Hair growth rates go through several shifts during a person’s lifetime. There are key periods where hair grows rapidly, and times when growth slows down. Understanding the stages of hair growth can help you care for your hair properly at each age.
Hair Growth in Babies
Hair growth begins while babies are still in the womb. Fine, downy hair called lanugo covers the skin by week 28 of pregnancy. After birth, lanugo hair is shed and replaced by vellus hair, which are short, fine hairs.
At birth, babies have all of their hair follicles formed. There are about 5 million follicles on their scalp. However, only a small percentage of follicles are active and growing hair at this stage.
During the first 6 months, up to 85% of the hairs on a baby’s scalp are in the growth phase (anagen) at one time. This results in very rapid hair growth rates in infants. The anagen phase for each hair is relatively short, lasting around 3 months. But because so many hairs are growing simultaneously, babies need frequent haircuts!
Toddler and Childhood Hair Growth
Hair growth rates slow down after infancy but remain faster than adult rates until puberty. Toddlers add around 6 inches per year to their hair length. For children aged 3 to 5 years, growth rates average 3 to 5 inches per year.
The biggest factor regulating hair growth at this age is nutrition. Diets adequate in protein, vitamins, and minerals support faster hair growth.
Average Hair Growth Rates in Children
| Age | Average Growth Rate |
|---|---|
| 0 to 1 year | 14 inches per year |
| 1 to 2 years | 6 inches per year |
| 3 to 5 years | 3 to 5 inches per year |
Puberty and Hair Growth
During puberty, hair growth patterns change in response to hormonal shifts. Puberty typically begins between ages 8 to 14 in girls and ages 9 to 15 in boys.
In both genders, pubic and underarm hair appears as rising levels of androgens prompt vellus hairs to transition into terminal hairs. Pubic and underarm hair grow faster and thicker than vellus hair on the rest of the body.
For adolescent males, facial hair begins to develop. Hair also begins growing on the arms, legs, chest, and back. The speed and amount of hair growth varies significantly among individuals based on genetics, hormones, and hair follicle sensitivity.
Pubic and Underarm Hair Growth
During puberty, hair growth rates increase in the pubic and underarm regions. This is related to activation of hair follicles by androgens.
| Stage of Puberty | Pubic/Underarm Hair Growth Rate |
|---|---|
| Prepuberty | No growth |
| Early puberty | Up to 1/2 inch per month |
| Mid to late puberty | Up to 1 inch per month |
Hair Growth Rates in Adults
Hair growth rates reach their peak during puberty and normally slow down as adults. However, growth rates vary significantly among individuals. Hair grows faster in young adults compared to seniors.
For most adults, scalp hair grows an average of 1/2 inch per month. This equates to about 6 inches of growth per year. However, some people’s hair may grow more slowly or rapidly.
Factors like nutrition, stress, illness, medications, and hormones impact hair growth. Pregnancy often accelerates hair growth due to increased estrogen.
Average Hair Growth Rates by Age
| Age Range | Scalp Hair Growth Rate |
|---|---|
| 20s to 30s | 6 to 12 inches per year |
| 40s to 50s | 5 to 10 inches per year |
| 60s and up | 3 to 7 inches per year |
Hair Growth Cycle Changes with Age
Hair growth rates slow down as we age partially because the anagen (growth) phase of the hair cycle becomes shorter. The other phases, catagen and telogen, become longer.
Each strand of hair on the scalp grows independently and goes through the phases of the hair cycle at different times. So while some hairs are growing quickly, others may be resting.
In young adults, up to 90% of hair follicles on the scalp are in anagen at a time. For seniors, only around 50% of scalp hairs are in the active growth phase.
Length of Hair Cycle Phases by Age
| Hair Cycle Phase | Length in Young Adults | Length in Seniors |
|---|---|---|
| Anagen (growth) | 2 to 7 years | 2 to 3 years |
| Catagen (transition) | 2 to 3 weeks | 4 to 6 weeks |
| Telogen (resting) | Around 3 months | 6 to 12 months |
Lifestyle Factors that Impact Hair Growth
Even though hair growth naturally slows with age, there are ways to help maximize your hair growth potential at any age:
Nutrition
Getting sufficient protein, vitamins, minerals, and healthy fats promotes faster hair growth. Important nutrients include vitamins A, C, D, B complex, iron, zinc, selenium, and omega-3s.
Scalp Massages
Gently massaging the scalp increases circulation and stimulates blood flow to hair follicles, which provides more nutrients for growth. One small study found scalp massages could boost hair thickness after 24 weeks.
Stress Management
High stress levels raise cortisol and other hormones that can reduce hair growth and even lead to excessive shedding. Managing stress through meditation, yoga, counseling, or other methods helps create the best environment for your hair to grow.
Hair Products and Styling
Use gentle hair care practices without excessive heat, tight styles, chemical processing, or damage from harsh cleansers. Avoid harsh treatments that traumatize the scalp and impair follicle function.
Medical Causes of Hair Growth Changes
In some cases, an underlying health condition affects hair growth patterns. Causes for abnormal hair growth include:
- Hormonal imbalances – thyroid disorders, menopause, PCOS
- Nutritional deficiencies – low protein, iron, zinc
- Autoimmune disorders – alopecia areata
- Skin conditions – fungal infections, psoriasis
- Medications – cancer treatment, beta-blockers
- Aging and genetics
See a dermatologist if you are experiencing sudden hair loss or growth changes to identify and treat any underlying causes.
Conclusion
Understanding natural hair growth patterns during each life stage can help you set reasonable expectations. While growth rates slow with age, proper hair care and nutrition maximizes the potential for healthy hair growth across the lifespan.