Bleeding & Melasma · Medication Guide
Tranexamic Acid in Thailand
What tranexamic acid is, what it treats for bleeding and for melasma, how well it works, its side effects, and how to get it safely in Bangkok. Reviewed by a licensed physician at a MOPH-registered men's health clinic.
- Skin results in 8–12 weeks
- Prescription medicine · doctor-screened for clot risk
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Medically reviewed by Dr. Noppon Arunkajohnsak (Win)
Menscape Clinic
Last reviewed
11 July 2026
49%
Less melasma severity
vs 18% on placebo, over 3 months
8–12
Weeks to skin results
off-label use, reviewed with your doctor
2009
Oral FDA approval
IV form in use since the 1980s
2 h
Plasma half-life
cleared mainly by the kidneys
Key takeaways
Tranexamic acid is a prescription antifibrinolytic: it slows the breakdown of blood clots, and is used to control or prevent heavy bleeding.
At low oral doses it also treats melasma off-label; in a placebo-controlled trial, melasma severity fell 49% over three months, versus 18% on placebo.
In Thailand it is a dangerous drug (ยาอันตราย) dispensed by pharmacists, and it is widely used for skin whitening, often without the clot-risk screening it needs.
Because it acts on clotting, a personal or family history of blood clots rules it out for some people, so a doctor must screen you before you start.
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What tranexamic acid is & how it works
Tranexamic acid is a prescription medicine known as an antifibrinolytic. In plain terms, it helps blood clots hold together for longer, so it is used to control or prevent heavy bleeding in surgery, dentistry, trauma and heavy periods.
The same medicine has a second, off-label use in dermatology. At low oral doses it treats melasma, the stubborn brown patches that develop on sun-exposed skin. It works because the clotting pathway it blocks also feeds the process that switches on pigment-producing cells, so calming one calms the other.
It is one option, not a cure-all. Whether it suits you, and at what dose, depends on why you want it, your health history and, above all, your risk of blood clots. That is what the doctor's assessment is for.
You bleed, blood clots
Your body builds a fibrin mesh to seal a wound and stop the bleeding.
Plasmin dissolves clots
An enzyme called plasmin normally breaks that mesh down once healing begins.
Tranexamic acid blocks it
It occupies the docking sites on plasminogen, so less plasmin forms and clots hold longer.¹
Less bleeding, less pigment
Bleeding is reduced, and in skin the same blocked pathway calms melasma.³
02
Getting tranexamic acid in Thailand
Thai FDA status
Registered with the Thai FDA and classified as a dangerous drug (ยาอันตราย). Oral 250 mg tablets are sold in Thailand under brands such as Transamine, alongside registered generics.⁶
Doctor-screened at Menscape
Because it acts on clotting, Menscape treats it as prescription-led. A licensed Thai physician reviews your personal and family clot history before it is dispensed by a licensed pharmacy, for pickup or delivery.
The whitening grey market
It is easy to buy over a Thai pharmacy counter, and many take it for whitening with no screening at all. That is the real risk: a hidden clot-risk factor turns a cosmetic choice into a dangerous one. A short check removes that gamble.
Thai FDA guidance. Regulators warn against unsupervised use of whitening and prescription medicines; their safety and effect depend on correct diagnosis and dosing.⁷
03
Does it work? The evidence
Tranexamic acid has decades of use as a bleeding medicine, and a growing evidence base in dermatology. In a randomised, double-blind, placebo-controlled trial of adults with moderate-to-severe melasma, oral tranexamic acid at 250 mg twice daily reduced melasma severity (mMASI) by 49% over three months, compared with 18% on placebo.³ Systematic reviews reach the same conclusion: low-dose oral tranexamic acid meaningfully improves melasma for most patients.⁵
For bleeding, the evidence is larger still. The CRASH-2 trial in over 20,000 trauma patients found that tranexamic acid reduced death from bleeding when given early.⁴ Two things to know before you start for skin: results build over 8–12 weeks and can fade if you stop, and melasma usually needs daily sun protection and topical treatment alongside it. This skin use is off-label, which is exactly why it should be doctor-supervised.
49%
Tranexamic acid
melasma severity (mMASI) down at 3 months
18%
Placebo
same measure, no active treatment
Randomised, double-blind, placebo-controlled trial in adults with moderate-to-severe melasma (Del Rosario et al., 2018). Individual results vary.³
04
Side effects & who shouldn't take it
Common side effects
Nausea, diarrhea, headache and abdominal discomfort are the most common, and are usually mild. Taking the tablet with food can help.¹
Serious but rare
Blood clots, including deep vein thrombosis, pulmonary embolism or stroke, are rare but serious, and are the reason screening matters. Changes in colour vision have also been reported with long-term use; stop and tell your doctor if your vision changes.¹
Not suitable for
Anyone with active or past blood clots, a clotting disorder, a history of stroke or subarachnoid haemorrhage, or an acquired colour-vision defect. The dose is reduced in kidney disease, and it is avoided in severe kidney impairment.¹
Interactions & warnings
Combined hormonal contraceptives and estrogen raise clot risk further. Testosterone therapy, smoking and long-haul flights add to it too. Tell your doctor every medicine and supplement you take.¹
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Alternatives & combinations
Topical · often combined
Depigmenting creams
Hydroquinone, azelaic acid or kojic acid applied to the skin, used with daily sun protection as the first-line approach to melasma and often alongside oral tranexamic acid.
