Recommended Diluent for Tranexamic Acid in Melasma Microneedling
Use normal saline to dilute tranexamic acid to a 4 mg/mL concentration for intradermal injections in melasma treatment. 1
Preparation Protocol
The American Academy of Dermatology specifically recommends preparing tranexamic acid solution by diluting with normal saline (not sterile water) to achieve a 4 mg/mL concentration when using the intradermal injection technique. 1 This guidance is further supported by the FDA labeling, which states that tranexamic acid injection may be mixed with electrolyte solutions (which includes normal saline) for infusion. 2
Why Normal Saline Over Sterile Water
- Normal saline is explicitly compatible with tranexamic acid according to FDA labeling, which lists electrolyte solutions as appropriate diluents. 2
- The FDA label specifically warns that tranexamic acid "should NOT be mixed with solutions containing penicillin" but does not contraindicate saline. 2
- Sterile water is not mentioned as a recommended diluent in either the guideline recommendations or FDA labeling for tranexamic acid preparation. 1, 2
Specific Dosing Parameters for Melasma Microneedling
- Prepare a 4 mg/mL solution using normal saline as the diluent. 1
- Administer 0.05 mL intradermal injections spaced 1 cm apart throughout melasma-affected areas. 1
- Maximum total dose is 8-16 mg per treatment session to minimize systemic absorption and thrombotic risk. 1
- Treatment frequency should be monthly sessions for 3-5 treatments. 1
Important Preparation Caveats
- The diluted mixture may be stored for up to 4 hours at room temperature prior to patient administration according to FDA guidelines. 2
- Inspect visually for particulate matter and discoloration prior to administration. 2
- Discard any unused portion after the treatment session. 2
- Do not mix tranexamic acid with blood or penicillin-containing solutions. 2
Alternative Consideration: Topical Application
While the question asks about dilution for injection, it's worth noting that topical application of 4% tranexamic acid immediately after microneedling achieves comparable efficacy with less invasiveness than intradermal injections. 1 Research demonstrates that topical 10% tranexamic acid with microneedling produces 65.92% improvement in mMASI scores. 3 However, when intradermal injection is chosen, normal saline remains the appropriate diluent at the 4 mg/mL concentration. 1