The Anagen Stage: How Long Hair Grows and What Shortens It
Your hair only grows for part of its life. This is the part that does the work.
The anagen stage is the active growing phase of the hair cycle, when the follicle is building new fibre at roughly one centimetre a month. On a healthy scalp it lasts between two and seven years and about eight or nine hairs in ten are in it at any moment. Its length is largely inherited, it sets the maximum length your hair can reach, and no cosmetic product has been shown to extend it.
Key takeaways
- Anagen is the growing phase. It lasts two to seven years and covers roughly 85 to 90 per cent of the hairs on a healthy scalp.
- How long it runs is mostly genetic, which is why some people can grow hair to the waist and others plateau at the shoulders however careful they are.
- Hair grows about 1cm a month, or roughly half an inch. That rate is remarkably stable and is not something a product speeds up.
- Things that cut it short: illness, sudden weight loss, iron shortage, childbirth, severe stress, and the inherited sensitivity behind pattern hair loss.
- What care genuinely does is protect the fibre already built, so the length you grow is length you keep.
What is the anagen stage, and how long does it last?
It is the period when cells at the base of the follicle divide rapidly and push keratin upwards into a growing hair. The follicle is anchored deep in the skin, it has an active blood supply, and it is working continuously. Nothing about the process is visible from the outside, which is why the whole cycle is so easy to misunderstand.
Scalp hair stays in this phase for two to seven years, and this is the single biggest difference between scalp hair and body hair. Eyebrow and eyelash follicles run a growing phase measured in weeks, which is why eyebrows never need cutting and the hair on your head does. Length is not a property of the hair, it is a property of how long the follicle was allowed to keep building.
How does the anagen stage differ from catagen and telogen?
The cycle has three named phases and a fourth event that most descriptions leave out. Knowing which one you are looking at is what stops people panicking about normal shedding.
| Phase | What the follicle is doing | How long | Share of scalp hairs |
|---|---|---|---|
| Anagen | Actively building new fibre | 2 to 7 years | About 85 to 90% |
| Catagen | Shutting down, detaching from its blood supply | About 2 to 3 weeks | Roughly 1% |
| Telogen | Resting, hair held in place but no longer growing | About 3 months | Roughly 10 to 15% |
| Exogen | The old hair releases as a new one starts beneath | The shedding event itself | 50 to 100 hairs a day |
Because each follicle runs its own timetable independently, a healthy scalp is a patchwork of all four states at once. That is the reason you do not moult. If the follicles ever synchronised, and after childbirth they partly do, you would shed in one alarming wave.
Why does the anagen stage decide your maximum hair length?
The arithmetic is simple and it explains a lot of frustration. Hair grows at close to 1cm a month, and that rate barely varies between people. So the length you can reach is the growth rate multiplied by how many years the growing phase runs.
Worked example. Three years of growing gives about 36cm, which is roughly shoulder length. Six years gives about 72cm, which is waist length. Same growth rate, same effort, completely different ceiling. If your hair has stopped getting longer and the ends look fine rather than broken, you have probably met your ceiling rather than done something wrong.
There is one important caveat, and it is the more common explanation. Most people who feel their hair will not grow past a certain point are losing length at the ends to breakage as fast as they gain it at the root. That is a fibre problem, not a cycle problem, and unlike the length of your growing phase it is genuinely fixable. Our guide to what hair growth expectations are realistic covers the timescales properly.
What shortens the anagen stage?
Anything that puts the body under sustained pressure can push follicles out of the growing phase early and into telogen. The shedding then shows up two to three months later, which is why the cause is so often missed.
- Illness with a high fever, or surgery. A classic trigger, and one of the most reliable.
- Rapid weight loss or a very restricted diet. The body deprioritises hair long before it deprioritises anything vital.
- Iron shortage. Common in menstruating women and worth a blood test rather than a guess.
- Childbirth. Oestrogen holds follicles in anagen during pregnancy, and the drop afterwards releases them together.
- Severe or prolonged stress. Real, well documented, and usually self limiting once the pressure lifts.
- Thyroid problems. Both an underactive and an overactive thyroid affect the cycle.
- The inherited sensitivity behind pattern hair loss. This one is different: it shortens the growing phase a little more with every cycle rather than once.
That last one deserves separating out, because it is the only entry on the list that is progressive. In pattern hair loss the follicle does not simply pause, it shrinks, and each new cycle is shorter than the one before until the hair produced is too fine to cover anything. Our guide to the stages and causes of pattern hair loss goes into it in detail.
What is the difference between hair loss, shedding and breakage?
These three get used interchangeably and they are not the same thing. Sorting out which one you have is the single most useful thing you can do.
- Hair loss is follicular. The follicle itself is producing less, as in pattern hair loss or alopecia areata. Hairs get finer over years.
- Hair shedding is a cycle event. Normal follicles were pushed out of the growing phase early and released together. Whole hairs, white bulb at the end, heavy fall for a few months, then recovery. See what hair shedding recovery actually looks like.
- Hair breakage is mechanical. The fibre snaps somewhere along its length. Short broken pieces with no bulb, split ends, a halo of frizz around the parting.
Only the third is really a hair care problem, and it is the one where a routine change shows up fastest.
Can anything lengthen the anagen stage?
Not from a bottle, and it is worth being blunt about that because a great deal of marketing rests on implying otherwise. There is no cosmetic ingredient with credible evidence that it extends the growing phase in humans. What the evidence does support is more ordinary: correcting a genuine shortfall, and removing whatever pushed follicles out of anagen in the first place.
