Chronic fatigue, frequent infections, or dull skin can be warning signs of a vitamin deficiency. Although these tiny molecules are only needed in small amounts, they determine energy, immune strength, and well-being. Which vitamins does the body really need, and how can you recognize a deficiency before serious problems arise? This guide shows you the path to optimal vitamin intake.
Key findings at a glance
-The 13 essential vitamins control energy production, immune defense and cell renewal
-Vitamin D deficiency affects over 60% of Germans and increases in dark months
-B vitamins combat chronic fatigue by optimizing energy metabolism
-Special vitamins promote skin health and give natural glow
-Targeted supplementation can close nutritional gaps and increase well-being
-Individual blood values show your personal vitamin needs
How do I know when my body is calling for vitamins?
Your body sends subtle signals long before a severe vitamin deficiency is diagnosed. Constant exhaustion despite adequate sleep can indicate a vitamin B deficiency. Frequent colds may indicate insufficient vitamin C or D intake. Dry skin, brittle nails, or dull hair can be signs of nutrient deficiencies.
Modern living conditions increase the risk of vitamin deficiencies. Stress dramatically increases the consumption of B vitamins and vitamin C. Lack of sunlight leads to vitamin D deficiency, while unbalanced diets or excessive dieting can create multiple nutrient deficiencies.
A blood test will give you certainty about your current vitamin status. Levels of vitamin D, B12, folic acid, and iron are particularly important. These symptoms can indicate nutrient deficiencies and should be taken seriously before long-term health problems develop.
The 13 essential vitamins: What makes them so special?
Which vitamins does the body need daily? The answer includes 13 essential compounds that your body cannot produce itself. They are divided into fat-soluble vitamins (A, D, E, K), which can be stored in the body, and water-soluble vitamins (B complex and C), which must be consumed regularly.
1. Vitamin A (Retinol)
Supports vision, the immune system, and skin regeneration. As an antioxidant, it protects cells from damage and promotes wound healing. It is especially important for night vision and healthy mucous membranes. The body can convert beta-carotene from orange-yellow vegetables into active vitamin A, although the conversion rate varies greatly from person to person. Alcohol consumption and smoking significantly increase vitamin A requirements, as these substances strain the liver and reduce its storage capacity.
2. Vitamin B1 (thiamine)
Converts carbohydrates into energy and supports nerve function. Deficiency leads to fatigue, poor concentration, and muscle cramps. Water-soluble, therefore daily intake is necessary. Coffee and tea can impair thiamine absorption, so a gap between intakes is recommended. Diabetics often have an increased need for B1, as glucose metabolism disorders increase consumption and promote excretion via the kidneys.
3. Vitamin B2 (riboflavin)
Plays a central role in energy metabolism and protects cells from oxidative stress. Important for healthy skin, eyes, and the nervous system. Supports the function of other B vitamins. Light-sensitive, which is why dairy products should be stored in dark packaging. A deficiency is often indicated by chapped corners of the mouth and a purple tongue. Athletes have an increased need, as B2 is used in energy production from fats.
4. Vitamin B3 (Niacin)
Regulates cholesterol levels and supports cardiovascular health. Promotes healthy skin and, in higher doses, can be used therapeutically for skin problems. The body can produce niacin from the amino acid tryptophan, but this process is inefficient. In grains, niacin is often found in a bound form and must be released through fermentation or alkaline treatment. High therapeutic doses can trigger a harmless "niacin flush" with skin reddening and a feeling of warmth.
5. Vitamin B5 (pantothenic acid)
Involved in hormone production and energy production. Supports wound healing and can improve stress resistance. It is found in almost all foods; deficiency is rare. The name is derived from the Greek "pantothene" (everywhere) because it is practically ubiquitous. It is particularly abundant in organ meats, eggs, and avocados. Stress and intense physical exertion can significantly increase the need, as B5 is needed for cortisol production in the adrenal glands.
6. Vitamin B6 (pyridoxine)
Regulates hormone balance and supports immune function. Important for protein metabolism and red blood cell formation. Can relieve PMS symptoms and stabilize mood. Involved in over 100 enzymatic reactions, particularly in amino acid metabolism. The contraceptive pill can lower B6 levels, which is why women using hormonal contraception often have an increased need. Very high doses above 100 mg daily can paradoxically lead to nerve damage, so moderate dosages are recommended.
7. Vitamin B7 (Biotin)
Promotes healthy hair, skin, and nails. Supports fatty acid synthesis and blood sugar regulation. Deficiency often manifests as hair loss and skin problems, but is rare. Biotin is partially produced by intestinal bacteria, which is why antibiotic treatments can impair biotin status. Raw egg whites contain avidin, which binds biotin and prevents absorption—a problem with excessive consumption of raw eggs. Pregnant women have an increased need, as biotin is important for fetal development.
8. Vitamin B9 (folic acid)
Essential for cell division and DNA synthesis. Especially important during pregnancy for the prevention of neural tube defects. Supports heart health and cognitive function. Synthetic folic acid from supplements is more readily available than natural folate from foods. Alcohol severely inhibits folic acid absorption, which is why regular consumption can lead to deficiencies. Certain medications, such as methotrexate, block folic acid metabolism and require close monitoring of blood levels.
