Seasonal Serotonin: How to Boost Your Mood Naturally This Winter

mariekesteen
Dec 11, 2025
6 min read

If winter hits and you quietly think, “Why do I feel so exhausted again?” - you’re not alone.For many women in perimenopause, winter can magnify everything: the low mood, the sugar cravings, the irritability, the exhaustion that feels deeper than sleep can fix.

And no, it’s not because you’re weak or “overreacting.”

A big part of your winter mood comes down to seasonal serotonin - and how your genetics, gut, and hormones decide to handle the darker months.

Let’s break it down so you can understand what’s actually going on in your body (and most importantly, what you can do to feel better).

Why Winter Affects Your Mood: The Light + Melatonin Connection

You might think that you are sleepy on winter mornings because you have too much melatonin, it's actually the opposite!

Melatonin is produced in response to morning light stimulation through the eyes - specifically sunlight. So when you don’t get enough light exposure within the first hour of waking :

You don’t produce enough melatonin,
Which means you may have trouble falling asleep and don’t sleep deeply,
Which means your body struggles to regulate mood, cravings, and energy.

This is why morning light therapy (10,000 lux for 15–20 minutes) can be a game-changer. It helps restore your natural melatonin cycle so your brain can actually rest again.

Light Therapy: Your Brain’s Morning Reset Button

Winter doesn’t just dim your mood - it messes with your melatonin rhythm too.

Here’s the real story: Melatonin is made in response to light entering your eyes and signalling your brain. So in winter, when there’s LESS light, your body can also lack melatonin because of the lack of sunlight in the morning.

That’s why so many women feel:

groggy all day
wired at night
restless in the early hours
“off” in their sleep rhythm

A 10,000-lux light lamp in the morning helps your brain regulate melatonin production properly again - and that has a knock-on effect on serotonin, energy, and mood.

It’s basically giving your body the sunlight it’s missing.

Light is your biological antidote.

Try this daily:

10-20 minutes of outdoor morning light
Or a 10,000-lux lamp within the first hour of waking
Ideally before coffee

Seasonal Serotonin and Genetics: Why Some Women Feel Winter Blues More Than Others

Your genetics play a huge role in how you respond to seasonal darkness.

The SLC6A4 gene (serotonin transporter gene)

People with the “short” version often experience:

Stronger mood dips in winter
More carb cravings
More sluggishness
Higher sensitivity to stress
Lower baseline serotonin

Some of us have genetic variations that make it harder to convert tryptophan → serotonin, or serotonin → melatonin. If you have variations on genes like TPH2, SLC6A4, COMT, or MAOA, you may:

Burn through serotonin more quickly
Have a harder time clearing stress hormones
Experience sharper mood drops during low-light months

This is why one friend skates through winter humming Christmas songs… and another (maybe you?) feels like she's wading through emotional mud until April.

You didn’t choose your blueprint - but now that you understand it, you can support it.

Food: Your Winter Mood Toolkit

Your body needs the right building blocks to maintain serotonin production - and winter is when those become even more crucial.

Top Serotonin-Supporting Nutrients - Tryptophan-rich foods:

Salmon (wild caught)
Eggs
Turkey or chicken
Pumpkin seeds
Sesame seeds / tahini
Chickpeas
Cashews

Important note for collagen lovers: Collagen does NOT contain tryptophan. Women who use collagen daily - especially those prone to low mood - might accidentally lower their tryptophan balance.For some of my clients, simply adding eggs, turkey, pumpkin seeds or a tryptophan supplement makes a huge difference in anxiety + mood.

B vitamins (especially B6, folate, B12, and riboflavin) are key for converting tryptophan → serotonin.

Your best dietary sources are:

Organ meats (liver is the queen of B vitamins)

Nature’s multivitamin
B6, folate, B12, riboflavin, choline - all in therapeutic levels

Leafy greens

Swiss chard
Kale
Rocket
Spinach (still valid, just not the only star!)

Also helpful:

Eggs
Sardines
Nutritional yeast
Beef
Lentils
Asparagus

These foods support methylation, neurotransmitter production, liver detox, AND hormone metabolism - which is why they’re so magic for women over 40.

Best Omega-3 Sources for Mood & Serotonin

For brain and hormone health, we need EPA + DHA, the active omega-3 fatty acids.

