Vitamin B12 plays an important role in keeping your body functioning properly, although it's often overlooked. It's involved in everything from energy production and muscle repair to supporting your mood and nervous system, and it also contributes to healthy hair growth. Despite its importance, many people don't get enough of it.Experts say older adults and people following vegan or vegetarian diets are among those most at risk of a vitamin B12 deficiency. However, it's not limited to these groups. Younger people can also become deficient, particularly if they don't eat a balanced, nutrient-rich diet.To get the low down on B12, I spoke to nutritional therapist Alexa Mullane, who explained: “B12 is naturally found mainly in animal products like meat, fish, eggs and organ meats. Vegetarian sources of B12 include chlorella, nori, nutritional yeast and certain mushrooms, but many vegans and vegetarians have insufficient levels of B12 because it’s not widely found in plants.”According to Mullane, not getting enough B12 can result in issues like anaemia, fatigue and more intense symptoms including shortness of breath, palpitations, pale skin, muscle weakness, numbness and tingling in hands or feet, blurred vision and memory loss. “Vitamin B12 is a water-soluble vitamin that is crucial for many functions in the body. It’s used to make DNA, it helps us to make energy and it’s vital for maintaining a healthy nervous system. We can’t make vitamin B12 ourselves so it’s essential that we get it from our diet,” she explains.It’s a notoriously difficult nutrient to absorb in the gut. According to experts at BetterYou: “At most, only one per cent of our dietary intake will be absorbed by the body, and that relies on digestive efficiency and the presence of a chemical called intrinsic factor. Tiredness, stress, ill-health, poor or limited diet will all reduce this absorption further.”For some people, taking a vitamin B12 supplement is one of the easiest ways to maintain healthy levels. This can be particularly helpful if your diet doesn't include many B12-rich foods, such as meat, fish, eggs or dairy. While most people get enough vitamin B12 through their everyday diet, those with dietary restrictions, food allergies or intolerances, or those following vegetarian or vegan lifestyles may benefit from a supplement to help support normal body and brain function.If anxiety and poor sleep are concerns, you may also find that other supplements, such as CBD oil , are worth considering. However, not all supplements offer the same benefits. Some are more easily absorbed by the body than others, while quality, purity and dosage can vary significantly between products. To help separate the good from the bad, we asked Alexa Mullane to share her recommendations on the best vitamin B12 supplements to buy, along with advice on how to take them. Read on for her expert picks.Read more: The best supplements to take in 2026