There’s a reason they call Vitamin B12 the “energy” vitamin – this essential nutrient powers just about everything in your body, from brain function to the growth of red blood cells.

Read on for ten reasons Vitamin B12 is your new BFF – including how it can help you maintain healthy skin and that lustrous, foxy mane:

1. Put a Little Pep in Your Step

If you start dragging your feet or feeling low, it could be a sign you’re missing one of the key vitamins for putting an extra little pep in your step – especially if you’re a vegetarian.

Why? Vitamin B12 is “virtually nonexistent in plant foods,” reports Malia Jacobson at Women’s Health.

“Not getting the recommended 2.4 micrograms per day could leave you feeling weak and tired. (This goes for you, too, vegans.),” she adds.

You can find this ultra-important nutrient in fish, red meat, turkey, and eggs – but if that’s against your diet, you’ll have to supplement. Check with your doctor to find out whether this means you.

2. Two Tickets to the Gun Show

Whether you’re working out like a maniac in the weight room or simply trying to burn off that baby weight, Vitamin B12 helps you power through your workout.

And if you don’t have enough in your system, you could feel weak in the knees.

“A severe B12 deficiency results in anemia, which can be picked up by an ordinary blood test,” explains Jane Brody at The New York Times.

That’s because working out your muscles consumes oxygen – and they need plenty of red blood cells to keep up with your Zumba instructor!

3. Improve Your Memory

There’s a reason they call fish “brain food” – rich in Vitamin B12, our friends from the sea also contain plenty of omega-3 fatty acids, which are linked to brain health.

Perhaps that explains why aging patients – who are at a higher risk for Vitamin B12 deficiency – are also at greater risk for degenerative diseases of the mind.

Strangely enough, symptoms of Vitamin B12 deficiency in older folks can “often mimic those of dementia, such as memory loss, disorientation, and difficulty thinking and reasoning,” reports nutritionist Stephanie Middleberg at Health.

Even the rest of you spring chickens should keep an eye out for these symptoms, too, Middleberg suggests.

4. Stay on an Even Keel

Between PMS and the ever-present threat of menopause, our emotional lives can feel like enough of a ticking time bomb as it is.

Turns out, getting enough Vitamin B12 is also an important part of managing your feelings.

“I routinely recommend both fish oil and the B vitamins to patients experiencing depression and anxiety,” writes Dr. Sheenie Ambardar at Huffington Post.

Of course, you should definitely check in with your doc to see if mood swings are symptoms of something more serious.

5. Maintain Killer Eyesight

While we can’t promise that taking B12 supplements will help you see in the dark, you do need this vitamin for healthy eyesight. (Not as sexy as having a superpower, but we’ll take it.)

“The optic nerve is responsible for carrying signals from the eyes to the brain; without it, even a patient with otherwise healthy eye could lose vision,” explain the minds behind Rebuild Your Vision, a vision health supplement research firm.

“B12 deficiency renders nerves, including the optic nerve, more brittle, and can cause damage to the optic nerve, resulting in decreased central vision.”

Make sure you’re eating plenty of fish and other meats, so you don’t wind up groping around in the dark!

6. Rev Your Metabolism

After you hit 30, nothing about your metabolism feels straightforward anymore. Say goodbye to eating pizza and junk food at any hour and hello to your desk salad.

If you’re getting enough Vitamin B12, though, that desk salad doesn’t have to be so sad. (In fact, go ahead and give yourself some points for eating veggies!)

“Inadequate amounts of B6, B12, folate, thiamin and niacin can leave you feeling depressed and fatigued, slow the body’s metabolism, and increase your risk for chronic diseases,” Dr. Samantha Heller told Today.

“Get the bulk of your B’s from food, where they pair up with other vitamins and minerals for a complete synergy of action.”

Time to put that spinach desk salad to work.

7. Fire Up Those Neurons

If you’re having trouble staying motivated through your morning meetings, a bowl of fortified cereal – chock-full of Vitamin B12 – might do you more good than a cup of coffee.

“Fortified cereals are also a great source of vitamin B12, linked to how well we remember things,” she adds.

Come on, science, who are you kidding? Coffee’s still the best.

8. Stick to the Straight and Narrow

Because Vitamin B12 is crucial for maintaining a healthy nervous system, patients who suffer from a deficiency often feel tingling sensations in their limbs.

“Depletion of your vitamin B12 stores leads to nerve damage,” writes Esther Crain at Health.

“No wonder pins and needles in your hands and feet, shaky body movements, and trouble walking are all consequences of long-term B12 deficiency.”

Here’s to standing our ground.

9. Fight Off Colds

When enough of this vitamin’s coursing through your veins, your immune system stays in tip-top shape.

That means all those cold germs that come home from your kid’s school or rub off on the subway won’t stand a chance.

Give your immune system a one-two punch with yogurt, which contains both Vitamin B12 and probiotics.

“It acts like a lock and key to keep the good stuff in and the bad stuff out,” says dietician Laura Manning at Women’s Health.

10. Show Off Healthy Hair, Skin, & Nails

Because Vitamin B12 regulates cell reproduction, it’s the key to making your hair, skin, and nails the picture of health.

Okay, so “cell reproduction” isn’t a super-sexy secret for getting perfect hair, but it is important, says health and beauty expert Tracy Piper.

“Your locks tell so much about your health, so when you’re deficient in certain vitamins and minerals, your hair doesn’t have optimal shine or bounce,” Piper told Harper’s Bazaar.

“B vitamins help your hair, skin and nails grow effortlessly,” she adds. “Do you have a moon on your fingernails? If not, that can be a sign of B12 deficiency and lack of circulation.”

Piper suggests taking an “active B complex” so your body can properly absorb all those nutrients.

Become the picture of health and get super shiny hair? What else could a girl ask for?

Whether you’re trying to breathe life back into tired, dull locks or simply stay on top of your health, one thing’s for sure – life looks pretty terrible with a B12 deficiency.

Because this vitamin is in charge of just about everything when it comes to energy, movement, and brain function, keep a good B complex on speed dial (just like any other BFF in your life).

As always, if you have any questions about supplementing, or your energy levels are lagging, it’s time to make an appointment with your doctor to get everything checked out.

(We promise to do our best to give you health and wellness info you can actually use – but we’re definitely not your family doc!)

No doubt about it – adulting is hard. But with Vitamin B12 in your corner, everything is way easier.