Do Cooler Temperatures Actually Affect Hair Growth?

Do cooler temperatures affect hair growth, or does it just feel that way once the weather shifts? The honest answer… it’s both! The cold weather does not directly slow the biological process that produces new hair, but it does change the environment around the follicle enough to make growth look and feel slower.

Here is what is actually happening under the surface, and where the science is solid versus still unclear.

What Happens to the Scalp When Temperatures Drop

Hair growth depends on the anagen phase, the active growth stage where cells inside the follicle divide rapidly to build new strands. That process is fueled by blood flow, which delivers oxygen and nutrients to the follicle.

When temperatures drop, the body prioritizes core warmth over surface circulation. Blood vessels near the skin, including the scalp, constrict to reduce heat loss, a response called vasoconstriction. Less blood reaching the surface means fewer nutrients and less oxygen reaching the follicle during the exact phase that depends on both.

This does not switch growth off. It is a matter of degree, not an on or off signal, and follicles that are already stressed from other factors are the ones most likely to feel it.

Does Cold Actually Change the Growth Rate

This is where the evidence gets more measured. Hair grows at roughly half an inch per month for most people, and no controlled study has shown that cold weather changes that underlying rate in a healthy scalp. What cold weather does affect is everything around growth: how the strand looks, how the scalp behaves, and how much shedding becomes noticeable.

So the honest framing is this: cold weather is unlikely to change how fast a strand grows once it is actively growing, but it changes the conditions the follicle needs in order to stay in that growth phase, and it affects how strong and hydrated the strand is by the time it reaches the surface.

The Scalp Dryness Problem

Cold air holds less moisture than warm air, and indoor heating strips even more of it out. This dry environment does two things at once. It can reduce sebaceous gland activity, meaning the scalp produces less of its own natural oil, and it pulls moisture directly out of the hair shaft and scalp skin.

A dry, tight scalp is a less stable base for hair to anchor into. Some research in the International Journal of Trichology has linked scalp condition directly to hair density and retention over time, since an irritated or compromised scalp environment disrupts the normal hair cycle regardless of what is happening at the ends. Flaking, itching, and tightness are the visible signs that this is starting to happen.

Why Shedding Can Feel Worse in Cold Months

If your scalp circulation and hydration are both under strain at the same time, follicles have less support to stay in anagen and are more likely to shift into telogen, the resting phase, sooner than they otherwise would. More hair sitting in telogen at once means more hair released around the same window, which shows up as noticeable shedding.

This overlaps with the seasonal shedding pattern tied to daylight hours, so cold weather and shorter days often compound each other rather than acting as separate issues.

How to Support Hair Growth Through Cold Weather

Bring blood flow back to the scalp. Since the core issue is reduced circulation, a daily scalp massage for five to ten minutes is one of the most direct ways to counteract it. Massage manually stimulates blood flow to the exact area cold weather is pulling it away from.

Use ingredients that support circulation. Peppermint oil and rosemary oil both encourage vasodilation, the widening of blood vessels, which works against the vasoconstriction cold weather causes. Applying either a few times a week gives the scalp a countermeasure rather than just waiting out the season.

Add moisture back into the routine. Winter hair care needs to work harder than summer hair care because the air is doing less of the work for you. A heavier conditioner, a leave-in treatment, or a weekly deep conditioning session helps offset what dry indoor and outdoor air pulls out.

Protect the scalp barrier. A scalp oil or serum applied directly to the scalp, not just the strands, helps replace the natural oil that cold air and heating suppress, keeping the base hair on this scalp more stable

Watch for compounding factors. Vitamin D typically declines through the darker months for people who get less sun exposure, and it plays a supporting role in the hair cycle. Keeping an eye on overall nutrition through winter gives the follicle one less thing working against it. A fact is that roughly 42% of women in the U.S. have vitamin D levels below the threshold recommended by the Institute of Medicine, according to national health data (so remember to take your vitamins!). 

The Bottom Line

Cold weather does not appear to change the fundamental rate at which hair grows. What it does change is the environment the follicle is growing in: less circulation, less natural oil, more moisture loss, and more overlap with seasonal shedding patterns. Address those conditions directly, and hair tends to move through winter looking and feeling like it never left its growth phase in the first place.

How Kerotin Supports Hair Through Colder Months

Kerotin's Nourishing Oil and Hair Growth Serum are formulated to work directly on the scalp, supporting circulation and replacing the moisture and natural oils that cold air and indoor heating pull out. Paired with the Collagen Shampoo and Conditioner for added hydration, the goal is to keep the follicle environment stable through winter rather than reacting once shedding or dryness has already picked up.

Frequently Asked Questions

Does cold weather actually slow hair growth? There is no controlled evidence that cold weather changes the underlying rate hair grows at, roughly half an inch per month for most people. What cold weather does affect is scalp circulation, moisture, and natural oil production, which can make growth look and feel slower even when the growth rate itself has not changed.

Why does my hair shed more in the winter? Reduced scalp circulation and increased dryness can push more follicles into the resting, or telogen, phase at once, which shows up as noticeable shedding. This often overlaps with the seasonal shedding pattern tied to shorter daylight hours in fall and winter.

Can scalp massage help with winter hair loss? Yes. Since reduced blood flow is a core mechanism behind cold weather's effect on the scalp, massaging the scalp for five to ten minutes daily helps stimulate circulation and counteract the vasoconstriction that cold triggers.

Does dry winter air affect hair growth? Indirectly. Dry air and indoor heating reduce natural scalp oil and pull moisture from the hair shaft, creating a less stable environment for hair to grow and anchor in, even though dryness alone does not stop the growth cycle.

What ingredients help hair through cold weather? Peppermint and rosemary oil support circulation through vasodilation, while richer conditioning ingredients and scalp oils help replace the moisture and natural oils that cold air and heating strip away.

References

1. Reduced blood flow to the scalp during cold exposure and its effect on the anagen phase. Benci International Academy.

2. Scalp condition and its direct link to hair growth and retention, citing research in the International Journal of Trichology. Jadu Beauty.

3. No clear-cut evidence that temperature changes the underlying hair growth rate. LEAFtv.

4. Cold-induced vasoconstriction and scalp circulation mechanisms. Traya.

5. Peppermint and rosemary oil for circulation and vasodilation. Bask & Lather Co.