By Leila Martyn, Founder of MyOva

The luteal phase is the second half of your menstrual cycle. It starts the day after you ovulate and ends when your next period begins. In a large study of more than 600,000 cycles it averaged 12.4 days, and most women fell somewhere between about 7 and 17 days [1]. During this phase the empty follicle that released your egg (the corpus luteum) makes progesterone. That hormone shift is why you might run warmer, feel hungrier, sleep worse or feel more on edge in the week or so before your period.

You're not imagining it. But "it's just your hormones" isn't the full answer either. Below are the 7 most common signs you're in your luteal phase, what's actually behind them, when a short luteal phase matters (and when it doesn't), and what helps.

New to MyOva? Join our mailing list for 20% off your first order, plus straight-talking hormone guides in your inbox. If your second half of the month is mostly about sleep, start with why you can't sleep before your period. If it's more about mood, read PMDD vs severe PMS.

In this guide

• What is the luteal phase?
• How long is the luteal phase?
• What happens to your hormones in the luteal phase?
• What are the 7 signs you're in your luteal phase?
• Is it PMS, PMDD or just your luteal phase?
• What is a short luteal phase, and does it matter?
• How do you know when your luteal phase starts?
• What actually helps in the luteal phase?
• Do supplements help with luteal phase symptoms?
• When should you see a GP?
• FAQ

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What is the luteal phase?

Your cycle has two halves, and they're split by ovulation. The first half is the follicular phase: your period, then a stretch where a follicle matures and oestrogen climbs. Ovulation is when that follicle releases an egg. Everything after that, up to the first day of your next period, is the luteal phase.

The name comes from the corpus luteum (Latin for "yellow body"). That's what the follicle turns into after it releases the egg. It works like a temporary gland, making progesterone and some oestrogen to prepare the womb lining in case an egg is fertilised. If no pregnancy happens, the corpus luteum breaks down, both hormones drop, and the lining sheds as your period.

Here's the bit that rarely gets taught: no ovulation means no corpus luteum, and that means no real luteal phase that cycle. That's why women with irregular cycles, including many with PMOS (PCOS), can't count on having one every month. More on that in our guide to anovulation.

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How long is the luteal phase?

The best real-world data comes from Bull and colleagues, who analysed 612,613 ovulatory cycles from more than 124,000 users of a temperature-tracking app [1]. They found:

• The average luteal phase was 12.4 days, with most falling between about 7 and 17 days.
• The average follicular phase was 16.9 days, with a much wider spread (about 10 to 30 days).
• About 18% of cycles had a luteal phase shorter than 11 days.
• Between ages 25 and 45, cycles got shorter mainly because the follicular phase shrank. The luteal phase didn't change significantly with age.

So the old textbook line that "the luteal phase is always 14 days" doesn't hold up. If your cycle is longer or shorter than average, the first half is usually the part that's moving. That matters if you're counting back from your period to guess when you ovulated. Day 14 is an average, not a rule.

One caveat: the app estimated ovulation from temperature data rather than ultrasound, so individual estimates can be a day or two out [1]. For population patterns, though, it's the largest dataset we have.

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What happens to your hormones in the luteal phase?

Think of the luteal phase in three parts:

1. Early luteal (just after ovulation): the corpus luteum forms and progesterone starts climbing.
2. Mid-luteal (about a week after ovulation): progesterone peaks, and oestrogen has a second, smaller bump. This is the window when a fertilised egg would implant.
3. Late luteal (the last few days): if there's no pregnancy, the corpus luteum winds down and both hormones fall. This drop is what triggers your period, and it's when premenstrual symptoms tend to peak.

Progesterone does more than prepare the womb lining. It nudges up your body's temperature set point and affects appetite and sleep [2]. In some women, it also seems to affect mood. These effects are normal physiology, and most women feel them mildly or not at all. For some they're hard to ignore.

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What are the 7 signs you're in your luteal phase?

Not everyone gets all of these, and the size of each effect varies a lot from woman to woman. Here's what the research shows for each.

1. Your temperature goes up slightly

After ovulation, your resting body temperature rises a little. NHS Inform describes it as "very small, usually around 0.2°C" [3]. In a lab study measuring temperature around the clock, the whole 24-hour curve sat about 0.4°C higher in the luteal phase than in the follicular phase [2]. You won't feel feverish, but you might notice you run warm at night.

2. You're hungrier

This isn't a willpower problem. A 2024 meta-analysis of 15 datasets found energy intake was higher in the luteal phase than the follicular phase. The crude average difference was 168 kcal a day [4]. That's about one extra snack. The authors flagged big differences between studies and relied on self-reported food diaries, so treat the number as a rough guide.

