these straighteners as ethical and do not contain formaldehyde, which can cause long-term burns, hair loss, and even cancer. Read also::https://carebeautyco.com/benefits-of-mud-therapy-for-body-face-and-hair/ Thus, all hair straighteners that contain other substances such as ammonium thioglycolate, thioglycolic acid, carbocysteine, guanidine hydroxide, potassium hydroxide, acetic acid or lactic acid instead of formaldehyde are safe and can be used for straightening hair. However, this type of treatment should be carried out by professional…