Medically reviewed on January 9, 2023 by Morgan Spicer, Medical Communications Manager. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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Like many other nutrients, vitamin B12 is critical for human health and development and if you don’t consume enough of it from food or supplements, you could be a candidate for developing vitamin B12 deficiency .
Mild to moderate deficiencies of vitamin B12 are fairly common, with about 40% of people in Western populations reported to experience them . But whether you suspect that you’re low on B12 or you’re currently in remission from a B12 deficiency, waiting for symptoms to dissipate can feel frustrating. The length and quality of your recovery process depend on the severity of your condition, but it can be immensely helpful to have some more insight into what to expect from the process.
Below, we’ll break down some B12 basics, signs and symptoms of a B12 deficiency, and what to expect from treatment so you can look forward to feeling like your energetic self again.
Vitamin B12 is one of eight B vitamins your body needs to make energy, form red blood cells, and perform other critical tasks . The B vitamins (and their names) are:
While each B vitamin plays a variety of important roles, vitamin B12 is critically important for three key physiological processes :
Despite being indispensable for some essential functions, the human body doesn’t make vitamin B12 on its own. Instead, humans have to acquire B12 through food sources, taking supplements, or receiving injections from a healthcare provider when they suspect a low Vitamin B12 level.
So you might be wondering: how much vitamin B12 should I take daily? Health experts’ recommended daily allowances (RDAs) for B12 intake recommendations vary by age, but the recommendations are the same regardless of your sex :
If you’re pregnant, the National Institute of Health recommends you ingest at least 2.6 micrograms of B12 per day; if you’re breastfeeding, 2.8 micrograms.
If you don’t get enough vitamin B12 or you have low B12 absorption, your body will start to respond. But before we get into the vitamin B12 deficiency signs and symptoms, let’s define those two terms :
If you don’t get enough B12 in your diet or through supplementation, you may develop one or more of the following symptoms :
Signs that healthcare providers use to detect a B12 deficiency include :
It’s important to note that the severity of the symptoms above depends on the extent of your B12 deficiency. If you’ve had a chronic, severe vitamin deficiency for many years, your symptoms will be more significant than they would be after a few weeks of decreased B12 intake.
If your healthcare provider detects low B12 levels, they’ll tell you how you can expect to see symptoms persist after you’ve begun their treatment protocol.
B12 deficiency is typically treated in one of two ways, and some providers use both methods simultaneously :
But how long to recover from vitamin B12 deficiency after each treatment? The amount of time it takes for either treatment to take effect depends upon the severity of your B12 deficiency, and on the resulting health impacts of being deficient .
If you have only mild symptoms of B12 deficiency, you should notice the effects of treatment relatively quickly. For instance, if you’ve only noticed mild fatigue, and your provider treats your deficiency with an intramuscular injection, you should notice an improvement in just a few days.
The same is true if your blood work only shows signs of mild abnormalities: high levels of reticulocytes (immature red blood cells), homocysteine (an amino acid broken down by vitamin B12), or methylmalonic acid (MMA, a byproduct of amino acid breakdown) should subside after just a few vitamin B12 injection treatments.
If you’ve noticed some mild symptoms of a vitamin B12 deficiency, it’s important to consult with your healthcare provider to rule out other possible causes. Following that, you’ll want to take the following steps under their supervision .
If your healthcare provider suspects a vitamin B12 deficiency, they’ll likely suggest a blood test to examine:
If you decide to proceed with testing, you can make an in-person appointment with a nearby testing facility.
No matter which testing option you use, the next step is to review the results with your healthcare provider.
When you discuss your test results, your provider will :
If you have a B12 deficiency, your healthcare provider may recommend one or more of the following treatment protocols :
As you proceed with treatment, your provider will likely ask you to keep track of your symptoms and whether they recede. You could do this in a variety of ways:
And, if you don’t notice an improvement, check in with your provider—they may be able to offer more insight to help you get to the bottom of your symptoms.
Whether it’s a suspected vitamin B12 deficiency or nausea that won’t let up, it’s not uncommon to avoid taking action on our health because of sheer inconvenience. But your well-being should never feel like a headache—and with Everlywell's vitamin B12 supplements, it's easy to get this key nutrient (as well as a range of other vitamins and supplements).