VITAMIN A

Vitamin A is a fat-soluble vitamin that is naturally present in many foods. Vitamin A is important for normal vision, the immune system, and reproduction. Vitamin A also helps the heart, lungs, kidneys, and other organs work properly.
retinol; Vitamin A; all-trans-Retinol; 68-26-8; Vitamin A1; Alphalin; Axerophthol; Afaxin; Vitamin A; alcohol; Oleovitamin A; Chocola A; Alphasterol; Apostavit; Aquasynth; Biosterol; Epiteliol; Ophthalamin; Agiolan; Agoncal; Anatola; Myvpack; Prepalin; Testavol; Veroftal; Aoral; Apexol
Avibon; Avitol; Axerol; Dofsol; Vaflol; Vitpex; Vogan; Disatabs Tabs; Lard Factor; all-trans-Retinyl alcohol; Bentavit A; Dohyfral A; Alcovit A; Anatola A; Vogan-Neu; A-Mulsal; Plivit A; Vi-Alpha; A-Vitan; All-trans retinol; Atars; trans-retinol; Vafol; all-trans-Vitamin A alcohol; Retrovitamin A; Homagenets Aoral; A-Sol; Hi-A-Vita; Sehkraft A; Vitamin A1 alcohol; all-trans-Vitamin A; A-Vi-Pel; ACON; ATAV; Vi-Dom-A; Super A; Anti-infective vitamin; Solu-A; Nio-A-Let; Vio-A; Antixerophthalmic vitamin; Del-VI-A; Vitavel A; Thalasphere; 11103-57-4; trans-Vitamin A alcohol;; Vitamin A alcohol, all-trans-; Vitamin A1, all-trans-; Retinol, all trans-; all-trans-Vitamin A1; Vitamin; A Oil; Vi-a; UNII-G2SH0XKK91; .beta.-Retinol; beta-Retinol; Vitamin A1 alcohol, all-trans-
(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraen-1-ol; (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraen-1-ol; (all-E)-3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol; 2,4,6,8-Nonatetraen-1-ol, 3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-, (all-E)-; Axerophtholum; CHEBI:17336; Wachstumsvitamin; Vitaminum A; Vitamine A; Vitavel-A; VITAMINA; NSC-122759; Retinolo [DCIT]; NCGC00017343-07; Cylasphere; Retinolo; Retinolum; Retinol [INN:BAN]; all-trans-Retinol, 95%; DSSTox_CID_3556; Hydrovit A; Retinolum [INN-Latin]; 3,7-Dimethyl-9-(2,6,6-trimethyl-1; cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol; DSSTox_RID_77080; DSSTox_GSID_23556; Ro-a-vit
tROL; Vitamin A alcohol (VAN), Antixerophthalmisches Vitamin; Aquasol A Parenteral; Vi-alpha; Vi-alpha; Rovimix A 500; Vitamin A1 alcohol, all trans; Retinol solution; (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-enyl)nona-2,4,6,8-tetr aen-1-ol; CAS-68-26-8; SMR000112036; Retinol; (Vit A); [11,12-3H]-Retinol; 9-cis,13-cis-Retinol; Vitamin A (USP); CCRIS 5444; HSDB 815; Vitamin A; [Natural]; SR-01000763813; Retin-11,12-t2-ol (9CI); EINECS 200-683-7; NSC 122759; BRN 0403040; Tegosphere VitA; .alpha.sterol; .alpha.lin; Retinyl A; trans-Retinol acid (Vitamin A)
1rbp; Vi-.alpha.; EINECS 234-328-2; 3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclchexen-1-yl)-2,4,6,8-nonatetraen-1-ol; (9Z)-Retinol; PubChem18446; 1gx8; Retinol-(cellular-retinol-binding-protein); Spectrum5_000993; Spectrum5_001997; Retinol, 95%, synthetic; EC 200-683-7; all-trans vitamin A alcohol; SCHEMBL3112; 3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonate-traen-1-ol; 3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol, (all-E)-; Alcohol; 9,13-dimethyl-7-(1,1,5-trimethyl-6-cyclohexen-5-yl)-7,9,11,13-nonatetraen-15-ol; all-trans-3,7; Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol; BIDD:PXR0102; 4-06-00-04133 (Beilstein Handbook Reference); MLS001066379; MLS001074751; MLS006010008; Retinol,; all-trans- (8CI); SPECTRUM1501203; GTPL4053; Vitamin A|||Retinoid analogues; DTXSID3023556; HMS501I08; Zinc-ethylenebis(dithiocarbamate); all-trans-13,14-Dihydro retinol; HMS1921B04

