It's a question that surfaces every winter, usually from someone who started a hair growth routine in autumn and feels like progress has stalled just as the clocks changed. Does hair actually grow slower in the colder months, or does it just feel that way?
The honest answer is: a little of both, and the "feels that way" part matters more than most people realise.
What the science actually shows
Hair growth isn't perfectly constant across the year. Research into seasonal variation suggests the proportion of follicles in the active growing phase shifts with the seasons, typically peaking in the warmer, brighter months. More follicles growing at once in summer, a greater share resting or shedding as the year turns towards autumn and winter.
So in a sense, yes: you may have marginally fewer hairs in active growth during winter, and a larger share taking a seasonal rest. But the effect on the actual speed of each growing hair is modest. The bigger, more noticeable seasonal story is about how many follicles are growing versus resting, rather than individual hairs slowing to a crawl.
Put simply: your hair probably isn't growing dramatically slower in winter. A slightly larger proportion of it is temporarily taking the season off.
Why winter makes progress feel stalled
Here's where perception does a lot of the heavy lifting, and understanding it will save you from quitting a routine that's actually working.
Seasonal shedding overlaps with your growth efforts. If autumn shedding is releasing a wave of hairs just as your new growth is coming through, the two can roughly cancel out visually. You're growing and shedding at the same time, so the mirror shows no net change even though real work is happening. This is deeply discouraging and almost entirely a timing illusion.
You see your scalp more in winter. Overhead indoor lighting, which you spend far more time under when it's dark by half four, is brutally unflattering to thinning hair. The same density that looked fine under summer daylight looks sparser under a kitchen spotlight. Your hair didn't change. The lighting did.
Dryness flattens everything. Winter hair is often drier, more static and lies flatter, which reads as less volume even when the hair count is identical.
Hats hide your progress from you. Not because they damage anything, but because you simply see your hair less, so the gradual change is harder to track.
The trap this sets
Put those together and you get a predictable, costly pattern. Someone starts a hair routine in September, full of motivation. By December they've hit the overlap of seasonal shedding, worse lighting, flatter hair and a natural dip in visible growth. The mirror says nothing is working. They quit, right at the point where hair routines genuinely start to deliver (month three to four), and right before spring would have made their progress obvious.
They don't quit because the routine failed. They quit because winter is the single worst time to judge your hair by eye, and nobody warned them.
How to actually track progress through winter
Photograph, don't inspect. Same spot, same angle, same lighting, once a month. Natural daylight near a window if you can, since it's the most consistent. Photographs are immune to the daily mood-and-lighting lottery that makes the mirror so unreliable.
Track shedding, not density, in the early months. Density changes too slowly to perceive. Shedding changes early enough to notice, so it's the better metric for the first couple of months. Fewer hairs in the brush is a real, trackable early win.
Judge at the right time. Not December. Give any hair routine until at least month four before deciding anything, which conveniently lands you in spring, when the seasonal cycle swings back in your favour and the lighting stops lying to you.
Keeping growth supported through the cold
You can't override the seasonal cycle, and you don't need to. What you can do is remove the winter factors dragging on your hair and keep supporting the underlying mechanism.
Protect against the dryness (covered fully in the central heating article in this series). Keep your vitamin D up through the dark months, since low vitamin D is linked to shedding and the UK can't make it from winter sun. And if hormonal thinning is part of your picture, keep supporting it consistently rather than pausing because the mirror looks flat.
Hormonal thinning is driven by DHT shrinking sensitive follicles, which is why our Hair Growth Softgels are formulated around saw palmetto (studied for its ability to help reduce DHT by up to 30%) and pumpkin seed oil (the subject of a 2014 clinical study in men, in which 400mg daily was associated with a 40% increase in hair count over 24 weeks), both at research-matched doses. That mechanism doesn't take the winter off, so neither should your routine.
The takeaway
Hair growth slows modestly in winter, mostly through more follicles resting rather than each hair crawling along. But the far bigger effect is on your ability to see progress, thanks to shedding overlap, grim lighting and flatter hair. Winter is when people quit routines that are working. Photograph monthly, judge in spring, keep supporting the mechanism, and let the season turn before you draw any conclusions.