The Mystery of Asymmetrical Hair Growth
Why does one side of your hair seem to grow faster than the other? This perplexing phenomenon is more common than you may think.
Introduction
If you part your hair down the middle, you may notice that one side appears noticeably longer and fuller. Why does hair grow faster on one side than the other? The answer is complicated, but it boils down to natural asymmetry in the body, hair growth cycles, hormonal influences, styling habits, and even sleep positions. Read on to learn why lock lengths can vary.
Natural Asymmetry
Human bodies are not perfectly symmetrical. Subtle differences between the left and right sides are normal. Hands, feet, facial features, and even organ placement may differ slightly. So it follows that hair growth patterns can also be asymmetrical.
In fact, numerous studies reveal hair density and thickness often vary between halves of the scalp. Over time, natural asymmetry can lead to visible differences in length on opposite sides. Genetics, hormone levels, and environmental factors during development contribute to these differences.
Cyclical Hair Growth
Hair growth occurs in repeating phases. During the active “anagen” phase, strands rapidly produce new cells and lengthen. This growth phase lasts 2–7 years before switching to a resting “telogen” phase when strands detach and shed. At any given time, around 85-90% of hair is growing while 10-15% is resting.
When growth cycles become staggered across the scalp, one section may have more follicles in active growth mode than the opposite side. This temporary imbalance results in varying growth speeds, causing observable length differences over time. As rests and growth periods continuously turnover, lengths should even out.
Hormonal Shifts
Hormones like estrogen, testosterone, thyroid, and growth hormone influence hair’s growth rate and longevity. Fluctuations in these levels can alter the hair growth timeline across the body. Changes due to menstrual cycles, pregnancy, menopause, or health conditions lead to deferred shedding, accelerated growth, or increased resting strands depending on the individual.
Varying reactions to hormonal changes on either side of the part may momentarily produce or extend one-sided growth spurts responsible for measurable length differences. As hormone levels stabilize, disparities typically balance out.
Part Lines and Styling
Most people favor one direction when parting and styling their hair. Consistently sweeping strands to the left or right imparts subtle directional forces. Repeated brushing, blow-drying, flat ironing, ponytails and braids gradually train hair on one side to curve differently than the other, influencing how strands clump and cascade beyond the scalp. These effects can create an illusion of increased length.
Sleeping Positions
The way you rest your head at night can also impact hair length over time. Sleeping more often on one side causes sustained pressure against the scalp slowing growth. Meanwhile, the free side remains unencumbered, allowing hairs to lengthen faster. Alternating positions minimizes this disparity.
Tips for Balancing Lopsided Locks
If uneven growth is concerning, try switching styling patterns and part lines frequently to distribute focal pressure points. Adjusting sleep positions regularly also helps. Boost circulation with frequent scalp massages to nourish follicles, and use damage-free ties and tools to minimize breakage.
While bothersome at times, localization hair growth differences are very common and hardly noticeable to others. Embrace asymmetry as normal, or creatively disguise it strategically parted styles. With patience, lengths naturally balance over time through hair’s cyclical shedding and regeneration.
The Takeaway
Uneven lock lengths from disparate hair growth patterns occur frequently but temporarily. Asymmetries arise from natural biochemical differences interacting with cycles, health, habits and time across the scalp. While visible, these fluctuations tend to self-correct and should not cause alarm.