Anagen Phase: How Long Hair Grows and What Cuts It Short
The anagen phase is the growing stage of a hair follicle, and its length is the single thing that decides how long your hair can ever get. On the scalp it runs roughly two to seven years, with hair growing about 1 cm a month. Someone with a two year growing stage will struggle past shoulder length no matter how well they look after their hair.
Our hair growth shampoo
Grow Me® Hair Growth Shampoo, £14.95. A sulphate free daily shampoo that supports a healthy scalp environment and helps reduce breakage, so lengths hold on and look fuller.
Key takeaways
- Growing stage length is mostly inherited. It sets your maximum length, and no product extends it.
- About 85 to 90 percent of scalp follicles are in this stage at any one time, which is why losing 50 to 100 hairs a day is normal.
- Scalp hair grows around 1 cm a month, so a two year growing stage caps you near 24 cm of length.
- Illness, childbirth, crash dieting and severe stress can push follicles out of growth early, which shows up as a shed two to three months later.
- What you can genuinely influence is how much of the length you keep once it has grown, not how long the follicle grows for.
What is the anagen phase and how long does it last?
The anagen phase is the active growing stage, when cells at the base of the follicle divide rapidly and push a hair fibre upward. On the scalp it lasts about two to seven years in most people. On the eyebrows and body it lasts weeks to a few months, which is exactly why eyebrows stop at a certain length and scalp hair does not.
That difference is the clearest illustration of the whole idea. The hair on your arm and the hair on your head are produced by the same kind of structure using the same machinery. The only meaningful difference is how long each follicle stays switched on. Everything about maximum length follows from that one variable.
Why growing stage length decides maximum length
| Where on the body | Typical growing stage | Practical result |
|---|---|---|
| Scalp | 2 to 7 years | Length of roughly 24 cm to 85 cm before the hair is released |
| Eyebrows and eyelashes | 1 to 6 months | Stops at a few centimetres, then sheds and restarts |
| Arms and legs | 1 to 2 months | Short, fixed length regardless of how long you leave it |
| Beard | Several months to years | Varies widely between individuals, which is why beard potential differs so much |
How does the growing stage fit into the rest of the cycle?
Each follicle moves through three stages on its own schedule. Growth comes first and lasts years. Catagen is a short transition of two to three weeks when the follicle shrinks back. Telogen is a resting stage of roughly three months, after which the old hair is released and a new one begins growing beneath it.
The key point is that follicles are not synchronised. Yours are scattered across all three stages at any given moment, which is why you shed a steady trickle rather than moulting. Around 85 to 90 percent are growing, 1 percent are in transition, and the remaining 10 to 15 percent are resting. That ratio is what makes 50 to 100 shed hairs a day unremarkable.
This page versus the neighbouring ones
This article is about what sets the length of your growing stage and what shortens it. If you want the plain definition and the biology of the stage itself, read the anagen stage page. If you want the whole cycle from start to finish in order, read the hair growth cycle guide. If you are losing hair in clumps during chemotherapy or after a severe illness, that specific pattern is anagen effluvium and has its own page.
What shortens the anagen phase?
Genetics sets the baseline, and a handful of things can cut a cycle short. High fever, major surgery, childbirth, rapid weight loss and severe emotional stress can all push a large batch of follicles out of growth prematurely. Because the resting stage is about three months long, the shed appears two to three months after the event rather than during it.
Iron deficiency and thyroid problems are the two medical causes worth ruling out with a GP if shedding persists beyond six months, because both are common, both are testable and both are correctable. Very low calorie dieting has the same effect through a different route: the body deprioritises hair when energy is short, since hair is not required for survival.
In genetic pattern hair loss the mechanism is different and worth stating separately. There, the growing stage gets progressively shorter with each cycle rather than being cut short once. The follicle produces a finer, shorter hair each time round, which is why the change is gradual over years rather than sudden.
How do you tell which stage your shedding is coming from?
Look at the root end of the shed hairs and at the timing. A hair released at the end of the resting stage has a small, pale, club-shaped bulb at the end. A hair that snapped has no bulb at all, just a blunt or frayed end. Sorting a handful of shed hairs into those two groups tells you a great deal in thirty seconds.
Timing does the rest of the work. A sudden increase in club-ended hairs two to three months after an illness, an operation, a birth or a period of severe stress points to a batch of follicles having left the growing stage together. A slow thinning of the parting over several years, with the shed hairs getting finer, points at a genetic pattern instead. Broken, bulb-less fragments mean the follicle is fine and your routine is the problem.
A thirty second check at the plughole
Collect what comes out in one wash. Bulb at the end and roughly the same thickness as the rest of your hair means a normal release at the end of a cycle. No bulb, uneven lengths, frayed ends means breakage. Thinner than the rest with a bulb, repeated over months, is the pattern worth taking to a GP. If your question is about products or a routine rather than a medical one, you can talk to Gail Waterman, our co-founder, as an AI avatar on the Watermans homepage.
Get a discount on the hair growth range
Join the Watermans mailing list and we will email a discount code straight to your inbox, so you can try the hair growth range for less. Made in the UK, over 6.5 million bottles sold since 2012.
Can you make the growing stage longer?
No cosmetic product extends the growing stage, and any product claiming to should be read sceptically. Length of growth is set by the follicle's own programming, which is inherited. What is genuinely within reach is removing the things that cut cycles short, which means eating enough, getting iron and thyroid checked if shedding persists, and not crash dieting.
