A research brief · November 2026

Endometriosis. What actually works.

A black cat lying upside down inside a fridge next to a carton of oat milk
For Dracula's wife.

I ran a research agent across the clinical trials, the Cochrane reviews and the drug pipeline, had it put this site together, and reviewed the whole thing.

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The short version

Five things, if you read nothing else.

Hormones control the pain in most women. Dienogest or a hormonal IUD is the evidence-backed first move.Lesions run on estrogen. Both cut the supply. Cochrane, 33 trials.

If those fail, the relugolix combination pill. Three in four women get real relief.FDA approved for endometriosis since 2022. Two Phase 3 trials, 1,261 women.

Get the pelvic floor assessed. It becomes a second pain source that no hormone touches.Physiotherapy takes about two points off a ten-point pain scale, and it holds at a year.

Surgery works when the surgeon is an excision specialist. Pair it with an IUD after.The IUD was the only drug that cut recurrence after surgery in a 16-trial analysis.

The first non-hormonal drug in history is in Phase 3. Results 2028. The trial is recruiting now.HMI-115, a monthly antibody injection. Phase 2 cut pelvic pain in half.

01

The ladder

Every clinic in the world climbs the same four rungs. What changes is how much evidence sits under each one.

Rung one

Painkillers

Where everyone starts. Guidelines recommend NSAIDs, but Cochrane found a single usable trial of 24 women. They take the edge off. Nobody has shown they do more.

Thin
Rung two

Hormones

Dienogest, the combined pill, or the hormonal IUD. Dienogest: 2.6 points off a ten-point pain scale across 33 trials. The pill works at about half that. The IUD is the one to have after surgery.

Strong
Rung three

GnRH antagonist pills

Relugolix combination in the US, linzagolix in Europe. They switch the ovaries off and add a little estrogen back so bone is protected. Three in four respond. Bone loss under 1% at two years.

Strong
Rung four

Excision surgery

Cochrane rates the pain evidence low quality. The fertility benefit is clear, and many women get years of relief. Outcomes depend on who holds the instrument: fellowship-trained excision specialist, not a general OB-GYN.

Mixed
02

Versus placebo

The only number that matters in a drug trial is the gap between the drug and the sugar pill. These are the treatments where that gap is large and the trial was blinded.

TreatmentPlacebo
Relugolix combinationperiod pain responders, 6 months
75%
28%
Linzagolix 200 mgperiod pain responders, 3 months
73%
24%
Relugolix combinationnon-period pelvic pain responders
62%
42%
Pelvic floor Botoxreported benefit at 1 month
73%
29%
Relugolix: SPIRIT 1 and 2, Lancet 2022, 1,261 women, placebo figures averaged across the two trials. Linzagolix: EDELWEISS 3, 2024. Botox: NIH Phase 2, 29 women, double-masked.
Spock from Star Trek calmly holding a black cat
Intermission. The science officer has read the NSAID trial and has concerns.
03

The part most doctors skip

Years of pelvic pain teach the pelvic floor muscles to clench. The spasm becomes its own pain source, and no hormone touches it. One assessment visit tells you whether this is part of your pain.

Pelvic floor physiotherapy

2.0points off a ten-point scale

Seven studies pooled in 2026. Hands-on local work and electrotherapy beat general exercise. A 2025 trial checked again a year later and the gain was still there.

Botox, for confirmed spasm

5 to 11months of relief per injection

100 units into the spasming muscles, done at specialist pain clinics. Most women in the NIH trial cut their pain medication. Small trial, properly blinded.

Acupuncture and exercise both show pain reductions across small trials. Low risk, thin evidence, reasonable to try.

04

Supplements

A huge market, almost no regulation. This is what the placebo-controlled trials show. One strict 2026 review that filtered for trial integrity found nothing beats placebo, so read the left column as cheap and plausible, not proven.

Has a signal

Vitamin C 1,000 mg and vitamin E 800 IU, dailyTop performer for period pain in the 2025 network analysis. Eight weeks is the tested window.
Curcumin, alongside dienogestOne clean double-blind trial in 2025: less pain of every type after eight weeks.
Melatonin, 3 to 5 mg at nightBetter sleep and less period pain in two trials when added to dienogest. High doses caused dizziness.

No signal

Vitamin DTwo placebo trials. Nothing on pain.
CBDA 102-woman trial found no benefit over placebo.
Low-dose naltrexoneThe only registered trial was terminated.
PentoxifyllineCochrane reviewed five trials. No effect.
N-acetylcysteineOne 2013 observational study, still no trial.
A soaking wet black kitten on a wooden floor, captioned: she discovered 2 things today, rain and regret
Also everyone who paid for the CBD.
05

What's coming

For forty years every endometriosis drug has been a hormone. That is changing. These are the trials that matter, in the order their results land.

