The Hair Growth Cycle
Healthy hair follows a three-phase cycle: the anagen (growth) phase, lasting three to five years; the catagen (regression) phase, spanning about one month; and the telogen (resting) phase, lasting roughly three months before shedding. In those with hair loss, the anagen phase shortens, leading to thinner, weaker strands.
This cycle aligns with seasonal patterns. Unlike animals, which grow thicker fur for winter, human hair peaks in spring to shield the scalp from intense ultraviolet rays, then diminishes in fall.
Types of Hair Loss
Alopecia, the medical term for hair loss, refers to absent or thinning hair in areas where it typically grows. It is divided into non-scarring alopecia, where follicles remain intact, and scarring alopecia, where follicles are permanently damaged.
Dr. Kwon explains, “Androgenetic alopecia accounts for 85 to 90 percent of cases, encompassing male-pattern and female-pattern baldness.” Driven by genetics, aging, and dihydrotestosterone (DHT), a testosterone derivative, its prevalence rises with global aging trends. Westernized diets high in fats and sugars, extreme dieting, smoking, and obesity worsen hair loss by triggering inflammation in the scalp’s subcutaneous fat layer.
Telogen effluvium, a temporary condition, causes diffuse thinning due to stress, nutritional deficiencies, or hormonal shifts. It’s common postpartum: elevated estrogen during pregnancy prolongs the anagen phase, but a hormonal drop after childbirth triggers shedding, peaking around three months and typically resolving by the child’s first birthday. Persistent cases may suggest underlying female-pattern baldness.
Alopecia areata, an autoimmune disorder, results in patchy baldness, while cicatricial alopecia arises from irreversible follicle damage due to trauma, burns, or infections.
Diagnosing Hair Loss
Early signs include thinning at the crown and frontal hairline compared to the occipital scalp, increased oiliness from enlarged sebaceous glands, and shrinking follicles. Dr. Kwon advises monitoring for greasier hair or smoother brushing, which may signal alopecia’s onset. Daily shedding exceeding 100 hairs or a receding hairline calls for medical evaluation.
Early diagnosis can significantly slow progression and promote regrowth. Clinicians assess scalp health, hair density, thickness, and bald patches. A pull test—gently tugging 50 to 60 hairs to see if more than 10 percent detach—screens for abnormalities. Trichoscopy and digital hair analysis measure density, diameter, and growth rates, while scalp biopsies confirm follicle status.
Treatment Strategies
Androgenetic alopecia, while incurable, responds to treatments that slow progression. Early intervention often involves oral finasteride or dutasteride, which inhibit 5-alpha-reductase, the enzyme producing DHT. Advanced cases benefit from topical minoxidil, which stimulates follicles to re-enter the anagen phase. Combining both approaches maximizes results.
Dr. Kwon notes, “Hair grows about one centimeter per month in the anagen phase, so six months of consistent treatment is needed for noticeable regrowth. Hair loss is a lifelong condition, and stopping medication often leads to relapse. Consulting a dermatologist for appropriate drug selection and dosing is essential.”
In severe cases, autologous hair transplantation—relocating follicles from the DHT-resistant occipital scalp to thinning areas—yields excellent outcomes. Pairing transplantation with ongoing medication preserves existing hair for optimal cosmetic results.
Debunking Hair Loss Myths
1. Shaving babies’ heads boosts hair thickness: False. Shaved hair may appear coarser due to blunt ends, but follicle count and hair caliber remain unchanged.
2. Frequent washing causes hair loss: False. Losing fewer than 100 hairs daily is normal, and regular cleansing supports scalp health. Harsh shampoos or hot water, however, should be avoided.
3. Hats cause baldness: False. Normal hat use is harmless, though tight headwear worn for extended periods may cause scalp irritation or folliculitis.
4. Hair loss skips generations: False. Genetic patterns vary among siblings due to lifestyle differences, not generational skipping.
5. Male baldness is maternally inherited: Partially true. Both parents contribute genetic factors, but male-pattern baldness is linked to X-chromosome genes from the mother.
6. Plucking gray hairs increases graying: False. Plucking doesn’t affect surrounding hair color, but repeated plucking may damage follicles, worsening thinning.
Prevention and Management
Dr. Kwon observes, “Hair loss is a natural part of aging, like wrinkles or declining vision. While it cannot be fully prevented, early detection and diligent management can significantly improve outcomes. Anyone noticing thinning or excessive shedding should seek a dermatologist’s advice promptly.”
He recommends maintaining a healthy weight with regular aerobic exercise to balance hormones, especially in women; adopting antioxidant-rich diets while avoiding processed foods; managing metabolic conditions like diabetes or hyperlipidemia; maintaining consistent sleep schedules to support follicle rhythms; quitting smoking to reduce oxidative stress; and avoiding tight hairstyles or excessive heat styling.
By understanding hair loss and adopting proactive habits, individuals can effectively manage this common condition, preserving both hair and confidence.
Lim Hye Jung, HEALTH IN NEWS TEAM
press@healthinnews.co.kr
