We've seen an uptick in posts recommending bioidentical progesterone as a treatment for PMDD, so we're here with a post to run through the science of it all with you.

Progestins vs Progestogen vs Progesterone

These words are often used interchangeably, but they mean different things. Most of the time, this doesn’t matter very much (so you’ll rarely see us correcting sub members). This time, it does matter!

Progesterone is the specific steroid hormone your ovaries make after ovulation. 

Bioidentical progesterone is a lab-made version of progesterone, with the same molecular structure as what your ovaries produce. 

Progestins are synthetic compounds that act on progesterone receptors but are structurally different from progesterone. Examples include drospirenone, levonorgestrel and norethisterone. This is what is in most hormonal contraceptives. 

Progestogen is the umbrella term for both natural progesterone and synthetic progestins together. 

Bioidentical progesterone is often marketed as inherently ‘better’ because it is structurally identical to your own hormone. Whilst it is true that it is structurally identical, it does not inherently mean it is ‘better’ or even that it is an appropriate tool. 

The Mechanisms Behind PMDD

People with PMDD do not have abnormal hormone levels. Multiple studies have shown that estrogen and progesterone levels across the cycle look the same as people without PMDD. What differs is sensitivity - our brains react abnormally to entirely normal hormone changes. 

Progesterone gets metabolised into a neurosteroid called allopregnanolone, which normally acts like a calming agent on GABA-A receptors. GABA is your main inhibitory/calming neurotransmitter - it’s the same receptor system benzodiazepines act on. In most people, rising allopregnanolone in the luteal phase is mood-neutral or even mildly calming. In people with PMDD, research has found altered or paradoxical sensitivity; instead of calming, it provoked anxiety, irritability, and depressive symptoms. 

The critical detail is that it’s about change, not level. 

The Role of Progestogens in Standard PMDD Treatments

Combined oral contraceptives (COCs) suppress ovulation, so there is no natural progesterone surge and no withdrawal. No ovulation = no luteal phase = no PMDD.

Progestogen-only pills are slightly more nuanced. Older POPs (like levonorgestrel and norethisterone) are not reliable at suppressing ovulation. Ovulation may still occur, so we still experience fluctuations during luteal. Newer POPs (like drospirenone and desogestrel) are different because they reliably suppress ovulation. They can be a useful option for people who can’t take estrogen (e.g. migraine with aura, clotting risk, etc). 

u/DefiantThroat has unpacked this more here: https://www.reddit.com/r/PMDD/comments/1qiiktu/birth_control_is_not_a_monolith_and_a_tiny_rant/

What matters for this discussion is that these methods work by suppressing ovulation, not because we are adding more progesterone into the system. 

Bioidentical Progesterone - What It Is and How It Works

Bioidentical (micronised) progesterone is structurally identical to what your ovaries produce. It is most commonly oral (e.g Utrogestan/Prometrium), vaginal (e.g. suppositories, gel), and compounded creams (more on this later). 

Like natural progesterone, it metabolises (partly) into allopregnanolone and acts on GABA-A receptors, producing anti-anxiety and sedative effects. This is the basis for why some people find it calming and sleep-promoting. 

Bioidentical progesterone has solid evidence in endometrial protection when taking estrogen (as in menopausal HRT), fertility treatment, and  perimenopausal/menopausal symptom relief. 

Oral bioidentical progesterone has poor bioavailability and undergoes heavy first-pass liver metabolism. It is cleared quickly and levels spike then drop, rather than staying flat. This makes achieving stable levels difficult. 

Unlike POPs, bioidentical progesterone does not reliably prevent ovulation. 

Why Bioidentical Progesterone Is Not Recommended for PMDD

Putting the mechanism and evidence together, we have several converging reasons: 

