Where on the scalp should platelet‑rich plasma (PRP) be injected one month after hair transplantation?

PRP Injection Location One Month After Hair Transplant

At one month post-transplant, inject PRP across the entire transplanted recipient area of the scalp using a point-by-point technique, covering all mapped areas where grafts were placed. 1

Target Areas for Injection

• Inject throughout the entire recipient zone where follicular units were transplanted, not just isolated spots 2, 1
• Map out all areas that received grafts during the transplant procedure before beginning injections 2, 3
• Mark the treatment zones clearly on the scalp prior to injection to ensure complete coverage 2, 3

Precise Injection Technique

Use a systematic point-by-point approach with the following parameters:

• Insert the needle at a 90-degree angle perpendicular to the scalp surface 2, 1, 3
• Inject to a depth of 2-4 mm (full bevel of the needle) into the dermis 2, 1, 3
• Space each injection point 1 cm apart in a grid pattern across the entire recipient area 2, 1, 3
• Use 30-gauge × 4 mm needles to minimize patient discomfort 2, 1, 3

Volume and Distribution

• Deliver a total of 5-7 mL of PRP per session 2, 1, 3
• Use 0.05 to 0.1 mL per cm² as the dosing guideline 2, 3
• Distribute the PRP evenly across all transplanted zones rather than concentrating in one area 2

Pre-Injection Preparation

• Have the patient shampoo and detangle hair before the session with no styling products applied 2, 3
• Comb through the treatment area before marking injection sites 2
• Apply pharmaceutical-grade topical numbing cream as PRP injections are associated with significant pain 3, 4
• Position the patient optimally so the entire scalp can be accessed from all angles 2

Critical Context for Month 1 Timing

This second injection at month 1 is part of the standard three-session post-transplant protocol: injection at time of transplant (month 0), month 1, and month 3, followed by maintenance every 6 months 1. The month 1 injection specifically helps:

• Reduce catagen loss of transplanted hair during the critical early phase 5
• Accelerate recovery of the recipient area skin 5
• Activate dormant follicles in the transplanted zone 5
• Support the transition of transplanted follicles from telogen to anagen phase 4

Technical Pitfalls to Avoid

• Do not activate the PRP before injection—nonactivated PRP shows 31% greater increases in hair count and density 1
• Do not skip areas within the recipient zone; incomplete coverage reduces efficacy 2
• Do not inject too superficially—the 2-4 mm depth is essential for reaching dermal papilla cells 2, 3
• Ensure PRP is prepared using a manual double-spin method targeting 1.0-1.5 million platelets per microliter 1, 3, 4

Combination Therapy Considerations

• Continue topical minoxidil 5% (1 mL twice daily) throughout the post-transplant period for optimal outcomes 1
• Maintain finasteride if started pre-transplant, as the triple combination (PRP + minoxidil + finasteride) represents the most effective approach 1