Brain
5 Signs of B12 Deficiency
Juztine · July 11, 2025
Last reviewed August 11, 2026
You might know B12 as a key ingredient in energy drinks. It’s true that B12 is a fantastic natural energizer, but it’s so much more than that.
Also known as cobalamin, B12 is essential for brain health, nerve function, blood production and more. Your body needs B12 every day to perform the tasks that keep you ticking, so not getting enough can lead to some serious health issues.
Even worse, the symptoms, such as tiredness and brain fog, are easy to miss or explain away as signs of aging (or eating a big lunch). That’s why it’s important to recognize the warning signs early.
In this article, you’ll learn the most common signs that your body is running low on vitamin B12.
You’ll also find out how Manna Liposomal Vitamin B12 can boost your levels back to normal in no time.
What Is Vitamin B12 and Why Is It Important?
Vitamin B12 (cobalamin) is a water-soluble vitamin that your body needs to function properly. It’s involved in several major body processes from digestion to brain health, nerve health and more.
It’s even the key player in DNA synthesis, which is required to make new cells (and keep you alive).
B12 is the most chemically complex of all the vitamins, which makes it more difficult for your body to absorb and use. Your body needs special proteins and stomach acid to unlock and absorb B12 from food, and if anything in that process breaks down, your B12 levels can quickly fall behind.
It’s estimated that up to 20% of the population suffers from B12 deficiency, and certain groups are more at risk, including the elderly [1]. Vegans and vegetarians may also fall short, since B12 is mainly found in animal-based foods.
You can only get B12 from food or supplements, and you need it every day. Most of the vitamin B12 in our diets comes from these foods:
- Red Meat
- Poultry (such as chicken and turkey)
- Fish and shellfish
- Eggs (especially egg yolk)
- Dairy products
Some foods, like breakfast cereals and plant-based milks, are fortified with B12. But for people who don’t eat animal products, these sources may not be enough. Even if you eat animal products, factors like medications or aging can affect how well your body absorbs B12.
Your body doesn’t need large amounts of B12 (about 2.4 mcg per day), but it needs a steady supply. If you don’t get enough, you could develop a deficiency that affects your energy, mood, memory and more.
Over time, a B12 deficiency can lead to permanent nerve damage and serious health issues. Studies have also suggested that a B12 deficiency may cause you to age more rapidly [2]. Don’t let it get to that point. Learn the warning signs of low B12 and take action early.
5 Signs You Need More B12
Vitamin B12 deficiency is difficult to detect because it shares symptoms with many other issues. It can also be subtle, manifesting in mild symptoms like tiredness and stress.
This makes a B12 deficiency especially dangerous, as serious consequences can creep up on you without you knowing.
Here are five common warning signs that you might need more B12.
1. Fatigue or Low Energy Levels
Vitamin B12 is a key ingredient for making red blood cells, which carry oxygen throughout your body. When your cells don’t get enough oxygen, you can feel weak, drained, or out of breath doing everyday tasks.
B12 is also a metabolism booster, helping convert food into energy. Without enough, you may struggle to stay alert and focused. If you’re constantly feeling sluggish, even after resting or eating well, it may be time for a liposomal B12 supplement.
Research has found that taking a B12 supplement can restore energy and mood if you’re deficient [3]. However, deficient people may need to take supplements consistently for a few weeks or months before seeing results.
2. Brain Fog or Memory Issues
Do you ever walk into a room and forget why? Or struggle to stay focused at work? B12 supports your brain by helping produce neurotransmitters—chemicals that allow your brain cells to communicate. It also plays a role in protecting your nerves.
When your B12 levels are low, that communication slows down, which can cause your mind to work more slowly too. We’re talking about forgetfulness, confusion and general brain fog. Over time, it can develop into more serious memory loss and even increase your risk of cognitive disorders.
Luckily, taking a B12 supplement has been found to reverse these symptoms. In one study, nearly 85% of participants showed improved cognitive function after taking B12 [4].
3. Mood Swings or Depression
Vitamin B12 helps your brain create serotonin and other neurotransmitters that regulate your mood.
