The Fascinating Journey of Hair Growth
Have you ever wondered why your hair grows to a certain length and then seems to stop? Or why some hairs fall out while others continue growing? The answer lies in understanding the hair growth cycle—a fascinating biological process that affects everything from your hair’s thickness and length to its overall health.
At Head Spa Toronto, we believe that knowledge is power. Understanding your hair’s natural growth cycle allows you to make informed decisions about treatments and care routines that truly support your hair’s health at every stage.
The Four Phases of Hair Growth
Hair doesn’t simply grow continuously until you cut it. Instead, each follicle on your scalp operates independently, cycling through four distinct phases:
1. Anagen (Growth Phase)
The anagen phase is where all the magic happens. During this active growth period:
- Hair cells divide rapidly at the root
- New hair forms and pushes up through the scalp
- The hair grows approximately 1 cm per month
- This phase lasts between 2-7 years for scalp hair
- At any given time, about 85-90% of your hair is in this phase
The length of your anagen phase is primarily determined by genetics, which explains why some people can grow their hair much longer than others. Research from the Canadian Dermatology Association shows that the average person’s anagen phase allows hair to grow to about 12-36 inches before moving to the next phase.
Interestingly, other body hair has a much shorter anagen phase—just a few months—which is why your eyebrows don’t grow to the length of your scalp hair.
2. Catagen (Transition Phase)
Following the growth phase, hair enters a brief transitional period:
- This phase lasts approximately 2-3 weeks
- The hair follicle shrinks and detaches from the dermal papilla
- Blood supply to the hair is cut off
- The hair is no longer growing but remains in place
- About 1-2% of your hair is in this phase at any time
The catagen phase serves as a regression period, where the lower portion of the hair follicle is destroyed. According to research published in the Journal of Investigative Dermatology, this controlled destruction and reformation process is crucial for maintaining healthy hair growth cycles.
3. Telogen (Resting Phase)
After the transition period, the follicle enters a resting state:
- This phase lasts about 3-4 months
- The follicle remains dormant
- The old hair (now called a “club hair”) remains attached
- No new growth occurs
- Approximately 10-15% of scalp hairs are in telogen at any time
During telogen, the club hair is completely formed with a hard, dry, white nodule at the root end. While it’s no longer growing, it’s not ready to fall out yet. The American Academy of Dermatology notes that this resting period is essential for follicle renewal and preparation for new growth.
4. Exogen (Shedding Phase)
The final phase involves the actual shedding of the hair:
- Old club hairs are released from the follicle
- This typically involves losing 50-100 hairs per day
- New hair begins to grow in the follicle
- The cycle returns to the anagen phase
Many sources only mention three phases, grouping exogen with telogen. However, recent research from the International Society of Hair Restoration Surgery recognizes exogen as its own distinct phase, as the mechanisms controlling shedding appear to operate independently from those that control resting.
The Science Behind Hair Growth Cycle Duration
Several factors influence how long your hair remains in each phase:
Genetic Factors
Your genetic makeup plays the most significant role in determining your hair growth cycle lengths, particularly how long your hair stays in the anagen phase. Research from Genetics Home Reference indicates that variations in over 200 genes can influence hair growth patterns.
Age-Related Changes
As we age, our hair growth cycles naturally shift:
- Anagen phases gradually shorten
- More follicles remain in telogen
- The result is thinner, shorter maximum hair length
- Growth rate typically slows
By age 50, many people experience anagen phases that are 25% shorter than in their youth, according to studies from Health Canada.
Hormonal Influences
Hormones significantly impact hair growth cycles:
- Thyroid hormones regulate the duration of the anagen phase
- Sex hormones (estrogens, androgens) influence follicle sensitivity
- Stress hormones can prematurely push hair into catagen
- Pregnancy often extends the anagen phase temporarily
The Canadian Medical Association Journal has published extensive research on how hormonal fluctuations throughout life—from puberty to pregnancy to menopause—create noticeable changes in hair growth patterns.
Health and Nutritional Status
Your overall health and nutritional status directly impact your hair cycles:
- Protein deficiency can shorten the anagen phase
- Iron and zinc deficiencies affect hair synthesis
- Vitamin D levels influence follicle cycling
- Biotin supports keratin infrastructure
Research from the Journal of Clinical and Aesthetic Dermatology demonstrates that nutritional interventions can meaningfully extend anagen phase duration in individuals with deficiency-related hair issues.
Understanding Daily Hair Loss
Many clients at Head Spa Toronto express concern about finding hair in their brush or shower drain. Understanding the growth cycle helps explain why this is completely normal.
With approximately 100,000-150,000 hairs on the average scalp and 10-15% in telogen phase at any time, the natural daily loss of 50-100 hairs represents just a tiny fraction of your total hair. This normal shedding makes room for new, healthy growth.