1. It doesn’t address the actual problem. PMDD isn’t caused by too little progesterone - it’s caused by an abnormal response to normal progesterone changes. Adding more progesterone doesn’t fix this sensitivity, it just adds more of the substance that the brain is reacting badly to. 
2. It can recreate or worsen the fluctuation problem. You haven’t eliminated the up-and-down pattern that seems to be the actual trigger - you’ve just shifted the whole pattern to a higher baseline. The peaks are higher, the troughs are higher, but the rate of change between each peak and trough is still there.  Further, oral bioidentical progesterone doesn’t produce flat, steady hormone levels. Instead, it produces peaks and troughs (dosing -> absorption spike -> rapid clearance -> trough -> next dose). 
3. There is direct clinical evidence of this backfiring. In studies of GnRH-agonist ‘add-back’ therapy - where ovulation is chemically suppressed and hormones are reintroduced to prevent menopause-like side effects - reintroducing progesterone has been shown to trigger PMDD-like symptoms in a subset of people. This is a clear demonstration that adding progesterone back into the system can recreate the problem that it’s meant to solve. 
4. No major guidelines recommend it as a standalone PMDD treatment. Formal evidence supporting bioidentical progesterone to treat PMDD is a mixture of weak and negative. The Royal College of Obstetrics and Gynaecology note that ‘There is good evidence to suggest that treating PMS with progesterone or progestogens is not appropriate.’ Keeping this in mind, they also highlight that micronised (or bioidentical) progesterone should be used in cases where percutaneous estradiol (a form of estrogen applied to the skin) is used to treat PMS, in order to prevent endometrial hyperplasia (thickening of the womb). They do note that ‘Progesterone may act as a diuretic and a central nervous system anxiolytic and so in theory could also alleviate PMS symptoms, although there is currently little evidence to demonstrate this’. It is important to note that the study supporting this focuses on ‘Progestogen intolerance and compliance with hormone replacement therapy in menopausal women’ rather than PMS or PMDD, whilst other studies suggest that current data is not solid enough to draw conclusions from or that there was no meaningful difference from placebo. [Note: PMDD is conflated with PMS in these guidelines. Our hope is that the next iteration will include distinction between the two.]

How could bioidentical progesterone improve PMDD symptoms?

1. Sleep. The calming effect is real and well documented. If poor sleep is making your PMDD worse (and for a lot of people it does!), then sleeping better can genuinely make your whole week feel better. That isn't the same as progesterone treating PMDD itself.
2. Short-term anxiety relief. Some people do get a real calming effect from progesterone, especially early on.
3. Overlapping issues, like perimenopause. As cycles change with age (or with comorbid conditions), some people develop other hormone-related problems alongside PMDD. These can include low-progesterone in the second half of the menstrual cycle and early perimenopause. Progesterone does have good evidence for these so if your symptoms are a mix of PMDD and one of these things, progesterone might be helping with the 'other thing'.
4. The placebo effect is huge. That doesn't mean anyone's experience is fake or 'just in their head'; placebo effects are real and physical. It just means personal stories need to be weighed carefully against proper trial data, because a lot of people would improve no matter what they took.

A Note on Marketing, Compounding, and Prescribing

The British Menopause Society’s April 2026 consensus statement on bioidentical HRT formalises a split between rBHRT (regulated bioidentical HRT), which is precise duplicates of human hormones developed through conventional pharmaceutical development and authorised by regulators, and cBHRT (compounded bioidentical HRT), which is precise duplicates of the same hormones but produced by specialist/compounding pharmacies and not subjected to the same regulatory pathway. 

The important distinction between the two is regulation, testing, and quality control. The BMS's actual position is unambiguous: they do not recommend prescribing cBHRT, on the basis that the same potential benefits are available through regulated products without the risks of unregulated compounding. 

In our experience moderating this space, a lot of the bioidentical progesterone recommendations you’ll see trace back to practitioners working outside mainstream endocrinology, gynecology, or psychiatry. Naturopaths, functional medicine practitioners, and compounding-pharmacy affiliated clinics in particular. This isn’t a credentialing snobbery point (plenty of well-qualified prescribers also prescribe progesterone off-label for symptom relief) but it is a pattern worth pointing out. The theory of treating PMDD with bioidentical progesterone tends to originate in and get amplified by spaces that mainstream endocrinology doesn’t recognise, sold alongside unregulated products that haven’t been tested against for safety or efficacy. 

When you see this recommendation in the sub, it’s worth questioning whether this was prescribed as a regulated product as part of a wider evidence-based plan or whether it came bundled as wild yam cream with a diagnosis of ‘hormone imbalances’ from a practitioner outside of the mainstream evidence base.

[Note: Wild Yam Cream is a scam, updated post incoming later this week]

Conclusion

We're not writing this to tell anyone their experience is wrong. We're writing it because the way this keeps getting recommended in here worries us, for reasons that go beyond "the evidence is weak." 

