Learn how the hair growth cycle works and what affects hair health, shedding, and growth, from genetics to lifestyle factors.
Hair growth is something most of us take for granted – until it starts behaving differently. Each strand on your head actually follows its own structured cycle of growth, transition, and rest before it sheds and a new hair takes its place. Getting to grips with how this works can shed light on why hair grows at different rates, why shedding happens, and what might be influencing the condition of your hair at any given time.
Hair follicles depend on nutrients delivered through the bloodstream to do their job properly. Some people choose to take hair growth pills alongside a balanced diet as a way of supporting their nutritional intake – though supplements are really just one piece of a much bigger picture. Genetics, hormones, lifestyle habits and the natural rhythm of the hair growth cycle all have a part to play.
What You'll Discover:
The three stages of the hair growth cycle
Hair grows in a repeating pattern made up of three main stages. Crucially, each strand operates on its own schedule – which is precisely why we don’t lose all our hair at once.
1. Anagen: the growth phase
This is where the action happens. During the anagen phase, cells in the hair follicle divide rapidly, pushing the strand upwards through the scalp. It can last anywhere from two to seven years, and that range matters – the longer a follicle stays in this phase, the longer the hair can ultimately grow.
It’s why some people can grow hair down to their waist whilst others find theirs seems to plateau at a certain length. Around 85-90% of the hairs on your scalp are in the anagen phase at any one time, with the root firmly anchored and drawing nutrients from the bloodstream.
2. Catagen: the transition phase
Once active growth ends, the hair moves into the catagen phase – a brief transitional window lasting roughly two to three weeks. The follicle shrinks, detaches from its blood supply, and the hair stops growing. It doesn’t shed just yet, though; it simply sits in place whilst the follicle prepares for what comes next.
Because catagen is so short, only a small fraction of follicles are in this stage at any given moment.
3. Telogen: the resting and shedding phase
The telogen phase is the resting stage. The follicle goes quiet, the hair stays put without any further growth, and after a few months, it eventually sheds as a new strand starts forming beneath it. This is entirely normal. Most people lose somewhere between 50 and 100 hairs a day – a figure that sounds alarming until you understand it’s just the cycle doing what it’s supposed to do.
Because hairs are all at different stages, shedding is gradual rather than sudden.
Factors that influence how hair grows
The cycle itself is the same for everyone, but several things can affect how quickly hair grows, how thick it looks, and how much of it ends up on your hairbrush.
Genetics
Your genes are arguably the biggest factor. They influence hair texture, thickness, colour, and – perhaps most importantly – how long your anagen phase lasts. If long hair runs in your family, there’s a good chance your growth phase is on the longer side. If your hair seems to stop at a certain length regardless of what you do, genetics is likely playing a role there too.
Hormonal changes
Hormonal shifts can throw the hair cycle off balance. Pregnancy, menopause, and certain medical conditions can all influence how follicles behave – sometimes shortening the growth phase or nudging more hairs into the shedding stage simultaneously. These changes are often temporary, but not always.
Stress
Significant stress – whether physical or emotional – can push hair follicles into the resting phase all at once. This is known as telogen effluvium, and it tends to show up as increased shedding a few months after the stressful event, rather than immediately. For most people, things return to normal once the underlying cause resolves.
Age
Hair naturally changes as we get older. The growth cycle can slow down, follicles may produce finer strands, and the anagen phase may shorten over time. These are normal changes, though the degree to which they happen varies considerably from person to person.
The role of nutrition in hair health
Hair follicles are among the most metabolically active cells in the body, which means they need a reliable supply of nutrients to function well. Several vitamins, minerals, and proteins are particularly relevant here:
- Protein – provides the building blocks for keratin
- Iron – helps carry oxygen to cells
- Zinc – supports tissue growth and repair
- Biotin and other B vitamins – involved in energy metabolism
- Vitamin D – plays a role in various cellular processes
A varied diet with plenty of eggs, legumes, leafy greens, nuts, seeds, whole grains, and fish can go a long way towards covering these bases. When the body is short on nutrients, it tends to prioritise vital organs, meaning hair follicles can miss out – which may contribute to changes in thickness or increased shedding over time.
Hair care habits and scalp health
Beyond what’s happening internally, how you treat your hair from the outside matters too. You won’t change your growth cycle by switching shampoos, but good habits can reduce breakage and keep existing strands in better shape.
Things worth considering include:
- Going easy on heat styling
- Cutting back on harsh chemical treatments
- Being gentle when brushing, particularly with wet hair
- Keeping your scalp clean and healthy
Breakage is often mistaken for hair loss, so minimising it can make a real difference to how your hair looks and feels overall.
Why hair growth takes time
Hair grows slowly – roughly one to one and a half centimetres a month on average. Because of this, any changes you make to your diet, routine, or lifestyle won’t produce overnight results. Improvements tend to become visible gradually, over several months rather than several weeks. That’s not a flaw in the system; it’s simply the nature of the cycle.
Understanding your hair’s natural cycle
The hair growth cycle is a continuous, finely tuned process shaped by genetics, hormones, nutrition, and general health. Every strand moves through growth, transition, and rest at its own pace, which keeps shedding spread out and manageable rather than dramatic.
Once you understand how the cycle actually works, it’s much easier to make sense of the changes you might notice – and to have realistic expectations about how long improvements take. Supporting your overall health through good nutrition, managing stress, and treating your hair with a bit of care can all help create the right conditions for it to do what it naturally wants to do.
