At a glance
- Allopregnanolone is a neurosteroid made when your body breaks down progesterone, and it acts on GABA-A receptors, the brain's main calming system.
- Levels rise through the luteal phase as the corpus luteum makes more progesterone, then fall sharply before your period.
- PMDD is linked to altered sensitivity to allopregnanolone, not abnormal levels of it (Schmidt et al., 1998, NEJM; Dubey et al., 2017, Molecular Psychiatry).
- Experimental drugs like dutasteride and Sepranolone aim to blunt its luteal rise or block its effect, but neither is a standard treatment yet.
- Coping tools can ease a hard moment, but they don't treat the underlying hormone pattern.
What is allopregnanolone?
Allopregnanolone is a neurosteroid your body makes by breaking down progesterone. It binds to GABA-A receptors, the brain's main calming system, the same receptors that alcohol and anti-anxiety medicines act on (a 2014 review in Progress in Neurobiology). In most people, that makes it soothing: it can ease anxiety and bring on a sense of calm.
Quick facts:
- Made mostly by the corpus luteum after ovulation, as a byproduct of progesterone
- Acts on GABA-A receptors, the same target as alcohol and benzodiazepines
- Crosses into the brain and shows up in blood and spinal fluid
- Levels track progesterone, rising and falling with your cycle
How does it relate to PMS and PMDD?
Progesterone rises through the luteal phase, the week or two after ovulation, as the corpus luteum produces it. Allopregnanolone rises along with it, then both drop in the days before your period starts.
For most women, that drop passes with mild, manageable symptoms.
PMDD is a different reaction to normal hormone changes, not abnormal hormone levels (Schmidt et al., 1998, NEJM; Dubey et al., 2017, Molecular Psychiatry). Research on allopregnanolone backs this up:
- A small study found women with PMDD respond differently to a standard dose of allopregnanolone than women without the condition do, pointing to a difference in sensitivity rather than in the amount their bodies make (a 2016 case-control study in Psychopharmacology)
- A 2006 trial in Psychoneuroendocrinology found women with PMDD and no history of depression had a different ratio of allopregnanolone to progesterone than other groups
Read more about what causes PMDD and how menstrual cycle hormones shift phase by phase.
What does the research say?
Researchers have tested several ways to change allopregnanolone levels or block its effect, in women with PMDD or severe PMS, to see whether that changes luteal-phase symptoms.
| Approach | What it targets | What researchers found |
|---|---|---|
| High-dose dutasteride | Blocks progesterone converting into allopregnanolone | Reduced core mood symptoms in a small randomized trial (2016, Neuropsychopharmacology, n=8 in the high-dose arm) |
| Sepranolone (UC1010) | Blocks allopregnanolone's effect at the GABA-A receptor | Lowered symptom scores in a phase 2 trial of 126 women with PMDD (2017, Psychoneuroendocrinology) |
| GnRH agonist (buserelin) | Lowers progesterone and allopregnanolone together | In women with severe PMS, not a confirmed PMDD diagnosis: symptom improvement tracked with falling allopregnanolone in responders (2007, Gynecological Endocrinology, n=12) |
| Low-dose alcohol infusion | Tests how allopregnanolone responds to GABA-A stimulation | In women with severe PMS, not a confirmed PMDD diagnosis: luteal-phase allopregnanolone dropped more after alcohol than in the follicular phase (2005, Psychoneuroendocrinology, n=14) |
These are research tools, not approved treatments. A 2021 systematic review of over 5,000 women found PMDD is also linked with lower luteal estradiol, suggesting more than one hormone pathway is involved (Frontiers in Neuroendocrinology, 2021). You can read more findings like these on our PMS and PMDD research page.
Why does it matter for treatment or coping?
None of the drugs above are approved PMDD treatments yet. Current guidelines still point to:
- SSRIs, which can work taken only in the luteal phase
- Certain hormonal contraceptives
- CBT (cognitive behavioral therapy)
A doctor decides what fits your history.
Allopregnanolone research doesn't change what helps on a hard night. Coping ideas can ease a moment. They don't treat PMDD itself. Niyora is a PMS and PMDD support app. Its Moon tool lets you write down what happened, see it from another angle, and draft a reply you can hold onto until you're calmer.
A few related terms worth knowing: the corpus luteum that makes the progesterone allopregnanolone comes from, the luteal phase when levels shift, and PMDD itself, the diagnosis these changes are studied in.
From the research library
Research on neurosteroids
167 studies in the library look at neurosteroids in PMS and PMDD. They were published from 1994 to 2026, and each one has a short summary of what was tested and found.
167
studies, 1994 to 2026
How strong the studies are
- Strong study design
- 11
- Moderate study design
- 45
- Early or limited evidence
- 111
Review, 2026
How well do SSRIs treat PMS?
SSRIs like sertraline and fluoxetine are first-line treatments for severe PMS. They work at low doses, are safe with few side effects, and reduce symptoms by affecting serotonin and brain chemistry related to mood.
