Melasma is a common, acquired disorder of hyperpigmentation affecting millions of people worldwide. It causes tremendous impact on the self esteem and quality of life of the affected people, especially females. While various topical agents have so far been the mainstay of treatment of melasma, they are plagued by side effects as well relapse and recurrences omce they are stopped. Oral tranexemic acid (TXA) is the latest tool in the armamentarium of melasma treatment. It has so far been used in various forms including oral, topical and injectable with variable but promising results. However, the dosing of TXA in melasma has been a cause of persistent speculation and this puzzle is what our study aims to shed some light on. Doses of TXA used for melasma in studies to date have ranged from 500 to 1,500mg daily.⁴⁵ A typical dose is 250 mg twice daily. Treatment is usually continued for 8 to 12 weeks.⁴⁵ This is in contrast to menorrhagia for which the dose is 3.9 to 4 g daily for up to 5 days per month.³⁴ However, there is still no consensus to guide the dose and duration of therapy. There is also not much clarity on the risk of relapse after stopping oral TXA and if maintenance treatment is required and if so, if the duration of maintenance regimen differes with different dosages of TXA. Studies have documented safe useof TXA for menorrhagia over the years with only minor side effects like nasal and sinus discomfort, back pain, musculoskeletal pain, oligomenorrhea, and abdominal cramps, with no evidence of ocular toxicity.^{22, 34, 35} Hence, at the dosages currently employed  and based on available data, it seems unlikely that TXA would increase risk of thrombotic complications, more so in the indications for which it is used in dermatology.

The present study is designed as a randomized, open label study in which 50 patients suffering from moderate to severe melasma according to the mMASI scores will be recruited and be divided into two arms to receive oral tranexemic acid at a dose of 250 mg twice a day or 500 mg twice a day for 12 weeks along with a sunscreen of SPF 30+.  The primary objective is to evaluate and compare the efficacy of the two different dosing regimens of TXA, that is, 250 mg twice daily versus 500 mg twice daily, using the mMASI score. The proportion of patients achieving mMASI 75 will be used as the proxy measure to assess the efficacy. The secondary aims will include assessing the MELASQOL score of the patients at baseline and the end of treatment to have an objective analysis of the impairment of quality of life caused by melasma, apart from noting any adverse effects, if any.