- Vitamin A
- Vitamin B1 (thiamine)
- Vitamin B2 (riboflavin)
- Vitamin B3
- Vitamin B5 (pantothenic acid)
- Vitamin B6
- Biotin (B7)
- Folate (B9)
- Vitamin B12
- Choline
- Inositol
- Vitamin C
- Vitamin D3
- Vitamin E
- Vitamin K1
- Vitamin K2
- Multivitamin-mineral
- PABA
No. 1Vitamin A
Vitamin A is a fat-soluble vitamin that the body stores in the liver, like a pantry stocked for later. It helps the eyes adjust to dim light, keeps the skin and the linings of the gut and lungs healthy, and supports the immune system. It comes ready-made (retinol) from animal foods, or the body makes it from beta-carotene in plants.
Main benefits
Vision and night vision, skin, gut and lung linings, immunity (WHO uses it in measles)
Food sources
Ready-made vitamin A is found in liver, cod liver oil, egg yolks and dairy; beta-carotene is found in carrots, sweet potatoes, pumpkin, dark leafy greens, mango and cantaloupe.
Signs you may be low
Poor night vision, dry eyes, dry or rough skin and frequent infections. People with poor diets, conditions that block fat absorption (such as celiac disease or cystic fibrosis) and young children in low-income countries are most at risk.
Amounts
Therapeutic: 25,000 IU a day in a cited skin-cancer prevention study. Safe limit: above 15,000 IU a day only under medical supervision; Pauling put the ceiling in good health at 50,000 IU. Beta-carotene "does not cause toxicity." RDA 2,300–3,000 IU. (Vitamin A, OMNS v04n09)
Cautions and interactions
Pregnancy: DoctorYourself.com notes possible harm to the baby even below 20,000 IU of retinol (pregnancy); keep retinol low and follow the midwife. Liver disease, heavy drinking. Isotretinoin or acitretin. Smokers avoid synthetic beta-carotene pills.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 4.
No. 2Vitamin B1 (thiamine)
Thiamine, or vitamin B1, helps the body turn carbohydrates into usable energy. The nerves, heart and brain lean on it heavily because they burn through so much fuel. The body stores only small amounts, so it needs a steady supply. Think daily delivery, not a warehouse.
Main benefits
Turns carbohydrate into energy; nerves, heart, brain
Food sources
Found in whole grains, fortified breads and cereals, beans and lentils, sunflower seeds and nuts.
Signs you may be low
Tiredness, irritability, poor appetite, and tingling or numbness in the hands and feet; severe lack can affect the heart and memory. Heavy drinkers, people on diuretics, people with diabetes and those eating mostly refined carbohydrates are most at risk.
Amounts
Maintenance: 25 mg. Therapeutic: 1,000–3,000 mg a day (MS protocol); 100–500 mg injections given by a doctor. RDA 1.1–1.2 mg. (OMNS v03n10, OMNS v14n15)
Cautions and interactions
Very safe by mouth. Alcohol, diuretics and high-sugar diets deplete it. Start high doses low; Dr. Lonsdale described temporary "paradoxical" worsening.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 3Vitamin B2 (riboflavin)
Riboflavin, or vitamin B2, helps cells release energy from food. It also helps switch on vitamin B6 and folate, and helps recycle glutathione, one of the body's main antioxidants. A real team player: half its job is helping other nutrients do theirs.
Main benefits
Energy; activates B6 and folate; recycles glutathione
Food sources
Found in milk, yogurt and cheese, eggs, liver and other organ meats, lean meats, almonds, mushrooms, spinach and fortified grains.
Signs you may be low
Cracks at the corners of the mouth, a sore red tongue, a sore throat, and itchy eyes that are sensitive to light. People who avoid dairy and meat, heavy drinkers and older adults are more at risk.