Seeds like chia and flax only contain ALA - which the body converts into EPA/DHA very poorly (less than 5%).

So for meaningful mood and inflammation support, you need the real deal:

Top EPA/DHA foods:

Wild-caught salmon (farmed has a weaker omega-3 profile)
Mackerel
Herring
Sardines
Anchovies

These directly support neuronal health, inflammation balance, and serotonin signalling - especially important in winter.

The Serotonin – Gut Connection

Let’s clear up a big myth first: “Is 90% of serotonin really made in the gut?”

Here’s the nuance doctors argue about:

Yes - the cells in the gut (enterochromaffin cells) produce a LOT of serotonin. Estimates sit around 80–90%. You have probably seen me write about 80% of your serotonin production depending on the health of your gut microbiome….
BUT the serotonin made in the gut does NOT cross the blood-brain barrier.So it doesn’t directly raise your brain serotonin levels.

What is true - and absolutely relevant for winter mood - is this:

The gut influences brain serotonin indirectly through:

The vagus nerve
Microbial metabolites (short-chain fatty acids, tryptamine-producing bacteria, etc.)
Inflammation signaling
Immune activity
Tryptophan metabolism (whether it gets turned into serotonin or shunted down the inflammatory kynurenine pathway)

So while your gut doesn’t “send serotonin to your brain,” it controls how efficiently your brain can make and use it.

Women with IBS, bloating, dysbiosis, or post-antibiotics often have lower mood resilience in winter - not because gut serotonin travels to the brain, but because the gut environment influences the entire system.

Gut Health & Mood: Meet Your Mood-Boosting Bacteria

Certain gut bacteria actually help support neurotransmitter balance, inflammation control, and the tryptophan–serotonin pathway.

Mood-positive bacteria include:

Bifidobacterium longum (shown to reduce anxiety-like symptoms)
Lactobacillus rhamnosus (impacts GABA signaling)
Bifidobacterium infantis (supports tryptophan metabolism)
Faecalibacterium prausnitzii (anti-inflammatory powerhouse)

These thrive when you feed them:

Fibres (veggies, fruits, legumes, nuts, seeds)
Polyphenols (berries, pomegranate, cocoa, green tea)
Fermented foods (sauerkraut, kefir, yogurt, kimchi)

I’ve seen women’s moods drastically shift simply by healing their gut inflammation - because the gut determines whether tryptophan becomes serotonin or gets diverted into inflammatory pathways.

Alcohol: The Dopamine Trap

Alcohol gives you a quick and very high dopamine boost… but then drops neurotransmitters BELOW baseline. This is what makes it so addictive by the way. We can easily get hooked on dopamine and it’s just impossible to achieve these high levels with a normal lifestyle and even dopamine boosting foods.

Meaning:

Lower serotonin
Poor sleep
More anxiety
More cravings
Lower motivation

Many women tell me:

“I sleep worse, wake anxious, and feel puffy the next morning.”

This is your nervous system asking for real nourishment, not temporary numbing. If you’re feeling winter-blah, alcohol is the one “treat” that gives less than it takes.

Ask yourself if your “normal tiredness” could actually be a winter mood low?

How healthy is your gut and what habits (or lack of habits) could impact your winter serotonin?

I still remember a client who came to me earlier this year saying:

“Every winter I feel like I disappear. I can’t get out of my own way.”

She had the classic symptoms most of my clients are experiencing: bloating, anxiety, carb cravings, stubborn weight gain.

We worked through her gut health step-by-step. By spring, she told me:

“I didn’t even realize how much my gut was affecting my mood.”

And this is why I created resources like my Hormone & Blood Sugar Balance Cookbook - every recipe is built to naturally support neurotransmitters, gut health, energy, and inflammation. If you need a gentle place to start, it’s a safe first step toward feeling “at home in your body” again.

Putting It All Together: Your Winter Serotonin Ritual

Here’s what I’d recommend:

Morning light therapy for 20 minutes
Protein + tryptophan-rich breakfast
Daily leafy greens + omega-3 fish
Fermented foods 3–4x per week
Limit alcohol to protect dopamine
Support with my Hormone & Blood Sugar Balance Cookbook recipes to keep meals simple and nourishing