Understanding the Hair Growth Cycle: Why Do We Lose Hair?
To understand the causes of hair loss, we first need to understand the normal hair growth cycle. Every strand of hair goes through three phases:
Anagen (Growth Phase): Lasts 2-6 years, during which the hair grows continuously. Normally, about 85-90% of hair is in the anagen phase.
Catagen (Transition Phase): Lasts 2-3 weeks, the hair follicle begins to shrink, and hair growth stops.
Telogen (Resting Phase): Lasts 3-4 months, the hair falls out naturally, and new hair begins to grow. Normally, about 10-15% of hair is in the telogen phase.
The essence of hair loss is a disruption of this cycle: either the anagen phase is shortened (hair falls out before reaching normal length), too many hairs enter the telogen phase simultaneously (massive shedding), or the hair follicles shrink and cannot grow new hair.
Different causes of hair loss affect this cycle in different ways, so treatment plans also vary.
Top 10 Common Causes of Hair Loss Explained
Here are the most common causes of hair loss in Hong Kong, ranked by frequency of occurrence:
| Rank | Cause of Hair Loss | Affected Group | Reversibility |
|---|---|---|---|
| 1 | Androgenetic Alopecia (AGA) | Both men and women | Controllable but hard to fully reverse |
| 2 | Stress-Induced Hair Loss | High-stress workers | Reversible |
| 3 | Nutritional Deficiency Hair Loss | Dieters, picky eaters | Reversible |
| 4 | Postpartum Hair Loss | Postpartum women | Self-recovering |
| 5 | Thyroid Issues | Mainly women | Reversible after treatment |
| 6 | Iron Deficiency Anemia | Mainly women | Reversible after iron supplementation |
| 7 | Medication Side Effects | People taking medication | Reversible after stopping medication |
| 8 | Alopecia Areata | Anyone | Mostly self-recovering |
| 9 | Traction Alopecia | People who often wear tight hairstyles | Reversible in early stages |
| 10 | Scalp Diseases | People with scalp issues | Improves after treatment |
Important Reminder: Hair loss is often not caused by a single factor, but rather a combination of multiple factors. For example, a person might have a genetic predisposition + high work stress + lack of sleep, all three working together to accelerate hair loss. Therefore, a comprehensive scalp analysis and lifestyle assessment are very important.
Specific Causes and Solutions for Female Hair Loss
The causes of female hair loss are more complex and diverse than those in men. Here are the specific factors for female hair loss:
Hormonal Changes
- Postpartum Hair Loss: Elevated estrogen levels during pregnancy prolong the hair's growth phase. The sudden drop in estrogen after childbirth causes a large amount of hair to enter the resting phase simultaneously. It is usually most severe 3-6 months postpartum and recovers on its own within 12 months.
- Menopausal Hair Loss: A decrease in estrogen leads to a relative increase in androgens, causing a hair loss pattern similar to men.
- Polycystic Ovary Syndrome (PCOS): High androgen levels lead to hair loss, often accompanied by irregular periods and acne.
Nutritional Factors
- Iron Deficiency: Women lose iron monthly due to menstruation, and combined with an unbalanced diet, they are prone to iron deficiency. Serum ferritin below 40ng/mL can affect hair growth.
- Extreme Dieting: Rapid weight loss (more than 4kg per month) can lead to protein and nutritional deficiencies, causing massive hair loss.
- Vitamin D Deficiency: Women in Hong Kong commonly lack Vitamin D, which affects hair follicle health.
Lifestyle
- Long-term tight ponytails or buns (Traction Alopecia)
- Frequent dyeing, perming, and use of high-heat styling tools
- Long-term use of silicone-containing hair products that clog follicles
Recommended Solutions:
- Regular blood tests to check iron, thyroid function, and hormone levels
- Balanced diet, ensuring adequate intake of protein and iron
- Reduce physical and chemical damage to hair
- Seek professional scalp care to specifically improve the scalp environment
Self-Assessment Methods for Hair Loss Causes
Before seeking professional help, you can preliminarily determine your hair loss type through the following methods:
Pull Test
Pinch about 60 hairs with your thumb and index finger and gently pull outward. If more than 6 hairs (10%) fall out, you may have an active hair loss problem.
Observe Hair Loss Pattern
- Frontal and crown thinning → Likely androgenetic alopecia
- Overall even thinning → Likely nutritional or stress-induced
- Circular bald patches → Likely alopecia areata
- Specific areas (e.g., hairline) → Likely traction alopecia
Check the Hair Roots
- White bulb at the root → Normal telogen shedding
- Root is black or broken → Likely hair damage and breakage
- Root is shrunken and thin → Likely follicle miniaturization
Record the Timeline
- Sudden massive shedding (stress event 2-3 months ago) → Stress-induced
- Gradual worsening (months to years) → Androgenetic alopecia
- Seasonal worsening → Likely normal seasonal shedding
When to Seek Professional Assessment: If you are still unsure of the cause after self-assessment, or if hair loss persists for more than 3 months without improvement, a professional scalp analysis is recommended. Canvas Academy offers free scalp analysis services, using a 200x microscope to observe the state of your hair follicles and help you accurately determine the cause of your hair loss.
Treatment Plans for Different Hair Loss Causes
Different causes of hair loss require different treatment strategies:
Androgenetic Alopecia
- Topical Minoxidil 5%
- Oral Finasteride (requires doctor's prescription, for men)
- Low-Level Laser Therapy (LLLT)
- PRP Injections (Platelet-Rich Plasma)
- Professional scalp care to improve the scalp environment
Stress-Induced Hair Loss
- Stress management (meditation, exercise, adequate sleep)
- Nutritional supplements (iron, zinc, biotin)
- Scalp massage to promote blood circulation
- Usually recovers on its own in 6-12 months
Nutritional Hair Loss
- Balanced diet, increase protein intake
- Supplement deficient nutrients (confirmed by blood test)
- Avoid extreme dieting
- Combine with scalp care to accelerate recovery
Postpartum Hair Loss
- Usually requires no special treatment, recovers within 12 months
- Can supplement iron and biotin to accelerate recovery
- Avoid excessive anxiety (anxiety worsens hair loss)
- Gentle scalp care to aid recovery
Hair Loss Caused by Scalp Diseases
- Treat the scalp disease first (seborrheic dermatitis, folliculitis, etc.)
- Professional deep scalp cleansing
- Improve the scalp microenvironment
- Proceed with anti-hair loss care after the scalp is healthy
Key Principle: The earlier the treatment, the better the results. Hair follicle miniaturization is a gradual process; once completely dead, they cannot regenerate. It is recommended to seek professional help within 3 months of noticing hair loss problems.