Amounts
Maintenance: 25 mg. Safe limit: "many times the RDA is without demonstrable toxicity"; neither site gives a therapeutic figure (400 mg a day is studied for migraine). RDA 1.1–1.3 mg. (OMNS v03n10, Riboflavin)
Cautions and interactions
Very safe. Turns urine bright yellow.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 4Vitamin B3
Vitamin B3 is used to build NAD, a molecule every cell needs to make energy. It comes in two main forms: niacin, which can cause a warm flush and improves blood fats, and niacinamide, which does not flush. Dr. Abram Hoffer studied it for mood and mental health.
Main benefits
Energy (NAD); mood (Hoffer); blood fats (niacin only); joints and calm (niacinamide)
Food sources
Found in chicken, turkey, tuna and other fish, beef, liver, peanuts, mushrooms, brown rice and fortified grains. The body can also make some from the amino acid tryptophan.
Signs you may be low
Tiredness, poor appetite, irritability and a rough red rash on sun-exposed skin; severe lack (pellagra) adds diarrhea and confusion. Heavy drinkers, people with poor gut absorption and those living on very limited corn-based diets are most at risk.
Amounts
Maintenance: 300 mg (OMNS); start at 25 mg three times a day and add 25 mg a day until a flush, working up to 1,000–1,500 mg a day in three doses. Therapeutic: niacin 3,000–9,000 mg a day in three doses (Hoffer's usual range); 2,000–5,000 mg for cholesterol; niacinamide 2,000–4,000 mg a day in up to 10 doses for arthritis (Kaufman). Safe limit: the amount that causes nausea; Hoffer estimated a fatal dose above 200,000 mg. RDA 14–16 mg. (Niacin Saturation, OMNS v14n20, Kaufman)
Cautions and interactions
Liver disease or heavy drinking; avoid sustained-release niacin; liver tests at gram doses. Niacin raises blood sugar and uric acid (diabetes, gout), irritates active ulcers, lowers blood pressure. Statins, blood pressure and diabetes drugs: doctor first. Pregnancy: doctor.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 5Vitamin B5 (pantothenic acid)
Pantothenic acid, or vitamin B5, is used to make coenzyme A, which the body needs to turn food into energy and to build fats and hormones, including those made by the adrenal glands. Its pantethine form lowers cholesterol and triglycerides.
Main benefits
Coenzyme A; energy; adrenal hormones; pantethine for blood fats
Food sources
Found in almost all foods, especially liver, eggs, chicken, beef, mushrooms, avocado, sunflower seeds, whole grains and milk.
Signs you may be low
True deficiency is rare because B5 is so widespread in food. Signs can include tiredness, irritability, poor sleep and burning or numb feet; it is mostly seen with severe malnutrition or heavy drinking.
Amounts
Safe limit: diarrhea and water retention only above 10 g a day. Neither site gives a daily dose; 100–500 mg is common. RDA (AI) 5 mg. (Pantothenic acid)
Cautions and interactions
Very safe. Pantethine may add mildly to blood thinners.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 6Vitamin B6
Vitamin B6 is one of the busiest workers on the payroll: it helps more than 100 enzymes do their work, mostly in handling protein. The body uses it to make brain messengers such as serotonin and dopamine, and to clear homocysteine from the blood. Researcher Bernard Rimland studied it together with magnesium in autism.
Main benefits
Over 100 enzymes; neurotransmitters; homocysteine; with magnesium in autism (Rimland)
Food sources
Found in chickpeas, poultry, fish such as tuna and salmon, liver, potatoes, bananas and fortified cereals.
Signs you may be low
A sore tongue, cracks at the corners of the mouth, a scaly rash, low mood, confusion and tingling hands and feet. People with kidney disease or autoimmune conditions, heavy drinkers and older adults are more at risk.
Amounts
Maintenance: 25 mg (OMNS); 10–50 mg is safe long-term. Therapeutic: 100–200 mg a day for PMS or carpal tunnel (P5P preferred; monitor after 3 months); Rimland and Dr. Saul report 200–500 mg divided for autism. Safe limit: nerve symptoms linked to more than 200–500 mg a day for months; Dr. Saul: "very, very few persons report symptoms on 1,000 mg daily." RDA 1.3–1.7 mg. (OMNS v21n50, B vitamins)
Cautions and interactions
Stop at any tingling or numbness; keep under 50 mg if neuropathy is present. Reduces levodopa when not combined with carbidopa. Can lower phenytoin and phenobarbital levels.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lessons 3, 7.
