Vitamins, Types, Deficiency, Symptoms, Treatments, Supplements
Table of Contents
What Are Vitamins?
Vitamins are organic compounds that are essential for the body in small amounts to maintain health, support growth, and ensure proper functioning of biological processes. Since the body either does not produce them at all or produces insufficient amounts, they must usually be obtained through diet or supplements.
Benefits of Vitamins for Humans
- Support Growth & Development: Vitamins help in cell growth, repair, and tissue formation, especially important in childhood and pregnancy.
- Boost the Immune System: Vitamins support immune responses, helping the body fight infections.
- Support Brain and Nervous System Health: Some vitamins help in energy production in brain cells, neurotransmitter synthesis, and protect nerves (e.g., preventing neuropathy)
- Maintain Healthy Skin, Hair, Eyes, and Nails: Vitamin A maintains healthy skin and vision and Biotin (Vitamin B7) strengthens hair and nails.
- Regulate Metabolism: Vitamins convert carbohydrates, fats, and proteins into energy.
- Help Prevent Chronic Diseases: Vitamins neutralize free radicals, reducing oxidative stress, which may lower the risk of Heart disease, Certain cancers, age-related vision loss.
- Support Blood Health: Vitamin K is essential for blood clotting and Vitamin B12 and folate (B9) are crucial for red blood cell production and preventing anemia.
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Vitamins Classification
Vitamins are classified based on solubility, which determines how they are absorbed, stored, transported, and excreted in the body. Here’s a breakdown of vitamin classification, including subcategories, based on their solubility, storage, excretion, and risk of toxicity.1. Fat-Soluble Vitamins
Fat-soluble vitamins (A, D, E, K) dissolve in dietary fats and are stored in the liver and adipose (fat) tissue. Unlike water-soluble vitamins, they can accumulate in the body, leading to potential toxicity if consumed in excess. These are stored in body fat and require dietary fats for absorption.2. Water-Soluble Vitamins
Water-soluble vitamins dissolve in water and are not stored in the body. Excess amounts of water soluble vitamins gets excreted in urine. They must be consumed regularly through diet. This group includes:- B-Complex Vitamins (8 types)
- Vitamin C (Ascorbic Acid)
| Type | Vitamins | Solubility | Storage | Excretion | Risk of Toxicity |
| Fat-Soluble | A, D, E, K | In fats | Liver and fatty tissues | Slowly (via feces) | Higher (can accumulate) |
| Water-Soluble | B-complex (B1–B12), C | In water | Not stored (except B12) | Rapidly (via urine) | Lower (excreted easily) |
Fat-Soluble Vitamins
These require dietary fats for absorption and are stored in the liver or adipose (fat) tissues.Vitamin A (Retinol, Beta-Carotene)
Functions:- Vision (especially night vision)
- Immune system support
- Skin and mucous membrane health
Deficiency: Night blindness, dry eyes, skin issues
Toxicity: Liver damage, headaches, birth defects (if in excess during pregnancy)
Vitamin D (Calciferol: D2 – ergocalciferol, D3 – cholecalciferol)
Vitamin D is very often asked in examsFunctions:
- Calcium and phosphorus absorption
- Bone and teeth health
- Immune modulation
Deficiency: Rickets (children), osteomalacia (adults), fatigue, bone pain
Toxicity: Hypercalcemia, kidney stones
Vitamin E (Tocopherol)
Functions:- Antioxidant (protects cell membranes from free radical damage)
- Immune function
- Skin healing
Deficiency: Nerve and muscle damage (rare, usually with fat malabsorption)
Toxicity: Increased risk of bleeding (high doses interfere with Vitamin K)
Vitamin K (Phylloquinone – K1, Menaquinone – K2)
Functions:- Blood clotting (synthesis of clotting factors)
- Bone metabolism (activates osteocalcin)
Deficiency: Excessive bleeding, bruising (especially in newborns or those on antibiotics)
Toxicity: Rare (but can interfere with anticoagulants like warfarin)
| Vitamin | Name | Function | Deficiency |
| A | Retinol | Vision, immunity, skin | Night blindness, dry skin |
| D | Cholecalciferol | Bone health, calcium absorption | Rickets, osteomalacia |
| E | Tocopherol | Antioxidant, skin, immune system | Nerve & muscle issues |
| K | Phylloquinone | Blood clotting | Bleeding tendency, bruising |
Features of Fat-Soluble Vitamins
- Solubility: Dissolve in dietary fat and oils
- Absorption: Absorbed in the small intestine along with fats
- Transportation: Carried in the bloodstream via protein carriers (like chylomicrons)
- Storage: Stored in liver and adipose tissue (long-term storage)
- Excretion: Slowly eliminated from the body, leads to risk of toxicity if overdosed
- Supplement Caution: Should not be taken in excess unless medically prescribed
Fat Soluble Vitamins Contraindications & Clinical Tips
Vitamin A (Retinol, Beta-Carotene) – Contraindications
- Pregnancy: Avoid high doses of retinol – risk of birth defects.
