• 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.

Vitamin C consists of a water-soluble vitamin known as vitamin C. Vitamin C is also known as L-ascorbic acid or ascorbate.  It occurs as a white or slightly yellow crystal or powder with a slightly acidic taste. On exposure to light, it gradually darkens. In the dry state, it is reasonably stable in air, but in solution, it rapidly oxidizes.

• Vitamin C helps in the growth and repair of tissues of bones, cartilage, tendons, skin, hair, muscles and many more.
• Along with that, it helps in wound healing and also enhances the absorption of iron in our body.
• Excess of free radicals can speed up the ageing process, vitamin C due to its rich antioxidant properties help to reduce the harmful effects of these free radicals. Vitamin C is very crucial for bone and teeth health.
• It improves vision and also regulates blood cholesterol levels.
• Owing to its numerous benefits, it is very important to take an adequate amount of vitamin C in your diet.

Possibly Effective for

• An eye disease that leads to vision loss in older adults (age-related macular degeneration or AMD).
• Irregular heartbeat (atrial fibrillation). Taking vitamin C before and for a few days after heart surgery helps prevent irregular heartbeat after heart surgery.
• Emptying the colon before a colonoscopy.
• Limb pain that usually occurs after an injury (complex regional pain syndrome). 
• Skin redness caused by injury or irritation (erythema). Using a skin cream containing vitamin C might decrease skin redness following laser resurfacing for scar and wrinkle removal.
• Airway infections caused by exercise. Using vitamin C before heavy physical exercise, such as a marathon, might prevent upper airway infections that can occur after heavy exercise.
• Swelling (inflammation) of the stomach (gastritis). Some medicine used to treat H. pylori infection can worsen stomach inflammation. Taking vitamin C along with one of these medicines called omeprazole might decrease this side effect.
• A condition in which red blood cells are broken down faster than they are made (hemolytic anemia). Taking vitamin C supplements might help manage anemia in people undergoing dialysis.
• High cholesterol. Taking vitamin C might reduce low-density lipoprotein cholesterol in people with high cholesterol.
• Lead poisoning. Consuming vitamin C in the diet seems to lower blood levels of lead.
• Osteoarthritis. Taking vitamin C from dietary sources or from calcium ascorbate supplements seems to prevent cartilage loss and worsening of symptoms in people with osteoarthritis.
• Pain after surgery. Taking 2 grams of vitamin C by mouth one hour before surgery might reduce pain and the need for opioid pain relievers after surgery. 
• Wrinkled skin. Skin creams containing vitamin C seem to improve the appearance of wrinkled skin. A vitamin C patch also seems to help reduce wrinkles.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using Vitamin C and call your doctor at once if you have:

• Joint pain, weakness or tired feeling, weight loss, stomach pain;
• Chills, fever, increased urge to urinate, painful or difficult urination; or
• Severe pain in your side or lower back, blood in your urine.

Common side effects may include:

• Heartburn, upset stomach; or

• Nausea, diarrhoea, stomach cramps.

• Transient mild soreness may occur at the site of intramuscular or subcutaneous injection.
• Too-rapid intravenous administration of the solution may cause temporary faintness or dizziness.
• Although vitamin C is generally considered safe, high doses can cause adverse effects, including heartburn, nausea, headaches, stomach cramps, and diarrhoea.
• Vitamin C is not stored in the body. If you take more than you need, the extra vitamin C will pass into your urine.
• Very large doses may also interfere with tests for sugar in diabetics and with tests for blood in the stool.