No. 7Biotin (B7)
Biotin, sometimes called vitamin B7 or vitamin H, helps enzymes break down fats, carbohydrates and protein, including steps that handle blood sugar. It is best known for its role in healthy hair, skin and nails.
Main benefits
Hair, skin and nails; blood-sugar metabolism
Food sources
Found in egg yolks, liver, salmon, beef, sunflower seeds, almonds, sweet potatoes and spinach.
Signs you may be low
Thinning hair, a red scaly rash around the eyes, nose and mouth, and brittle nails. Deficiency is uncommon; people on long-term anticonvulsants, heavy drinkers, pregnant women and those who eat a lot of raw egg whites are more at risk.
Amounts
Neither site gives a dose; 2,500–10,000 mcg is common for hair and nails. RDA (AI) 30 mcg.
Cautions and interactions
Distorts many lab tests (thyroid, troponin, hormones): stop 2–3 days before blood work and tell the doctor. Anticonvulsants deplete it.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 8Folate (B9)
Folate, or vitamin B9, is needed to make and repair DNA and to build healthy red blood cells. It also feeds methylation, the process the body uses to flip genes on and off like light switches and to clear homocysteine. Enough folate before and in early pregnancy helps prevent neural tube defects in the baby.
Main benefits
DNA; red blood cells; methylation; prevents neural tube defects
Food sources
Found in dark leafy greens such as spinach, beans and lentils, asparagus, Brussels sprouts, avocado, liver and citrus fruits. Folic acid, the synthetic form, is added to many breads and cereals.
Signs you may be low
Tiredness, weakness, shortness of breath, a sore tongue and irritability, from a type of anemia with large red blood cells. Pregnant women, heavy drinkers and people with gut absorption problems are most at risk. A blood test confirms it.
Amounts
Maintenance: 2,000 mcg (OMNS optimum). RDA 400 mcg (600 in pregnancy). (OMNS v03n10)
Cautions and interactions
Always pair with B12 (folic acid can hide B12 deficiency). Methotrexate and some anticonvulsants interact. Methylfolate can cause anxiety or insomnia in some; start low.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 9Vitamin B12
Vitamin B12 keeps nerves healthy, helps build red blood cells and supports memory and energy. Working with folate, it also helps clear homocysteine from the blood. The body can store it for years, so a shortfall can creep up slowly, like a slow leak in a savings account.
Main benefits
Nerves; memory; red blood cells; energy; homocysteine
Food sources
Found almost only in animal foods: liver, fish, meat, eggs and dairy. People who eat no animal foods rely on fortified foods or supplements.
Signs you may be low
Tiredness, pale skin, tingling or numb hands and feet, poor balance, memory problems and low mood. Older adults, vegans, and people taking metformin or acid blockers are most at risk. A blood test confirms it.
Amounts
Maintenance: 500 mcg (OMNS). Therapeutic: 1,000 mcg by injection at least weekly (doctor); nasal B12 twice a week; Dr. Saul (Masterclass) 1,000 mcg a day under the tongue. Safe limit: "I know of no side effects whatsoever to B-12 overdose" (Saul). RDA 2.4 mcg. (OMNS v03n10, Nasal B12)
Cautions and interactions
Very safe. Metformin, acid blockers, age and vegan diets lower it. Avoid cyanocobalamin in Leber's hereditary optic neuropathy. High doses occasionally trigger acne.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lessons 3, 7.
No. 10Choline
Choline is a nutrient the body uses to make acetylcholine, a brain messenger for memory and muscle control. It also builds cell membranes and helps carry fat out of the liver (think moving van, not storage unit). During pregnancy it supports the baby's developing brain.
Main benefits
Acetylcholine for memory; liver fat; cell membranes; baby's brain in pregnancy
Food sources
Found in eggs (especially the yolk), liver, beef, chicken, fish, soybeans, wheat germ, broccoli and Brussels sprouts. Lecithin is a concentrated source.