- Liver disease: Avoid excessive supplementation due to hepatotoxicity risk.
- Smokers: High-dose beta-carotene supplements increase risk of lung cancer.
Vitamin A – Clinical Tips
- Monitor use in pregnant women – excess vitamin A is teratogenic.
- Beta-carotene (from plants) is safer than retinol (animal-derived) — less risk of toxicity.
- Consider supplementation in patients with night blindness, chronic dry eyes, or malabsorption.
Vitamin D (D2 – Ergocalciferol, D3 – Cholecalciferol) Contraindications
- Hypercalcemia, hyperparathyroidism
- Sarcoidosis, tuberculosis (granulomatous diseases → increased vitamin D activation)
- Monitor calcium and phosphorus levels during high-dose therapy to avoid kidney stones and vascular calcification.
Vitamin D – Clinical Tips
- Check 25(OH)D – 25-hydroxyvitamin D levels to evaluate deficiency before supplementing.
- Osteoporosis
- Chronic kidney disease
- Elderly patients with low sun exposure
Vitamin E (Tocopherol) – Contraindications
- High doses can increase bleeding risk (especially with anticoagulants like warfarin or aspirin).
- Avoid high-dose use in patients with vitamin K deficiency or active bleeding.
- May reduce platelet aggregation – caution in upcoming surgery.
Vitamin E – Clinical Tips
- May help in conditions involving oxidative stress: Alzheimer’s, fatty liver, skin aging (limited evidence).
- Sometimes used in premature infants to prevent retinopathy (with caution).
- Interacts with statins, anticoagulants, and chemotherapy drugs.
Vitamin K (K1 – Phylloquinone, K2 – Menaquinone) – Contraindications
- Avoid larger intake of vitamin K during warfarin therapy – can significantly alter INR levels.
- Not for anticoagulant reversal in patients without bleeding or elevated INR.
- IV administration of vitamin K can rarely cause anaphylactoid reactions – give slowly or consider oral/IM form when appropriate.
Vitamin K – Clinical Tips
- Essential for patients on warfarin: Counsel them to keep vitamin K intake consistent (not necessarily low, just stable).
- Phytonadione (Vitamin K1) is used as an antidote for warfarin overdose.
- Consider supplementation in patients with long-term antibiotic use, which disrupts gut flora that produce vitamin K.
| Vitamin | Clinical Tips | Contraindications/Cautions |
| A | Avoid high doses in pregnancy; treat night blindness | Teratogenic, liver disease, smokers |
| D | Check levels first; treat osteoporosis, CKD | Hypercalcemia, granulomatous disease |
| E | May help in oxidative stress; watch with anticoagulants | Increased bleeding risk, surgery issues |
| K | Important in warfarin therapy; gut flora role | Interferes with warfarin, IV risk |
Water Soluble Vitamins
Water-soluble vitamins are not stored in large amounts in the body. They are excreted in urine, so regular intake is essential. They include: B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic Acid), B6 (Pyridoxine), B7 (Biotin), B9 (Folic Acid), B12 (Cobalamin), Vitamin CVitamin B1 (Thiamine)
- Function: Carbohydrate metabolism, nerve function
- Deficiency: Beriberi, Wernicke-Korsakoff syndrome (in alcoholics)
- Clinical Use: IV thiamine for alcohol withdrawal to prevent encephalopathy
- Caution: Give before glucose in malnourished patients to avoid precipitating Wernicke’s encephalopathy
Vitamin B2 (Riboflavin)
- Function: Energy metabolism, redox reactions
- Deficiency: Cheilitis, glossitis, sore throat
- Clinical Use: Sometimes used for migraine prevention
- Caution: Can cause yellow-orange urine (harmless)
Vitamin B3 (Niacin / Nicotinic Acid)
- Function: Cholesterol metabolism, NAD/NADP coenzymes
- Deficiency: Pellagra – “3 Ds“: Dermatitis, Diarrhea, Dementia
