Progesterone, Brain Fog & Why Collagen Can’t Read Google Maps

In this episode of On the ’Mones, we unpack three things many women quietly worry about - progesterone, memory changes, and the wellness advice that sounds scientific but absolutely isn’t.

First, we deep-dive into progesterone. Why it’s not always a gentle background hormone, how it acts in the brain, and why some women feel calmer while others feel anxious, flat, or completely unhinged when they start it. We explain the real science behind "progesterone intolerance", PMDD, GABA receptors, and why “just push through it” is terrible advice.

Then, I get personal about brain fog, the kind that messes with your confidence and identity. We talk estrogen, cognition, working memory, task overload, and why perimenopause doesn’t steal intelligence; it steals your buffer.

Finally, it’s Woo of the Week, and we’re taking on collagen powders and protein marketing. What actually happens when you eat protein? Does collagen really know where your sore knee is? (Spoiler: no.) We separate legitimate nutrition from seductive nonsense and explain what the evidence actually says.

This episode isn’t about doing more; it’s about understanding better.

If you’ve ever thought:

• “Progesterone made me feel worse. What’s wrong with me?”
• “Why does my brain feel different lately?”
• “Is this supplement actually doing anything?”

You're in the right place. 

Whether you are in perimenopause, approaching menopause, or simply trying to understand your hormones, I've got you. 

Read more about this episode at Medication Clarity Clinic - Kate's own medication education and telehealth consulting site: https://medicationclarity.com.au