Signs you may be low
Fat buildup in the liver and muscle damage are the main recognized signs. Pregnant women and people who eat few eggs or little meat are most at risk.
Amounts
Maintenance: lecithin, three or more tablespoons a day (each gives about 1,700 mg phosphatidylcholine). Safe limit: choline 3.5 g a day. (Lecithin, Choline)
Cautions and interactions
Fishy body odor, nausea or low blood pressure at high doses; Orthomolecular.org notes it may trigger seizures in epilepsy.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 11Inositol
Inositol is a sugar-like compound the body makes on its own and uses for signaling inside cells, including how cells respond to insulin. The two main supplement forms are myo-inositol and D-chiro-inositol, names only a chemist could love.
Main benefits
Insulin signaling; PCOS; studied for panic and OCD
Food sources
Made by the body from glucose. Also found in citrus fruits, beans, whole grains, nuts and cantaloupe. Lecithin supplies it as phosphatidylinositol.
Why people take it
People take it most often for PCOS, to support insulin sensitivity and regular cycles. It has also been studied for panic disorder and OCD, but the evidence there is limited.
Amounts
Supplied with lecithin (about 1,000 mg phosphatidylinositol per tablespoon). Neither site gives a separate dose; 2–4 g (PCOS) and 12–18 g (anxiety studies) are research amounts. (Lecithin)
Cautions and interactions
Stomach upset at high doses. May lower blood sugar with diabetes drugs. Case reports of mania in bipolar disorder. Pregnancy: doctor.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 3.
No. 12Vitamin C
Vitamin C is a water-soluble antioxidant the body uses to build collagen, the scaffolding for skin, blood vessels, bones and gums. It supports the immune system, helps neutralize toxins and histamine, helps the body absorb iron from plants, and is needed to make adrenal hormones and brain chemicals. Humans cannot make it, so it must come from food.
Main benefits
Collagen; immunity; antioxidant and antitoxin; antihistamine; adrenal and brain chemistry; iron absorption
Food sources
Found in bell peppers, citrus fruits, kiwi, strawberries, broccoli, Brussels sprouts, papaya, guava and tomatoes. Cooking and long storage lower the amount.
Signs you may be low
Tiredness, bleeding or swollen gums, easy bruising, slow wound healing and frequent infections; severe lack is scurvy. Smokers, heavy drinkers, people on dialysis and those who eat few fruits and vegetables are most at risk.
Amounts
Maintenance: 2,000 mg (OMNS optimum); healthy bowel tolerance 4–15 g a day (Cathcart); Pauling recommended 6,000–18,000 mg a day, at least 3,000 mg for prevention, and took 18,000 mg himself (OMNS v14n12, v06n20). Therapeutic (oral): "8,000 to 40,000 mg per day for an adult" (Saul); bowel tolerance in grams per 24 hours: mild cold 30–60, flu 100–150, mononucleosis 150–200+ (Cathcart); 6–18 g or to bowel tolerance with lysine 5–6 g and proline up to 2 g (Pauling–Rath heart therapy, OMNS v18n27); 1 g an hour at the start of a cold (Pauling, OMNS v21n11). Therapeutic (IV, licensed practitioner only): 400–700 mg/kg per 24 hours (Cathcart); Riordan test series of 15, 25 and 50 g. Safe limit: reduce to just below loose stool; "up to 50 grams per day, infused slowly, are not toxic." Other views (the course follows Pauling and Saul): Dr. Brownstein, 3,000–5,000 mg a day when healthy, doubled or tripled when ill. Dr. Blaylock prefers buffered calcium or magnesium ascorbate, 1,000 mg three times a day between meals. RDA 75–90 mg. (Practical Notes, Titrating to Bowel Tolerance, OMNS v16n07)
Cautions and interactions
Kidney stones (oxalate) or kidney disease; iron overload (hemochromatosis); G6PD deficiency (screen before high or IV doses). Distorts some glucose-meter and stool-blood tests. Chewables wear enamel. Sodium ascorbate adds sodium.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 2.