- Clinical Use: High doses used to treat dyslipidemia (↑HDL, ↓LDL, ↓Triglycerides)
- Caution: Flushing, hepatotoxicity at high doses; co-administer aspirin to reduce flushing
Vitamin B5 (Pantothenic Acid)
- Function: Coenzyme A synthesis
- Deficiency: Very rare; symptoms include fatigue, irritability, numbness
- Clinical Use: General health and energy, but no strong evidence in disease treatment
Vitamin B6 (Pyridoxine)
- Function: Amino acid metabolism, neurotransmitter synthesis
- Deficiency: Neuropathy, irritability, cheilitis, glossitis
- Clinical Use: Prevents peripheral neuropathy in patients on isoniazid (TB drug) or hydralazine
- Caution: High doses may also cause neuropathy
Vitamin B7 (Biotin)
- Function: Coenzyme in fatty acid synthesis and gluconeogenesis
- Deficiency: Rare; seen with raw egg white consumption (avidin binds biotin), causes hair loss, rash, depression
- Clinical Use: Hair, skin, nail supplements (limited evidence)
- Caution: Can interfere with lab tests (e.g., thyroid function, troponins)
Vitamin B9 (Folic Acid)
- Function: DNA/RNA synthesis, red blood cell formation
- Deficiency: Megaloblastic anemia, neural tube defects in fetus
- Clinical Use: Prenatal vitamins, anemia, methotrexate toxicity
- Caution: Can mask B12 deficiency, leading to progression of neuropathy
Vitamin B12 (Cobalamin)
- Function: DNA synthesis, myelin formation
- Deficiency: Megaloblastic anemia, neuropathy, glossitis
- Clinical Use: Pernicious anemia, malabsorption syndromes, metformin or PPI-related deficiency
- Caution: Requires intrinsic factor (IF) for absorption; parenteral forms preferred in deficiency
Vitamin C (Ascorbic Acid)
- Function: Antioxidant, collagen synthesis, iron absorption
- Deficiency: Scurvy (bleeding gums, poor wound healing)
- Clinical Use: Wound healing, iron absorption, immune support
- Caution: High doses can cause kidney stones; caution in renal patients
| Vitamin | Function | Deficiency | Clinical Use | Caution |
| B1 | Carb metabolism | Wernicke’s, Beriberi | Alcohol use, IV thiamine | Give before glucose |
| B2 | Redox reactions | Glossitis, cheilitis | Migraine prevention | Yellow urine |
| B3 | NAD/NADP coenzyme | Pellagra | Dyslipidemia | Flushing, hepatotoxic |
| B5 | CoA synthesis | Rare fatigue, numbness | General support | Minimal |
| B6 | Neurotransmitters | Neuropathy, anemia | Isoniazid neuropathy prevention | High dose neurotoxicity |
| B7 | Metabolism coenzyme | Hair loss, rash | Skin/hair support | Interferes with labs |
| B9 | DNA synthesis | Megaloblastic anemia | Pregnancy, anemia | Masks B12 deficiency |
| B12 | RBC/myelin synthesis | Anemia, neuropathy | Pernicious anemia | Needs IF for absorption |
| C | Collagen, antioxidant | Scurvy | Immune support, iron uptake | Kidney stones at high dose |
Features of Water Soluble Vitamins
- Solubility: Dissolve in water
- Absorption: Absorbed directly into the bloodstream from the small intestine
- Storage: Not stored in large amounts; excess is excreted in urine
- Excretion: Rapidly excreted through urine; lower risk of toxicity (except B6, B3 in high doses)
- Daily Requirement: Needed daily due to lack of long-term storage
- Deficiency Risk: Higher risk if intake is inadequate or in malabsorption conditions
- Toxicity Risk: Generally low; excess is eliminated, but high doses of B6 or B3 can cause adverse effects
- Main Functions: Coenzyme roles in energy metabolism, red blood cell production, nervous system function, and antioxidant activity
- Heat Sensitivity: Many vitamins are sensitive to heat and can be destroyed during cooking, e.g. Vitamin C, B-complex vitamins.
