Vitamins and supplements have never been more popular — yet many people are unsure which ones they actually need, how much to take, or whether they make any real difference. This comprehensive guide cuts through the confusion so you can make informed choices for your health.

What Are Vitamins and Why Does Your Body Need Them?

Vitamins are organic compounds your body requires in small amounts to function correctly. Unlike macronutrients (protein, carbohydrates, fat), vitamins don’t provide energy — but without them, the processes that generate and use energy simply can’t work.

There are two categories:

  • Fat-soluble vitamins (A, D, E, K) — stored in body fat and the liver. Because they accumulate, excessive intake can become toxic.
  • Water-soluble vitamins (B group and C) — not stored in significant amounts, so regular intake through diet or supplements is important. Excess is generally excreted in urine.

Essential minerals such as calcium, iron, magnesium and zinc are also covered under the umbrella of “supplements” and play equally critical roles in hundreds of biological processes.

The 10 Most Important Vitamins and What They Do

Vitamin A — Supports vision (especially night vision), immune function and skin cell turnover. Found in liver, oily fish, dairy. The UK government recommends 700mcg/day for men and 600mcg/day for women.

Vitamin B12 — Critical for red blood cell production, nerve health and DNA synthesis. Only found naturally in animal products, making supplementation essential for vegans. Deficiency causes fatigue, tingling and, if prolonged, irreversible nerve damage.

Vitamin C — A powerful antioxidant that supports collagen formation, immune function and iron absorption. The UK Reference Nutrient Intake (RNI) is 40mg/day, though many experts recommend 200–500mg for optimal immune support.

Vitamin D — Perhaps the most important vitamin for UK residents. Made by skin on exposure to UVB sunlight — something we get very little of between October and April. Vitamin D is essential for calcium absorption, bone health, immune function and mood regulation. The NHS recommends everyone take 10mcg (400IU) daily in autumn and winter.

Vitamin E — An antioxidant that protects cell membranes from oxidative damage. Important for skin health. Found in nuts, seeds and vegetable oils.

Vitamin K — Essential for blood clotting and, in the form of K2, for directing calcium into bones rather than arteries.

Folate / Folic Acid — Critical for cell division and DNA synthesis. Particularly important before and during early pregnancy to prevent neural tube defects. The NHS recommends 400mcg daily for women trying to conceive.

Iron — Transports oxygen in the blood. Deficiency (anaemia) causes fatigue, breathlessness and impaired concentration. Women of childbearing age are particularly at risk.

Magnesium — Involved in over 300 enzymatic reactions. Supports muscle function, nerve signalling, energy production and sleep quality. Many UK adults consume less than the recommended amount.

Zinc — Supports immune defence, wound healing, protein synthesis and testosterone production. Short-term deficiency impairs immune function noticeably.

Who Needs Supplements — And Who Doesn’t?

The “food first” principle remains sound — a varied, balanced diet is the best way to meet most nutritional needs. However, certain groups genuinely benefit from supplementation:

  • Pregnant women — folic acid (400mcg) and Vitamin D (10mcg) are recommended by the NHS throughout pregnancy
  • Adults over 65 — Vitamin D, B12 (absorption declines with age)
  • Vegans and vegetarians — B12, iron, zinc, omega-3, iodine
  • People with limited sun exposure — Vitamin D year-round
  • Women with heavy periods — iron
  • People with absorption conditions (Crohn’s, coeliac) — multiple vitamins

How to Choose the Right Vitamin Supplement

Not all supplements are equal. Key considerations include:

  • Bioavailability — the form of the nutrient affects how well it’s absorbed. Magnesium glycinate is better absorbed than magnesium oxide. Methylcobalamin B12 is better for some people than cyanocobalamin.
  • Dosage — more isn’t always better. Stick to recommended amounts unless under medical supervision.
  • Format — tablets, capsules, gummies, liquids. Gummies are popular with children but often contain added sugar.
  • Certifications — look for GMP (Good Manufacturing Practice) certified products.

Vitamins Available at Chemist 2 Customer

At Chemist 2 Customer, we stock a comprehensive range of vitamin and mineral supplements from trusted brands. Browse our full selection:

Frequently Asked Questions

Can you take too many vitamins? Yes — particularly fat-soluble vitamins (A, D, E, K) which accumulate in the body. Always follow recommended doses.

What’s the best time of day to take supplements? Fat-soluble vitamins are best taken with a meal containing fat. Water-soluble vitamins (B and C) can be taken at any time, though B vitamins are often taken in the morning to support energy.

Should you take vitamins with food? Most supplements are better absorbed with food and cause less stomach upset this way.

For more detailed advice, explore our related guides: Best Vitamins for Women, Essential Vitamins for Men, and Children’s Vitamins Guide.