No. 13Vitamin D3
Vitamin D3 acts more like a hormone than a typical vitamin, an overachiever with a modest job title. It helps the body absorb calcium for strong bones, supports muscle strength and a balanced immune system, and helps calm inflammation. It also plays a part in mood and brain health.
Main benefits
Immunity; bone; muscle; mood and brain; calms inflammation
Food sources
Made by the skin in sunlight. Few foods supply much: oily fish such as salmon, sardines and mackerel, cod liver oil, egg yolks and fortified milk.
Signs you may be low
Tiredness, bone or muscle aches, weakness, low mood and frequent infections. People with darker skin or little sun exposure, older adults, people with obesity and those living far from the equator are most at risk. A blood test confirms it.
Amounts
Course authority, Dr. Joseph Mercola: sunlight first (near solar noon, large areas of skin, never burn); test 25(OH)D and aim for 60–80 ng/mL (sufficiency starts around 40). His guideline amounts: adults 5,000 IU a day, pregnancy 8,000 IU, ages 5–10 2,500 IU, under age 5 35 IU per pound, adjusted by retesting every 3–6 months. Always with magnesium and vitamin K2 (about 100–200 mcg of K2 per 1,000 IU, citing Rhéaume-Bleue; the ratio is not settled). D3, not D2. (Mercola: Vitamin D, Vitamin D resources) OMNS: 2,000 IU for basic prevention; 4,000–6,000 IU to reach 40–70 ng/mL; 5,000–10,000 IU or 60–100 IU per kg (MS protocol); safe up to 10,000 IU a day long-term; toxicity only above 150 ng/mL or above 40,000 IU a day for long periods. Other views: Dr. Blaylock, 5,000 IU to reach 65–100 ng/mL; Grant and colleagues, about 8,000 IU a day if untested. RDA 600–800 IU. (OMNS v21n04, OMNS v14n15, Supplement limits)
Cautions and interactions
Test 25(OH)D periodically. High blood calcium, sarcoidosis or other granulomatous disease, parathyroid disease, kidney stones or kidney disease, lymphoma. Thiazide diuretics and digoxin: doctor first.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 4.
No. 14Vitamin E
Vitamin E is a family of fat-soluble antioxidants (tocopherols and tocotrienols) that protect cell membranes from damage. Drs. Evan and Wilfrid Shute used it for heart and circulation problems, and it protects the skin. Tocotrienols are being studied in cancer research.
Main benefits
Membrane antioxidant; heart and circulation (Shutes); skin; tocotrienols in cancer research (Brownstein)
Food sources
Found in sunflower seeds, almonds, hazelnuts, wheat germ, sunflower and safflower oils, avocado, spinach and red palm oil (a rich source of tocotrienols).
Signs you may be low
Deficiency is rare and mostly linked to problems absorbing fat. Signs include muscle weakness, poor coordination, numbness and vision problems; people with cystic fibrosis, Crohn's disease, liver disease or very low-fat diets are most at risk.
Amounts
Maintenance: 200–400 IU natural mixed tocopherols (at least 200, perhaps 400 IU in pregnancy). Therapeutic (Shute protocol): 450–1,600 IU for coronary disease; 600–1,600 IU for thrombophlebitis and burns; start at 200 IU and raise 200 IU every 2 weeks. Safe limit: "as high as 3200 IU per day harmlessly"; no more than 1,200 IU on anticoagulants. Dr. Brownstein: delta-tocotrienol 100–200 mg a day for prevention (alpha-tocopherol may block it); Dr. Blaylock: mixed tocopherols 400–800 IU plus about 100 mg tocotrienols. RDA 22 IU. (Shute protocol, Vitamin E, OMNS v03n10)
Cautions and interactions
Blood thinners (no more than 1,200 IU, and only with the doctor), bleeding disorders; stop about 2 weeks before surgery. High blood pressure or rheumatic heart disease: start at 75 IU and raise slowly (Shute). Digitalis and insulin users: doctor. Take about 9 hours apart from iron.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 2.