Water Soluble Vitamins Contraindications & Clinical Tips
| Vitamin | Contraindications / Cautions | Clinical Tips |
| Vitamin B1 | Hypersensitivity (rare) |
|
| Vitamin B2 | No major contraindications |
|
| Vitamin B3 |
|
|
| Vitamin B5 | Generally safe |
|
| Vitamin B6 | Hypersensitivity |
|
| Vitamin B7 | None reported |
|
| Vitamin B9 | Undiagnosed anemia (can mask B12 deficiency and worsen neurologic damage) |
|
| Vitamin B12 | Hypersensitivity (rare) |
|
| Vitamin C | Kidney stones (oxalate stones) G6PD deficiency (risk of hemolysis at high doses) |
|
Vitamins Use for Different Body Functions
🧠 Vitamins for Brain & Nervous System
- Vitamin B1 – Nerve function, memory, and energy metabolism
- Vitamin B6 – Neurotransmitter synthesis
- Folic Acid (B9) – Brain development (especially in fetus), mental clarity
- Vitamin B12 – Myelin sheath protection, nerve health
- Vitamin D – Cognitive function, mood regulation
- Vitamin E – Antioxidant, protects neurons from damage
👁️ Vitamins for Eyes
- Vitamin A – Essential for night vision, prevents dry eyes
- Vitamin C – Reduces risk of cataracts, antioxidant
- Vitamin E – Protects retina from oxidative damage
- Vitamin B2 – Prevents eye fatigue and cataracts
❤️ Vitamins for Heart & Cardiovascular System
- Vitamin B6, B9, B12 – Lower homocysteine levels (linked to heart disease)
- Vitamin C – Strengthens blood vessels, reduces arterial stiffness
- Vitamin D – Supports blood pressure regulation
- Vitamin E – Antioxidant, may help prevent LDL oxidation
💪 Vitamins for Muscles
- Vitamin B12 – Prevents muscle fatigue caused by nerve damage
- Vitamin D – Enhances muscle strength and prevents weakness
- Vitamin E – Protects muscle cells from oxidative damage
🦴 Vitamins for Bones & Teeth
- Vitamin A – Bone growth and development
- Vitamin C – Collagen production for bone matrix
- Vitamin D – Helps calcium absorption
- Vitamin K – Regulates bone mineralization
🧴 Vitamins for Skin, Hair, and Nails
- Vitamin A – Healthy skin cell turnover
- Vitamin C – Collagen synthesis for skin firmness
- Vitamin E – Antioxidant protection from sun damage
- Biotin – Strengthens hair and nails
- Niacin – Improves skin barrier, reduces acne
🩸 Vitamins for Blood & Immunity
- Vitamin A – Supports mucosal immunity
- Vitamin D – Modulates immune response
- Vitamin K – Blood clotting factors
- Vitamin B12 & B9 – Red blood cell production
- Vitamin C – Boosts immunity, white blood cell function
👶 Pregnancy & Fetal Development
- Vitamin A – Organ and vision development
- Vitamin D – Bone and immune development
- Vitamin B6 – Reduces nausea and supports fetal brain
- Folic Acid (B9) – Prevents neural tube defects
- Vitamin B12 – Nervous system development
🧬 Vitamins That Help Lower Cholesterol
- Niacin (Vitamin B3): ↑ HDL, ↓ LDL, ↓ triglycerides (Niacin in high doses can cause flushing)
- Vitamin B5: ↓ LDL, ↓ triglycerides
- Vitamin D: May improve lipid profile in deficiency
- Vitamin E: Antioxidant, supports HDL
Dosage Forms – Vitamins
| Dosage Form | Description | Examples |
Oral Vitamins | ||
| Tablets | Compressed powder; may be chewable, coated, or time-released. | Vitamin C, Multivitamins |
| Capsules | Gelatin shell filled with powder, liquid, or granules. | Vitamin D, Vitamin E |
| Softgels | One-piece soft gelatin capsules containing oil-based vitamins. | Fish Oil (Omega-3), Vitamin D3 |
| Chewable Tablets | Flavored tablets intended to be chewed before swallowing. | Children’s multivitamins, Vitamin C |
| Effervescent Tablets | Dissolved in water before ingestion; fizzy and fast-absorbing. | Vitamin C, B-complex |
| Lozenges / Troches | Dissolve slowly in the mouth; good for localized absorption. | Vitamin B12 |
| Powders | Mixed with liquids; useful for high doses or blended nutrients. | Vitamin C powder |
