Why Am I Exhausted Before My Period? The Science Behind PMS Fatigue

Ever feel like your energy disappears a few days before your period?

Getting out of bed feels harder, your concentration isn't quite there. Exercise feels more difficult. You could happily cancel every plan you have and go to bed at 8pm. You're not alone. 

Fatigue is one of the symptoms commonly associated with the premenstrual phase, and there are several biological reasons why your energy can feel different before your period.

Your hormones affect much more than your reproductive system

Oestrogen and progesterone are best known for their roles in the menstrual cycle. But they also interact with systems throughout the body, including the brain, nervous system, metabolism, body temperature and sleep.

As you move through the luteal phase and approach menstruation, hormone levels change significantly. For some women, those changes are associated with changes in mood, energy and sleep quality.

Research examining menstrual cycle related sleep has found that sleep quality can change across the cycle, with premenstrual sleep disruption particularly relevant in women experiencing PMS or PMDD [1]. And poor sleep can obviously make fatigue worse.

You might not actually be low energy

Sometimes the issue isn't simply how much energy your body produces. It's how well you are recovering.

If your sleep is disrupted, your body temperature changes, you're experiencing cramps, you're feeling anxious or your mood is low, you may wake up feeling exhausted even if you spent eight hours in bed [1].

This creates a cycle:

Hormonal changes → poorer sleep → reduced recovery → daytime fatigue.

What about iron?

This is particularly important if you have heavy periods.

Iron is needed to make haemoglobin, the protein in red blood cells responsible for transporting oxygen around the body. If you lose significant amounts of blood during menstruation, your risk of iron deficiency increases.

Iron deficiency anaemia can cause symptoms including tiredness, lack of energy, shortness of breath, headaches, palpitations and pale skin.

The NHS specifically identifies heavy periods as a common cause of iron deficiency anaemia [2].

This is why persistent or severe fatigue shouldn't automatically be blamed on PMS. If you're exhausted every month, particularly if you have heavy periods, it's worth speaking to your GP and asking whether your iron status should be checked.

Nutrients involved in energy production

Your body needs a wide range of nutrients to produce and use energy efficiently. These include iron, vitamin B12, folate, riboflavin, magnesium and vitamin B6.

That doesn't mean taking more vitamins will automatically make you energetic. If you already have adequate nutritional status, more isn't necessarily better. But ensuring you meet your nutritional requirements is an important part of supporting normal energy metabolism.

This is why we created Buzz

Soov's Buzz 7 Day Period Fatigue Support is designed specifically for the days when period related tiredness can be most noticeable. Each daily sachet contains vitamin D3, CoQ10, iron bisglycinate with vitamin C, vitamin B12 and Siberian ginseng [3].

The formula is designed around nutritional support for energy metabolism, red blood cell formation and general wellbeing.

For women who experience fatigue as part of broader PMS symptoms throughout the month, Flow provides a daily cycle support formula containing magnesium, vitamin B6, vitamin B12, folate, vitamin D3 and other nutrients and botanical extracts [4].

But don't ignore extreme fatigue

Feeling a little more tired before your period can be normal. Feeling completely unable to function every month is different.

If fatigue is severe, persistent or getting worse, speak to a healthcare professional. Particularly if you also experience very heavy periods, shortness of breath, dizziness, palpitations or unusual weakness. Sometimes PMS isn't the whole story.

Your energy deserves support too

Your menstrual cycle is not simply seven days of bleeding. It's a month long biological process involving changing hormones, metabolism, sleep, mood and nutrient requirements.

So if you notice your energy changes predictably every month, don't dismiss it. Start tracking it. Look at your sleep. Look at your diet. Look at your periods. And make sure your body is getting the nutritional support it needs.

Feel drained every month? Explore Soov Buzz here.

1. Reviews of menstrual cycle and sleep
2. NHS guidance on iron deficiency anaemia and heavy periods
3. Soov Buzz product formulation
4. Soov Flow product formulation