No. 15Vitamin K1
Vitamin K1 is the plant form of vitamin K. The liver uses it to make the proteins that help blood clot, the body's built-in patch kit, and it also plays a part in building bone.
Main benefits
Blood clotting; bone
Food sources
Found mainly in dark leafy greens such as kale, collards, spinach and Swiss chard, plus broccoli, Brussels sprouts, cabbage and soybean and canola oils.
Signs you may be low
Easy bruising, nosebleeds, bleeding gums and heavy periods. Newborns, people who absorb fat poorly and those on long-term antibiotics are most at risk.
Amounts
Neither site gives a dose; leafy greens supply it. RDA (AI) 90–120 mcg. (Vitamin K)
Cautions and interactions
Warfarin: keep intake steady and never change it without the doctor.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 4.
No. 16Vitamin K2
Vitamin K2 is a group of forms of vitamin K, mainly MK-4 and MK-7. It switches on proteins that guide calcium into bones and teeth and help keep it out of the arteries, a sort of traffic cop for calcium. It is often paired with vitamin D3.
Main benefits
Moves calcium into bones and teeth and out of arteries
Food sources
Found in natto (fermented soybeans, the richest source of MK-7), hard and soft cheeses, egg yolks, butter, liver and chicken.
Why people take it
People take it mostly to support bone strength and to help keep calcium out of the arteries, often alongside vitamin D. The evidence is promising but still mixed, especially for the arteries.
Amounts
Maintenance: 100 mcg, or 100 mcg for each 5,000–10,000 IU of vitamin D3; 180 mcg a day used in trials; Grant and colleagues suggest 150–200 mcg a day with vitamin D. Safe limit: "at any dose tried, there was no apparent toxicity" (MK-7 study). MK-4 is used at up to 45 mg in Japanese bone studies. (OMNS v19n28, OMNS v18n22)
Cautions and interactions
Warfarin (Coumadin): never start or stop without the doctor. Other blood thinners: ask the doctor.
Taught in Orthomolecular Nutrition (Part 2 of the Holistic Orthomolecular Nutrition certification), Lesson 4.
No. 17Multivitamin-mineral
A multivitamin-mineral combines many vitamins and minerals in one product. A high-potency formula gives a good base of the B vitamins, trace minerals and some vitamin D, but it does not hold enough vitamin C, E, D or magnesium on its own. A foundation, not the whole house.
Main benefits
A base of the B vitamins, trace minerals and some vitamin D; does not hold enough vitamin C, E, D or magnesium
Food sources
Not a food but a combined supplement. The same nutrients come from a varied diet of vegetables, fruits, whole grains, beans, nuts, eggs, fish and meat.
Why people take it
People take it as nutritional insurance, to fill small gaps in an imperfect diet. It is popular with older adults, people on restricted diets and anyone who wants a simple daily base.
Amounts
Common amount: as labeled, split between meals (Dr. Saul takes his twice a day with food); extra C, E, D and magnesium are taken separately.
Cautions and interactions
Iron-containing formulas: not for men or women past menopause unless iron is low. Retinol (preformed vitamin A) in pregnancy. Vitamin K content with warfarin. Take thyroid medication 4 hours apart.
Reference entry: not taught in a course Lesson.
No. 18PABA
PABA (para-aminobenzoic acid) is a compound that forms part of the folate molecule. Bacteria use it to make folate, but humans cannot, so it is not considered a true vitamin for people. Call it an honorary member of the B family. It was once a common ingredient in sunscreens.
Main benefits
Part of the folate molecule; skin (historically vitiligo and sun sensitivity)
Food sources
Found in small amounts in liver, eggs, whole grains, brewer's yeast, molasses and mushrooms.
Why people take it
People have taken it for skin conditions, historically vitiligo and sun sensitivity. The evidence is limited and mostly old.
Amounts
Common amount: 100–500 mg a day. Gram doses are prescription-only and doctor-supervised.
Cautions and interactions
Sulfa antibiotics (blocks their action). Liver problems at high doses; low blood sugar. Pregnancy: no safety data.
Reference entry: not taught in a course Lesson.