There are two different types of vitamin A. The first type, preformed vitamin A, is found in meat, poultry, fish, and dairy products. The second type, provitamin A, is found in fruits, vegetables, and other plant-based products. The most common type of provitamin A in foods and dietary supplements is beta-carotene.
Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, and several provitamin A carotenoids (most notably beta-carotene).[1][2][3] Vitamin A has multiple functions: it is important for growth and development, for the maintenance of the immune system, and for good vision.[4][5] Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule[6] necessary for both low-light (scotopic vision) and color vision.[7] Vitamin A also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-like growth factor for epithelial and other cells.[5][8]
In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal.[3]
All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a retinyl group.[1] Both structural features are essential for vitamin activity.[9] The orange pigment of carrots (beta-carotene) can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels.[3] Alpha-carotene and gamma-carotene also have a single retinyl group, which give them some vitamin activity. None of the other carotenes have vitamin activity. The carotenoid beta-cryptoxanthin possesses an ionone group and has vitamin activity in humans.
Vitamin A can be found in two principal forms in foods:
•    Retinol, the form of vitamin A absorbed when eating animal food sources, is a yellow, fat-soluble substance. Since the pure alcohol form is unstable, the vitamin is found in tissues in a form of retinyl ester. It is also commercially produced and administered as esters such as retinyl acetate or palmitate.[10]
•    The carotenes alpha-carotene, beta-carotene, gamma-carotene; and the xanthophyll beta-cryptoxanthin (all of which contain beta-ionone rings), but no other carotenoids, function as provitamin A in herbivores and omnivore animals, which possess the enzyme beta-carotene 15,15'-dioxygenase in the intestinal mucosa to cleave and convert provitamin A to retinol.

Vitamin A deficiency can occur as either a primary or a secondary deficiency. A primary vitamin A deficiency occurs among children and adults who do not consume an adequate intake of provitamin A carotenoids from fruits and vegetables or preformed vitamin A from animal and dairy products. Early weaning from breastmilk can also increase the risk of vitamin A deficiency.
As some carotenoids can be converted into vitamin A, attempts have been made to determine how much of them in the diet is equivalent to a particular amount of retinol, so that comparisons can be made of the benefit of different foods. The situation can be confusing because the accepted equivalences have changed.
For many years, a system of equivalencies in which an international unit (IU) was equal to 0.3 μg of retinol (~1 nmol), 0.6 μg of β-carotene, or 1.2 μg of other provitamin-A carotenoids was used.[47] This relationship is alternatively expressed by the retinol equivalent (RE): one RE corresponded to 1 μg retinol, 2 μg β-carotene dissolved in oil (it is only partly dissolved in most supplement pills, due to very poor solubility in any medium), 6 μg β-carotene in normal food (because it is not absorbed as well as when in oils), and 12 μg of either α-carotene, γ-carotene, or β-cryptoxanthin in food.[48]
Newer research has shown that the absorption of provitamin-A carotenoids is only half as much as previously thought. As a result, in 2001 the US Institute of Medicine recommended a new unit, the retinol activity equivalent (RAE). Each μg RAE corresponds to 1 μg retinol, 2 μg of β-carotene in oil, 12 μg of "dietary" beta-carotene, or 24 μg of the three other dietary provitamin-A carotenoids.
Vitamin A, also known as retinol, has several important functions.
These include:
•    helping your body's natural defence against illness and infection (the immune system) work properly
•    helping vision in dim light
•    keeping skin and the lining of some parts of the body, such as the nose, healthy
Good sources of vitamin A
Good sources of vitamin A (retinol) include:
•    cheese
•    eggs
•    oily fish
•    fortified low-fat spreads
•    milk and yoghurt
•    liver and liver products such as liver pâté – this is a particularly rich source of vitamin A, so you may be at risk of having too much vitamin A if you have it more than once a week (if you're pregnant you should avoid eating liver or liver products)
You can also get vitamin A by including good sources of  beta-carotene in your diet, as the body can convert this into retinol. 
The main food sources of beta-carotene are:
•    yellow, red and green (leafy) vegetables, such as spinach, carrots, sweet potatoes and red peppers
•    yellow fruit, such as mango, papaya and apricots

Vitamin A is a fat-soluble vitamin. It can be found in many fruits, vegetables, eggs, whole milk, butter, fortified margarine, meat, and oily saltwater fish. It can also be made in a laboratory. Carotenoids are a group of yellow or orange chemicals found in plants. Some of these can be converted to vitamin A in the body.

Vitamin A is most commonly used for treating vitamin A deficiency.

People also use vitamin A to reduce complications of diseases such as malaria, HIV/AIDS, and measles, and for fertility, diarrhea, vision, child development, skin disorders, infections, and many other conditions, but there is no good scientific evidence to support most of these uses.

How does it work ?
Vitamin A is required for the proper development and functioning of our eyes, skin, immune system, and many other parts of our bodies.
Functions in Your Body
Vitamin A is essential for your health, supporting cell growth, immune function, fetal development and vision.
Perhaps one of the best-known functions of vitamin A is its role in vision and eye health.
Retinal, the active form of vitamin A, combines with the protein opsin to form rhodopsin, a molecule necessary for color vision and low-light vision.
It also helps protect and maintain the cornea — the outermost layer of your eye — and the conjunctiva — a thin membrane that covers the surface of your eye and inside of your eyelids.
Additionally, vitamin A helps maintain surface tissues such as your skin, intestines, lungs, bladder and inner ear.
It supports immune function by supporting the growth and distribution of T-cells, a type of white blood cell that protects your body from infection.
What’s more, vitamin A supports healthy skin cells, male and female reproduction and fetal development.

