Part width greater than 5mm correlates with Ludwig stage II classification and is used as an entry criterion in clinical trials for female pattern hair loss (FPHL). This single measurement, tracked monthly with millimeter precision by myhairline.ai, provides an objective, reproducible metric for monitoring FPHL progression and treatment response.
This content is for informational purposes only and does not constitute medical advice.
Why Part Width Is the Key Metric for Female Hair Loss
Male pattern hair loss follows the Norwood scale, which tracks recession at the temples and vertex. Female pattern hair loss is different. FPHL typically presents as diffuse thinning along the central part, with the hairline preserved. The Ludwig scale classifies this as:
| Ludwig Stage | Part Width | Description |
|---|---|---|
| Stage I | 1-3 mm | Barely perceptible thinning along the part |
| Stage II | 3-8 mm | Noticeable widening, scalp visible through hair |
| Stage III | 8+ mm | Significant thinning, large area of visible scalp |
Part width is a direct, measurable indicator of thinning severity. Unlike density counts that require magnification, part width can be measured from a standard overhead photo.
Dermatologists use part width as a clinical endpoint in FPHL research. It is reliable because it has high inter-rater agreement (different observers measure similar values) and is sensitive enough to detect treatment response over 6 to 12 months.
Step 1: Establish Your Baseline Part Width
Take your first measurement before starting or changing any treatment. Consistent photo technique is everything.
Setup requirements:
- Overhead lighting (bathroom ceiling light works well)
- Hair dry and unstyled (no products, no heat styling)
- Part your hair in your natural center part
- Do not use a comb to force a wider or narrower part
Camera position:
- Hold your phone 6 to 8 inches directly above the top of your head
- The camera should point straight down at the part line
- Include the full length of the part from forehead to crown
Timing:
- Same time of day each session
- Same day of the week or month
- After sleeping (natural, undisturbed part)
Take 2 to 3 photos per session and use the clearest one for your myhairline.ai analysis.
Step 2: Understand What Your Baseline Measurement Means
Once myhairline.ai calculates your initial part width, use the clinical reference ranges to contextualize your starting point:
| Part Width (mm) | Clinical Significance | Action Level |
|---|---|---|
| Under 2 mm | Normal density | Monitor annually |
| 2-3 mm | Early Ludwig I | Monitor every 3 months |
| 3-5 mm | Ludwig I to early II | Consider dermatologist consultation |
| 5-8 mm | Ludwig II | Treatment recommended |
| Over 8 mm | Ludwig III | Urgent dermatologist referral |
A single measurement tells you where you are. Monthly tracking tells you whether you are stable, improving, or worsening.
Step 3: Track Monthly for Trend Detection
Take your part width photo on the same schedule each month. The key to reliable tracking is eliminating variables:
- Same lighting setup every time
- Same camera distance and angle
- Same hair state (clean, dry, natural part)
- Same time of day
Over 3 to 6 months, your measurements will reveal a trend. Even sub-millimeter changes become meaningful when tracked consistently.
| Month | Part Width | Trend |
|---|---|---|
| Baseline | 4.2 mm | Starting point |
| Month 1 | 4.3 mm | Stable (within measurement noise) |
| Month 2 | 4.1 mm | Stable |
| Month 3 | 4.5 mm | Possible widening |
| Month 4 | 4.7 mm | Widening trend confirmed |
| Month 5 | 4.8 mm | Consistent widening |
A progressive widening pattern over 3+ months is the signal to consult a dermatologist and discuss treatment options.
Step 4: Using Part Width to Evaluate Treatment Response
If you start treatment (minoxidil 2% or 5% for women produces 40-60% moderate regrowth), your part width data becomes the primary outcome measure. Track for a minimum of 6 months after starting treatment.
Treatment is working if:
- Part width decreases by 1 mm or more over 6 months
- Part width stabilizes after a pre-treatment widening trend
- Visual density along the part line improves in comparison photos
Treatment may not be effective if:
- Part width continues to widen at the same rate as pre-treatment
- No change after 6 to 9 months of consistent treatment use
- Additional thinning appears beyond the part line
For women, treatment options include:
| Treatment | Mechanism | Expected Part Width Effect |
|---|---|---|
| Minoxidil 2% | Follicle stimulation | Narrowing in 40-60% of users |
| Minoxidil 5% | Stronger follicle stimulation | Potentially faster response |
| Spironolactone | Anti-androgen (oral) | Stabilization or narrowing |
| PRP therapy | Growth factor injection ($500-2000/session) | 30-40% density increase |
| Low-level laser | Photobiomodulation | Modest improvement |
Step 5: Take Your Data to Your Dermatologist
A 6 to 12 month part width tracking record is powerful clinical documentation. When you visit your dermatologist, bring:
- Your part width measurements over time
- Before-and-after comparison photos taken under consistent conditions
- Treatment log showing exactly what you used, when you started, and any changes
- Notes on any side effects or observations
This data gives your dermatologist a quantified progression history that is far more useful than "I think my hair is thinner." It allows them to assess treatment response objectively and make data-informed adjustments.
Common Measurement Pitfalls
Parting Too Forcefully
If you comb your part aggressively, you create an artificially wide part. Let your hair fall in its natural center part for consistent measurements.
Inconsistent Lighting
Overhead light makes the part look wider by illuminating the scalp. Side lighting minimizes visible scalp. Use the same lighting direction every session.
Wet Hair vs. Dry Hair
Wet hair clumps together, making the part appear wider. Always measure with dry hair. If you wash your hair on tracking day, wait until it is fully dry.
Changing Part Location
Your natural part should be in the same location each time. If you switch from a center part to a side part between sessions, the measurements are not comparable.
Beyond Part Width: Additional Metrics for FPHL
While part width is the primary metric, your female hair loss tracking guide can include:
- Ponytail circumference: Measured at the base, tracked monthly
- Shedding count: Daily hair fall on pillow or in shower
- Scalp visibility: Scored on a 1-5 scale under consistent lighting
- Part line length: How far back the visible thinning extends
Combining part width with part line photo techniques creates a comprehensive tracking profile.
Start Measuring Today
Capture your first part width reading now. Visit myhairline.ai/analyze to take a standardized overhead photo and establish your baseline measurement. Whether you are monitoring early thinning or evaluating treatment response, objective data is the foundation of informed decisions.
This article is for informational purposes only and does not constitute medical advice. Consult a qualified dermatologist for diagnosis and treatment of female pattern hair loss.