• Vitamin A is vital for a healthy immune system, bone growth, vision, cell recognition and reproduction. Vitamin A often works as an antioxidant, fighting cell damage, but it also has many other uses. It has a vital role in the formation of heart, lungs, and kidney.
• Other functions of vitamin A include the formation and maintenance of teeth, bones, soft tissue, white blood cells, the immune system and mucus membranes. 
• Most people get enough vitamin A from their diets. However, a doctor might suggest vitamin A supplements to people who have vitamin A deficiencies. People most likely to have vitamin A deficiency are those with diseases (such as digestive disorders) or very poor diets.

• Vitamin A is used for improving the eyesight, maintaining cells of the skin and the lining of the digestive, urinary and respiratory tracts.
• It also helps in the formation of red and white blood cells in our body that are important to carry out the various essential functions of our body.
• Topical and oral retinoids are common prescription treatments for acne and other skin conditions, including wrinkles. 
• Oral vitamin A is also used as a treatment for measles and dry eye in people with low levels of vitamin A. 
• Vitamin A is also used for a specific type of leukemia.
• Vitamin A has been studied as a treatment for many other conditions, including cancers, cataracts, and HIV. However, the results are inconclusive.

• Night blindness
• A higher risk of infections, especially in the throat, chest, and abdomen
• Follicular hyperkeratosis, leading to dry, bumpy skin.
• Fertility issues
• Delayed growth in children
• Symptoms of vitamin A toxicity include dry skin, joint pain, vomiting, headaches, confusion.

• If you take too much of Vitamin A, it can lead to birth defects, abnormalities of the liver and disorders of the central nervous system.
• It can also decrease bone mineral density, leading to an increased risk of osteoporosis.
• This is because an excess of Vitamin A suppresses the building up of bones and increases its breakdown.
• The rate of calcium absorption by Vitamin D can also get affected due to excess of Vitamin A. Therefore, it is advised to use Vitamin A only as directed by your doctor.
• Interactions. Vitamin A supplements may interact with some birth control pills, blood thinners (Coumadin), acne medicines (isotretinoin), cancer treatments, and many other drugs.
• People who drink heavily or have kidney or liver disease shouldn’t take vitamin A supplements without talking to a doctor.

• Selenium is used in the treatment of natural deficiency.
• Selenium is essential for the conversion of thyroxine (T4) to the biologically active thyroid hormone triiodothyronine (T3) thereby it is important in thyroid hormone functioning.
• Selelium is not produced in the body but is needed for the proper immune system and thyroid function.
• It is found in soil, water and some food.

• Selelium is a powerful mineral. It plays a key role in metabolism and the functioning of the Thyroid glands.
• Selenium has antioxidant properties.
• Selenium is used to cure Prostate cancer.
• Some of the diseases due to deficiency of selelium are HIV, Crohn’s disease.
• It is also used to treat diseases like Asthma, Arthritis, Dandruff and Infertility.

• Selenium deficiency produces biochemical changes that might predispose people who experience additional stresses to develop certain illnesses.
• Side effects may include fingernail loss, skin rash, fatigue, irritability and weight loss.

It is observed that overdose of Selelium may increase the chances of non- melanoma (Skin cancer).

• Methylcobalamin/Mecobalamin is a form of vitamin B12 that restores its level in the body thereby helping in treating certain anaemias and nerve problems.
• It is required for the integrity of myelin, neuronal function, proper red blood cell formation and DNA synthesis

• It is used to treat Vitamin B12 deficiency in people with Pernicious Anemia.
• It is a beneficial drug to most of the common disorders like cardiovascular disorders, diabetes, anaemia, hyperhomocysteinemia and degenerative disorders.
• Methylcobalamin helps in the synthesis of neuronal lipids, regeneration of axonal nerves and has neuroprotective activity, which promotes neurons to function properly and thus improves Alzheimer disease, Parkinsonism, Dementia and neuropathic syndromes.
• It is an approved treatment for peripheral neuropathy.
• It also helps in balancing the levels of homocysteine, which is produced in excess can cause inflammation of blood vessels.

• Nausea and vomiting
• Diarrhoea
• Decreased appetite
• Dizziness
• Headache
• Skin rash
• Chest pain and discomfort

• Methylcobalamin can show some serious side effects in patients who might suffer from other conditions.
• Everyone needs to consume this medicine only after clinical consultation. The serious side effects of Methylcobalamin can include the formation of clots in limbs, depleted levels of potassium in the blood, a buildup of fluid in the lungs, heart failure and in some cases, anaphylactic reactions such as swollen tongue and throat, and hives.
• Consuming Methylcobalamin is not advisable for patients suffering from optic atrophy, which is a nerve condition that affects the eye.
• People who are suffering from infections or patients who have a low iron level in their body should be careful before taking Methylcobalamin and should only do so after the consultation of the doctor.
• It is not advised for mothers to consume Methylcobalamin if they are breastfeeding. Mother’s milk is a rich source of Vitamin B12 and consuming additional supplements while breastfeeding can have adverse effects on the baby.