9. Vitamin B12 (cobalamin)
Essential for the nervous system and blood formation. Deficiency leads to anemia, fatigue, and neurological problems. Found almost exclusively in animal products. Requires intrinsic factor from the stomach for absorption, which is why stomach diseases can lead to B12 deficiency. The liver can store B12 for years, which is why deficiency symptoms do not appear until later. Older people often produce less stomach acid, which makes B12 absorption from foods more difficult and necessitates supplementation.
10. Vitamin C (ascorbic acid)
Strengthens the immune system and promotes collagen formation. As a powerful antioxidant, it protects against free radicals and improves iron absorption. Water-soluble, high doses are excreted. Smokers have twice the vitamin C requirement of non-smokers because cigarette smoke causes oxidative stress. Absorption is dose-dependent—the body can utilize a maximum of 200-400 mg at a time. Liposomal vitamin C circumvents this limitation and achieves higher tissue concentrations than conventional forms.
11. Vitamin D (calciferol)
Regulates calcium absorption and strengthens bones. Modulates the immune system and can prevent autoimmune diseases. The only vitamin the body can produce itself through sunlight. Skin pigmentation significantly influences vitamin D synthesis – people with dark skin require longer sun exposure. Obesity can impair vitamin D utilization, as the fat-soluble vitamin is stored in fatty tissue and becomes less available. The optimal time of day for vitamin D synthesis is between 10 a.m. and 3 p.m., when UVB radiation is at its strongest.
12. Vitamin E (Tocopherol)
Protects cell membranes from oxidation and supports immune function. Promotes wound healing and can slow skin aging. Particularly effective in synergy with vitamin C. Exists in eight different forms, with alpha-tocopherol being the most biologically active. Vegetable oils are rich in vitamin E, but quickly lose their potency when heated and stored. People with lipid indigestion have difficulty absorbing vitamin E and require water-soluble forms or higher dosages.
13. Vitamin K (Phylloquinone)
Regulates blood clotting and bone health. The K2 form transports calcium to the bones and prevents arteriosclerosis. Works optimally with vitamin D. K1 is found in green leafy vegetables, while K2 is produced by intestinal bacteria and is found in fermented foods. Antibiotics can disrupt the K2-producing intestinal flora and lead to deficiency symptoms. Blood-thinning medications such as warfarin act as vitamin K antagonists, so their use must be monitored by a doctor.
Can vitamins beat your fatigue?
Chronic fatigue may be your body's cry for help, demanding certain vitamins. B vitamins play a key role in energy production in your cells. Without sufficient B1, B2, B6, and B12, carbohydrates, fats, and proteins cannot be efficiently converted into usable energy.
Vitamin B12 deficiency is particularly insidious because the symptoms appear gradually. Fatigue, difficulty concentrating, and depression can be early signs. Vegetarians and vegans are particularly at risk, as B12 is mainly found in animal products. Vitamin B12 deficiency often develops unnoticed and, if left untreated, can lead to irreversible nerve damage.
Vitamin D also plays an underestimated role in energy levels. Studies by the USZ show a direct link between low vitamin D levels and chronic fatigue. Especially in the winter months, when sun exposure is low, a vitamin D deficiency can lead to persistent exhaustion.
Minerals and vitamins work synergistically together. Iron transports oxygen to the cells, while vitamin C improves iron absorption. Magnesium activates over 300 enzymes and is essential for ATP production. This nutrient combination forms the foundation for stable energy.
How do vitamins make your skin glow?
Your skin reflects your internal nutritional status. Vitamins for the skin work at the cellular level and can produce visible improvements that no cream can achieve.
Vitamin C acts as a master antioxidant and collagen booster. It neutralizes free radicals that accelerate skin aging and stimulates the body's own collagen synthesis. Regular vitamin C intake can reduce wrinkles and firm the skin.
Vitamin A and its derivatives are considered the gold standard in anti-aging medicine. They accelerate cell renewal, refine pores, and can even reduce acne scars. Topical application of retinol shows dramatic results, but internal administration is also crucial.
Vitamin E protects the skin barrier and enhances the effects of vitamin C. These two antioxidants work synergistically and can repair sun damage and reduce inflammation.
Biotin and zinc round out the beauty vitamin portfolio. They strengthen skin, hair, and nails from within and can lead to visible improvements when taken regularly.
Which vitamins strengthen your immune system?
Your immune system is a complex network that continually requires vitamins to strengthen it. Vitamin C is in the spotlight, but the reality is more nuanced.
Vitamin D regulates both innate and adaptive immunity. It activates T cells and modulates inflammatory responses. People with optimal vitamin D levels have been shown to suffer less from respiratory infections.
The B vitamins support the production and function of immune cells. B6 is particularly important for antibody formation, while B12 enables immune cell division. Folic acid plays a key role in the DNA synthesis of new defense cells.