3. Your body may use a little more energy

A meta-analysis found resting metabolic rate was slightly higher in the luteal phase [5]. The effect was small, and in studies published since 2000 it wasn't statistically significant. So a small bump in appetite may partly reflect a small bump in energy use. It isn't a licence to eat double, and it isn't a reason to feel guilty for being hungry either.

4. Your sleep feels worse

A review in Sleep Medicine Clinics found self-reported sleep quality "worsens in some, but not all, women when premenstrual symptoms emerge" [6]. In a sleep-lab study, women with severe PMS rated their late-luteal sleep as significantly worse. Both they and women without PMS woke more after falling asleep in the late luteal phase [7]. The lab didn't find a sleep-structure problem specific to PMS, but that doesn't make the tiredness any less real.

For a deeper look, see Can't Sleep Before Your Period? Why It Happens and What Helps.

5. Tender breasts and bloating

The NHS lists breast tenderness, bloating and cramping among the most common premenstrual symptoms [8]. They tend to build through the late luteal phase and usually ease once your period starts.

6. Mood shifts

Mood swings, irritability, anxiety and feeling low are all on the NHS list [8]. For most women these are noticeable but manageable. For a smaller group they're severe enough to wreck relationships and work for a week or two every month. That's a different conversation (see the next section).

7. Skin, hair and headaches

Spotty skin, greasy hair, headaches and food cravings round out the NHS list [8]. If headaches are your main issue, our guide to hormonal headaches covers the patterns and what helps.

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Is it PMS, PMDD or just your luteal phase?

These sit on a spectrum:

• Normal luteal changes: noticeable but not disruptive. Most women have some.
• PMS: the Royal College of Obstetricians and Gynaecologists (RCOG) says about 4 in 10 women have premenstrual symptoms, and 5 to 8% of those have severe PMS [9].
• PMDD (premenstrual dysphoric disorder): a severe, mood-led condition. A 2024 Oxford meta-analysis found about 1.6% of women meet the strict criteria when symptoms are properly tracked. Figures around 3% come from provisional diagnoses without enough tracking [10].

The research on this is actually pretty clear on one point. PMDD isn't about having "abnormal" hormone levels. In a landmark 1998 trial, researchers switched off women's own ovarian hormones with medication. Symptoms went away in women with PMS. When the researchers added back normal levels of oestrogen or progesterone, symptoms came back in those women but not in women without PMS [11]. Their brains react differently to normal hormone changes. Later work points to a neurosteroid made from progesterone, called allopregnanolone, as part of the story [12].

Your diagnosis is a starting point, not a verdict. If your luteal phase feels like a different person takes over, read PMDD vs severe PMS and PMDD Support: What Helps.

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What is a short luteal phase, and does it matter?

You'll see "luteal phase defect" all over fertility forums, often with a supplement attached. Here's what the American Society for Reproductive Medicine (ASRM) actually says in its 2021 committee opinion [13]:

• Luteal phase deficiency is linked to a luteal phase of 10 days or less.
• There's controversy about how to diagnose it, and no single test is reliable.
• It occurs in fertile women with normal periods too.
• It "has not been proven to be an independent entity causing infertility or recurrent pregnancy loss".
• Even if you could diagnose it accurately, it's unclear whether treating it improves outcomes.

So one short luteal phase on your app isn't a reason to panic. A consistent pattern, especially alongside trouble conceiving or unpredictable cycles, is worth raising with your GP.

The test your GP can do: a progesterone blood test taken about 7 days before your expected period (day 21 only if you have a 28-day cycle). UK labs treat a result of about 30 nmol/L or more as good evidence you ovulated. A lower result doesn't rule ovulation out, and timing matters [14]. If your cycles are irregular, getting the timing right can take repeat tests. Our guide to signs of low progesterone goes deeper.

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How do you know when your luteal phase starts?

Your luteal phase starts the day after ovulation, so the real question is how to spot ovulation. Your options:

• Basal body temperature: take your temperature at the same time each morning before getting up. A small rise that holds for several days suggests you've ovulated [3]. It confirms ovulation after the fact, so it can't predict it.
• Ovulation (LH) tests: urine strips detect the hormone surge that comes before ovulation. Your luteal phase usually begins a day or two after a positive result.
• Apps and wearables: they're more useful when you feed them real data (temperature or LH) than when they guess from period dates alone. See our roundup of apps and devices for tracking ovulation.
• A symptom diary: the NHS suggests keeping one for at least 2 cycles and taking it to your GP [8]. Note the day, your symptoms and how bad they are (0 to 10).

