Understanding Luteal Fatigue
Many women notice a drop in energy in the days leading up to their period. You might feel more tired than usual, less motivated, more emotionally sensitive, or like everyday tasks take more effort.
This can be frustrating, but it’s often driven by normal hormonal changes in the late luteal phase of the cycle. Understanding why it happens and what supports your body best during this window can help you feel more like yourself again.
Why am I so tired before my period?
1) Progesterone and its calming effects
During the luteal phase (after ovulation until your next period), progesterone rises. Its key role is to stabilise the uterine lining in case implantation occurs (1).
Progesterone also affects the brain. It can cross the blood–brain barrier and is converted into neuroactive compounds such as allopregnanolone, which interacts with GABA-A receptors (your brain’s main calming signalling pathway) (2).
For some women, this feels grounding or sleep-supportive. For others, it can feel like:
lower drive or motivation
brain fog
needing more sleep
reduced tolerance for stress
2) Higher energy needs after ovulation
After ovulation, core body temperature rises slightly. Across research, resting energy expenditure may increase modestly in the luteal phase, but the magnitude of the change varies widely between women (3).
In practical terms, some women benefit from a little more fuel in the second half of the cycle, with research suggesting approximately 100-300 kcal more per day (9). If intake doesn’t match demand, you may notice:
energy dips
reduced exercise tolerance
irritability
stronger cravings
3) Blood sugar handling may shift
You’ll often see the claim that progesterone reduces insulin sensitivity in the luteal phase. The reality is that blood sugar balance across the cycle is variable, and not every woman experiences a meaningful change. That said, higher-sugar or refined-carbohydrate meals may lead to a quicker rise and fall in energy (4).
If you’re prone to energy crashes leading up to your period, it’s worth being more intentional with meal structure (especially your carbohydrate quality and pairing).
4) Prostaglandins and systemic symptoms
In the late luteal phase, progesterone falls in preparation for menstruation. As progesterone levels drop, prostaglandin production increases in the endometrium, helping trigger uterine contractions that shed the lining (5).
Prostaglandins don’t just affect the uterus, but are also linked to systemic symptoms many women recognise around bleeding, including fatigue, nausea, bowel changes, and headaches (especially when prostaglandin activity is high) (5).
How to support energy before your period
1) Stabilise energy with balanced meals
If you experience more noticeable dips in energy prior to your period, you don’t need to remove carbohydrates entirely. Instead, use them strategically.
Aim for complex carbohydrates paired with protein, fat, and fibre. This slows digestion, supports blood sugar balance, leading to steadier energy levels.
Easy snack ideas during the luteal phase:
Greek yoghurt, berries, and nuts/seeds
Oatcakes and houmous
Apple and almond butter
Eggs on wholegrain toast
Edamame, olive oil and salt
2) Add more fuel
As your energy demand increases slightly, you might like to increase your food intake throughout the day. Some examples include:
an extra slice of sourdough at lunch
adding oats or chia to yoghurt
an extra portion of rice/potatoes with dinner
a handful of nuts and fruit mid-afternoon
3) Check key nutrients that support energy and cycle health
If fatigue is persistent or severe, or accompanied by heavy bleeding, it’s worth checking for a deficiency.
Iron
Iron supports oxygen transport and energy production. Heavier periods and regular menstruation can increase iron loss, so it is important to include regular food sources such as:
red meat, sardines
lentils, beans, chickpeas
spinach, pumpkin seeds
Try to pair iron with vitamin C (peppers, citrus, berries) to improve absorption.
Magnesium
Magnesium supports muscle relaxation (supporting cramps) and sleep. Try to incorporate:
pumpkin seeds, almonds, cashews
cacao, wholegrains, leafy greens
B vitamins
B12, B6 and folate support support energy production and red blood cell production. Food sources include:
B12: eggs, dairy, fish, fortified foods
Folate: legumes, leafy greens
B6: chickpeas, poultry, potatoes, bananas
Vitamin D
Vitamin D is essential for immune regulation, energy production and mood support. Sources include:
oily fish, eggs, fortified foods
Sunlight is our main source of vitamin D, so if you also live in the UK, you will also know how cloudy and grey our winter months are! It is recommended to supplement daily with at least 400 IU, ensuring not to exceed the upper limit of 4000 IU (8).
