Hair and toenails are both made of keratin and go through a growth cycle. However, there are differences between hair growth and toenail growth. Toenails tend to grow slower than hair. On average, hair grows about 1.25 cm per month, while toenails only grow about 1 mm per month. Despite the slower growth rate, toenails require more time to regenerate completely than hair. The entire growth cycle for toenails is 12-18 months, while the hair growth cycle is shorter at 2-7 years.
Hair Growth Rate
Human hair grows at a rate of about 1.25 cm per month on average. This amounts to about 15 cm per year. However, hair growth rates can vary significantly depending on factors like age, health, genetics, and diet.
Hair goes through three distinct phases during the growth cycle:
- Anagen phase – active hair growth
- Catagen phase – transitional phase marking the end of active growth
- Telogen phase – resting phase before hair sheds
The anagen phase lasts about 2-7 years. This is when active hair growth occurs and accounts for about 85-90% of the hair growth cycle. Hair grows about 1 cm every 28 days during this phase.
The catagen phase is much shorter, lasting only about 2-3 weeks. This signals the end of active hair growth.
Finally, the telogen phase is a resting period that lasts about 2-3 months. At the end of the telogen phase, the hair falls out and a new one begins growing in the follicle beginning the cycle again.
On the scalp, about 85-90% of hair follicles are in the anagen phase while only about 10-15% are in the telogen phase at any given time. This ensures minimal shedding and continuous hair growth.
Factors like hormonal changes, stress, pregnancy, certain medications, and nutritional deficiencies can disrupt the normal hair growth cycle and cause temporary hair loss or reduced growth rates.
Average Growth Rates by Age
Hair growth rates can vary at different life stages:
- Newborns – about 1 inch per month
- 1-2 years old – about 6 inches per year
- Young adults – 0.5 inch per month
- Adults – 0.4 inch per month
- Elderly – 0.1 inch per month
Hair grows fastest in the first few years of life, slows through adulthood, and continues decelerating with age.
Genetics also plays a key role in determining individual hair growth rates. Some people naturally have faster hair growth than others. Hair texture and type can also impact growth rates. For example, straight hair may grow faster than curly hair in some cases.
Under optimal conditions with a healthy scalp and diet, maximum hair growth can reach up to 1.3 cm per month. But on average, expect hair to grow about 15 cm or 6 inches per year. Proper nutrition and limiting damage from harsh hair treatments helps maintain optimal growth.
Toenail Growth Rate
While hair on the scalp grows rapidly, toenails have a much slower growth rate. Human toenails typically grow about 1 mm per month. This amounts to about 1 cm every 10-12 months.
Just like hair, toenails go through distinct phases of growth:
- Anagen – active growth phase (4-6 months)
- Catagen – transitional phase (2-3 weeks)
- Telogen – resting phase (3-4 months)
The entire toenail growth cycle from start to finish is about 12-18 months long.
During the anagen phase, or active growth phase, new nail cells generate in the nail matrix located at the base of the nail behind the cuticle. The nail plate grows forward as new cells push out old ones. This phase lasts about 4-6 months in toenails.
In the catagen transitional phase, growth stops and the nail prepares to detach from the nail matrix.
Finally, the telogen or resting phase is when the nail plate becomes loose and sheds from the nail bed. This stage lasts about 3-4 months for toenails before a new nail starts growing.
Toenail growth rate averages just under 1 mm per month. But this can vary based on health factors like nutrition, medications, chronic diseases, and age. Fungal infections, injuries, and nail trauma can also impact the growth rate.
Average Growth Rates by Age
Just like hair, toenail growth rate slows down with age:
- Newborns – 0.5 mm per week
- Children – 0.5-1.2 mm per week
- Young adults – 1-1.2 mm per week
- Adults over 60 – 0.5 mm per week
Toenails grow fastest in youth and slow as you get older. In the elderly population, nail growth may happen at only half the rate of younger adults. Poor circulation and nutrition can contribute to slower nail growth in seniors.
Comparing Hair and Toenail Growth
Now that we’ve examined growth rates, how do hair and toenail development compare?
Speed
Hair grows significantly faster than toenails.
– Hair – About 1.25 cm per month
– Toenails – About 1 mm per month
Over a year, hair may grow 15 cm while toenails will only reach 1 cm of growth.