- Eat enough, and enough protein. Hair is largely keratin. Very low calorie dieting is one of the most reliable ways to shorten the growing phase.
- Get iron, vitamin D and B12 checked if you are shedding, rather than guessing. Topping up a nutrient you are not short of does nothing. Our honest look at whether hair supplements work sets out where the evidence actually sits.
- Address the trigger. If the cause was a crash diet, illness or a period of severe stress, the follicles usually return to anagen on their own within three to six months.
- Give it time. Because the growing phase is measured in years, nothing about it responds in weeks.
GrowPro® Hair Growth Gummies
Biotin, zinc, silica and the B vitamins, in a sugar free vegan gummy. Worth taking if your diet is genuinely patchy. Not worth taking if your bloods are normal, and we would rather you got the test than bought the tub on spec.
Free hair cycle tracker
A one page tracker for working out where you actually are. A twelve month shedding log with the two to three month lag built in, the wash day hair count that tells you what is normal, the photo method that removes lighting and parting from the comparison, and the four blood tests worth asking about before you spend anything.
What daily care genuinely helps hair built during the anagen stage?
Since you cannot make the growing phase longer, the whole of the controllable side is protecting the fibre it produces. A hair that took four years to grow and snaps off at the shoulder is four years of growing thrown away, and unlike the cycle itself this part responds within weeks.
- Detangle with conditioner in, from the ends upwards. Dry combing from the roots down is where most breakage happens.
- Turn the heat down. Medium rather than maximum, and let hair air dry to about eighty per cent first.
- Take the tension off. Tight styles pull hair out at the root regardless of which phase it is in, and that damage can become permanent. Our guide to the early signs of traction alopecia shows what to watch for.
- Deep condition weekly. The longer a hair has been on your head, the more weathered it is, so the ends of long hair need more help than the roots.
- Protect it overnight. A smoother pillowcase and a loose plait cost nothing and reduce friction.
Masque Me® Hair Mask
A weekly deep conditioner for the mid lengths and ends, where years of accumulated wear actually sits. This is the product on the page most likely to change what you see in the mirror, because retention is the part you control.
Grow Me® Hair Growth Shampoo
A sulfate free everyday cleanser with biotin, caffeine, rosemary and niacinamide. It keeps the scalp comfortable and reduces breakage. It does not lengthen the growing phase, and nothing sold as a cosmetic does.
Frequently Asked Questions
How long is the anagen stage for scalp hair?
Two to seven years for most people, with the average sitting around three to five. Eyebrow and eyelash follicles run a growing phase of only a few weeks, which is why those hairs stay short without ever being trimmed.
What percentage of my hair is in the anagen stage right now?
On a healthy scalp, roughly 85 to 90 per cent. About 10 to 15 per cent is resting in telogen and around 1 per cent is in the short transitional catagen phase. A meaningful drop in that share is what produces visible shedding.
Does cutting my hair make it grow faster?
No. Growth happens at the follicle, below the skin, and scissors never get near it. Regular trims help because they remove split ends before the split travels up the shaft, so you lose less length to breakage. The rate itself does not change.
Can stress really shorten the growing phase?
Yes, and it is one of the better documented triggers. Significant physical or emotional stress can push a batch of follicles out of the growing phase early into telogen, and the shedding appears two to three months later. It usually settles once the trigger passes.
Why has my hair stopped getting longer?
Two likely explanations. Either you have reached the ceiling your growing phase allows, in which case the ends will look healthy and blunt, or you are losing length to breakage as fast as you gain it, in which case the ends look wispy, uneven and split. The second one is fixable.
Does hair grow faster in summer?
Slightly, in some studies, and the effect is small enough that you will never see it. Seasonal shedding in autumn is far more noticeable than any seasonal change in growth rate.
Can a shampoo extend the anagen stage?
There is no credible human evidence that a cosmetic product extends the growing phase, and any product implying it does is making a claim it cannot support. What a good shampoo does is keep the scalp comfortable and reduce breakage, which protects the hair the growing phase has already produced.
How soon after fixing the cause will my hair recover?
Follicles generally re-enter anagen within three to six months of the trigger being removed, then grow at about 1cm a month from there. So expect the shedding to stop first, short new hairs along the parting next, and visible density last, usually at nine to twelve months.
The Bottom Line
The anagen stage is the growing phase of the hair cycle, it runs for two to seven years, and its length is mostly written into your genes. That sets a ceiling on how long your hair can get, and no product on any shelf raises it. What you can control is everything after the hair leaves the follicle: how much of it survives brushing, heat, tension and time. Protect the fibre you have already grown, get the underlying triggers checked if you are shedding, and judge any change over months rather than weeks.
Watermans products are 100% cosmetic and do not treat medical hair loss. Individual results may vary. Watermans is a UK made, vegan and cruelty free brand, with over 5 million bottles sold since 2012.
Sources & References
- NHS, Hair loss, on normal shedding and when to seek advice.
- British Association of Dermatologists, information leaflets on telogen effluvium and androgenetic alopecia.
- Paus R and Cotsarelis G, The biology of hair follicles, New England Journal of Medicine, 1999. The standard reference for cycle phases and their durations.
- Milner Y et al., work describing exogen as a distinct shedding event separate from telogen, Journal of Investigative Dermatology.
- Guo EL and Katta R, Diet and hair loss, Dermatology Practical and Conceptual, 2017, on nutrient shortfalls and the hair cycle.
- NICE Clinical Knowledge Summaries, guidance on investigating iron deficiency and thyroid function.