When your body doesn’t have enough B12, these chemicals can drop, causing you to lose control of your mood. You might feel irritable, overwhelmed, or more sensitive than usual. Or, you might just feel generally unhappy with life.
While many things can affect your mental health, a B12 deficiency is one often overlooked possibility. And if it isn’t fixed, those mood swings can turn into full-blown disorders, leaving you feeling depressed and unable to function.
4. Tingling Sensations or Numbness
A “pins and needles” feeling in your hands or feet can be a red flag for B12 deficiency. That’s because B12 keeps your nerves healthy.
When your levels drop, the protective covering around your nerves (called myelin) starts to break down. This can disrupt nerve signals and lead to sensations like tingling, numbness, or burning.
If left untreated, nerve damage from B12 deficiency can become permanent, so it’s important to catch it early and start taking a B12 supplement [5]. B12 supplementation has been found to regenerate and restore nerves if it’s taken early enough [6].
5. Weakness or Difficulty with Coordination
B12 helps you maintain muscle control and balance. When levels are too low, your nervous system can’t send proper signals to your muscles. This may cause you to feel physically weaker or more off-balance than usual, especially when walking or standing.
You might notice your legs feel shaky, or you’re stumbling more often. If you’re deficient for too long, you can suffer from severe issues with motor control and an increased risk of falls. This is especially dangerous for older adults. If you’re feeling woozy or weak, age may not be the only explanation.
Taking B12 daily may help you stay more confident on your feet. It’s also been found to improve muscle recovery and growth after a workout, making it a favorite of gymgoers [7].
It’s Easier Than You Think to Run Low on B12
Many people assume they’re getting enough Vitamin B12, especially if they eat a relatively balanced diet. But the truth is, B12 deficiency is quite common, and it doesn’t always have obvious symptoms.
You can start running low long before you realize something’s wrong, especially if you are a vegan, vegetarian, over 60, or are taking certain medications like acid reducers or metformin. If you’ve been experiencing any of the symptoms above, it’s time to increase your daily B12 intake with food or supplements.
Taking a daily B12 supplement like Manna Liposomal Vitamin B12 is one of the easiest ways to increase your levels and experience the benefits of a B12 boost, such as more energy, focus and a brighter mood. Manna supplements use advanced liposomal delivery to help more B12 absorb into your bloodstream.
Each nutrient is wrapped in tiny fat-like spheres called liposomes that protect it during the journey through your treacherous digestive tract. Many other B12 capsules or tablets pass through your digestive system without being fully absorbed. With Manna, your body gets up to 10x more nutrition from every serving.
So, if you’ve been dragging through your day, struggling with mental clarity, or feeling weak, don’t brush it off. Your body could be asking you for more B12.
Manna Liposomal Vitamin B12 is a simple, effective way to give your body the B12 it wants (and can actually use), so you can feel like yourself again.
FAQ
The most common signs include fatigue, brain fog, mood swings, tingling in hands or feet, and muscle weakness. These symptoms can worsen over time if untreated.
Low B12 levels can disrupt serotonin production, which may lead to mood swings, irritability, and even depression if not corrected.
Older adults, vegans, vegetarians, and people taking medications like acid reducers or metformin are at higher risk due to absorption issues or dietary gaps.
You can boost B12 levels through diet (meat, fish, dairy) or supplements. Liposomal B12 supplements offer better absorption for faster results.
Untreated B12 deficiency can lead to nerve damage, memory loss, cognitive decline, and increased risk of falls or serious health issues over time.
Liposomal B12 uses fat-like liposomes to protect the vitamin through digestion, allowing your body to absorb up to 10x more compared to standard tablets.
Sources:
- https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11084641/
- https://www.washingtonpost.com/wellness/2023/12/04/vitamin-b12-supplements-energy-fatigue/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7077099/
- https://www.mountsinai.org/health-library/diseases-conditions/vitamin-b12-deficiency-anemia
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8294980/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10542023/
References
- NIH Office of Dietary Supplements — VitaminB12 — Causes, signs, and at-risk groups for B12 deficiency.
This article is for educational purposes only and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Manna products are not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any new supplement, especially if you are pregnant, nursing, taking medication, or managing a medical condition.
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