This is the honest ceiling on the whole subject. A better routine will not give you a five year growing stage if you have a two year one. It will, however, mean you actually reach the length that two years allows, which most people never do, because the last 20 cm of hair is several years old and has survived every wash, brush, dryer and ponytail in between.
Why does retention matter more than growth rate?
Hair grows at roughly 1 cm a month whatever you do, so the variable you control is how much of it survives. A hair at shoulder length has been through around two years of handling. Every snap along the fibre shortens the visible result, which is why two people with an identical growing stage can end up at very different lengths.
Three different problems get confused here and they need separating. Hair loss is follicular, driven by genetics, hormones or a condition, and the follicle itself is affected. Hair shedding is a cycle event, where more follicles than usual leave the growing stage at once and release their hairs a few months later. Hair breakage is mechanical, where the fibre snaps along its length and the follicle is entirely fine. Only breakage responds to how you wash, dry and style, and it is by far the most common reason people stall at one length.
Loss, shedding and breakage are not the same thing
| Problem | What is actually happening | What helps |
|---|---|---|
| Hair loss | The follicle is producing finer hair or none at all, usually over years | A GP or dermatologist for anything progressive. Cosmetic products cannot alter the follicle. |
| Hair shedding | More follicles than usual left the growing stage together, releasing hairs 2 to 3 months later | Time, plus checking iron and thyroid with a GP if it lasts beyond six months |
| Hair breakage | The fibre snaps along its length; the follicle is unaffected | Less heat, gentler detangling, conditioner every wash, looser styles |
A daily cosmetic shampoo with caffeine, biotin and Baicapil that reduces breakage, so more of the length your growing stage produces actually stays on your head. Vegan and made in the UK.
Condition Me® Hair Growth Conditioner
Smooths the cuticle and cuts the snapping that happens when wet hair is combed. Conditioner on every wash is the single highest-value habit for length retention.
Does diet change how long hair grows for?
Diet cannot lengthen the growing stage, but serious shortfalls can end cycles early. Iron deficiency is the best documented dietary cause of shedding, particularly in women with heavy periods. Severe protein restriction and very low calorie dieting have the same effect. Eating adequately protects the cycle you have; eating extra does not extend it.
Supplements are worth a plain word. If you are deficient in something, correcting the deficiency helps, and a blood test tells you whether you are. If you are not deficient, taking more of it does not push the follicle beyond its programming. Biotin deficiency, the one most heavily marketed, is genuinely rare in people eating a normal diet.
GrowPro® Hair, Skin & Nails Gummies
A hair, skin and nails gummy with biotin, zinc and selenium for people who want to cover the basics alongside their diet. A supplement supports normal hair, it does not change how long a follicle grows for.
For the neighbouring detail, the anagen stage page covers the biology of the growing stage itself, while how hair grows from follicle to fibre walks the full sequence in order. If you are shedding rather than thinning, how long telogen effluvium lasts gives the timeline, and anagen effluvium covers the sudden, clumped loss that happens when growth is interrupted abruptly.
Frequently asked questions
How long is the anagen phase on the scalp?
Roughly two to seven years for most people, which is why maximum length varies so much between individuals. With hair growing about 1 cm a month, a two year growing stage caps length near 24 cm and a six year one allows over 70 cm.
What percentage of hair is growing at once?
About 85 to 90 percent of scalp follicles at any given moment. Around 1 percent are in the short transition stage and the remaining 10 to 15 percent are resting, which is what makes 50 to 100 shed hairs a day normal.
Can stress shorten the growing stage?
Severe stress can push a batch of follicles out of growth early. Because the resting stage lasts about three months, the shedding appears two to three months after the stressful period, which is why the cause is so often missed.
Does cutting your hair affect how fast it grows?
No. Cutting happens at the fibre, metres away from the living part of the follicle under the skin. Trimming does not speed growth, though removing split ends stops splits travelling upward and costing you more length.
Why does my hair stop at the same length every time?
Almost always because your growing stage ends there, because breakage is removing length as fast as you gain it, or both. If your ends look thin and ragged rather than blunt, breakage is the larger part of it.
Does the growing stage get shorter with age?
It tends to, gradually, alongside a slow reduction in the diameter of each hair. In genetic pattern hair loss the shortening is faster and more pronounced in specific areas, typically the temples and crown in men and the parting in women.
Can a follicle restart growing after resting?
Yes, that is the normal cycle. A follicle releases its old hair at the end of the resting stage and begins producing a new one. This is why a temporary shed recovers, while a progressive genetic pattern does not.
Do hair growth supplements extend the growing stage?
There is no good evidence that any supplement lengthens the growing stage in someone who is not deficient. Correcting a genuine deficiency such as iron can stop a shed, which is a different thing from extending the cycle.
What is the bottom line on the anagen phase?
The anagen phase sets your ceiling and you inherited it. Two to seven years of growth at about 1 cm a month is what decides whether your hair can reach your shoulders or your waist, and no shampoo, supplement or serum changes that number. Accepting the ceiling is the starting point for doing anything useful.
What is left is genuinely worth doing. Protect the cycles you have by eating properly and getting persistent shedding investigated, then keep the length you grow by cutting breakage. That is where the difference between two people with the same genetics actually comes from.
If breakage is what keeps costing you length, a hair growth shampoo built around reducing snapping is the sensible place to start the routine.
Watermans products are 100% cosmetic and do not treat medical hair loss. Individual results may vary.