However, when the percentage of hairs in telogen increases significantly—a condition called telogen effluvium—you may notice excessive shedding. This often occurs 2-3 months after a triggering event like:
- Major psychological stress
- Surgery or illness
- Significant weight loss
- Childbirth
- Medication changes
The good news is that telogen effluvium is typically temporary, with hair cycles returning to normal within 6-9 months in most cases.
Seasonal Hair Growth Patterns
Interestingly, research from the University of British Columbia shows that humans, like other mammals, experience subtle seasonal shifts in their hair growth cycles. Studies indicate:
- Hair growth is fastest during late spring and summer
- Hair loss increases during fall months (typically October/November)
- Winter shows the slowest growth rates
- These patterns are more pronounced in northern climates like Canada
These seasonal variations likely evolved as adaptations to changing environmental conditions and remain programmed in our biology despite modern indoor living.
Hair Growth Cycles and Treatment Timing
Understanding your hair’s growth cycle allows for strategic timing of treatments for maximum effectiveness:
Treatments Most Effective During Anagen
- Hair coloring and perming show best results
- Growth-stimulating treatments have maximum impact
- Laser therapy shows optimal effectiveness
- Nutrition interventions yield noticeable results
Treatments Focused on Catagen/Telogen
- Scalp detoxification helps prepare for new growth
- Anti-inflammatory treatments reduce premature catagen entry
- Stress-reduction therapies help regulate cycle timing
- Specialized care prevents excessive shedding
At Head Spa Toronto, we design treatment protocols that consider your hair’s cycle status for optimal results.
How We Analyze Your Growth Cycle
During your consultation at Head Spa Toronto, our specialists use advanced diagnostic techniques to assess your unique growth cycle patterns:
- Microscopic Analysis: Using specialized equipment to examine your hair at the follicular level
- Growth Phase Assessment: Determining what percentage of your hair is in each phase
- Density Measurement: Calculating the number of active follicles per square centimeter
- Growth Rate Monitoring: Measuring how quickly your hair grows during anagen
- Shedding Evaluation: Assessing whether your daily hair loss falls within normal ranges
This comprehensive approach allows us to develop personalized treatment plans that work with your natural cycles rather than against them.
Optimizing Your Hair Growth Cycle
While you can’t fundamentally change your genetically-determined growth cycle, you can optimize each phase with proper care:
Supporting the Anagen Phase
- Ensure adequate protein intake (minimum 0.8g per kg of body weight daily)
- Maintain optimal iron levels (consider testing if you suspect deficiency)
- Use gentle haircare products that don’t damage the cuticle
- Minimize heat styling and chemical treatments
- Consider supplements with biotin, zinc, and vitamins D and E
Preventing Premature Catagen Entry
- Manage stress through regular exercise and mindfulness practices
- Avoid harsh styling practices that cause follicle inflammation
- Maintain balanced hormones through regular health check-ups
- Protect hair from environmental damage (UV, pollution, extreme temperatures)
- Consider scalp treatments that reduce inflammatory cytokines
Supporting Healthy Telogen and Exogen
- Use gentle, sulfate-free shampoos that don’t strip the scalp
- Brush hair with wide-tooth combs to prevent pulling club hairs prematurely
- Maintain proper scalp hydration with appropriate moisturizing treatments
- Consider scalp exfoliation to clear pathways for new growth
- Manage seasonal shedding with appropriate supportive treatments
Professional Treatments for Each Cycle Phase
At Head Spa Toronto, we offer specialized treatments designed for each phase:
Anagen-Optimizing Treatments
- Growth Factor Therapy: Specialized serums containing peptides that support follicle function
- Scalp Microcirculation Enhancement: Techniques that increase nutrient delivery to growing hairs
- Biomimetic Treatments: Products that mimic the scalp’s natural biological environment
Catagen-Regulating Treatments
- Anti-Inflammatory Protocols: Reducing factors that trigger premature transition
- Stress-Response Modulation: Treatments that help normalize cortisol’s effects on hair cycles
- Follicle-Protecting Formulations: Specialized products that support follicle integrity during transition
Telogen/Exogen Support
- Gentle Exfoliation: Removing barriers to emerging new growth
- Microbiome Balancing: Creating an optimal environment for new anagen hairs
- Seasonal Adjustment Protocols: Treatments that address changing needs throughout the year
Conclusion: A Cycle-Conscious Approach to Hair Care
Understanding your hair’s natural growth cycle transforms how you approach hair care. Rather than focusing solely on the visible hair, this knowledge allows you to care for the complex biological system that creates it.
At Head Spa Toronto, our cycle-conscious approach has helped countless clients achieve healthier, more beautiful hair by working in harmony with nature’s timetable rather than against it.
Whether you’re concerned about thinning, excessive shedding, or simply want to optimize your hair’s natural potential, understanding your growth cycle is the first step toward effective solutions. Book a consultation today and discover how our cycle-specific treatments can transform your hair health from the inside out.