Transcript

SPEAKER_00 0:00

You're listening to On the Moans, where we have conversations about hormones, midlife, and the moments that make us wonder, is it just me? I'm Kate. I'm a 48-year-old pharmacist and newly minted perimenopausal oversharer. This is where we talk openly about the changes we aren't prepared for, so we never have to feel alone in them again. I acknowledge the Camaragle people of the Eora Nation, the traditional custodians of the land which I am recording today. I pay my respects to elders past and present, and I extend that respect to all Aboriginal and Torres Strait Islander peoples listening. Always was, always will be, Aboriginal Land. Hello friends, welcome to episode 3 of On the Moans, the podcast where we talk about hormones, brains that suddenly feel like sieves, and the wellness advice that sounds great but doesn't quite survive a basic science check. Today we're learning about progesterone. I want to talk about something that's been worrying me about my memory, and then we're moving on to collagen and protein. We need to have a proper chat about what actually happens when you eat protein and what your body does with it. So grab a coffee or maybe a protein shake if that's your thing, and let's get on the moans. I have a friend who is positive for the BRCA mutation. So at a very young age, as in in her late 20s, she chose to have the risk minimization surgery of a double mastectomy and hysterectomy and ooforectomy. As in, she went in one day, a fully functioning young woman, and came out in complete menopause. So she started her HRT journey very early, and I'll get her on the show so she can tell you all about her experience in her own voice. But I remember her telling me that progesterone was so, so calming, that it helps sleep, that it takes the edge off, that it makes you feel soft and settled and womanly. So when I started my own HRT journey, I had high hopes for progesterone. And luckily for me, this has been my experience too. So the obvious question now is, if it's true, why do some women feel worse when they start it? And the answer is because progesterone isn't actually a gentle passive hormone, it's an active one, and it does a hell of a lot more in your brain than it ever did in your uterus. When we talk about progesterone, most people picture the uterus. Periods, pregnancy, lining, thickening, and shedding, sloughing layers. I really just wanted to use that word. But in day-to-day life, especially in perimenopause, progesterone is primarily a brain hormone. Progesterone itself is just the starting point. In your body, it gets converted into a metabolite called allopregnanolone, and that's where things can get interesting and spicy. Alopregnanolone acts on the GABA-A receptor in the brain. GABA A is your main inhibitory neurotransmitter. It's the same calming pathway targeted by benzodiazepines, sleeping tablets, the Z drugs, you know, think zoone, and alcohol. In most people, activating that pathway slows the brain activity down. You feel calmer, sleepier, less anxious, which is what you want from your sleeping tablet and your anxiolytic. But GABA is not calming in everyone. The GABA A receptor isn't one single receptor, it's a whole family of receptors made up of different subunits, and the exact mix you have in your brain affects how you respond. In some people, stimulating that pathway doesn't calm, it destabilizes. So instead of feeling relaxed, they feel agitated, anxious, flat, ragey, wired but tired, like they want to crawl out of their own skin. And this is why there's a really strong overlap between women who don't tolerate progesterone and women who don't tolerate benzodiazepines. If you've ever heard someone say Valium makes me anxious or sleeping tablets make me feel awful, that's not psychology, that's receptor biology. Progesterone isn't failing in these women, their brains just process neurosteroids differently. This becomes even more obvious when we talk about PMDD. Premenstrual dysphoric disorder isn't caused by abnormal hormone levels. The levels are often completely normal. The problem is that the brain has an abnormal sensitivity to normal hormonal changes, particularly to rising and falling progesterone. So it's not the amount, it's the fluctuation. And that's why symptoms hit in the luteal phase and vanish when hormones drop at the start of the bleed. Same hormones, different brain response. Also, we need to talk about the uterus because this is where people get confused and sometimes scared off progesterone entirely. If you have a uterus and you're taking estrogen, you must have progesterone. Full stop. Estrogen stimulates the uterus lining. Progesterone stabilizes it. Without progesterone, estrogen can cause the lining to thicken in an uncontrolled way. So if you have a uterus and you having estrogen, this isn't optional. It's not a nice to have, it's protective. If a woman still has her uterus and says, I feel awful on progesterone, I'll just stop it, the answer isn't fine, ditch it. It's okay. We need to rethink the dose, the route, or the schedule. And now here's something that surprises people. Even if you don't have uterus, progesterone can still have a role because again, they may have removed your uterus, but they left your brain in, right? And progesterone is upfront a brain hormone. Some women without a uterus use progesterone for sleep, anxiety, mood stabilization, migraine modulation, or because estrogen alone feels too stimulating. But the key difference is choice. If you don't have a uterus, progesterone is optional. If you do have a uterus, it's mandatory, but how you use it can be flexible. Another source of confusion is progesterone versus progestins. They are not the same thing. Progesterone is bioidentical. It binds to progesterone receptors and gets metabolized into neuroactive compounds like allopregnatolone. Progestins are synthetic. They were designed to protect the uterus, not to feel good in the brain, and they don't just act on progesterone receptors. They often bind to androgen receptors, glucocorticoid receptors, and all sorts of places they weren't invited to be. That's why some people say progesterone made me feel terrible when actually what they took was a progestin in a pill or a device. Different molecule, different pharmacology, different side effect profile. A lot of progesterone's bad reputation comes from progestines wearing its name tag. Progesterone is usually the