the good medicine guide to brain fog / by emily penn

Have you ever had brain fog? You know, that feeling like your brain is somehow outside of your head, or you feel like you’re underwear. Your thinking is fuzzy, it’s nearly impossible to focus on anything, and maybe you forget simple things like words.

It’s one of the most annoying and debilitating symptoms, and it can show up frequently.

In this guide, I’ll go over the most common causes of brain fog, as well as some other potential causes if they don’t help. I’ll also include some of my favorite products that have actually made a difference for me in terms of brain fog and cognitive function.

Common Causes of Brain Fog

  1. Lack of sleep. Not getting enough sleep disrupts our brain cells’ ability to communicate with each other. This can cause temporary mental lapses that affect memory and visual perception.

    Aim to get 7-9 hours of quality sleep per night. Avoid screens before bed and sleep in a dark, cool room. (1)

  2. Dehydration. It only takes a 2% decrease in brain hydration to affect your short-term memory. Chronic dehydration can actually cause brain cells to shrink! (2)

    Drink about 1/2 your body weight in ounces of water per day. I’ve also found electrolytes to be incredibly helpful for brain fog, and for many other things. I’m a big fan of LMNT.

  3. Low blood sugar. When blood sugar is low, our cells aren't receiving sugar/glucose and can't function properly. (3)
    Keep blood sugar steady by eating regularly, and prioritizing protein, healthy fats, and fiber at meals.

  4. Inflammation. Inflammation in the brain can be experienced as that foggy feeling, trouble with memory, and even depression. (4)

    Eating an anti-inflammatory diet full of whole foods, getting proper sleep, and reducing stress are all good strategies to keep inflammation in check. You can also check out my guide to inflammation here.

  5. Screen time. I think most of us know that weird, spaced-out feeling we get if we’ve been staring at our phone or computer for too long. Research has shown that screens and digital media have negative impacts on our brain health, including effects similar to those seen in adults with symptoms of mild cognitive impairment in the early stages of dementia. (5, 6)
    Reduce screen time if possible, take frequent breaks, and try blue light-blocking glasses.


Other Potential Causes of Brain Fog

If you’ve optimized all of the areas above and are still experiencing brain fog, here are a few other places to look.

  1. Your thyroid. Brain fog is a common symptom of hypothyroidism and Hashimoto’s (the autoimmune version of hypothyroidism, and the most common). I suggest having a full thyroid panel that tests for TSH, T3, T4, and thyroid antibodies. TSH itself doesn’t give us enough information to go on, since this number can sometimes be normal while there is still thyroid dysfunction. Check out this guide for more testing info and optimal numbers.

  2. Autoimmune disease in general. Inflammation is a large factor in autoimmune disease and may impact brain function.

  3. Food sensitivities. Yes, brain fog can be a result of food sensitivities! Gluten, dairy, and soy are some of the most common food sensitivities, but it’s important to figure out your personal sensitivities. You can start by eliminating these foods for 3 weeks (and any others you suspect don’t work for you), and see if symptoms improve. The Whole30 is also a great resource for an elimination diet.

  4. Gut dysbiosis/leaky guy. Usually with leaky gut or an imbalanced microbiome, there’s inflammation, which can lead to brain fog. Address any potential gut issues.

  5. Medications. Brain fog could be a side effect of medications. Speak with your doctor if you suspect one of your medications is causing brain fog.

  6. Nutrient deficiencies. Deficiencies in vitamin D, vitamin B12, omega-3 fatty acids, magnesium, and iron, could potentially contribute to brain fog.

Supportive Products for Brain Fog

Over the years, I’ve been testing and searching for products that promise enhanced focus and clarity. While most days, my brain feels pretty good, I’ve been through situations that have left me brain foggy (copper IUD, mold, periods of stress/poor sleep).

The products I’m sharing here are the ones where I’ve actually noticed reduced brain fog, enhanced brain function, and clarity.

  1. LMNT Electrolytes - these are my favorite electrolytes. I’ve used them on and off over the years, but last summer I found them incredibly helpful for long-distance running, overall hydration, and yes - brain fog. I start my day with one packet, and on days where I’m losing a lot of sweat or feeling extra dehydrated/run down, I’ll even have two. Their whole thing is that we actually need more salt, not less, and they’ve got lots of science on their website backing up that claim. I will say that I feel noticeably better when I’m having these regularly. Use my link and you’ll get a free sample pack with your order.

    Pro tip: yes, they are very salty at first, but your taste will adjust. You also have to find the right amount of water to add it to, for your taste preference. I add it to my 28-oz Yeti and that’s perfect for me.

  2. Four Sigmatic “Think” Products - I have tried tons of different powders and adaptogens over the years, and for the most part, they’ve just been okay - not life-changing. Recently, I decided to try the Four Sigmatic “Think Starter Kit” and this combination of products has provided the most notable difference of anything so far. I feel more focused and less distracted when I use all three (and believe me, I’ve experimented trying to figure out if any one provides more of a boost over the others, but ultimately it seems they work best all together).

    The coffee is organic and tested for toxins, and includes lion’s mane and chaga.

    The creamer is simply coconut milk powder, l-theanine, lion’s mane, vanilla, and monkfruit. I’ll be honest, I don’t love the taste of the creamer on its own. I use NutPods in my coffee as well, and then I use about 1/2 a tablespoon of the creamer and I don’t taste it, and I do think the l-theanine is what gives me a boost.

    The Focus blend contains mushrooms and herbs that are known to support focus and brain health. It has an earthy, hardly perceptible taste in coffee.

    Overall, I was impressed that I actually noticed a difference. I suggest ordering the Think Starter Kit (also comes with a frother!), as it’s more cost-effective. You can also get $20 off your first order by using this link (this makes the kit only $50, which is an amazing deal).

  3. Moon Juice Brain Dust - I find Moon Juice products in general to be super effective (I’ve been taking their SuperHair daily for years, and I got my mom hooked on SuperYou years ago, too), and their Brain Dust was one of the first products I found that felt like it really gave me a boost. It’s a blend of adaptogens that you can easily add to coffee or smoothies.


When addressing brain fog, I think it’s most important to dial in the foundations (sleep, hydration, blood sugar), and if you’re still struggling, dig deeper with the other strategies I mentioned. Use the supportive products if they call to you, but they certainly won’t make up for a lack of sleep or something bigger going on the body.

Hope this helps! Let me know about your journey with brain fog, and any other strategies or products that have helped you!