Can’t figure out why you’re tired all the time?

The obvious answer is that you’re probably not sleeping enough. After all, very few people are getting the recommended seven to nine hours per night. 

RELATED: 6 Tips for Better Sleep

But there are other, not-so-obvious factors that may be affecting your energy levels. From what and how you’re eating to the hormones circulating throughout your body—it’s all connected.

If you’ve conquered your insomnia but still feel like you’re always dragging (or running on caffeine), consider these possible causes.

5 Common Causes of Fatigue 

You’re Dehydrated 

Studies suggest that even mild dehydration can mess with your energy levels, causing fatigue and making it difficult to concentrate. You should be drinking (on average) 64 ounces a day. If you have trouble making that happen, consider these tips to make your H2O more exciting.

You’re B12 Deficient 

B vitamins are often called “the energy vitamins.” Specifically, not getting enough B12 can make you feel weak and tired. Vegans and vegetarians are especially at risk for B12 deficiency. Follow this advice to try to get enough in your diet, or you may need to supplement.

You’re Not Eating Enough Protein 

Carbs give you fast energy, but protein takes longer for the body to break down, giving you sustained energy. Especially if you’re frequently exercising, you may not realize how much protein is required to help your body repair and build muscle. Salmon is a great option since it’s filled with protein and delivers those beloved B vitamins.

You’re Eating Too Infrequently

Long stretches without fuel can leave you running on empty. Eat small meals or snacks every three to four hours to keep your energy level steady. Just remember to avoid sugary snacks since high-sugar foods will only provide a quick rush and then an energy crash.

You’re Thyroid Is Out of Whack

Countless people are walking around with undiagnosed thyroid issues that lead to constant fatigue and weight gain. According to UCLAHealth.org, some symptoms include joint or muscle pain or weakness, a puffy face, and unexpected weight gain. If your symptoms seem to match, consider heading to your MD for tests.

Of course, don’t forget: While any of these scenarios may be draining your energy, fixing them won’t negate the need for a good night’s sleep…every night.