Brain fog: where it comes from and how to lift it

What brain fog is

A symptom, not an illness.

You read the same paragraph three times. You walk into a room without knowing why. The word you are looking for stays on the tip of your tongue. That is what is called brain fog.

The term is not a medical diagnosis. It is a way of describing a set of sensations: thinking in slow motion, attention that drops out, a less reliable memory. American researchers who asked patients with postural tachycardia syndrome about this symptom found the same words again and again: forgetful, foggy, difficulty thinking and concentrating.

The good news is that in the vast majority of cases, brain fog has everyday causes that can be identified and reversed. The bad news is that there is rarely only one. Sleep, stress, hydration, diet and caffeine often stack up. That is why the article that follows works cause by cause before offering a concrete plan.

The symptoms

How do you know if you are in the fog?

Brain fog is recognised by a cluster of small signs that last longer than a bad day. If you recognise yourself in several of these situations, you are in the right place.

• You struggle to stay focused on a task for more than a few minutes.
• You forget appointments, names or what you were about to say.
• You search for words, especially at the end of the day or in meetings.
• Making a simple decision feels disproportionately hard.
• You feel tired from the morning, even after a full night.
• You feel as if you are behind glass, a little absent from what is going on.

These signs are not specific: they are found in fatigue, chronic stress, certain deficiencies or certain illnesses. It is their duration, their intensity and the symptoms alongside them that point to one cause rather than another. We come back to this in the when to see a doctor section.

The common causes

Where does brain fog come from?

The causes fall into two families. Lifestyle causes, by far the most common, and medical causes, not to be overlooked when the fog settles in. Here are the main ones.

Sleep

Sleep, the first culprit in brain fog.

If you could change only one thing, it would be this. The brain does not rest at night: it sorts, consolidates memories and clears up. Researchers at the University of Rochester showed in mice that the space between brain cells widens by about 60 % during sleep, which makes it easier to clear the waste produced during the day. Also worth reading: maritime pine: benefits, dosage and precautions.

In humans, the American sleep societies recommend at least 7 hours a night for adults, consistently. Below that, and especially night after night, concentration, working memory and mood all suffer. And one catch-up night at the weekend does not erase a week of debt.

If you sleep enough but wake exhausted, snore loudly or fall asleep during the day, speak to your doctor: a sleep disorder such as apnoea can sustain the fog. To go further, read our guide to adaptogenic mushrooms, plants and sleep.

Stress and anxiety

Brain fog and anxiety: the vicious circle.

The link between brain fog and anxiety is one of the most frequent questions, and it is very real. When you are stressed, part of your attention is taken up by worry. Less is left for reading, listening or remembering. The result: you forget, you worry about it, and the fog thickens.

Lasting stress also disrupts sleep, appetite and the urge to move, three levers of mental clarity. Cortisol, the stress hormone, normally follows a daily rhythm, high in the morning and low at night. When that rhythm is disrupted, you feel both tired and wired. We explain it in detail in our article on high cortisol.

A few simple habits help break the circle: writing down what is on your mind before bed, three minutes of slow breathing before a hard task, walking without your phone, and reducing the number of things running in parallel. On the plant side, ashwagandha and reishi are the most studied for accompanying stressful periods: they are combined in our Anti-Stress formula.

Water and food

What you drink and eat matters.

Dehydration is often underestimated. In a study at the University of Connecticut, a water loss of around 1.5 % of body weight — barely perceptible — was enough to impair alertness and working memory in young men, and to increase their fatigue and tension. The simplest habit in this article: a large glass of water on waking, then a bottle within reach.

What is on your plate matters too. A meal very rich in fast sugars often causes an energy rise followed by a dip. A skipped meal leaves you short of fuel. And some deficiencies — iron, vitamin B12 or vitamin D — come with fatigue and concentration problems. To go further, discover Siberian ginseng, benefits and dosage.

Gluten and sugar are often cited as causes of brain fog. In coeliac disease it is a known symptom, which can be diagnosed. Without a diagnosis, cutting out a food blindly rarely helps: start with overall balance.

Coffee

Coffee, ally or culprit?

Coffee wakes you up, that is true. But when it becomes a crutch, it can also sustain the fog. First because a large caffeine dose gives a peak of alertness followed by a fall. Then because a late coffee shortens sleep. And finally because the body adapts: without its dose, it demands one.

Caffeine withdrawal is in fact well described. A literature review by Juliano and Griffiths lists among its symptoms headache, fatigue, drowsiness and difficulty concentrating, generally appearing 12 to 24 hours after the last coffee and lasting two to nine days. If your fog lifts with the first cup, perhaps it is your dependence talking.

The aim is not necessarily to give up coffee, but to lower the dose and spread it better. That is what many of our customers do with Brainstoorm, our mushroom coffee at 20 mg of caffeine per cup, against roughly 80 mg for an espresso. If you are hesitating, our article on why replace your coffee with a mushroom coffee and adaptogenic plants covers the question. Here is what those who made the switch say:

When to see a doctor

The signs that should send you to a doctor.

In most cases, brain fog improves within a few weeks once you work on sleep, stress, water, diet and caffeine. Some situations, however, call for medical advice without delay.

A simple blood test often rules out iron or vitamin B12 deficiency, or a thyroid imbalance. For women in perimenopause or menopause, brain fog is a frequent symptom, worth discussing with your doctor or gynaecologist.

The three-step plan

How to lift brain fog in three weeks.

Changing everything at once never lasts. Here is a three-stage progression, one week each. The goal is not perfection, but habits that stick.

A typical day

A day designed to see clearly.

Here is what a day designed for mental clarity can look like. Nothing extreme: small choices, at the right moment, that add up.

For busy weeks, the Entrepreneur Pack combines Focus and Energy, and the Limitless Pack adds Anti-Stress and Sleep +.

Who it is for

A mental clarity routine is for you if…

• You juggle screens, meetings and parallel tasks.
• You are going through an intense period: exams, a launch, a move, young children.
• You want to drink less coffee without losing your morning ritual.
• You have already seen your doctor and are looking for day-to-day support.
• You prefer formulas with stated doses, developed in Toulouse, bought once or by monthly subscription (−30 %).

Sources

1. Ross A. J., Medow M. S., Rowe P. C., Stewart J. M. (2013). What is brain fog? An evaluation of the symptom in postural tachycardia syndrome. Clinical Autonomic Research, 23(6).
2. Xie L. et al. (2013). Sleep drives metabolite clearance from the adult brain. Science, 342(6156).
3. Watson N. F. et al. (2015). Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep, 38(6).
4. Ganio M. S. et al. (2011). Mild dehydration impairs cognitive performance and mood of men. British Journal of Nutrition, 106(10).
5. Juliano L. M., Griffiths R. R. (2004). A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology, 176(1).
6. Mori K. et al. (2009). Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytotherapy Research, 23(3).

Keep reading

To go further.

Brain fog touches on focus, stress and sleep. Here are our most useful guides and pages to continue, or discover our guide to mushrooms and adaptogenic plants.