Procedural · specialist
Chemical peels & lasers
Dermatologist procedures for melasma that resists creams. Tranexamic acid can support them, but on its own it does not replace them.
For bleeding · situational
Cause-specific measures
When the goal is bleeding control, the right alternative depends on the source, from local measures to other agents. A doctor matches the treatment to the cause.
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How prescription works at Menscape
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Book your consultation today.
Message us on WhatsApp or LINE
A few minutes on your phone: your goal, health history, current medicines, and any personal or family history of blood clots. It is PDPA-protected.
Doctor consultation
A licensed Thai physician reviews your case by video or in clinic at Asoke, confirms whether tranexamic acid fits your goal, and screens your clot risk.
Prescription, if suitable
If the doctor approves, you receive a prescription and a dose set for your use. The medicine is dispensed by a licensed pharmacy, for pickup or delivery.
Follow-up & monitoring
For melasma, progress is reviewed at 8–12 weeks and the plan adjusted. For bleeding use, follow-up is matched to your situation.
The doctor decides. Starting a conversation is not a commitment and does not guarantee a prescription. If tranexamic acid is not right for you, your doctor will say so and discuss alternatives.
Medically reviewed by
Dr. Noppon Arunkajohnsak (Win)
Menscape Clinic, Bangkok
“Tranexamic acid is a good medicine that is too often taken carelessly for whitening. Because it changes how your blood clots, I always screen a patient's personal and family clot history before it is used for the skin.”
- Reviewed
- 11 July 2026
- Next review
- January 2027
- Editorial standard
- Each guide is checked against the Thai FDA label and the primary literature, then reviewed by a licensed physician.
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Frequently asked questions
Can I buy tranexamic acid over the counter in Thailand?
You can often buy it from a Thai pharmacy, where it is a dangerous drug (ยาอันตราย) dispensed by a pharmacist. But it acts on how your blood clots, so it should be screened by a doctor first, especially for off-label whitening use. Buying it online with no check at all is where people get into trouble.
Does tranexamic acid really help melasma?
Yes, at low oral doses it has solid evidence. In a placebo-controlled trial, melasma severity fell 49% over three months, versus 18% on placebo. It works best alongside daily sun protection and topical treatment, not on its own.
How long does it take to lighten melasma?
Most people see visible improvement over 8–12 weeks, and it is reviewed with your doctor along the way. Pigment can return if you stop the medicine or skip sun protection.
Is it safe? What about blood clots?
For most screened patients it is well tolerated. The main serious risk is blood clots, which is why a doctor checks your personal and family history first. If you have had a DVT, pulmonary embolism or stroke, it is usually not suitable.
Can men take tranexamic acid for melasma?
Yes. Melasma affects men too, especially in sunny climates, and the medicine works the same way regardless of sex. The same clot-risk screening applies before starting.
Can I take it with testosterone therapy?
Tell your doctor if you are on testosterone therapy. It can raise the blood's tendency to clot, so combining it with an antifibrinolytic needs careful review. Sometimes it is fine, sometimes it is not.
What is it used for besides skin?
Its original and best-evidenced use is bleeding control: heavy bleeding, dental procedures, surgery and trauma. The melasma use is a lower-dose, off-label application of the same medicine.
Is a teleconsultation enough, or do I need to visit the clinic?
For melasma, a teleconsultation is usually enough. Your doctor may ask you to come in to the clinic at Asoke if an in-person check is needed, or for bleeding-related use.
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References
1. U.S. FDA. Lysteda (tranexamic acid) prescribing information. Ferring Pharmaceuticals. Accessed July 2026.
2. U.S. FDA. Cyklokapron (tranexamic acid injection) prescribing information. Pfizer. Accessed July 2026.
3. Del Rosario E, et al. Randomized, placebo-controlled, double-blind study of oral tranexamic acid in the treatment of moderate-to-severe melasma. J Am Acad Dermatol. 2018;78(2):363-369.
4. CRASH-2 trial collaborators. Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients (CRASH-2): a randomised, placebo-controlled trial. Lancet. 2010;376(9734):23-32.
5. Bala HR, et al. Oral tranexamic acid for the treatment of melasma: a review. Dermatol Surg. 2018;44(6):814-825.
6. Thai Food and Drug Administration — drug registration database, ndi.fda.moph.go.th. Accessed July 2026.
7. Thai FDA (อย.) consumer warnings on unsupervised use of whitening and prescription medicines, oryor.com. Accessed July 2026.
This guide is educational information, not medical advice. Tranexamic acid is a prescription medicine; its use for melasma is off-label and must be assessed and monitored by a licensed physician.
This guide is part of the Menscape medication library
Book a consultationConsidering tranexamic acid for melasma? Get it screened, not just sold.
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