| Granules | Larger particles than powder; sometimes in single-dose sachets. | Multivitamin granules |
| Liquid Solutions / Syrups | Ready-to-drink or dose; ideal for children or elderly. | Multivitamin syrups |
Topical Vitamins | ||
| Creams / Ointments | Applied to skin for local or systemic effect. | Vitamin A Cream & Vitamin E cream |
| Gels | Clear or semi-solid topical forms. | Vitamin C serum |
| Patches | Transdermal systems for continuous release. | Vitamin B12 patch |
Parenteral Vitamins | ||
| Intramuscular Injection (IM) | Injected into muscle. | Vitamin B12 (cyanocobalamin) Inj |
| Intravenous Injection (IV) | Directly into the bloodstream. | Vitamin C infusion |
| Subcutaneous Injection (SC) | Under the skin, less common for vitamins. | B12 sometimes given SC |
Others | ||
| Nasal Sprays | For rapid systemic absorption. | Vitamin B12 spray |
| Sublingual Tablets/Sprays | Absorbed under the tongue. | Vitamin B12, Vitamin D |
| Gummies | Chewable, flavored gel-based; popular for kids and adults. | Multivitamins, Biotin gummies |
Vitamin Supplements
Vitamin supplements are products designed to provide essential vitamins that may not be consumed in sufficient quantities through diet alone. They’re available in various dosage forms (like tablets, capsules, liquids, and gummies) and can contain single vitamins or a combination of multiple vitamins (like multivitamins).
Types of Vitamin Supplements
Vitamin supplements are categorized based on their composition, purpose, formulation and origin.| Type | Description | Examples |
Based on Composition | ||
| Single-Vitamin Supplements | Contain only one specific vitamin. | Vitamin D3, Vitamin B12, Vitamin C |
| Multivitamins | Contain a combination of essential vitamins (often with minerals). | Daily multivitamin, Children’s chewable multivitamin |
| Vitamin Complexes | Focus on a group of related vitamins. | B-complex (B1, B2, B6, B12, etc.) |
Based on Purpose or Target Group | ||
| Prenatal Vitamins | For pregnancy support | Folic acid, iron, DHA, Vitamin D |
| Geriatric Vitamins | For older adults | Calcium, Vitamin D, B12, antioxidants |
| Pediatric Vitamins | Formulated for children | Gummy multivitamins, chewable C |
| Sports/Active Lifestyle | Support energy & recovery | B vitamins, Vitamin E, antioxidants |
| Immune Support | Boost immune function | Vitamin C, D, zinc, elderberry blends |
| Hair/Skin/Nail Support | Promote growth & repair | Biotin, Vitamin E, C, A |
Based on Dosage Form | ||
| Tablets | Compressed solid form | General use |
| Capsules / Softgels | Gelatin shell; often oil-based | Fat-soluble vitamins like D & E |
| Gummies | Chewable, flavored | Kids & adults who dislike pills |
| Liquid Drops / Syrups | Fast absorption | Infants, elderly, or those with swallowing issues |
| Powders | Mixed with water or food | High-dose Vitamin C or blends |
| Injections | Medical use, IM or IV | Vitamin B12 in deficiency |
| Sublingual / Nasal | Rapid absorption without digestion | B12, Vitamin D |
Based on Origin or Preference | ||
| Natural/Whole Food-Based | Derived from real food sources | Organic multivitamins |
| Synthetic | Lab-created; identical to natural | Most over-the-counter vitamins |
| Vegan / Vegetarian | Free from animal products | Vegan D2, plant-based B12 |
| Allergen-Free / Clean Label | Free from gluten, dairy, soy, etc. | Hypoallergenic multivitamins |
Vitamin-Drug Interactions
Vitamins and medications can interact in surprising ways. Some combinations may reduce effectiveness, while others increase the risk of side effects. Whether you’re taking daily supplements or prescription meds, knowing how they work together is essential for your health.
