Lemon juice
The idea behind using lemon juice is almost the same as using apple cider vinegar because the citric acid in lemon juice helps in fading away from the dark pigmentations on the skin due to melasma. You can use a dilute solution of lemon juice in water and rub it on the dark patches of skin to lighten the skin. Try to rest the diluted solution on your skin until it becomes dry and penetrates efficiently. Moreover, the use of lemon juice in diluted solutions is very effective for normal skin growth too.
Lemon juice acts as a bleaching agent and lightens the dark patches on the surface of the skin, thus reducing the dark areas. Although lemon juice is very brightening for the skin, it is important to understand that the lemon juice might pose some side effects on your skin, especially on your face. Lemon juice might cause irritation and inflammation, which ultimately worsens the skin condition for melasma patients. Hence there are not enough scientific studies to back the brightening effects of lemon juice, but the effectiveness of this remedy depends on either it suits you or not.