How to take vitamins

Understanding what vitamins to take begins with assessing your diet, lifestyle, and health conditions. This is best done with a qualified health practitioner.

Taking vitamins and other supplements isn’t always necessary, but there are cases in which they may be recommended or beneficial. Certain health conditions, diets, or lifestyles can increase the body’s demand for a specific nutrient. You may experience symptoms such as fatigue, low mood, frequent infections, muscle aches, or sleeplessness. In other cases, you may have been diagnosed with a condition that requires nutritional support.

Signs of Vitamin B Deficiencies¹ (note that each vitamin B plays a different role in the body and lab tests may be necessary to identify specific deficiencies)

• Fatigue, low energy (all B vitamins)
• Muscle weakness (B12)
• Low mood, irritability, difficulty concentrating (B9, B12)
• Tingling or numbness in hands and feet (B12)
• Mouth sores, cracked lips, or inflamed tongue (B2)
• Pale skin or anemia (B12)
• High homocysteine (B6, B9, B12)

Signs of Vitamin D Deficiency²

• Frequent infections (coughs, colds, flu)
• Fatigue, low energy 
• Muscle weakness or aches
• Mood changes, including seasonal affective disorder
• Slow wound healing
• Hair loss
• Bone pain or lower back pain

Signs of Vitamin C Deficiency³

• Slow wound healing
• Frequent bruising or bleeding gums
• Dry and/or fragile skin 
• Frequent infections
• Joint aches 
• Scurvy (uncommon in developed countries)

Signs of Zinc Deficiency⁴

• Poor immune system function, frequent infections
• Slow wound healing
• Loss of taste or smell
• Thinning hair 
• Skin irritations, such as rashes, acne
• Poor appetite
• Diarrhea
• Changes in nail shape

Signs of Iron Deficiency⁵

• Unexplained tiredness or weakness
• Shortness of breath during physical activity
• Paleness in the skin and/or inside of the eyelids
• Cold hands and feet
• Brittle nails or hair loss
• Frequent headaches or dizziness

Signs of Calcium Deficiency⁶

• Muscle spasms, cramping
• Coarse hair
• Dry skin, psoriasis, itching
• Poor dental health
• Brittle nails
• Numbness or tingling in fingers
• Bone pain, low bone density, increased risk of fractures

Signs of Magnesium Deficiency⁷

• Muscle cramps, spasms
• Ongoing fatigue or weakness
• Difficulty sleeping 
• Low mood, anxiety, irritability
• Abnormal heart rhythm
• Frequent migraines and/or headaches

• Good for: B12, Vitamin D
• How they work: Sublingual vitamins are held under the tongue and absorbed directly into the bloodstream via the mucous membranes in the mouth, bypassing the digestive system. 
• A 2019 study found that sublingual vitamin B12 was more effective in restoring B12 levels than intramuscular B12 injections⁸. A 2024 systematic review also found that sublingual B12 is preferred over intramuscular and oral supplements due to higher compliance with patients⁹. 
• Vitamin D3 oral sprays were found to be as effective as taking capsules, and may be more beneficial for people with gastrointestinal disorders¹⁰. 

• How they work: Fat-soluble vitamins are absorbed by the small intestine. These vitamins are best taken alongside dietary fat as they are dissolved into micelles (tiny fat droplets created by bile salts) to be absorbed into intestinal cells, then packaged into lipoprotein particles that enter the lymphatic system and then the bloodstream. Dietary fat enhances this process by about 30% because the fat provides material for micelle formation.
• A 2025 study found that micelle formation increased the uptake of vitamin D into intestinal cells, with vitamin D3 being more efficient than vitamin D2¹¹. 
• People with fat malabsorption syndromes (such as celiac disease, Crohn's disease, and chronic pancreatitis) are at risk of low vitamin D. Recent research has suggested that the vitamin D metabolite 25-hydroxyvitamin D3 is better absorbed in these patients as it is not as fat soluble¹².

• Best for: People with difficulty swallowing, children
• How they work: Liquid vitamins are easier to administer (depending on taste).
  The bioavailability of liquid vitamins compared to tablets/capsules depends on the specific formulation and nutrient. Some studies show improved absorption for certain nutrients in liquid form, while others show no significant difference. Liposomal and nanoemulsion vitamins may have superior bioavailability compared to oil-based or standard fat-soluble liquid vitamins¹³.  However, it’s worth noting that liquid vitamins are less stable than solid supplement forms (tablets, capsules, powders) due to their vulnerability to water, light, oxygen, temperature, and pH, which accelerate degradation¹⁴. This can result in reduced potency, particularly for methylfolate. Supplements in the form of gummies or liquids are unlikely to provide therapeutic benefit.

• Best for: Nutrients affected by light, air, moisture. Precise dosing.
• How they work: Capsules and tablets are broken down in the digestive system, with some nutrients undergoing first-pass metabolism in the liver before entering systemic circulation.
• Softgels are flexible capsules made from gelatin or vegetable cellulose. Softgels are often most effective for fat-soluble nutrients and essential fatty acids such as fish oil (Omega-3s) because the lipid structure is incorporated into the micelles more easily. 
• Capsules are generally made from gelatin or cellulose, and can contain a wide variety of nutrients in powders or granules. 
• Tablets generally contain more excipients than capsules and softgels (binders, fillers, lubricants, coatings) to maintain shape, improve taste, and control drug release, but they can support a greater quantity of active ingredients in a single unit.

Some large tablets can be cut with a tablet splitter, which may make them easier to swallow. Large capsules can be opened and the contents sprinkled onto food or liquid. 

Otherwise, try bending your head towards your chest when swallowing.

• Taking too many water-soluble vitamins at once.
  These are not stored in the body, so any excess is flushed out. It’s best to take water-soluble vitamins in divided doses so that they can be absorbed more efficiently.
  
• High doses are best.
  Some vitamins and minerals can cause side effects when taken in high doses. High doses of vitamin C, magnesium, zinc, and iron can cause diarrhea, while iron and calcium can also cause constipation.
  
• Taking B vitamins at night.
  B vitamins can be stimulating and may cause sleeplessness.
  
• Assuming all supplements are the same.
  Cheaper brands (such as those sold by supermarkets or budget retailers) may use poor-quality ingredients that are inactive forms, less bioavailable, or even include undeclared, potentially harmful ingredients in addition to being significantly less potent than the label claims.

Some nutrients are most effective when taken with food, particularly fat-soluble vitamins (A, D, E, K) and probiotics.

B vitamins are water-soluble and can generally be taken with or without food, but may cause digestive upset in some people if taken on an empty stomach. In general, methylfolate and active B12s can be taken on an empty stomach without causing upset.