The eight B vitamins are water-soluble nutrients that work synergistically in your body. Unlike fat-soluble vitamins, your body doesn't store them well—you need a consistent daily intake. Here's what each B vitamin does and how to know if you're falling short.
The 8 B Vitamins Explained
B1 (Thiamine)
Role: Converts carbohydrates into energy; essential for nerve function
Deficiency signs: Fatigue, irritability, poor memory, muscle weakness
Best sources: Whole grains, pork, legumes, nutritional yeast
B2 (Riboflavin)
Role: Energy production, antioxidant functions, maintains healthy skin and eyes
Deficiency signs: Cracked lips, sore throat, skin inflammation, light sensitivity
Best sources: Eggs, dairy, almonds, spinach, mushrooms
B3 (Niacin)
Role: DNA repair, energy metabolism, cholesterol management
Deficiency signs: Fatigue, headaches, skin problems, digestive issues
Best sources: Chicken, tuna, peanuts, mushrooms, green peas
B5 (Pantothenic Acid)
Role: Synthesizes coenzyme A; crucial for hormone and cholesterol production
Deficiency signs: Rare, but includes fatigue, numbness, restlessness
Best sources: Avocados, mushrooms, sunflower seeds, chicken
B6 (Pyridoxine)
Role: Amino acid metabolism, neurotransmitter synthesis (serotonin, dopamine), immune function
Deficiency signs: Depression, confusion, weakened immunity, skin rashes
Best sources: Chickpeas, salmon, potatoes, bananas, poultry
B7 (Biotin)
Role: Fat and carbohydrate metabolism; supports hair, skin, and nail health
Deficiency signs: Hair loss, brittle nails, skin rashes, fatigue
Best sources: Egg yolks, nuts, seeds, salmon, avocados
B9 (Folate)
Role: DNA synthesis, cell division, crucial during pregnancy for neural tube development
Deficiency signs: Fatigue, mouth sores, gray hair, cognitive issues
Best sources: Leafy greens, legumes, asparagus, citrus fruits
Note: Look for methylfolate (L-5-MTHF) supplements, not folic acid, for best absorption.
B12 (Cobalamin)
Role: Nerve function, DNA synthesis, red blood cell formation, energy
Deficiency signs: Fatigue, weakness, numbness/tingling, memory problems, mood changes
Best sources: Animal products (meat, fish, eggs, dairy); vegans must supplement
Note: Look for methylcobalamin form for best bioavailability.
Who's at Risk for Deficiency?
- Vegetarians and vegans (especially B12)
- Older adults (reduced absorption)
- Those with digestive disorders
- Heavy alcohol users
- People taking certain medications (metformin, PPIs)
B-Complex vs. Individual B Vitamins
Because B vitamins work together, a B-complex is often preferable to individual supplements—unless addressing a specific deficiency. Look for activated forms: methylcobalamin (B12), methylfolate (B9), and pyridoxal-5-phosphate (B6).
B vitamins are your body's energy currency. A good B-complex is foundational for anyone feeling chronically fatigued.