Common Vitamin-Drug Interactions
| Vitamin | Interacting Drug(s) | Effect |
| Vitamin K | Warfarin | ↓ Warfarin’s anticoagulant effect (increased clot risk) |
| Vitamin D | Antiepileptics, corticosteroids, orlistat, cholestyramine | ↓ Vitamin D absorption/metabolism |
| Vitamin B12 | Metformin, PPIs, H2 blockers, colchicine | ↓ Absorption → deficiency → neuropathy/anemia |
| Folic Acid (B9) | Methotrexate, trimethoprim, phenytoin | ↓ Folic acid levels |
| Vitamin B6 | Isoniazid, hydralazine, penicillamine | ↓ B6 → neuropathy risk |
| Vitamin C | Aspirin, oral contraceptives, chemotherapy | May ↑ or ↓ effectiveness; large doses can ↑ kidney stone risk |
| Vitamin E | Anticoagulants (warfarin, aspirin), chemotherapy | ↑ Bleeding risk in high doses |
| Vitamin A | Retinoids (isotretinoin), liver disease meds | Risk of toxicity when combined |
| Vitamin B3 | Statins | ↑ Risk of muscle toxicity (rhabdomyolysis) |
| Multivitamins with minerals | Antibiotics (tetracyclines, fluoroquinolones), levothyroxine | ↓ Drug absorption due to chelation |
General Tips for Managing Vitamin–Drug Interactions
- Timing matters: Separate vitamins and interacting drugs by 2–4 hours when possible.
- Fat-soluble vitamins (A, D, E, K) can be affected by GI medications that reduce fat absorption (like orlistat, bile acid sequestrants).
- B-complex vitamins are commonly depleted by chronic alcohol use and various medications.
- Monitor labs and symptoms when vitamins are affected by long-term drug therapy.
- Always ask patients about OTC vitamins, supplements, and herbals—they’re often overlooked.
Vitamins: Storage and Stability
Proper storage of vitamins ensures their potency, safety, and effectiveness over time. Many vitamins are sensitive to factors like heat, light, moisture, and air, which can degrade their active ingredients.
Vitamins Storage Guidelines
- Heat Speeds up degradation, especially for B-complex and Vitamin C. Store below 25°C (77°F); avoid direct sunlight or heat sources
- Light Causes photo-degradation, particularly Vitamin A, D, B2 (riboflavin). Use amber bottles or store in a dark place
- Moisture Promotes hydrolysis and microbial growth. Keep containers tightly closed; avoid bathroom storage
- Oxygen Can oxidize vitamins like C, A, E. Store in airtight containers with desiccants
- Time Potency naturally decreases over months or years. Monitor expiration dates and avoid long-term open storage
Vitamins Stability Guidelines
- Vitamin A: Light-sensitive; degrades in presence of oxygen and heat
- Vitamin D: Stable under normal conditions but degrades with long light/heat exposure
- Vitamin E: Prone to oxidation; store with antioxidants in airtight containers
- Vitamin C (Ascorbic acid) Highly unstable in light, heat, and alkaline pH; oxidizes quickly
- Vitamin B1 (Thiamine) Sensitive to heat and alkaline pH
- Vitamin B2 (Riboflavin) Extremely light-sensitive; degrade under fluorescent lighting
- Folic Acid (B9) Sensitive to light and heat
- Vitamin B12 Stable in solid form but degrades in light or acidic/alkaline solutions
Prescription-Only Vitamin Formulations
While many vitamins are available over-the-counter, prescription-only vitamins serve specific medical purposes and are tailored for clinical use. Prescription only vitamins are needed when higher doses or therapeutic indications require medical supervision. Here’s why they may be necessary:
- Higher Potency for Medical Conditions
- Special Formulations
- Better Absorption and Bioavailability
- Close Medical Supervision
- Covered by Insurance
| Brand Name | Generic Name | Indication / Notes |
| Nascobal | Cyanocobalamin (Vitamin B12) Nasal Spray | Treatment of B12 deficiency, especially in pernicious anemia or absorption issues |
| Cyanokit | Hydroxocobalamin (Form of Vitamin B-12) | Cyanide poisoning antidote |
| Folvite | Folic Acid (Vitamin B9) | Treats folate deficiency, anemia, pregnancy supplementation |
| Metanx | L-methylfolate + Methylcobalamin + B6 | Diabetic neuropathy, advanced folate/B12 support |
|
Ocuvite PreserVision AREDS 2
|
Vitamins C, E, Zinc, Copper, Lutein, Zeaxanthin | For age-related macular degeneration (some formulations are Rx-only) |
| Nephro-Vite | Multivitamin for renal patients | Used in patients on dialysis |
| Benzacot | Vitamin B1 (Thiamine) | Used for thiamine deficiency, including Wernicke’s encephalopathy |
| Vitacon | Vitamin K1 (Phytonadione) | Antidote for warfarin overdose or Vitamin K deficiency |
| AquADEKS Rx | Fat-soluble vitamin combo | Cystic fibrosis, cholestasis, fat malabsorption syndromes |
| Repliva 21/7 | Iron + Folic Acid + B Vitamins | Iron deficiency anemia with vitamin support |
| Thera-Vit Rx | Multivitamin/Mineral combo | Nutritional supplementation in chronic illness |
| Calcitriol (Rocaltrol) | Vitamin D3 active form | Hypocalcemia in CKD or parathyroid disorders |
| Drisdol | Ergocalciferol (Vitamin D2) | Used for vitamin D deficiency |
| Meyer’s Cocktail (IV) | Combo (B complex, C, Mg, Ca) | Used in alternative therapy for fatigue, migraines, fibromyalgia |
- Higher potencies often make vitamins Rx-only.