The cost of getting things wrong isn’t neutral.  Every time someone gets steered towards bioidentical progesterone instead of towards SSRIs, COCs, or the other options with real evidence behind them, that's time spent on something that isn't likely to work, while the things that are shown to work - and for a lot of people, work amazingly - get pushed further down the list. We're talking about someone potentially spending months feeling like they're failing at treatment, or feeling worse than when they started, because the thing that was confidently recommended to them in a support space was working against the exact mechanism driving their symptoms. 

The part that worries us the most is that we don’t see the failures. Someone posts that bioidentical progesterone helped them, and that post gets saved, shared, upvoted, and repeated to the next person who asks. Nobody comes back a month or two later to post "actually this made me feel so much worse" or "turns out I was in perimenopause the whole time and this wasn't PMDD at all." Why would they? There's no reason to return to a support group to publicly say a recommendation someone gave in good faith backfired on you, or that you'd misattributed your symptoms in the first place. So the visible evidence in here skews entirely positive, while the people it didn't work for, or actively hurt, just quietly disappear from the conversation. That's not a knock on anyone who's posted about their own good experience - it's just how selection bias works in a support community, and it's exactly why we think it's worth actually laying out the research rather than going on what gets posted and upvoted. 

As always, our mod posts will be updated as any new science or guidelines emerge.

Obviously the whole ultra-processed food thing is about food...but I have noticed that the changes I've made and the content I've been consuming have caused changes in other parts of my life too.

For example:

• I'm more aware of the science surrounding what I consume, so I have also been paying more attention to the science surrounding other aspects of my wellbeing. Mindfulness, sleep, walking, etc. Where I would usually just read a couple of articles and take it all at face value, I'm now looking at the actual studies behind recommendations and making decisions based on risks, benefits, and effort.
• In taking an 80-20 approach to UPFs, I've also learned to apply this to other aspects of my life. Where I would usually be upset at not achieving perfection, I'm far more comfortable now.
• I think about consumerism and the push for us to buy + consume products more than I did previously. My treats lean more towards experiences and hobbies or high quality products with a long lifespan now.
• In order to avoid ultra-processed breakfasts and lunches, I've been making my own rather than purchasing them. My plastic waste has reduced in a big way because of this!
• I've gotten better at telling good faith arguments apart from people who are out to say something incorrect or controversial for the sake of it. I'm not sure what it is, but engaging in conversations surrounding food has made it a lot easier to identify these patterns and extrapolate.

So, what about you?

The sub has been very busy recently, with many posts echoing the same sorts of emotions, so I thought I'd put the link to our WhatsApp community out there again for anyone who needs it.

I started the community about 2.5 years ago because PMDD is such an isolating illness... the guilt, the arguments, the shame spirals, the feeling like you're the only one who "gets" why it feels like the end of the world. I didn't want to feel that alone anymore, and I figured other people probably didn't either.

We're now 140 members strong, with chats for:

• Ranting/venting/hating
• The Void (send anything, no judgment, messages auto-delete after 24hrs)
• Sharing your wins and wholesome content
• Relationships & PMDD
• Wellbeing chat
• General chatter, gossip, and getting to know each other
• Memes

We're not here to talk medical management. We want to chat, laugh, cry, rage, and make genuine friends with people who understand.

Gender inclusive, no diagnosis required, PMDD and PME welcome, come as you are.

Oh, and we have regular animal pictures - cats, dogs, chickens, ducks, geese, pigs, goats, horses, the lot 🐐

https://chat.whatsapp.com/HunH5MkU7QiATJpBaKW0gp

Edit: Follow the link to join, then head into General and send a quick intro. Once you've done that, we will accept your requests into sub-groups! :)

After I messaged our mod group chat this morning to inform everyone I wanted to leave work and bulk buy beads, u/DefiantThroat suggested we bring this to the whole community as a little game.

For example:

Luteal has hit. I'm gonna leave work and go bulk buy beads.

Now, it's your turn! Post your luteal impulse and support purchases down below.

Context: I am in the UK, where it has been too fucking hot for many weeks now. We have no air con and my floor-to-ceiling, whole-wall windows face the sun most of the day. I have endometriosis, which can cause heat intolerance, so I have made the shit decision to not take my luteal prozac to minimise the risk of becoming dehydrated and feeling even worse. As such, I am experiencing true Luteal Rage™.

