The Hormone and Immune Story Behind Endometriosis
For years, endometriosis has been described as an "oestrogen problem" or “oestrogen dominance”. That's partly true, but it misses most of the story. When I explain to clients what's happening at a cellular level, the reaction is often relief. Finally, their experience makes sense.
Your blood oestrogen is probably normal
This surprises many people. When researchers compare women with and without endometriosis, the oestrogen levels in their blood are much the same.
The excess oestrogen is made inside the lesions themselves. Each lesion works like a tiny factory producing its own supply. It turns up an enzyme called aromatase, which makes oestrogen, and turns down another enzyme that would normally convert strong oestrogen into a weaker form.
Then a vicious circle kicks in. Oestrogen triggers an inflammatory messenger called prostaglandin E2 (the same family of chemicals behind period cramps). Prostaglandin E2 then tells the factory to make even more oestrogen. It also encourages new blood vessels to grow, giving the lesion its own supply line so it can survive and spread.
This is also why a blood test for oestrogen won't tell you whether you have endometriosis.
When the receptors change
Oestrogen works by docking into receptors, and there are two main types, alpha and beta. In healthy tissue they're balanced, with alpha leading. In endometriosis the balance flips and beta takes over.
That wouldn't necessarily be a problem, except both receptors start misbehaving:
The alpha receptor drives inflammation and uncontrolled growth.
The overactive beta receptor stops damaged cells from self-destructing, as they're meant to. Normally the body clears faulty cells. In endometriosis they survive.
Progesterone resistance: the brakes that stop working
Progesterone is oestrogen's natural counterbalance. It calms growth in the womb lining, reduces inflammation and prepares the lining for pregnancy.
In endometriosis, the tissue becomes resistant to progesterone. You may be ovulating well and making plenty of it, but the lesions can't hear it. It's like pressing the brake pedal on a car where the brakes have been disconnected.
Part of the reason lies in progesterone's two receptors. One acts like an accelerator, switching progesterone's helpful effects on. The other acts like a brake on that accelerator. In endometriosis lesions, the accelerator receptor is often undetectable, while the brake receptor is everywhere.
This matters for two reasons:
It's why testing progesterone levels doesn't reveal the problem.
It's why simply taking progesterone isn't the answer. If the tissue isn't listening, adding more doesn't solve it. The better question is what made the tissue stop listening in the first place.
A quick word on medical treatment
Conventional treatment usually starts with anti-inflammatory painkillers, then the pill, then stronger options that switch off the ovaries.
These treatments can bring real relief. But they work mainly by quietening hormones at the level of the brain. They don't address the inflammation, immune changes and nervous system changes that keep the cycle turning.
The immune system's clean-up crew
Macrophages are immune cells whose job is to find and clear things that shouldn't be there. In endometriosis there are two to three times more of them in the pelvis, yet they clear less. They've switched from "attack" mode into "repair and build" mode.
Picture a cleaning crew who arrive to clear a mess and start building an extension instead. These macrophages release signals that:
grow new blood vessels to feed the lesions
help lesions multiply
help lesions invade surrounding tissue
Natural killer (NK) cells are the body's security guards against abnormal cells. In women with endometriosis, the numbers in the blood are normal, but there are far fewer in the pelvis, where they're needed. Plus, the ones that are present work at a fraction of their usual strength.
The lesions also display what's essentially a "don't attack me" signal. So the immune system ends up treating tissue that shouldn't be there as a friend.
The result is a strange mix: plenty of inflammation, but the immune system tolerating the lesions instead of clearing them. And with no resolution, the inflammation becomes chronic, feeding right back into the loop that makes more lesions and grows them.
How we can support this naturally
This is why I don't approach endometriosis with one supplement or one diet. The goals are to:
calm the local oestrogen factory
reduce inflammation
limit the new blood vessels feeding lesions
help the immune system resolve instead of simmer
Research supports several natural compounds here:
green tea and resveratrol (found in red grapes)
turmeric
ginger, which is excellent for period pain too
rosemary, pomegranate and nettle
omega-3 fats and the compounds made from them, which help the body switch off inflammation once it has done its job
One study of the antioxidant NAC also showed some encouraging results in women with endometriosis.
Dosing, timing and combinations matter, and not everything suits everyone. Please work through this with a qualified practitioner rather than stacking supplements on your own.
The TCM view
In Chinese medicine, lesions that build their own blood supply and resist the body's attempts to clear them fit the picture of long-standing Blood stasis. The underlying terrain is often weakened Qi, which means reduced defensive capacity.
Acupuncture and herbs aim to move stagnant Blood and strengthen the body's defences at the same time. To me, that mirrors the modern goal of calming inflammation while supporting immunity.
If this has helped your own endometriosis make more sense, I'd love to support you further. Book a consultation at Vale of Health, and follow @valeof.health for the final part of this series on endometriosis pain.