Most dermatologists prescribe oral tranexamic acid for melasma in courses of three to six months. Three months is the minimum needed to see meaningful results, and six months is the upper limit supported by current evidence and expert consensus. The optimal duration hasn’t been firmly established, but clinical trials consistently fall within that window.
The Standard Treatment Course
The typical oral dose used in studies is 250 mg taken twice daily, though some protocols go up to 500 mg twice daily. At these doses, treatment courses in clinical trials have ranged from 8 weeks to 6 months, with most lasting 3 months. An expert consensus statement from Indian dermatologists, who treat melasma at high volume, recommends a minimum of three months and a maximum of six months per course.
In one trial of 74 patients taking 250 mg twice daily for six months, 94.6% showed improvement within the first one to two months, and nearly 96% achieved fair to excellent results by the end of the six-month course. Across multiple trials, melasma severity scores dropped by 49% to 95% depending on the study. So while you may notice lightening early, the full benefit builds over time.
When You’ll Start Seeing Results
Most people notice their melasma beginning to lighten within the first two months. In a large retrospective study of over 500 patients who responded to treatment, improvement was visible within two months of starting. That said, the changes continue to accumulate through month three and beyond, which is why stopping too early can leave results on the table.
If you’ve been taking it for three months with no visible change at all, that’s a reasonable point to reassess with your prescriber whether continuing makes sense or whether a different approach is needed.
What Happens After You Stop
Melasma is a chronic condition, and pigmentation can return after stopping treatment. In one study of 503 patients who improved on tranexamic acid, the relapse rate was 27.2%. That means roughly one in four people saw their melasma come back to some degree after discontinuing the medication.
This is one reason some dermatologists use tranexamic acid in repeated courses rather than a single round. After completing a three- to six-month course, you might stop for a period and then restart if pigmentation returns. The research doesn’t yet define a standardized maintenance protocol, so decisions about repeat courses are typically made on a case-by-case basis. Consistent sunscreen use after stopping is critical, since UV exposure is the single biggest trigger for melasma recurrence.
Why Six Months Is the Usual Upper Limit
Tranexamic acid works by blocking a process called plasmin activation, which in melasma triggers pigment-producing cells to darken the skin. It was originally developed to control heavy bleeding, and it reduces the body’s ability to break down blood clots. At the low doses used for melasma (far below what’s used for bleeding disorders), the clotting risk appears small. Across multiple trials totaling hundreds of patients, no major blood clot events have been reported at melasma-level doses.
Still, the six-month ceiling exists as a precaution. The longer you take any medication that affects clotting pathways, the more theoretical risk accumulates. Most side effects reported in studies were mild: stomach upset, headache, and occasional changes in menstrual flow. These typically resolve on their own or after stopping the medication.
Who Should Not Take It
Oral tranexamic acid is not appropriate for everyone. You should avoid it if you have:
- A history of blood clots in the veins or arteries, or active clotting disease
- Current use of hormonal birth control, which independently raises clot risk
- Current anticoagulant therapy
- Severe kidney problems, since the drug is cleared through the kidneys
- Pregnancy or breastfeeding
- Defective color vision, because changes in color perception can be a side effect and would be harder to detect
The overlap between melasma triggers and these contraindications is worth noting. Hormonal birth control and pregnancy are two of the most common causes of melasma, yet both rule out oral tranexamic acid. For these patients, topical formulations or other treatments are safer options.
Topical vs. Oral Forms
Tranexamic acid also comes in topical formulations, including creams and serums, often at concentrations of 2% to 5%. These carry essentially no systemic clotting risk because very little of the drug enters the bloodstream through the skin. Topical versions can be used for longer periods with fewer safety concerns, though they tend to produce more modest results than the oral form. Some dermatologists combine both routes, or pair oral tranexamic acid with other topical treatments like hydroquinone or vitamin C for a more aggressive approach during the three- to six-month window.
If you’re looking at over-the-counter serums containing tranexamic acid, these are the topical form and are generally considered safe for ongoing use. They work best as part of a broader regimen that includes daily broad-spectrum sunscreen, which remains the foundation of any melasma management plan.