Comparing Standard Platelet-Rich Plasma and Light-Enhanced Platelet-Rich Plasma for Treating Hair Loss in Androgenetic Alopecia: A Randomized Controlled Trial

This study will use written standard operating procedures SOPs to standardize PRP preparation as per MCT System instructions, injection technique, photobiomodulation device operation, and outcome assessment across all participants and all three treatment arms. Following confirmation of eligibility and informed consent, participants will be randomized in a 1:1:1 ratio to one of three parallel arms: standard PRP alone, red-light enhanced PRP with adjunctive cooling, or blue-light enhanced PRP with exosome protocol. Randomization will use a computer-generated block randomization sequence, generated centrally by a study team member independent of recruitment and outcome assessment. Allocation will be concealed using sequentially numbered, sealed, opaque envelopes, opened only after a participant's eligibility has been confirmed and consent obtained, in order to prevent selection bias in group assignment.

PRP will be prepared using a Medical's Cellenis® PRP System (Eclipse). A target volume of 6-10 mL of PRP will be collected per patient. Whole blood will undergo a two-step centrifugation protocol: an initial spin at 1,600 RPM for 10 minutes, followed by a second spin at 3,000 RPM for 10 minutes, with plasma separation completing after approximately 20 minutes total processing time.

Two of the three arms will additionally receive photobiomodulation (PBM), the application of specific wavelengths of light to biological tissue to modulate cellular activity, delivered as a 10-minute treatment cycle with a Metacell Technologies System. Red light (approximately 630-660 nm) has been studied for its capacity to enhance cellular metabolic activity and support tissue repair, while blue light (approximately 400-470 nm) has documented antimicrobial and anti-inflammatory properties relevant to scalp health.

Red-light protocol: Stimulus 1: 620 nm, 1 J/cm², 10 minutes; Stimulus 2: 4°C cooling, 15 minutes.

Blue-light protocol (exosome-based): Stimulus 1: 467 nm, 1 J/cm², 10 minutes; Stimulus 2: 37°C, 10 minutes.

Following treatment, the prepared product will be extracted into a U225 syringe/device and injected into the scalp problem area at a depth of 4 mm.

Participants will attend a total of three PRP treatment sessions, administered at baseline, 1 month, and 2 months. Hair outcomes will be assessed using the TrichoLab spot template and virtual tattoo technique at baseline and at 1, 2, 6, 9, and 12 months following initial baseline.

All source documents (informed consent forms, visit notes, trichoscopy images, adverse event logs) will be maintained at the study site and cross-referenced against data entered into the study database.

Data validation will occur at two levels: (1) at the point of entry, using predefined range and consistency checks (e.g., hair density values within physiologically plausible bounds, visit dates falling within the expected window relative to baseline and treatment schedule), with any flagged discrepancies resolved by the study coordinator before the record is finalized; and (2) periodically, through manual review of a random sample (10-20%) of case report forms against original source documents to confirm accuracy.

Site monitoring will be conducted by the principal investigator at each treatment and follow-up visit to confirm protocol adherence (correct arm assignment per the randomization envelope, correct PRP preparation and injection technique, correct light therapy device settings for the assigned arm). An internal audit of the full dataset will be performed at the midpoint of the study (approximately month 6) and again at study completion, reviewing enrollment records, randomization logs, adverse event reports, and outcome measurements for completeness and consistency. Since this is a single-site pilot trial, monitoring will be internal rather than conducted by an external contract research organization (CRO); if the REB requires third-party oversight, this can be arranged and added to the protocol.

Data entered into the study database will be validated against predefined range and consistency rules specific to this trial. Examples include: hair density and hair diameter values falling within physiologically plausible bounds established from prior trichoscopy literature; visit dates falling within expected windows relative to the baseline date and treatment/follow-up schedule (baseline, 1, 2, 6, 9, 12 months); arm assignment matching the sealed randomization envelope opened for that participant; and adverse event severity codes matching a predefined coding list. Any entry falling outside these rules will be automatically flagged for review by the study coordinator, who will cross-check the flagged value against the original source document before the record is finalized or corrected. Source documents: clinic visit notes, trichoscopic images, standardized photographs, adverse event logs, and signed consent forms will be retained at the study site.

A data dictionary will be maintained listing each variable collected in the study, its source, and its valid range or coding scheme. Key variables include: hair density (hairs/cm², measured via trichoscopy at each visit), hair shaft diameter (µm, measured via trichoscopy), treatment arm assignment (categorical: standard PRP, red-light enhanced PRP, blue-light enhanced PRP), and visit timepoint (categorical: baseline, 1, 2, 6, 9, 12 months).

Written SOPs will govern each stage of the study: participant recruitment and screening (in-clinic discussion and online advertising, followed by eligibility confirmation); informed consent; randomization and allocation concealment (computer-generated block randomization, sealed opaque envelopes); blood draw and PRP preparation using the MetaCell Technologies System; PRP injection technique; photobiomodulation device operation for the red-light and blue-light arms, including cooling application in the red-light arm; trichoscopic imaging and photography protocol; adverse event identification, grading, and reporting; and data entry, storage, and management. SOPs will be reviewed and version-controlled by the principal investigator, with any protocol amendments documented and communicated to all study personnel.

This trial will enroll 30 participants (10 per arm). Given this sample size, the study is designed as a pilot/exploratory trial rather than a definitively powered efficacy trial. Rather than being derived from a formal power calculation targeting a specific minimum clinically important difference, the sample size was selected based on feasibility (single-site recruitment capacity) and the goal of generating preliminary effect size estimates, safety data, and procedural feasibility data (e.g., time per treatment, tolerability of light therapy and cooling) to inform the design and power calculation of a larger, adequately powered follow-up trial.

Participants who miss a scheduled follow-up visit (1, 2, 6, 9, or 12 months) will be contacted and offered a rescheduled visit within a predefined window (e.g., ±2 weeks) to minimize missing data. If a data point remains unavailable, uninterpretable, or is not reported, it will be recorded as missing rather than imputed as zero, carried forward from a prior visit, or otherwise estimated. Primary analyses will be conducted on available cases at each timepoint. If missingness for any variable exceeds 10% of the sample, a sensitivity analysis will be conducted to assess whether missing data materially affects the study conclusions.

Between-group comparisons of the primary and continuous secondary outcomes (hair density, hair diameter) across the three arms will be analyzed using one-way ANOVA at each assessment timepoint. Where the overall ANOVA is significant, post hoc pairwise comparisons (with correction for multiple comparisons) will identify which specific arms differ. Repeated-measures ANOVA will assess within-group change over the 12-month follow-up. Significance threshold: p \< 0.05. Given the modest per-arm sample size, results will be reported alongside effect sizes and interpreted as preliminary/hypothesis-generating.

• Hair Density Terminal and Vellus (N/cm^2) [Time frame: Trichoscopy taken at baseline, 1 month, 2 months, 6 months, 9 months, 12 months]
• Mean Thickness (um) [Time frame: Trichoscopy taken at baseline, 1 month, 2 months, 6 months, 9 months, 12 months]
• Cumulative Hair Thickness (mm/cm^2) [Time frame: Trichoscopy taken at baseline, 1 month, 2 months, 6 months, 9 months, 12 months]