Strong study design
Systematic review, 2026
Why do some women experience mood changes linked to their menstrual cycle?
Evidence shows these women have normal hormone levels but heightened sensitivity in their brains and cells to hormone changes. This explains PMDD and some postpartum and perimenopausal mood problems, and has led to new treatments.
Strong study design
Case-control study, 2024
Do steroid hormone levels change differently across the menstrual cycle in women with PMDD?
Yes. Progesterone rises earlier in the cycle in women with PMDD, leading to higher levels around ovulation and a sharper drop in the late luteal phase. This different pattern may trigger symptoms.
Strong study design
Systematic review, 2022
Does the stress hormone cortisol change across the menstrual cycle?
Yes, but only slightly. Across many studies, cortisol was a little higher in the first half of the cycle (follicular phase) than the second half (luteal phase), and higher during a period than right before it, but most other phase comparisons showed no clear difference.
Strong study design
Systematic review, 2022
Is taking antidepressants only at certain times as effective as taking them every day for PMS?
Yes. Intermittent dosing works just as well as taking them every day, with effects starting within hours and peaking within 2 days.
Strong study design
Survey study, 2022
What causes PMS and PMDD and what new treatments are being studied?
PMS and PMDD involve changes in hormone sensitivity, serotonin levels, genetic factors, and inflammation. New treatments under research target progesterone receptors and inflammatory pathways.
Strong study design
Clinical trials
Allopregnanolone and Dynamic GABA-A Receptor Plasticity in Selective Serotonin Reuptake Inhibitor Responsive Premenstrual Dysphoric Disorder
Recruiting now, United States
A Study of Efficacy and Safety of Sepranolone (UC1010) in Patients With Premenstrual Dysphoric Disorder (PMDD)
Completed, Germany
Stress & Premenstrual Symptoms Study
Completed, United States
Questions people ask
What does allopregnanolone do in the brain?+
Allopregnanolone acts on GABA-A receptors, the brain's main calming system, the same targets used by alcohol and anti-anxiety medicines. In most people, that makes it soothing and lowers anxiety. Allopregnanolone levels rise with progesterone in the luteal phase, then fall in the days before your period starts.
Is allopregnanolone the same thing as progesterone?+
No. Allopregnanolone is a neurosteroid made when your body breaks down progesterone. Progesterone itself doesn't act directly on GABA-A receptors the way allopregnanolone does. The two rise and fall together through the menstrual cycle, but allopregnanolone is the metabolite behind most of progesterone's calming, brain-level effects.
Does allopregnanolone cause PMDD?+
Not exactly. PMDD is a different reaction to normal hormone changes, not abnormal hormone levels (Schmidt et al., 1998, NEJM). Research on allopregnanolone backs this up: women with PMDD seem to respond differently to a standard dose of it than women without PMDD do, pointing to a difference in sensitivity rather than in levels.
Can a drug that blocks allopregnanolone treat PMDD?+
Researchers have tested drugs like Sepranolone and dutasteride that block allopregnanolone's rise or its effect on the brain. Early trials found fewer symptoms in some women with PMDD. Neither is an approved PMDD treatment yet. Current guidelines still point to SSRIs, certain hormonal contraceptives and CBT, decided with a doctor.
Why do allopregnanolone levels change before your period?+
Allopregnanolone is made from progesterone, mostly by the corpus luteum after ovulation. Progesterone rises through the luteal phase, so allopregnanolone rises with it, then both drop sharply in the days before your period starts. That drop happens every cycle, not only in PMS or PMDD.
Sources
- 1.5α-Reductase Inhibition Prevents the Luteal Phase Increase in Plasma Allopregnanolone Levels and Mitigates Symptoms in Women with Premenstrual Dysphoric Disorder, Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 2016
- 2.Associations of histories of depression and PMDD diagnosis with allopregnanolone concentrations following the oral administration of micronized progesterone, Psychoneuroendocrinology, 2006
- 3.Allopregnanolone decrease with symptom improvement during placebo and gonadotropin-releasing hormone agonist treatment in women with severe premenstrual syndrome, Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology, 2007
- 4.The effect of a low dose of alcohol on allopregnanolone serum concentrations across the menstrual cycle in women with severe premenstrual syndrome and controls, Psychoneuroendocrinology, 2005
- 5.Variation in genes and hormones of the hypothalamic-pituitary-ovarian axis in female mood disorders - A systematic review and meta-analysis, Frontiers in neuroendocrinology, 2021
- 6.Treatment of premenstrual dysphoric disorder with the GABA A receptor modulating steroid antagonist Sepranolone (UC1010)-A randomized controlled trial, Psychoneuroendocrinology, 2017
- 7.The role of allopregnanolone in depression and anxiety, Progress in neurobiology, 2014
- 8.Women with premenstrual dysphoric disorder have altered sensitivity to allopregnanolone over the menstrual cycle compared to controls-a pilot study, Psychopharmacology, 2016