When was the last time you had your vitamin B12 level checked? It may have been longer than you think.

Vitamin B levels are not typically checked as part of routine blood work, meaning you could easily be one of the 15% of people with a vitamin B12 deficiency or one of the almost 40% that are borderline.1 This leads to a crucial question: Why is this even important?

To answer this question, we'll take a quick look at what exactly vitamin B12 is, what it does for the body, and who can benefit from it.

Plus, we'll explain why liquid and sublingual B12 are superior when it comes to potency and bioavailability (how easy it is to absorb) compared with other types of vitamin B12, and last but not least, we'll share our top 5 candidates for best B12 supplements on the market! 

What is Vitamin B12?

Vitamin B12 is simply a water-soluble vitamin, or nutrient, that your body absolutely needs to ensure your nerves and blood cells stay healthy.2 It plays an essential role in the formation and metabolism of your red blood cells (RBCs), as well as in your ability to produce DNA (the genetic material in your cells).

In regards to your nerve cells, vitamin B12 helps maintain their overall health and works to form their protective covering, known as the myelin sheath. At the same time, vitamin B12 helps to prevent you from developing megaloblastic anemia, which is characterized by extreme tiredness and weakness.

When your B12 levels are low, your production of RBCs, which carry oxygen throughout your body, is negatively affected.

When your body doesn’t have enough RBCs to do this, you’ll become very tired and weak. You may also experience neurological symptoms, such as tingling and numbness in your hands and feet.

B12 and Immunity

B12 is a key player in the immune system as it increases your white blood cell count. White blood cells are involved in protecting the body against both infectious disease and foreign invaders. When your count is low, you're more at risk for pathogens entering your system.

People at risk of being deficient in b12 are vegans, vegetarians and people over the age of 50.  

Why Liquid B12 Is More Effective

If you've ever shopped for vitamin B12, you may have noticed it comes in a variety of forms — pills, sprays, gummies, liquid drops, etc. For some, choosing the right B12 supplement boils down to personal preference (if you have a hard time swallowing pills, for example, you might prefer a gummy or spray). 

However, most experts agree that the best way to ingest B12 is sublingually, or under the tongue since they are highly "bioavailable" (easier to absorb). Thus, liquid drops, sprays and caplets that dissolve under the tongue are absorbed faster than gummies and pills, which must first be broken down in the intestine. 

Still, sprays can get a little messy (and sticky!), which is why we recommend liquid B12 drops. They're fast-acting, concentrated, and most reviewers find they have a pleasant taste. For additional tips on what to look for and what to avoid, check out our B12 buying guide below. 

Your Complete Vitamin B12 Checklist:

Contains Methylcobalamin

As a naturally sourced form of B12, methylcobalamin is far more bioavailable than B12's synthetic form, cyanocobalamin. Research also shows that it stays in your body longer and at a higher level than cyanocobalamin.5

Opt for Well-Known Manufacturers

While lesser-known manufacturers may be just as good as their counterparts, you can’t always count on this. Opting for a manufacturer that you can trust is only using the highest-quality ingredients and is testing them for purity and potency.

Look for Sublingual or Liquid B12

Sublingual, or under-the-tongue, supplements start to work immediately, unlike tablets and pills, which must be digested first. Similarly, liquid drops are fast-acting and typically contain high concentrations of vitamin B12. 

The Right Dose

You’ll see supplements with anywhere from 500 mcg of vitamin B12 to more than 8,000 mcg — the ideal dose for a B12 supplement, however, is actually 5,000 mcg for optimal potency.

Warning Signs and Reasons to Avoid Buying a Vitamin B12 Supplement:

Synthetic Forms of B12

Be wary of any supplement containing cyanocobalamin or hydroxocobalamin. These are not only ineffective but can also cause uncomfortable and even dangerous side-effects.

Extremely High Doses

While many nutrients, such as Vitamin C, are not harmful in large quantities, taking too much Vitamin B can cause health complications and unnecessary strain on your liver and other organs.

Remember, you should always speak with your physician before starting any type of supplement. He or she can also advise you on a good dosage to start off with.

Our Specialized Ranking System

Now, that you have a better understanding of vitamin B12 and how you can benefit from the supplement, it’s time to look at some of the most popular supplements on the market. At Smarter Reviews, we employ a comprehensive evaluation system to analyze and measure the full value of products. This is based on ingredients, safety, potential effectiveness, return policies, and overall customer satisfaction. We call our method the Smarter Reviews Ranking System.

Top 5 Vitamin B12 Supplements

We looked at the most popular Vitamin B12 supplements available and narrowed them down to the top 5. Here's what we found...