Growth Cycles
While toenails have a longer growth cycle at 12-18 months, the active growth phase is much shorter compared to hair.
Most hair follicles spend 2-7 years in the active anagen phase. But toenails only actively grow for about 4-6 months before transitioning to the resting phase.
Hair also has a higher percentage of follicles in the anagen phase at 85-90% compared to toenails which have fewer than 50% of nails growing at a time.
Age Differences
Both hair and toenails grow fastest in youth and have declining growth rates as you age. However, the peak growth for toenails happens earlier in childhood while hair reaches maximum growth rates after puberty.
Toenails may grow slightly faster than scalp hair in the first year after birth. But after early childhood, hair takes off and continues growing rapidly through the teen years when toenail growth has already started slowing.
Regrowth Time
If you shave your head, hair will regrow back in full length after about 2-7 years. But if you lose a toenail, it takes about 12-18 months to regenerate the entire nail.
So while toenails have a slower growth rate overall, a brand new toenail requires more time to rebuild than hair.
What Impacts Growth Rates?
Let’s examine the key internal and external factors that affect hair and toenail growth.
Age
As discussed, both hair and toenails grow fastest in youth. Growth slows down with advancing age as cell regeneration declines.
Health and Nutrition
Good circulation and nutrition are essential for optimal hair and nail growth. Anemia, thyroid disorders, diabetes, deficiencies in vitamins and minerals can all impact growth rates. Adequate protein intake is particularly important.
Medications
Certain prescription drugs like beta blockers, retinoids, NSAIDs, and chemotherapeutic agents can temporarily alter hair/nail growth. Growth usually rebounds after stopping medications.
Genetics
Genes influence hair color, texture, thickness, and growth cycles. The hereditary makeup you inherit affects growth rates.
Pregnancy
Hormonal changes during pregnancy can cause faster hair growth. But some women experience postpartum hair loss after giving birth as hormones shift again.
Damage
Physical trauma, harsh products, and damage from chemical processing can impact growth cycles and rates for both hair and nails.
Disease
Certain medical conditions that interfere with nutrition absorption like Crohn’s disease can reduce growth. Autoimmune disorders may also contribute to hair loss.
Stress
Stress triggers can prematurely shift hair into the shedding phase, resulting in thinning and reduced growth. Cortisol imbalance from chronic stress affects hair.
Tips for Healthy Hair and Nail Growth
While growth rates are determined mostly by internal controls, you can help optimize healthy hair and nail growth.
Eat a Nutritious Diet
Make sure to get sufficient protein, iron, zinc, vitamins A, C, D, and B complex. Consider a supplement if diet is inadequate.
Take Biotin
Some research suggests biotin supplements may thicken hair and nails, although more studies are needed.
Avoid Damage
Use gentle hair products, avoid harsh chemicals/processing, and handle hair gently when wet. Avoid nail damage by wearing gloves for hand protection.
Stimulate Blood Circulation
Scalp massages may boost circulation. Apply cuticle oil to nails. Soak nails in warm water.
Stay Hydrated
Drink plenty of water to support cell growth and healthy blood flow.
Manage Stress
Chronic stress takes a toll on hair growth and may worsen hair loss. Try relaxation techniques like meditation.
Allow Time Between Nail Trims
To allow nails to reach full length, wait 2-3 months between trims. Trim damaged ends only when needed.
Talk to Your Doctor
If you notice a dramatic change in growth rate or excessive shedding, see your doctor to check for underlying causes. Medication adjustments or treatment may help.
The Bottom Line
While both hair and toenails are made of keratin, hair grows significantly faster at an average rate of 1.25 cm per month compared to just 1 mm per month for nails.
Hair also has a longer active growth phase lasting years while toenails only actively grow for months at a time. Both growth rates slow down with age.
To maximize healthy growth of hair and nails:
– Eat a nutritious diet adequate in protein, vitamins, and minerals
– Stimulate blood flow through massage, warm water soaks, oils
– Avoid damage from harsh treatments and trauma
– Address excessive shedding or growth changes with your doctor
With proper care, you can help support optimal hair and nail growth through all the cycles and phases. But remember that hair will always grow quicker than your toenails!