first hormone to fall in perimenopause, not estrogen. Ovulation becomes irregular before estrogen production shuts down, and if you don't ovulate, you don't make progesterone. So you end up with this weird hormonal landscape where estrogen can be normal, high, or chaotic, and progesterone is missing. That's why perimenopause often starts with anxiety or sleep issues, PMS type symptoms, and mood changes long before hot flushes show up. This is why people talk about estrogen dominance. It's not because estrogen is high, but rather progesterone is absent. And hopefully, you can be progesterone deficient and progesterone intolerant at the same time. Deficiency looks like a short luteal phase or spotting or poor sleep or estrogen-driven symptoms. Intolerance looks like anxiety, depression, agitation, sedation, or emotional blunting. And women are left feeling they have to choose between feeling hormonally unbalanced or feeling mentally awful. And that's a pretty shit choice. Finally, let's bring this back to PMS and PMDD because this is where progesterone gets blamed for everything. In classic PMS, progesterone support can help some women. In PMDD, progesterone often makes things worse, not because it's wrong, but because the brain reacts badly to change. PMDD is a disorder of neurosensitivity, not hormone deficiency, which means more progesterone isn't better. Cycling isn't always better, and just pushing through it is probably the worst advice imaginable. So if you've ever been told progesterone is calming and thought, cool, but it makes me feel insane, you're not broken, you're not traumatic, and you're definitely not imagining it. So now we know that progesterone is not just a fluffy background hormone. Let's talk about how we actually give it. When people say I'm on progesterone, that could mean a few different things, and those differences matter a lot. Let's start with micronized progesterone because this is what most people mean when they say body-identical progesterone. It's progesterone that's been processed into tiny particles so your body can absorb it properly. The biggest fork in the road here is oral versus vaginal, and they are not interchangeable experiences. When you take progesterone orally, it goes straight to the liver. That first pass metabolism converts a large chunk of it into allopregnatolone. That neurosteroid we talked about earlier. This is why oral progesterone has such a strong effect on the brain. And as we've discussed, for some women that's magic. They sleep better, they feel calmer, takes the edge off the day. For others, it's a disaster. Sedation, low mood, anxiety, brain fog, that hungover feeling the next morning. This is also why timing matters. Oral progesterone is not a whenever you remember it medication. It's a nighttime drug. Morning dosing is almost always guaranteed to make someone feel awful. And if someone tells you they didn't tolerate progesterone but they were taking it in the morning, that's not intolerance, that's just pharmacology. Vaginal progesterone behaves very differently. It still protects the uterus, but far less of it gets converted into allopregnant alone. That means much lower exposure for the brain. For women with anxiety or PMDD or a history of paradoxical reactions, vaginal progesterone is often a much better choice. Now dosing. This is where the more is better myth needs to die. Progesterone is not linear. Higher doses don't necessarily make you feel calmer. In fact, for some women, higher doses pushes them straight into the agitational or emotional blunting realm. The most effective dose is the lowest dose that does the job, not the one that looks the most impressive on paper. And that sentence is true of all medications. I'm just trying to think of an example where more is more when it comes to medications. In medicine, when people say higher doses work better, what they usually mean is the lower dose didn't actually work. Once a drug is doing its job, more doesn't make it better, it just makes it more likely to give side effects. It's like two drinks and you're a weapon on the pool table, but four drinks and you can't sink a single ball and it's like pool cues at dawn. Progesterone is exactly like that. The goal isn't to see how much you can tolerate, it's to find the smallest amount that does what you need it to do. I digress. Where were we? Progesterone dosing, take it at night. Um, and vaginal delivery isn't the same as oral delivery, she says, stating the obvious. And then there's cycling versus continuous dosing. A lot of women are told they must cycle progesterone to mimic a natural cycle. That sounds logical, but for women with PMDD or hormonal sensitivity, cycling can actually make things worse. Fluctuations are often the problem, not the solution. For some women, low continuous dose progesterone is far more tolerable than cycling on and off every month. Again, individual people, individual brains, individual plans. Which brings us to the marina. The marina contains levo-norgesterol, a progesterone, delivered directly into the uterus because it's local, systemic levels are low for most women. That's why it's often used as endometrial protection alongside estrogen in perimenopause and menopause. For many women, the marina is brilliant. It protects the uterus, reduces bleeding, and avoids the brain effects of oral progesterone. But not everyone tolerates it. Some women are extremely sensitive even to low systemic progestin exposure. They can experience mood changes, anxiety, depression, or that this isn't me feeling. If that happens, it doesn't mean the marina is dangerous, it just means it's the wrong progesterone for that brain. And the same applies to other progestin-containing options, the implant, the depot injection, some combined oral contraceptives. These are not interchangeable with progesterone, and a bad experience with one doesn't necessarily predict how you'll respond to the other, but it does give helpful clues. This is where history is gold. If someone has hated the pill, hated the implant, hated the marina, and hates benzodiazepines, that tells you a lot about how carefully progesterone needs to be handled. And finally, let's talk timing, the quiet hero of tolerability. Progesterone should be generally taken at night, consistently, with a plan. Not try this and see. Not push through for three months, and not everyone feels better, so you should too. If progesterone helps, you'll