- Vitamin-mineral combinations for renal, hepatic, or anemic patients are often prescription-only.
- IV or injectable forms are always Rx-only.
- Prenatal vitamins with DHA or iron > 1 mg folic acid may be Rx-only.
Vitamin D Supplements
Vitamin D supplements are important for a variety of health reasons:
- Supports Healthy Bones and Teeth
- Prevents Bone-Related Disorders
- Boosts Immune Function
- Supports Heart Health and Mood
- Important During Pregnancy
- Needed in Older Adults
Types of Vitamin D Supplements
| Type | Form/Name | Strengths Available | OTC or Rx | Key Notes & Uses |
| Vitamin D2 | Ergocalciferol | 400 IU, 800 IU (OTC); 50,000 IU (Rx) | OTC & Rx | Plant-based. Used for deficiency, but less potent than D3. |
| Vitamin D3 | Cholecalciferol | 400 IU, 600 IU, 1,000 IU, 2,000 IU, 5,000 IU, 10,000 IU (OTC); 50,000 IU (Rx) | OTC & Rx | Animal-based. Preferred for supplementation and deficiency. |
| Calcitriol | 1,25-dihydroxyvitamin D3 | 0.25 mcg, 0.5 mcg (capsules); 1 mcg/mL (oral solution and IV) | Rx only | Active form. Used in CKD, hypocalcemia, hypoparathyroidism. |
| Alfacalcidol | 1-alpha-hydroxyvitamin D3 | 0.25 mcg, 1 mcg (capsules) | Rx only | Prodrug converted in liver. Used in renal failure. |
| Doxercalciferol | Vitamin D2 analog | 2.5 mcg, 5 mcg (capsules); IV: 4 mcg/mL | Rx only | Used in secondary hyperparathyroidism in dialysis patients. |
| Paricalcitol | Vitamin D2 analog | 1 mcg, 2 mcg, 4 mcg (capsules); IV: 2 mcg/mL | Rx only | Synthetic analog. Less hypercalcemia risk; used in CKD. |
Vitamin D2 vs D3
| Feature | Vitamin D2 (Ergocalciferol) | Vitamin D3 (Cholecalciferol) |
| Source | Plant-based (mushrooms, yeast) | Animal-based (lanolin from sheep’s wool, fish oil); also synthesized in skin via sunlight |
| Chemical Structure | Ergocalciferol | Cholecalciferol |
| Potency | Less potent, shorter duration of action | More potent, longer-lasting in the body |
| Bioavailability | Less stable, degrades faster | More stable and bioavailable |
| Effectiveness | Less effective at raising blood 25(OH)D levels | More effective in raising and maintaining vitamin D levels |
| Availability | Rx (50,000 IU), limited OTC | Widely available OTC and Rx (400 IU – 10,000 IU, also 50,000 IU Rx) |
| Half-life | Shorter | Longer |
| Common Use | Sometimes used for vitamin D deficiency treatment | Preferred form for supplementation and deficiency treatment |
- Better absorption
- Longer duration in the body
- More effective in increasing serum vitamin D levels
