What actually happens during this transition

Perimenopause is the period leading up to menopause—the point at which you have gone 12 consecutive months without a period. For many women, it begins sometime in their 40s and can last for several years. During this time, the ovaries do not "shut down" in a gradual and orderly fashion: hormone levels fluctuate, sometimes abruptly, from one cycle to the next.

Progesterone tends to be the first to drop as cycles without ovulation become more frequent. Estrogen, conversely, can have unpredictable spikes and dips. Since these hormones also act on the brain, muscles, bones, and metabolism, it is no wonder that signs appear in seemingly unrelated areas: brain fog, mid-afternoon fatigue, lighter sleep, mood swings, and digestive changes.

In this article, Viva Saudável explains why this phase is a turning point for long-term health, which daily pillars make the biggest difference, which specific situations warrant medical attention, and where nutritional supplements—like magnesium, vitamin D3 with K2, or omega-3—can play a complementary role.

Perimenopause and aging: why the curve is no longer smooth

It is common to imagine aging as a slow and steady decline. Data suggests that, for women, the menopausal transition can be a period of acceleration. A study published in the journal PNAS analyzed samples from over 3,100 women using an "epigenetic clock"—a marker that estimates biological age based on DNA methylation patterns.

Researchers observed that earlier menopause was associated with an older biological age in the blood, and that surgical removal of both ovaries was also associated with this increase. The authors' conclusion is cautious: menopause may accelerate epigenetic aging. This was an observational study with measurements at a single point in time, so it does not prove cause and effect—but it reinforces the idea that this phase deserves more attention than just "waiting for it to pass."

Bones tell a similar story. In the SWAN study, rapid bone density loss begins as early as perimenopause, about a year before the last menstrual period, and not just after it. In other words: the time to strengthen habits is before, not after.

A house, not just a thermostat

A useful way to think about health during perimenopause is to imagine the body as a house. Hormones are the heating system: important, but unable to compensate for fragile foundations, broken windows, or failing electrical wiring. Focusing only on hormones is like adjusting the thermostat in a house with cracks in the walls. These are the four structural pillars, from the ground up.

Brain fog and the four o'clock slump

Forgetting words in the middle of a sentence, losing your train of thought in a meeting, feeling energy disappear in the mid-afternoon. These signs are not a lack of willpower nor are they "just age." They are often the expression of changes in energy metabolism, sleep, and how the brain responds to hormonal fluctuations—estrogen and progesterone also act as messengers in the nervous system.

Imagine the body as a tree. It is common to look at each leaf separately: one specialist for memory lapses, another for irregular cycles, another for mood. But if several leaves are wilting at the same time, it is worth looking at the trunk and the roots—sleep, glucose stability, muscle mass, digestion, stress.

A simple step is to keep a record of sleep, meals, energy, and symptoms for two or three weeks. This log helps identify patterns and makes the conversation with your doctor more productive. Clinical assessment may include tests such as ferritin, vitamin B12, vitamin D, or thyroid function, because common deficiencies and changes at this age can mimic perimenopause symptoms.

The gut as a foundation: barrier, microbiota, and fiber

The intestinal wall is a thin barrier, kept sealed by structures called tight junctions. Research suggests that an excess of ultra-processed foods, alcohol, chronic stress, and insufficient sleep can increase the permeability of this barrier, keeping the immune system on alert. It is an active area of study, with evidence still being built, but it is consistent with what is known about diet and low-grade inflammation.

The most solid strategy remains nourishing the microbiota well. Probiotics and prebiotics are part of this conversation: prebiotics are fibers that serve as food for gut bacteria—found in leeks, onions, asparagus, oats, legumes, and slightly unripe bananas—and fermented foods provide live microorganisms. As for probiotic supplements specifically for perimenopause, studies are still preliminary, so the base should always be your plate.

Fasting or breakfast? What makes sense at this stage

Intermittent fasting is often presented as a universal solution. In perimenopause, specific evidence is limited, and the experience of many women is mixed: when sleep is already fragmented and energy fluctuates, skipping breakfast and only eating in the mid-afternoon can worsen unregulated hunger, irritability, and energy crashes.

A more prudent approach is to give the body signs of stability: a breakfast in the first or second hour after waking, built around three elements.

• Protein first — eggs, Greek yogurt, fresh cheese, tofu, or a protein shake. Protein contributes to maintaining muscle mass and helps maintain satiety throughout the morning.
• Color on the plate — fruit, vegetables, seeds. Variety in plants nourishes the microbiota.
• Complex carbohydrates — oats, sourdough bread, sweet potatoes, or brown rice, which provide more stable energy than simple sugars.

There is no single rule. Some women feel fine with shorter eating windows; the important thing is to observe your own body's response, especially in terms of sleep, energy, and hunger.

GLP-1 receptor agonist medications: what to consider

Medications in this class are increasingly used in weight and glucose management, and research has also been exploring broader metabolic effects. In perimenopause, they warrant some precautions: they slow down stomach emptying, alter intestinal transit, and reduce appetite—which makes it more difficult to achieve the necessary protein intake.

Without attention to protein and strength training, part of the weight lost may be muscle mass, precisely the tissue that this phase already tends to lose. The decision to start or maintain this type of medication is always a medical one, and no drug replaces the work done on the foundations of the house.

Real situations, practical answers

Some of the most frequent situations at this stage—and where to start for each of them.

Smart supplementation in perimenopause

Nutritional supplements can be a useful complement when diet is not enough or when needs increase. However, they do not replace the foundations of this house—and they work best when those foundations are well cared for.

Food supplements should not be used as a substitute for a varied and balanced diet or a healthy lifestyle. Do not exceed the recommended daily intake. In case of medication, pregnancy, or a medical condition, consult a healthcare professional.

Frequently asked questions

Sources and references