Ever feel like your hair just won’t grow past a certain point, no matter how well you care for it? The reality is, hair growth is a complex biological process—governed by your genes, your health, and how you treat your scalp. While some people experience steady, visible growth, others may hit frustrating plateaus due to a range of underlying factors.
Hair grows in a predictable cycle, but even small disruptions in that cycle can lead to slower growth, shorter strands, or more frequent shedding. Fortunately, science gives us a clear roadmap for understanding what’s happening at the root level—and what you can do to support stronger, longer growth over time.
How the Hair Growth Cycle Works—and What Disrupts It
Your hair isn’t just sitting still—it’s moving through a carefully orchestrated three-phase cycle that determines how long, thick, and fast it grows. On average, hair grows about half an inch per month, but genetics and other factors can influence the rate.
Here’s how the growth cycle works:
- Anagen (Growth Phase):
This is the marathon phase—lasting two to six years, depending on your genetics. More than 80% of your hair is in anagen at any time. The longer this phase lasts, the longer your hair can grow. - Catagen (Transition Phase):
A short, two-week window when the follicle starts to shrink and prepares to rest. - Telogen (Resting/Shedding Phase):
This phase lasts two to four months. Hair stops growing and eventually falls out to make room for a new strand.
Why does this matter?
If your anagen phase is shorter due to genetics or environmental stressors, your hair may stop growing sooner—and appear "stuck" at a certain length.
The Role of Genetics in Hair Growth: Can DNA Limit Hair Length?
Just like height or eye color, your genes play a major role in determining how fast and long your hair grows. Studies show that genetic variants in certain growth-factor genes can affect how each phase of your hair cycle is regulated—especially the anagen phase, which determines hair length and speed.
Some people are born with a naturally shorter anagen phase, which caps the maximum length your hair can reach. Others may have genetic factors that slow the rate of follicle activity or cause early transitions to the telogen (rest) phase. In both cases, hair may grow more slowly, or seem to stall out entirely.
Translation:
If long, fast-growing hair doesn’t come naturally to you, your DNA might be partly responsible. But that doesn’t mean you’re stuck—there are still ways to help your hair reach its full potential.
Recommendations for Hair Growth Deficiency, Based on Risk
We’ve sorted our science-backed tips into low, medium, and high-risk categories based on Happy Head’s StrandIQ™ analysis, so you can take action based on your unique biology.
Hair Growth Support Strategies for People with Low Risk
If you’re genetically low-risk for slow hair growth, simple tweaks to your routine can help keep hair strong and healthy:
- Eat for your hair
Protein, iron, and vitamin C are essential building blocks for hair structure and scalp circulation. - Avoid overwashing
Shampooing too often can strip away natural oils that protect and nourish your strands. - Snip split ends
Trimming doesn’t make hair grow faster—but it does prevent breakage, helping you retain length over time.
Medium-Risk Options: Trimming, Supplements & Scalp Care Tips
If your StrandIQ analysis indicates medium risk—or you’ve hit a growth plateau—consider upgrading your routine:
- Trim regularly
Take off about ¼ inch every six to eight weeks to keep ends healthy and prevent damage from traveling upward. - Shampoo less, condition more
Shampoo only when needed, but don’t skip conditioner—it locks in moisture and reduces breakage. - Fuel your follicles
Eat a diet rich in iron, protein, and vitamin C. Consider adding hair-support supplements with biotin, collagen, or zinc. - Avoid frequent chemical processing
Dyeing and straightening can erode the outer layer of your hair, weakening its structure and growth potential.
High-Risk or Clinical-Level Hair Growth Interventions
If your hair growth has noticeably stalled—or if you’re seeing ongoing shedding despite your best efforts—it may be time to look beyond the basics. High-risk cases often involve genetic or systemic causes that require deeper support. That doesn’t mean you’re out of options, but it does mean precision care matters more than ever.
Here’s where to focus:
- Talk to a dermatologist
Persistent hair growth issues could be linked to hormonal imbalances, autoimmune conditions, or follicular miniaturization. A specialist can help diagnose what's happening beneath the surface using scalp biopsies, blood work, or advanced imaging. - Ask about prescription growth stimulants
Topical minoxidil and oral finasteride or dutasteride (for men) are FDA-approved for hair loss—but in high-risk cases, dermatologists may recommend compounded formulas, combination treatments, or newer therapies such as topical clascoterone or oral spironolactone (especially for women). - Test for underlying nutritional and hormonal imbalances
If you’ve already improved your diet and supplements but still aren’t seeing results, lab testing can help pinpoint hidden deficiencies (e.g., vitamin D, ferritin, zinc) or thyroid or androgen imbalances that may be slowing growth. - Focus on follicular protection
At this stage, it’s essential to minimize cumulative trauma. Use silk or satin pillowcases, avoid heat styling, and opt for loose, protective hairstyles. For textured or tightly curled hair, tension-free styles and regular hydration can make a major difference in preserving fragile new growth.
The Bottom Line: Personalized Solutions for Better Hair Growth
Hair that grows slowly—or not at all—can feel discouraging. But with the right strategy, you can work with your biology, not against it. Whether you’re just trying to maintain healthy strands or overcome a stubborn plateau, your growth cycle can be supported with science-backed habits, smart styling, and targeted treatments.
At Happy Head, we’re here to help you take the guesswork out of hair care. By understanding your unique genetic profile through tools like StrandIQ, you can create a custom routine that matches your growth potential—and helps your hair thrive long-term.
References
StrandIQ SNP Marker Count: 10
StrandIQ Genes for Trait:
B9D2, EGF, HELLPAR, IGF1, LINC02456, LTA, TGFB1, TMEM91, TNF, VEGFA
References:
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This content, including StrandIQ™ DNA analysis reports and any Happy Head products and/or services referenced therein, is for informational and cosmetic purposes only. It is not intended to diagnose, treat, cure, or prevent any disease. This content does not constitute medical advice and should not be used to make healthcare decisions. References to prescription treatments are educational in nature. Always consult a licensed healthcare professional for any medical concerns or treatment decisions.