Then count from ovulation to the day before your next period. Do that for 3 cycles and you'll know your own luteal length, which beats any average.

One important warning: if you're using tracking to avoid pregnancy, learn it properly. NHS Inform says natural family planning can be up to 99% effective when followed exactly, but may only be around 75% effective in real life because of mistakes [3].

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What actually helps in the luteal phase?

This is what I wish someone had told me: you don't need a complicated "luteal protocol". The NHS self-help list for premenstrual symptoms is short [8]:

1. Exercise regularly. Whatever you'll actually keep doing.
2. Eat a balanced diet, with smaller meals every 2 to 3 hours if hunger or energy dips hit you.
3. Get plenty of sleep. Protect your bedtime in the week before your period.
4. Reduce stress, for example with yoga or meditation.
5. Use painkillers such as ibuprofen or paracetamol for cramps or headaches.
6. Don't smoke, and limit alcohol.

What about cycle syncing your workouts?

Cycle syncing is everywhere on social media, so it's worth knowing what the evidence says. A 2020 meta-analysis found exercise performance "might be trivially reduced" in the early follicular phase (your period), with no meaningful difference between other phases. The authors concluded that "general guidelines on exercise performance across the MC cannot be formed" [15]. Translation: if you feel flat in your late luteal phase, ease off. If you feel strong, lift heavy. Your body is trying to tell you something, and your own pattern beats a generic calendar.

What about food?

Given the extra hunger [4], plan for it rather than fighting it. Build an extra protein- or fibre-rich snack into your late luteal days so you're not running on empty by 4pm. No food has been shown to change your luteal phase length, whatever a meme says.

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Do supplements help with luteal phase symptoms?

Let's be straight about this. The NHS says complementary therapies and supplements may help some women with PMS, but there is "not much evidence that they work". It names vitamin B6, calcium, vitamin D and magnesium as ones people try, and advises checking with a GP or pharmacist first if you take other medicines [8]. RCOG describes the evidence for supplements as mixed [9].

What we can say, using the wording UK law allows (the Great Britain nutrition and health claims register) [16]:

• Vitamin B6 contributes to the regulation of hormonal activity, normal psychological function and the reduction of tiredness and fatigue.
• Magnesium contributes to normal psychological function, normal function of the nervous system and the reduction of tiredness and fatigue.

Those are general nutrient roles. They aren't promises about PMS or PMDD. On safety, Food Standards Scotland advises not taking more than 10 mg of vitamin B6 from supplements a day unless a medical professional advises it [17]. Add up every product you take, because B6 turns up in a lot of them.

It's not a magic fix. But it gives your body what it's often missing.

A safety note on 5-HTP: Cycle Support contains 5-HTP, which may interact with antidepressants that act on serotonin, including SSRIs [18]. SSRIs are a common treatment for PMDD, so if you take one, talk to your GP before starting. No supplement is a treatment for PMS or PMDD.

For a closer look at the most-studied nutrient here, read why vitamin B6 keeps coming up in PMS research.

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When should you see a GP?

The NHS says to see a GP if lifestyle changes haven't helped or your symptoms are affecting your daily life [8]. Treatments a GP may offer include the combined pill, cognitive behavioural therapy (CBT) and antidepressants, with referral to a specialist if needed [8].

Also book in if:

• Your cycles are irregular or you rarely get periods, as you may not be ovulating.
• Your app keeps showing a luteal phase of 10 days or less and you're trying to conceive.
• You have bleeding between periods or after sex.
• Your mood in the luteal phase feels unsafe. Don't wait for an appointment in that case (see the crisis box above).

Take your symptom diary. Two cycles of real data changes the conversation. If you've felt brushed off before, our guide to advocating for yourself at the GP has scripts that work.

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Frequently asked questions

Can you get pregnant during the luteal phase?
The fertile window is the days before ovulation and the day of ovulation itself, so pregnancy late in the luteal phase is unlikely. But you can only be sure where your luteal phase starts if you've confirmed ovulation. Cycle tracking isn't reliable contraception unless you've learned it properly [3].

Why am I so hungry before my period?
Energy intake is higher in the luteal phase on average, by roughly 168 kcal a day across studies [4]. Resting energy use may also rise slightly [5]. Plan an extra filling snack rather than relying on willpower.

Is a 10-day luteal phase bad?
Ten days or fewer is the usual definition of a short luteal phase. It also happens in fertile women, and it hasn't been proven to cause infertility on its own [13]. If it's a consistent pattern and you're trying to conceive, mention it to your GP.