2026

Esketamine

Phase 3, Netherlands. Targets the nervous system's pain amplification rather than the lesions.

Phase 3 · recruiting
2027

Vipoglanstat

Phase 2, Sweden. Blocks the specific prostaglandin behind the pain without the stomach and kidney cost of NSAIDs. Fully enrolled.

Phase 2 · enrolled
2027

Metformin

Phase 2, Boston Children's Hospital. A diabetes drug as an add-on, on the theory that blood sugar regulation calms the inflammation.

Phase 2 · running
2028

HMI-115

An antibody that blocks the prolactin receptor. Non-hormonal, one injection a month, no bone loss, no hot flashes. Phase 2 cut period pain 42% and non-period pelvic pain 50%, published in The Lancet's women's health journal this month. FDA Fast Track and Breakthrough status. The first non-hormonal endometriosis drug to reach Phase 3.

Phase 3 · recruiting · NCT07318688
2030

Dichloroacetate

Edinburgh. A repurposed cancer drug that starves lesions of lactate. A 100-woman randomized trial just finished; the definitive UK trial reports around 2030.

Feasibility done
06

If it were me

The order I'd take it in.

Audit the current plan

Painkillers or a basic pill only: dienogest or a hormonal IUD is the next step. Hormones already failed: relugolix combination, which has the strongest trial data on the market.

Get the pelvic floor assessed

One visit with a pelvic floor physiotherapist. If there's spasm, that's a second pain source with its own fix.

Choose the surgeon, not the surgery

Never excised, or only ablated: find a fellowship-trained excision specialist. Hormonal IUD afterward so it lasts.

Run the cheap stack for eight weeks

Vitamin C 1,000 mg and vitamin E 800 IU daily. Curcumin if on dienogest. Melatonin 3 to 5 mg at night if sleep is bad. Keep a pain log and judge by the numbers.

Get on the HMI-115 list

Phase 3 is recruiting under NCT07318688. Enrolling means a real shot at the drug two years before it can be bought.

Research, not medical advice. Everything here is something to bring to a specialist.

The literature+
Cochrane 2025 · Progestagens for endometriosis pain, 33 RCTs Obstet Gynecol 2025 · Network meta-analysis of drug treatments, 31 RCTs EJOG 2025 · Progestogens vs combined pill, 7 trials BJOG 2026 · Post-surgery drug network meta-analysis, 16 RCTs Cochrane 2017 · NSAIDs for endometriosis pain Lancet 2022 · Relugolix SPIRIT 1 and 2 Phase 3 trials Hum Reprod 2024 · Relugolix two-year extension Hum Reprod 2024 · Linzagolix EDELWEISS 3 Phase 3 Cochrane 2020 · Laparoscopic surgery for endometriosis BMJ 2024 · PRE-EMPT trial, hormones after surgery Pain Med 2026 · Physiotherapy meta-analysis J Physiother 2025 · Exercise and pelvic floor training RCT EClinicalMedicine 2026 · Pelvic floor Botox Phase 2 RCT Arch Gynecol Obstet 2024 · Acupuncture meta-analysis PLoS One 2025 · Exercise systematic review PLoS One 2024 · Vitamin C and E meta-analysis Pain Res Manag 2021 · Vitamin C and E triple-blind RCT Gynecol Obstet Invest 2026 · Supplements, strict placebo-controlled review Phytomedicine 2025 · Curcumin plus dienogest RCT Obstet Gynecol Sci 2026 · Melatonin plus dienogest RCT PLoS One 2023 · Melatonin 20 mg placebo RCT Reprod Biol Endocrinol 2022 · Vitamin D systematic review Cochrane 2021 · Pentoxifylline ClinicalTrials.gov · DREAMLAND CBD trial ClinicalTrials.gov · Low-dose naltrexone trial, terminated Lancet OGWH 2025 · HMI-115 Phase 2 ClinicalTrials.gov · HMI-115 Phase 3, recruiting ClinicalTrials.gov · Vipoglanstat Phase 2 ClinicalTrials.gov · Esketamine Phase 3 ClinicalTrials.gov · Metformin Phase 2 NHS HRA · Dichloroacetate EPiC2 trial NICE 2025 · Relugolix combination appraisal ESHRE 2022 · Endometriosis guideline