usually know fairly quickly. If it worsens things, that's information, not failure. So if there's one thing I want people to take away from this part of the episode, it is progesterone isn't one experience. Root matters, dose matters, timing matters, and brain sensitivity matters. And I know that was five things. And the goal isn't to force your body to tolerate hormones, it's to work with how your brain actually responds. I've always prided myself on being quick, like not sporty, run fast, quick, but brain quick, thinking on my feet, mentally holding multiple things at once, seeing the whole picture. I find this stimulating, not draining. I was the person who could juggle conversations, interruptions, and tasks and still get it right. And lately I've been a bit slow, and I hate saying that out loud, not ignorant, just vague, disorganized in ways that don't feel like me. And I've been doing things and afterwards I've been thinking, hang on, that wasn't like me. I'll give you some examples and we can nut it out together. In episode one, I explained that I left a hospital pharmacy job I've been doing for 23 years. So that's 23 years of familiarity, pattern recognition, muscle memory. My brain was likely on autopilot, and it was one of the reasons I left, if I'm being honest. Now I work in community pharmacy one day a week, as well as in community palliative care one day a week. I've been doing the community pharmacy gig for about 18 months, community palliative care since April, so that's about eight months. The palliative care role is very familiar to me, but the community pharmacy role not so much. And I'm only doing it one day a week, and I'm finding it cognitively brutal. I never get into a flow, I never build a rhythm, I never pick up where I left off, and I'm working with people who've been doing it full-time for decades. Every shift to me feels like day one. So instead of relying on habit memory, I'm relying on working memory, and my working memory is fragile, it seems. Yesterday was a classic example. The pharmacy I work in is the classic village pharmacy. Small community, and the owner knows everyone's names and exactly what they want as they walk through the front door. I'm getting better, but I'm nowhere near her level of expert personalized service yet. Anyway, we do a lot of home deliveries, and this day two older ladies rang back to back, both wanting deliveries. So I had one woman's items in one hand, panadole or something simple, and the other woman's items in the other hand, and I charged them correctly, and I labelled them correctly. And remember, I'm a person who can do multiple things at once and get it right, or at least that's how I identify. I might add that any pharmacist out there is likely yelling at me that pharmacy 101 is literally finish the one job you were doing before you start doing the next one. So the fact that I've just admitted to doing two different persons' medications at the same time means I deserve your judgment. And then somehow, I know it's almost impossible to imagine how, I put both orders into the same bag and delivered them to the one person. I don't actually remember doing this, but it was the best explanation that we could come up with at the end of the day when we couldn't find poor old Mrs. What's her name's delivery, and then the other Mrs. What's her name rang to say that she got extra stuff that she didn't ask for. Luckily for me, our community is small and close, and we can fix errors like this reasonably easily. And the thought I had wasn't, oops, it was what the actual fuck. How did my brain allow me to do that? That's not me. Also, I've been having some I can't see at moments, or as my children love to tease me, boy looks. They're throwing that back at me quite rightfully since I've been smugly saying, Did you have a boy look for years and years? Oh how the worm has turned. I'll be looking for something actively searching, and it's right there. I did this with the dog's eye drops. Couldn't find them, but I knew Audrey, my daughter, had used them last. She was babysitting, so I rang her to ask where she'd left them. And she tells me exactly where they are, and I go to that spot and I can't see them. I assume she's wrong. I even give her a little bit of attitude, like, are you sure you put them there? Sigh, I'm going to have to have a little bit more help locating them. Okay, well I'm looking right at that spot and they're not there. And then there they are. Exactly where she said. And afterwards, I feel awful. Not just because I was wrong, and certainly not because I'd given her some attitude. I mean, come on now. But mostly because that behaviour isn't me. I might say that she gleefully piled on the shit when she got home. She was all like, and you were giving me attitude and saying, Are you sure you put them there? And I could hear the tone in your voice. And look, I had to take it because she was right on both counts. Damn it! Without making excuses, can I just mention that one week ago my GP increased my estrogen dose up to three pumps of estrogel? Estrogen isn't just about periods or hot flushes, it acts directly on the prefrontal cortex, executive function, the hippocampus, memory and spatial awareness, neurotransmitters like dopamine and acetylcholine. When estrogen levels are changing, not necessarily low but unstable, women can experience reduced working memory, poor task switching, irritability when corrected, mistakes that only make sense after the fact. And tellingly, my daughter Audrey noticed it before I did. She actually said, I think this is a sign of perimenopause. You're not usually this vague. I did speak to my GP about it, and she soothed me by telling me that if you know you are forgetting things that isn't dementia, well thanks. I didn't think it was dementia, but now that you've mentioned it, I feel so much better. I joke, my GP is the best. Shout out to Dr. Sarah Farrell at Sydney Women's Wellness Clinic. And I thought, okay, I'm a pharmacist, I can approach this intellectually. What does the evidence say might help cognition right now? So I've started creatine because there's good emerging evidence that it supports brain energy metabolism and cognitive performance, particularly under stress or sleep deprivation. I'll link the receipts to the study in the show notes. And maybe it'll have a side effect of making me swole, you never know. And if you could see my little stick arms and