So, I am here to vent. Please feel free to join my rage. Advice is not welcome.

•It is too fucking hot

•We are literally experiencing the actualisation of global warming and Taylor Swift still has a private jet.

•PMDD sucks so fucking bad

•I am exhausted from seeing constant misinformation about PMDD everywhere. It is tiring and annoying and dangerous.

•I am getting acupuncture for endometriosis and it has done nothing for either my endometriosis or my PMDD so far. I feel like I'm wasting my time and energy on it.

•I was offered homeopathic medicine for endometriosis. Fuck off.

•Endometriosis, migraines with aura, and PMDD is such a shit combination and I just wish I didn't have one of these.

•I feel like a horrible, terrible person. I wish I could just keep up with my routine for all 4 weeks of the month instead of allowing everything to fall apart every luteal.

•I need a new job but every luteal I don't have the emotional or physical energy to apply for jobs. During my period I am in too much physical pain. I get 1 week.

•See above point but the gym.

•Every luteal, I wonder how I'm going to do this for another 20+ years. I do not feel like I can.

Thanks for sticking with me through my vent.

r/StopEatingSeedOils user asks for evidence seed oils are bad, accidentally starts a 400-comment epistemology war:

Post: What is the evidence seed oils are bad? : r/StopEatingSeedOils

Highlights include:

On users saying the answers don't provide actual evidence:

>Not evidence,' bleats the sheeple, brain too atrophied by credentialism to recognize a deductive chain without a white-coated priest waving a p-value at them

Your good old conspiracies:

>The companies that make the seed oils own the government, universities and medical sector

>Doctors getting paid off to say cigarettes are healthy

And not a single piece of evidence being provided.

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I don't usually make posts like this but this has been weighing on me.

In the last couple of weeks, I have been accused of being a man 4 times. Three of those times, the accusations were directed at the entire r/PMDD mod team. The fourth time, I had an image of my face turned into a man using AI, which was then sent back to me as evidence that I was a 'man and a pervert'. So, let's talk about it.

All 5 members of the r/PMDD mod team are cisgender women.

Not only is this accusation ridiculous, it's also deeply hurtful.

I have lived with PMDD and endometriosis since before my first menstrual cycle. Between those two conditions, I have spent more than 15 years navigating chronic pain, severe cyclical symptoms, medical dismissal, and the exhausting, often demoralising process of trying to find treatment and support that actually works. Like many of you, I have spent countless hours researching, trialling different approaches, and searching for answers in the middle of the night when the symptoms made sleep impossible.

Over the years I have dedicated a significant amount of time to PMDD advocacy, education, and peer support. I have spoken with members of this community through voice and video calls, attended conferences in person, and built working relationships with researchers, clinicians, and advocates in the PMDD space. I mention this not because my experience is more important than anyone else's, but because it is genuinely distressing to have my identity, my motives, and my lived experience questioned and mocked by the very community I have given so much of myself to.

If you want 'proof' that r/PMDD mod team are *really* women, you won't be getting it. Nobody should feel the need to justify their existence because of conspiracy theorists and bad faith actors.

Using someone's gender as a weapon - suggesting they are a man to discredit them or question their right to be here - is not just hurtful to the person it is aimed at. It contributes to an environment that is less safe and less welcoming for transgender and gender-diverse members of this community too.

We don't always get things right, but we're always ready to acknowledge this and learn from our mistakes. We want this to be a community where you feel welcome and safe. You are welcome to question us, challenge us, and raise concerns, *which you can do by sending us a Modmail*. Healthy pushback is part of how any community stays honest and we *always* engage respectfully with genuine concerns.

What is not acceptable is personal abuse, public callouts, accusations about our identities, and AI-manipulated images of our faces.

We moderate this community because we care about it deeply. Every member of this mod team is here because they have lived experience of PMDD, because they want this to be a space where people feel understood, supported, and safe. We are not faceless accounts. We are women with PMDD, with our own histories, diagnoses, struggles, jobs, families, and lives. We give a significant amount of our time and emotional energy to maintaining this space for free, because we believe it matters.

- a very luteal (and very upset) mod