Keep in mind that baking soda has a very high pH, which opens the hair cuticle and makes it more susceptible to damage. According to Denniston, “Apple cider vinegar will help seal the hair cuticle to defrizz hair and give it shine,” Apple cider vinegar can be found in most grocery stores. “[It] will also rebalance the scalp’s pH after using baking soda, helping the scalp stay moisturized and protected.”