legs, you'd be laughing at me right now. I've joined an Olympic weightlifting gym because, ladies, we need to lift heavy. But we'll go into that in another episode. And I've started fish oil because omega-3s have evidence for supporting brain health, attention, and processing speed. You have to have the right dose though, and it's a lot, by the way, but there are some great formulas out there that don't taste or smell or repeat fishy. So it's not because they're magic and not because they fix hormones, because they're low-risk, evidence-supported, and rational supports. I will never know if in the end these small tweaks made a difference or not, but what is important to me right now is that I'm trying to give myself the best chance to age well. My grandmother lived to a few months before her 99th birthday, so I have long livers in my family. I'm trying to set myself up the best I can to be robust and strong in my later years. That's informed self-care. So what I've been describing is cognitive overload plus hormonal turbulence. And it feels scary because it messes with my identity, especially if competence has always been my thing. If you ask me what word I wanted people to know me by, it wouldn't be kind or happy or clever, it would be capable. I need to be capable. This isn't me becoming incapable. This is a new role with no continuity, high interruption, low automation, plus a recent oestrogen dose change. Perimenopause doesn't steal intelligence, it steals the buffer, the margin you used to have for chaos, multitasking, and interruptions. That's what shrinks. So if you're listening to this thinking, I used to be sharp, what's happening to me? Please hear this. You're not broken, you're not stupid, and you're not alone. Sometimes the kindest thing we can do is to stop gaslighting ourselves and say, hmm, this feels different, and it deserves. Curiosity, not shame. Because this isn't a decline, it's adaptation, and we're still very, very good at that, even on froggy brain days. Alright, woo of the week. Today we're talking about collagen powders, collagen drinks, and the very seductive idea that you can eat something that knows exactly where to go in your body. You know the ones hair, skin, nails, joint support, glow from within, as if collagen gets swallowed, hops into your bloodstream, checks Google Maps and says, Rhino, sore right knee first, then a quick stop at the cuticles before the final push towards growing those long, luscious locks. I wish, I mean truly. Let's start with the bit I actually agree on. Protein is not woo and is genuinely important. Most women do not eat enough protein, especially as we age. Protein is essential for muscle mass, bone health, hormones and enzymes, immune function, skin structure, recovery from exercise, and yes, connective tissue like tendons and ligaments. As estrogen drops, muscle loss accelerates and protein needs go up, not down. So if you struggle to heat your protein targets, which are 1.2 to 1.6 grams of protein per kilogram of body weight per day, and for some women, especially very active ones, up to 2 grams per kilogram of body weight per day, protein powder is a completely reasonable, convenient, practical, often helpful supplement. No argument here. Now, collagen specifically, and here's where the woo creeps in. Collagen is a protein, but it's an incomplete protein. It's low in key amino acids like leucine, which is critical for muscle protein synthesis. That already makes it a poor choice as your main protein source. The bigger issue here is when you eat collagen or protein, it doesn't stay as whole collagen or protein. It gets denatured by stomach acids, broken down by enzymes, chopped into amino acids and small peptides. Your body absorbs glycine, proline, hydroxoproline, and other amino acids. Your body then says, cool, raw minerals, and then it uses them wherever they're needed most. Your body is not a targeted delivery service. There's no biological mechanism where the collagen you eat goes to your hair because the tub says hair, or to your skin because the label is pink, or to your right knee because that's the one that hurts. Your body prioritizes vital organs, muscle repair, immune proteins, enzymes, and neurotransmitters. If there's enough left over, some of those amino acids may contribute to collagen synthesis in joints, skin, or connective tissue, but that is indirect, nonspecific, and highly individual. So, do collagen supplements work? Some studies show small improvements in joint pain or skin elasticity. Effects are modest, not miraculous. Benefits likely come from general amino acid availability, not targeted collagen repair, and many studies are industry funded. So if someone says my knee feels better on collagen, that can be true without it meaning collagen is rebuilding their knee cartilage like Lego. Correlation does not equal collagen GPS. The marketing is the problem, not the protein. What I take issue with is not protein or collagen powder, it's the story. The idea that one scoop gives you shiny hair, two scoops gives you wrinkle-free faces, three scoops gives you regenerated joints. That's just not how human physiology works. Your body is a chaotic, brilliant, survival-focused system, not a beauty concierge. If you want protein, prioritize complete protein sources, aim for adequate total daily protein, use protein powders if they help you hit your targets. If you like collagen, fine as an add-on, not a hero. Don't expect miracles, and don't let the marketing convince you it's medical treatment. Eat protein, lift heavy things, sleep. Those three do more for your joints, skin, and longevity than any beige powder ever will. Prescribe or pass? Protein powder, prescribe. Collagen as a magical targeted fix? Pass. If you take one thing away from today, let it be this. Progesterone isn't making you stupid, your brain is adapting to a shifting hormonal environment. And collagen isn't a magic GPS-enabled molecule that knows exactly where your sore knee is. And I know that's two things. As always, this isn't about doing more, it's about understanding better. If this episode has made something click, share it with a friend who's convinced her collagen powder is personally rebuilding her cartilage. And if you want more evidence based hormone chat without the wellness woo, find me at Prescribe or Pass on TikTok and Instagram. I'm Kate, thanks for being with me on the Mones. I'll see you next episode. Bye bye.