Why Won't My Hair Grow? The Real Culprit Might Be Breakage, Not Growth

If you've been growing out your hair for a year and it looks exactly the same length as it did 12 months ago, it's easy to assume something is wrong with your hair growth. But for a lot of people, that's not actually what's happening. Hair is growing the way it's supposed to—it's just not sticking around long enough to show it.

This is one of the most misunderstood parts of hair health. Growth and length are related, but they're not the same thing. And once you understand the difference, "why won't my hair grow past this length" starts to look like a different, and often less daunting, question.

Every hair on your scalp cycles through phases: an active growth phase (anagen), a short transition phase (catagen), a resting phase (telogen), and shedding (exogen). At any given time, 85% to 95% of your scalp hair is in that active growth phase, each strand lengthening by about 1 centimeter a month for anywhere from two to six years before it rests and eventually sheds.¹

That means most of what's on your head is, biologically, growing hair. When people say their hair "won't grow," a shortened growth phase may only be part of the story. Internal factors like stress, hormonal shifts, nutrient gaps, and aging can all push hairs out of the growth phase early or keep them in resting longer and contribute to hair thinning^8,9,10—which is exactly what Nutrafol Hair Growth Nutraceuticals are formulated to help address from within. But there's a second, less-talked-about explanation that has nothing to do with the growth phase at all: The hair is growing just fine, and it's breaking off before that growth ever becomes visible.

Here's the simplest way to think about it:

Length = Growth − Breakage

Imagine if your hair grows 12 centimeters this year but breaks off 12 centimeters from split ends and snapped strands. Your length stays exactly where it started. From the mirror, that looks identical to hair that isn't growing at all—even though it's doing exactly what it should.

This is the piece most people miss. Growth happens at the root. Breakage happens along the shaft and at the ends. You can have a completely healthy growth cycle and still feel stuck, because the two forces are canceling each other out.

You don't need special equipment to get a sense of what's going on. A couple of simple checks can point you in the right direction:

If you try these checks and still aren't sure, or if your hair length genuinely hasn't changed after a year of consistent care, that's worth bringing to a dermatologist or primary care doctor, who can rule out other factors contributing to hair thinning.

Hair strands are more vulnerable than they look. The cuticle—the hair's outer protective layer—is only a few cell layers thick, and once it's compromised, the core part of the hair, the cortex, has little defense left.^11,12 A few everyday categories of damage do most of the work:

Heat styling. Blow dryers, flat irons, and curling irons denature the proteins that give hair its structure, and repeated heat exposure cracks and lifts the cuticle over time.^5,13

Chemical treatments. Coloring, bleaching, perming, and straightening all have to work inside the hair's cortex to make a lasting change, which means they inevitably strip away some of the hair's natural protective barrier along the way.¹¹

Everyday wear and tear. Brushing, especially when hair is wet, and friction from pillowcases, collars, and tight hairstyles gradually wear down the cuticle from root to tip—a process dermatologists call "weathering." Wet hair can stretch up to 30% of its length without damage, but stretching beyond that point, which easily happens when combing wet, brittle hair, causes real breakage.¹¹

Environmental exposure. UV rays, pollution, and substances in our shower water can all damage the hair over time, leaving strands more prone to snapping.^14,15,16

Aging: As we age, our hair spends less time in its active growing phase, and individual strands tend to become finer, with fewer protective cuticle layers—which may make them more prone to breaking.^10,17,18 Gray and white hairs add another layer of complexity: they carry less of the internal lipid that keeps a fiber flexible and sealed,¹⁹ so they tend to feel drier and can be more susceptible to wear and tear. Bleaching, heat styling, and chemical treatments can compound with age-related changes, making it even harder to keep your hair looking and feeling healthy.^20,21

Textured and curly hair is often naturally more porous due to its shape (twists and bends), which forces the cuticle to open, making it more vulnerable and prone to damage during everyday grooming. It also has lower tolerance for stress before it breaks.^11,22,23

Porosity is how well hair absorbs and holds onto moisture, and it's one of the biggest factors in whether hair breaks before it reaches its full length.^2,24

Low-to-medium porosity hair has a smooth, sealed cuticle with an intact outer lipid layer. It retains moisture well, resists damage, and generally looks shiny and manageable.^3,4,25 High-porosity hair—usually the result of heat, chemical treatments, or ongoing wear and tear—has a lifted, open cuticle with little protective lipid layer left. It absorbs moisture quickly, loses it fast, and is more prone to dryness, frizz, split ends, and breakage.^24,25

This is why two people can follow the exact same "hair growth" advice and get completely different results with their length: one person's hair is retaining what it grows, and the other's is breaking it away just as quickly.

If breakage is the missing piece for your hair, Nutrafol Strand Serum was created for you.

Strand Serum is a physician-formulated, shake-activated serum built around a patent-pending DualFusion™ Complex—a two-phase, oil-and-water system designed to work at the cuticle and cortex at the same time. The oil phase, built on Hemisqualane and Rosehip Fruit Extract, helps replenish the hair's surface lipid layer so hair feels smoother. The water phase, built on Milk Thistle Seed Extract and a Wild Olive Extract derived from stem cells, helps penetrate into the cortex, strengthen hair, and help seal split ends.

In clinical testing, consistent use of Strand Serum reduced breakage by up to 83% over time and visible split ends by 62%, left hair up to 6 times stronger, and helped protect against heat up to 450°F while controlling frizz for up to 72 hours.^† It's tested on all hair types and textures, and is formulated for anyone with high-porosity, damaged, color-treated, or chemically treated hair.

To use it, shake well. Start with 2 to 3 drops (up to 15 as needed) in your hands and apply to towel-dried mid-lengths and ends after washing and conditioning. Then comb through and style as usual. It can be reapplied to dry hair after styling and throughout the day for extra strength and protection.

Getting to your length goal usually means supporting hair health from more than one angle. Nutrafol's approach breaks it down into a three-part routine: supplements that target several key root causes of hair thinning from within, scalp support that helps maintain the environment for hair to grow, and strand protection that helps protect the hair you're already growing from breaking off before it gets there.

Hair Growth Nutraceuticals address the internal side. A healthy scalp routine supports the environment hair grows from. And Strand Serum picks up where those leave off—protecting the length once it's out of the follicle.

Is it possible for hair to grow and break at the same time? 

Yes. Growth happens at the root and breakage happens along the shaft and at the ends, so both can be happening at once. When breakage roughly matches growth, visible length stays flat, even though the hair is actively growing.

How long does hair actually take to grow? 

On its own, scalp hair grows about 1 centimeter a month on average, or roughly 12 centimeters a year, and stays in its active growth phase for several years before resting and shedding.¹

How can I tell if my hair is breaking instead of just not growing? 

Look closely at the ends: broken hairs have blunt, uneven tips, while new growth tapers to a soft point. A gentle tug test that pulls off short, several-millimeter fragments is another sign of breakage rather than a growth issue.⁶

Does heat styling really stop hair from getting longer? 

Heat styling doesn't stop the growth phase, but repeated high heat can crack and lift the hair's protective cuticle layer, which makes strands more likely to snap before they reach their full length.⁵

What supports hair that keeps breaking? 

Reducing heat and chemical exposure, being gentler with wet hair, and using a formula designed to strengthen the cuticle and cortex—like Nutrafol Strand Serum's dual-phase approach—can all help reduce breakage over time.

When should I see a doctor about hair that won't grow? 

If your length hasn't visibly changed after a year of consistent, gentle care, or if you're noticing thinning alongside other health concerns, it's worth talking to a dermatologist or primary care doctor to rule out other contributing factors.