The basic number
On average, scalp hair grows about 0.3 to 0.4 millimeters a day. That adds up to roughly half an inch (about 1.25 centimeters) a month, or around six inches a year. The number comes from studies that measured hair growth in people of different ages and backgrounds.
Half an inch a month sounds slow, but it is steady. If you have a short haircut and want shoulder-length hair, you are looking at about two years of growth. Hair on other parts of the body, like eyebrows and arms, grows more slowly and stops at a shorter length.
The hair growth cycle
Every hair on your head follows a cycle with three main phases. The first is anagen, the growing phase. For scalp hair, anagen lasts two to seven years. That long growing phase is why scalp hair can get so long. About 85 to 90 percent of your hairs are in anagen at any moment.
The second phase is catagen. It lasts two to three weeks. The hair stops growing and the root shrinks. The third phase is telogen, the resting phase, which lasts about three months. At the end of telogen the old hair falls out and a new one starts growing in the same follicle.
Because every hair is on its own schedule, you shed some hair every day. Losing 50 to 100 hairs a day is normal. It only becomes a problem when hairs fall out faster than new ones grow in, or when the growing phase gets shorter and shorter.
What changes your growth speed
Genetics set your baseline. Some people simply have longer anagen phases and faster growth. Age matters too. Growth tends to slow a little after your 30s, and the hairs themselves can get thinner.
Hormones play a big role. In male and female pattern hair loss, a hormone called DHT (dihydrotestosterone) shrinks sensitive follicles over time. Each cycle produces a shorter, finer hair, until the follicle makes almost nothing. Thyroid problems, pregnancy, and menopause can also shift the cycle.
Health and nutrition matter. Low iron, low protein, crash dieting, major illness, surgery, and high stress can push many hairs into the resting phase at once. That causes a wave of shedding two to four months later, called telogen effluvium. The good news is that it usually reverses once the cause is fixed.
Myths about growing hair faster
Cutting your hair does not make it grow faster. Hair grows from the root, and scissors never touch the root. Trims do remove split ends, which can make hair look healthier.
Most "hair growth" shampoos and vitamins have little evidence behind them. Biotin supplements only help if you are actually biotin deficient, which is rare. If your diet is reasonable, extra vitamins will not speed things up.
What actually helps
Two medicines have strong clinical trial evidence for pattern hair loss. Minoxidil extends the growing phase and increases the size of the follicle. It is FDA-approved as a topical foam or liquid, and doctors also prescribe low-dose oral minoxidil off-label. Finasteride is a daily pill that lowers DHT. It is FDA-approved for men with pattern hair loss, and studies show it slows loss and regrows hair in most men who take it.
Both take time. You usually need three to four months before you notice less shedding, and six to twelve months to see real regrowth. They also only work while you keep using them. If you stop, the hair you gained will gradually fall out over the next several months.
Hair loss treatment from Zen IV Spa
If your hair seems to be growing slower or thinner than it used to, a video visit with our medical director can tell you whether pattern hair loss is the cause. Zen IV Spa offers finasteride for $49 a month, oral minoxidil for $59, a topical minoxidil spray for $69, or the full program with all of them for $149. Everything ships to your door in New York and New Jersey. See the options at /hair-loss/, call (332) 239-2005, or book your free visit at https://zenivspa.zenoti.com/webstoreNew/services.
Common Questions
Does hair grow faster in summer?+
Some small studies show slightly faster growth in warm months, but the difference is tiny. You will not notice it.
Why is my hair not growing past a certain length?+
Your anagen phase sets your maximum length. If your growing phase is three years, your hair will reach about 18 inches and then shed. Breakage from heat or chemicals can also make it seem stuck.
Is shedding 100 hairs a day too much?+
No. Up to 100 a day is normal. If you see clumps, a widening part, or a receding hairline, that is worth checking.
Can minoxidil make hair grow faster?+
It mainly keeps hairs in the growing phase longer and makes them thicker. Some people do notice faster growth, but the main effect is more hair rather than quicker hair.
How long does it take for regrowth after a stressful event?+
Shedding from stress usually shows up two to four months after the event and recovers over six to nine months once the stress is gone.
Sources: American Academy of Dermatology on hair growth and shedding; Loussouarn et al., worldwide diversity of hair growth, European Journal of Dermatology 2016; FDA prescribing information for finasteride (Propecia) and minoxidil (Rogaine).
All treatments are medical services. Every guest is screened, and every treatment is prescribed by a licensed provider. Nothing on this page is medical advice for you personally, and the opinions summarized here belong to the doctors named, not to Zen IV Spa. Talk to a provider before starting or stopping anything.
