How Fast Does Hair Actually Grow? What You Can and Can’t Change

Type “how to grow hair faster” into a search bar and you’ll find an industry waiting for you: oils, gummies, serums, supplements and routines, all promising to accelerate something that is, for the most part, fixed. So let’s start with the honest answer, then spend the rest of this article on the part nobody sells, which happens to be the part that actually works.

The Number: About One Centimetre a Month

Human scalp hair grows at roughly one centimetre per month, which works out at around 12 to 15cm a year, or somewhere near half an inch a month in old money. Individual rates vary a little around that, but not dramatically.

What sets your rate is largely out of your hands: genetics first and foremost, then age, since growth slows gradually over the decades, and hormonal and general health status. Nothing you apply to the outside of your head meaningfully changes the speed at which a follicle produces hair. That’s the bit the industry would prefer you didn’t know.

Why Some People Can’t Grow Long Hair At All

Here’s the concept that explains more than any product claim: terminal length.

Each hair on your head grows for a set period, its growing phase, which lasts somewhere between two and seven years depending on the person. At the end of that period the hair sheds and a new one starts. Multiply your growth rate by your growing phase and you get your terminal length: the longest that hair can possibly get before it naturally lets go.

Someone with a seven-year growing phase can grow hair well past their waist. Someone with a two-year growing phase will find their hair stubbornly stops somewhere around the shoulders no matter what they do, because each hair reaches the end of its life and sheds before it can get any longer. That isn’t a failure of your routine or your products. It’s the length your genetics allow, and no oil changes it.

Knowing this is genuinely freeing, because it redirects effort to where effort works.

The Thing You Can Actually Change: Retention

Here’s the reframe. Most people who feel their hair “won’t grow” are growing hair perfectly well at the root, and losing it at the ends. Hair grows at a centimetre a month; if it’s snapping off at a similar rate through breakage, the visible length never changes. It looks like a growth problem. It’s a retention problem, and retention is entirely within your control.

The oldest hair on a shoulder-length head is several years old. It has been washed hundreds of times, brushed thousands, heated, tied back, slept on and exposed to hard water throughout. Of course the ends are fragile. Protecting that investment is where the real gains are.

Handle wet hair carefully. Hair is at its most vulnerable when wet. Use a wide-tooth comb rather than a brush, work from the ends upward rather than dragging from the roots down, and pat or squeeze rather than rubbing with a towel.

Ease off the heat. Regular high-heat styling is the single biggest cause of mid-length breakage. Lower temperatures, less frequent use and a heat protectant when you do use it make a measurable difference over months.

Loosen the styles. Tight ponytails, buns and braids create tension at the follicle and stress along the shaft. Varying where you tie your hair, and tying it more loosely, prevents both breakage and the traction damage that repeated tension can cause at the hairline.

Deal with hard water. Most of the UK lives with mineral-heavy water that leaves hair rougher and more prone to snapping, which we covered in detail in our guide to hard water and your hair.

Trim, counterintuitively. Trimming doesn’t make hair grow faster, that’s a myth. But removing split ends stops them travelling further up the shaft, which prevents you losing more length than the trim cost you.

The Other Thing You Can Change: The Scalp

Growth happens in the follicle, and the follicle sits in the scalp, so scalp condition is the one place where topical care is working at the right address. A scalp congested with product buildup, or dry, tight and irritated, is not an ideal environment for the hair emerging from it.

This is why the sensible routine is clear before feed. Our Hair Follicle Cleansing Tonic clears accumulated buildup from the scalp and follicles, and following with the Hair Follicle Feed & Regrowth Tonic applies its herbs to a scalp that’s actually able to absorb them. For everyday washing, a scalp-kind formula like our Hair Loss Prevention Shampoo asks less of the skin than heavy-detergent products.

The few minutes of massage while applying is worth doing properly rather than rushing, both for circulation and because it’s the part of a routine people most often skip. We covered the technique in our scalp massage guide.

And Nutrition, With One Caveat

Hair is built from what you eat, so protein and iron genuinely matter. The important caveat: correcting a deficiency helps, while topping up beyond what you need does not. If your iron is low, fixing it can make a real difference to hair. If it’s already normal, more won’t add anything.

This is the honest problem with the hair supplement industry: most of it sells insurance against deficiencies most people don’t have. If you suspect one, particularly if you’re also tired or run down, a blood test through your GP tells you far more than a bottle of gummies.

Frequently Asked Questions

How fast does hair grow?

Around one centimetre a month, or roughly 12 to 15cm a year, with modest variation between individuals.

Can anything make hair grow faster?

Not meaningfully. Growth rate is largely genetic. What you can influence is how much length you keep, by reducing breakage, and the condition of the scalp the hair grows from.

Why has my hair stopped growing past a certain length?

Usually terminal length: each hair grows for a set number of years, then sheds. If your growing phase is short, hair reaches its maximum and lets go before it can get longer. Breakage at the ends produces the same appearance.

Does trimming make hair grow faster?

No, but it prevents split ends travelling up the shaft, so it helps you retain the length you grow.

Do hair growth supplements work?

They can help if you have a genuine deficiency, particularly iron. If your levels are already normal, extra doesn’t accelerate growth. A blood test is more useful than guessing.

How long to see a difference from a new routine?

Give it at least three months. That’s roughly one hair cycle, and at a centimetre a month it’s also the point where any change in length becomes visible.