Does the luteal phase get shorter with age?
In the largest app study, the luteal phase didn't change significantly between ages 25 and 45. Cycles got shorter mainly because the follicular phase shrank [1]. Things change again in perimenopause, when cycles become less predictable.

Should I exercise differently in my luteal phase?
Not by rule. A meta-analysis found no basis for general cycle-based exercise guidelines, only a possible trivial dip during your period [15]. Train by how you feel.

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The bottom line

Your luteal phase is the roughly 12-day stretch between ovulation and your period. Rising, then falling, progesterone explains why you might run warmer, eat more, sleep worse and feel more fragile before your period. Most of that is normal. What isn't normal is symptoms that take over your life, or cycles where you're not ovulating at all. Hormonal literacy isn't complicated, it's just rarely taught. Track 2 to 3 cycles, learn your own pattern, and take that data to your GP if something doesn't add up.

Further reading

• 9 Signs of Low Progesterone (And What Your Body Might Be Telling You)
• PMDD vs Severe PMS: How to Tell the Difference
• Can't Sleep Before Your Period? Why It Happens and What Helps
• Anovulation: What It Is, Why It Happens and What Helps
• Best Magnesium for Sleep: 5 Forms Compared for Women

This article is for general information only and isn't medical advice. MyOva products are food supplements, not medicines, and aren't intended to diagnose, treat, cure or prevent any disease. Speak to your GP or pharmacist before taking supplements if you're pregnant, breastfeeding, taking medication or managing a diagnosed condition.

References

1. Bull JR, Rowland SP, Berglund Scherwitzl E, Scherwitzl R, Gemzell Danielsson K, Harper J. Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles. npj Digital Medicine. 2019;2:83.
2. Baker FC, Waner JI, Vieira EF, Taylor SR, Driver HS, Mitchell D. Sleep and 24 hour body temperatures: a comparison in young men, naturally cycling women and women taking hormonal contraceptives. Journal of Physiology. 2001;530(3):565-574.
3. NHS Inform. Natural family planning (fertility awareness).
4. Tucker JAL, McCarthy SF, Bornath DPD, Khoja JS, Hazell TJ. The effect of the menstrual cycle on energy intake: a systematic review and meta-analysis. Nutrition Reviews. 2025;83(3):e866-e876.
5. Benton MJ, Hutchins AM, Dawes JJ. Effect of menstrual cycle on resting metabolism: a systematic review and meta-analysis. PLoS ONE. 2020;15(7):e0236025.
6. Baker FC, Lee KA. Menstrual cycle effects on sleep. Sleep Medicine Clinics. 2022;17(2):283-294.
7. Baker FC, Kahan TL, Trinder J, Colrain IM. Sleep quality and the sleep electroencephalogram in women with severe premenstrual syndrome. Sleep. 2007;30(10):1283-1291.
8. NHS. PMS (premenstrual syndrome). Reviewed 18 June 2024.
9. Royal College of Obstetricians and Gynaecologists. Management of Premenstrual Syndrome: Green-top Guideline No. 48. BJOG. 2017.
10. Reilly TJ, et al. The prevalence of premenstrual dysphoric disorder: systematic review and meta-analysis. Journal of Affective Disorders. 2024. See also the University of Oxford news release, 30 January 2024.
11. Schmidt PJ, Nieman LK, Danaceau MA, Adams LF, Rubinow DR. Differential behavioral effects of gonadal steroids in women with and in those without premenstrual syndrome. New England Journal of Medicine. 1998;338(4):209-216.
12. Hantsoo L, Epperson CN. Allopregnanolone in premenstrual dysphoric disorder (PMDD): evidence for dysregulated sensitivity to GABA-A receptor modulating neuroactive steroids across the menstrual cycle. Neurobiology of Stress. 2020;12:100213.
13. Practice Committees of the American Society for Reproductive Medicine and the Society for Reproductive Endocrinology and Infertility. Diagnosis and treatment of luteal phase deficiency: a committee opinion. Fertility and Sterility. 2021;115(6):1416-1423.
14. Gloucestershire Hospitals NHS Foundation Trust Pathology. Progesterone.
15. McNulty KL, Elliott-Sale KJ, Dolan E, Swinton PA, Ansdell P, Goodall S, Thomas K, Hicks KM. The effects of menstrual cycle phase on exercise performance in eumenorrheic women: a systematic review and meta-analysis. Sports Medicine. 2020;50(10):1813-1827.
16. Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register.
17. Food Standards Scotland. Vitamin B6 (pyridoxine).
18. Memorial Sloan Kettering Cancer Center. About Herbs: 5-HTP. Updated 2 June 2022.

References