Vitamin A regulates mucosal immunity—your first line of defense against pathogens. It keeps the respiratory, intestinal, and urinary tracts healthy and functioning.
Zinc enhances the effects of these vitamins and is itself a potent immunomodulator. It has been proven to shorten the duration of colds and support wound healing.
Is vitamin D the answer to many problems?
Vitamin D occupies a special position because the body can produce it itself—in theory. In practice, over 60% of Germans suffer from a deficiency , which rises to over 80% in the winter months.
The skin needs UVB radiation to synthesize vitamin D. Between October and March, sunlight in Germany is insufficient, even for daily walks. Sunscreen, which we rightly use, also blocks vitamin D production.
Vitamin D deficiency can have serious consequences — from fatigue and depression to increased susceptibility to infections and bone fractures.
The optimal dosage is between 1000–4000 IU daily, depending on current blood levels. Values between 75–125 nmol/L are considered optimal. Vitamin K2, as a cofactor, is crucial because it directs calcium into the bones and prevents arteriosclerosis.
High-quality vitamin D3 K2 drops offer optimal bioavailability and allow for precise dosing. The liquid form is better absorbed than tablets and can be individually adjusted.
When do I need which vitamins does my body need?
Vitamin needs change with each stage of life. Pregnant women need 400–800 µg of additional folic acid to prevent neural tube defects. Iron needs double as blood volume increases.
Children and adolescents have an increased need for vitamin D for bone growth and B vitamins for brain development. Vitamin A supports growth, while zinc strengthens the immune system.
Adults often struggle with stress, which depletes B vitamins and vitamin C. Working at a computer screen increases the need for vitamin A for eye health. Exercise increases the need for antioxidant vitamins.
With age, nutrient absorption decreases. Stomach acid production decreases, impairing B12 absorption. The skin produces less vitamin D, while the need for antioxidants increases.
Natural sources vs. dietary supplements: Which is useful and when?
A balanced diet forms the foundation of vitamin intake. However, modern foods often contain fewer nutrients than before. Long transport routes, storage, and processing significantly reduce vitamin content.
Certain vitamins are difficult to obtain through diet. Vitamin D is found in significant quantities only in oily fish. Vitamin B12 is found practically exclusively in animal products. Folic acid is heat-sensitive and is lost during cooking.
High-quality nutritional supplements can fill these gaps. MTM Supplements offers scientifically sound, pharmaceutical-grade products. Bioavailability is often higher than with natural sources because no interfering substances are present.
Quality criteria for supplements:
-Pharmaceutical purity and potency
-Optimal dosage form (drops often better than tablets)
-Synergetic combinations (D3 + K2, B complex)
-Regular laboratory checks
-Transparent ingredient information
Overdose is rare with water-soluble vitamins, as excess amounts are excreted. Fat-soluble vitamins can accumulate, so dosage recommendations should be followed.
Is your health worth your investment?
Which vitamins does the body need for optimal health? The answer varies from individual to individual, but certain basic principles apply to everyone. A basic supplementation with vitamin D3/K2, a high-quality B complex, and vitamin C can fill most gaps.
Have your vitamin levels checked regularly, especially vitamin D, B12, and folic acid. Pay attention to your body's signals—chronic fatigue, frequent infections, or skin problems could indicate deficiencies.
A combination of a nutrient-rich diet and targeted supplementation offers the best protection. Invest in quality over quantity—your health will thank you in the long run.
FAQ
Which vitamins should you take daily?
The most important daily vitamins are vitamin D3 (1000-2000 IU), B complex, vitamin C (500-1000 mg), and, if needed, B12. These cover the most common deficiencies and support energy, the immune system, and basic functions.
How do I recognize a vitamin deficiency in myself?
Chronic fatigue, frequent colds, poor wound healing, concentration problems, or skin changes can be indicators. However, only a blood test can provide definitive information about your vitamin status.
Can you overdose on vitamins and what are the risks?
Water-soluble vitamins (B, C) are usually excreted, and overdose is rare. Fat-soluble vitamins (A, D, E, K) can accumulate. Vitamins A and D have side effects in extreme overdoses, but are safe at normal doses.
Can medications affect vitamin absorption?
Yes, many medications impair vitamin absorption. Proton pump inhibitors reduce B12 absorption, and antibiotics destroy gut-friendly bacteria that produce vitamins. If you are on long-term medication, your vitamin status should be checked regularly.
What role do vitamins play in weight loss?
B vitamins optimize metabolism and can support fat burning. Vitamin D deficiency is often associated with obesity. Adequate vitamin intake can reduce cravings and increase energy levels for exercise.
Are vegan vitamin supplements as effective as conventional ones?
Yes, vegan vitamins are equally effective. Vitamin B12 from bacterial cultures is identical to animal-derived B12. Vitamin D3 from lichens is more bioactive than D2 from fungi. Look for high-quality vegan capsule shells instead of gelatin.
How long does it take for a vitamin deficiency to improve?
It depends on the vitamin and the severity. Vitamin C takes effect within days, while B12 can take weeks to months. Vitamin D takes 2-3 months to reach optimal levels. Regular checkups will reflect progress.