Omega-3s
Omega-3 fats (EPA and DHA) are important because they help regulate inflammatory signalling and can support a healthy prostaglandin balance.
Plant foods like chia, flax and walnuts provide ALA, which the body can convert into EPA and DHA, but this conversion is limited, particularly for DHA (6). Oily fish provides EPA and DHA directly, and algae oil is a great vegan alternative.
Aim for at least two portions of fish per week, including one oily fish (such as salmon, sardines, mackerel or herring). If you choose a supplement, look for a reputable brand with clearly stated EPA/DHA content.
Antioxidant support
Inflammation and oxidative stress can play a role in menstrual symptoms for some women (7). Polyunsaturated fats, including omega-3s, are important for hormone signalling, but because they’re highly unsaturated, they’re also more prone to oxidation. The best approach is to pair oily fish (or algae-based DHA/EPA) with a diet rich in antioxidants and lifestyle habits that support the body’s antioxidant defences.
So if you’re increasing omega-3 intake, pair it with:
colourful plants daily
olive oil, herbs/spices, green tea
nuts/seeds in sensible portions
sleep and stress support (breathing techniques, creativity, fun!)
When to get personalised support
If premenstrual fatigue is significantly affecting your quality of life, or it’s paired with heavy bleeding, severe pain, bowel changes, or mood symptoms, personalised nutrition and lifestyle support can help identify your specific drivers and build a plan that is specifically tailored to you.
These suggestions are not meant to replace professional medical advice, so always consult your healthcare provider if you are experiencing symptoms affecting your daily life, and before combining supplements with prescription medications.
Thiyagarajan DK, Basit H, Jeanmonod R. Physiology, menstrual cycle. Florida: StatPearls Publishing.
Nagy, B., Szekeres-Barthó, J., Kovács, G.L., Sulyok, E., Farkas, B., Várnagy, Á., Vértes, V., Kovács, K. and Bódis, J. (2021). ‘Key to life: physiological role and clinical implications of progesterone’. International Journal of Molecular Sciences, 22(20), p.11039. https://doi.org/10.3390/ijms222011039
Benton, M.J., Hutchins, A.M. and Dawes, J.J. (2020). ‘Effect of menstrual cycle on resting metabolism: A systematic review and meta-analysis’. PloS one, 15(7), p.0236025. https://doi.org/10.1371/journal.pone.0236025
Hirschberg, A.L. (2012). ‘Sex hormones, appetite and eating behaviour in women’. Maturitas, 71(3), p.248-256. https://doi.org/10.1016/j.maturitas.2011.12.016
Bernardi, M., Lazzeri, L., Perelli, F., Reis, F.M. and Petraglia, F. (2017). ‘Dysmenorrhea and related disorders’. F1000Research, 6, p.1645. https://doi.org/10.12688/f1000research.11682.1
Burdge, G.C. and Calder, P.C. (2005). ‘Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults’. Reproduction Nutrition Development, 45(5), p.581-597. https://doi.org/10.1051/rnd:2005047
Zheng, S.H., Chen, X.X., Chen, Y., Wu, Z.C., Chen, X.Q. and Li, X.L. (2023). ‘Antioxidant vitamins supplementation reduce endometriosis related pelvic pain in humans: a systematic review and meta-analysis’. Reproductive Biology and Endocrinology, 21(1), p.79. https://doi.org/10.1186/s12958-023-01126-1.
NHS. (2023). Vitamin D. Available at: Vitamin D
Tucker, J.A., McCarthy, S.F., Bornath, D.P., Khoja, J.S. and Hazell, T.J. (2025). ‘The effect of the menstrual cycle on energy intake: a systematic review and meta-analysis’. Nutrition reviews, 83(3), p.866-876. https://doi.org/10.1093/nutrit/nuae093