Ever feel like your gut’s got a secret calendar?
You’re cruising through the month, then - bam - suddenly bloated, irritable, and crying over a missing sock. Sound familiar?
Spoiler alert: It might not just be your hormones. New Aussie-led research is turning heads with what it’s uncovering about your gut microbiome - and it could be the key to smoother cycles.
1. The Aussie Breakthrough: The Hudson Institute’s Gut-PMS Clinical Trial
Right now, the Hudson Institute in Melbourne is leading a world-first research project with Monash University, exploring how your gut bacteria shift throughout your cycle¹.
Participants in the trial are:
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Submitting stool samples (yep, glamorous)
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Tracking gut symptoms, moods, and bloating
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Testing a gut-friendly supplement for three months
The aim? To see whether supporting the gut microbiome with dietary strategies can relieve PMS symptoms, especially anxiety and digestive upset.
It’s big news for period pain and gut health - and it’s happening right here in Australia.
2. Gut Rewiring: Understanding the Gut-Brain-Hormone Axis
Think of your body like a 3-way group chat between your gut, brain, and hormones. And yep - they talk a lot.
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Your gut microbiome regulates digestion, immunity, and even mood.
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Your brain and gut are connected via the vagus nerve - a literal information superhighway.
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Your hormones (oestrogen and progesterone) rise and fall throughout your cycle, affecting everything from metabolism to mood.
Some gut bacteria help regulate oestrogen by producing enzymes like beta-glucuronidase². If those bacteria are out of balance, it can lead to oestrogen dominance – a culprit behind mood swings, breast tenderness, bloating, and heavy periods.
And guess what makes that worse? Stress. It disrupts gut balance, lowers microbial diversity, and during your luteal phase (hello, PMS week), it hits even harder².
3. What the Science Says (and Why It Matters)
Studies are now finding clear differences between the microbiomes of women with and without PMS.
A 2022 Japanese trial³ showed:
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Lower levels of beneficial bacteria like Parabacteroides and Megasphaera in women with PMS
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Higher levels of Anaerotaenia (not so helpful in large amounts)
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Lower butyrate – a short-chain fatty acid that supports mood and calms inflammation
Other studies also show gut diversity drops during the luteal and menstrual phases². That drop? Linked to symptoms such as bloating, constipation, fatigue, and irritability.
4. The Hey Sister! Community Shares the Truth
Real stories from real women:
Real Women, Real Relief: Gut + PMS Support
"Love my Hey Sister product. It has helped so much with cramps & PMS symptoms. It makes me feel better knowing I’m putting good things into my body too!!"
Amber E. – Verified Buyer
"I’ve struggled with incredibly painful periods and PMS for as long as I can remember… But wow, I’m honestly amazed. Not only did I experience no pain, but I also had more energy and was in a great mood. This is by far the best I’ve ever felt during my period."
Julia K. – Verified Buyer
"I suffer from incredibly painful periods that cause me to miss work each month… On top of significantly reducing my pain, I found it removed all PMS symptoms of back pain, bloating, tiredness and mood swings."
Sarah P. – Verified Buyer
These stories match what science is showing: gut balance and hormone balance go hand-in-hand.
5. How to Love Your Gut (Especially Before Your Period)
You don’t need a science degree or a gut-health glow-up. Just these simple tweaks:
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Eat more fibre: Oats, chia seeds, sweet potatoes, greens
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Add prebiotics: Garlic, onion, leeks, bananas, asparagus
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Try probiotics: Fermented foods (kimchi, kefir, sauerkraut) or plant-based supplements
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Ease up on sugar & alcohol: Especially pre-period - they mess with your gut
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Move gently: Yoga, walking, stretching - all support digestion and lower stress
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Track your cycle: Spot patterns and prep your gut before PMS hits
6. Why Hey Sister! Works
Hey Sister! was formulated to support exactly what the science is spotlighting:
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100% organic, vegan, gluten- and dairy-free
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Includes Khaya senegalensis, a powerful plant-based prebiotic
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Supports gut health, balances hormones, and reduces inflammation
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Works with your cycle, not against it
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No chemicals, no bandaid fixes, just long-term cycle wellness
7. Let’s Be Brave, Informed, and Honest
Period health shouldn’t be mysterious or shame-filled. If you’re feeling off before your period - mentally, physically, emotionally - your gut might be asking for backup.
And you don’t have to do it alone.
Have you noticed changes in your digestion, anxiety, or skin before your period?
Have gut-friendly foods or supplements helped?
Share your story with #HeySisterRelief or comment below. Let’s keep the convo going - and keep the shame out of it.
FAQs
Q: How does gut health affect PMS and period pain?
A: Your gut helps metabolise hormones and regulate inflammation. Microbiome imbalances can disrupt oestrogen levels, trigger bloating, and worsen PMS symptoms² ³.
Q: Can stress affect my gut during PMS?
A: Absolutely. Stress impacts the gut-brain axis, reducing good bacteria and increasing inflammation - which can spike mood swings and cramping².
Q: Are probiotics and prebiotics helpful for PMS?
A: Early research suggests yes. They support microbial diversity, reduce inflammation, and may improve digestion and mood during the cycle³.
Q: How do Hey Sister! products support gut health?
A: They include natural prebiotics like Khaya senegalensis, which nourish good gut bacteria and support hormonal regulation.
Q: When will I feel results from gut support?
A: Most people notice improvements in 2–3 cycles, with consistent gut-loving habits and support.
🔗 References
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Hudson Institute (2025). Reducing period pains with better gut health: A gut microbiome study targeting PMS and anxiety.
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Symprove (2022). The microbiome and the menstrual cycle: is there a link?
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Takeda, T. et al. (2022). Characteristics of the gut microbiota in women with premenstrual symptoms.