Vitamin A include:
•    alitretinoin
•    beta carotene
•    bexarotene
•    dichlorphenamide
•    etretinate
•    isotretinoin
•    mipomersen
Using vitamin A safely
Eating or applying too much vitamin A can have side effects and may even be harmful.
Some side effects associated with consuming too much preformed vitamin A include:
•    headaches
•    blurred vision
•    dizziness
•    liver damage
•    nausea
•    coma
Beta carotene
Ingesting too much beta carotene can turn the skin yellow or orange. This condition is not harmful and will dissipate when the amount of beta-carotene in the diet is reduced.
Medications with vitamin A ingredients
Some medications contain vitamin A, including certain prescriptions used to treat psoriasis, obesity, and T-cell lymphoma. Taking vitamin A supplements while using these medications may dangerously increase vitamin A levels in the body, potentially causing side effects including liver damage.
THE SKIN BENEFITS OF VITAMIN A
You know the drill when it comes to caring for your skin: cleanse, tone, moisturize, apply sunscreen, and maybe try a few other treatments, like masks or anti-agers. Amid so many possibilities (and products) to help your skin looks its best, though, there are a few nutrients that skin really needs—and vitamin A is one of them. Whether you get it from your diet or in a topical cream, the protective and nourishing properties of A, and the nutrients your body uses to make it, lend a hand in keeping skin healthy, firm and radiant.
What does Vitamin A do for your skin? Unlike many other nutrients, vitamin A is a group of compounds that includes its active forms (retinal, retinol and retinoic acid) and other provitamin A carotenoids, like beta-carotene. Beta-carotene (and the other carotenoids) is the form of vitamin A that we get directly from the plant foods we eat. The pre-formed or active forms are found in animal foods. In our bodies, beta-carotene is converted into the retinol form of vitamin A.
Here’s what happens when you feed your body vitamin A:
1. IT PROTECTS AGAINST UV DAMAGE AND SLOWS SIGNS OF AGING.
Most of your vitamin A intake comes from eating foods rich in beta-carotene and provitamin A carotenoids, which are potent antioxidants. Not only do these squelch free radicals that break down collagen (your skin’s support structure) and contribute to fine lines and saggy skin, they also lessen skin’s sensitivity to the sun, providing some natural protection against sun-induced redness and pigmentation.
2. IT ENCOURAGES HEALTHY SKIN CELL PRODUCTION.
Retinal, retinol and retinoic acid are important to cell production and growth. Vitamin A also stimulates fibroblasts—the cells responsible for developing tissue that keeps skin firm and healthy—in the deep layers of your skin. Because vitamin A and carotenoids play such a big role in cell and tissue growth, not getting enough can lead to weakened skin, causing problems ranging from dryness to wounds that heal more slowly.
3. IT PROTECTS AGAINST INFECTION.
Your skin is an important part of your immune system; think of it as your body’s bouncer—a first line of defense against bacteria, pollutants and infection. By promoting cell production, vitamin A helps strengthen this barrier, protecting your complexion from harmful irritants that attempt to attack the surface.

4. IT SMOOTHES WRINKLES.
Topical vitamin A treatments in the form of retinol (found in over-the-counter products) and retinoic acid (found in prescription creams) are proven wrinkle-fighters and many dermatologists’ go-to recommendation for combating signs of aging. Research has shown that these ingredients are able to stimulate collagen production: When collagen becomes damaged due to UV exposure and other aggressors, wrinkles begin to develop, much like cracks in a weak foundation. Retinoids “turn on” cells responsible for making new collagen, strengthening your skin and filling in fine lines below the surface so skin looks smoother. One study found that after using a prescription-strength vitamin A cream for 10 to 12 months participants noticed significantly fewer wrinkles, and medical experts noted an 80 percent increase in collagen.
5. IT EVENS SKIN TONE AND GIVES YOU A GLOW.
Vitamin A creams can help lighten sun-induced brown spots and boost skin radiance in two ways: First, by increasing and normalizing skin cell turnover, which helps you shed pigmented, damaged and rough surface cells, making room for healthier cells and allowing light to bounce off more evenly. Secondly, retinoids may block an enzyme needed for melanin (pigment) production, further helping to deliver an even-toned, glowing complexion.
6. IT CLEARS UP ACNE.
Pimples form when pores become clogged with dead skin cells, bacteria and oil, providing the perfect breeding ground for Propionibacterium acnes, a common bacteria responsible for blemishes. When vitamin A creams stimulate cell turnover the same process happens within the pores themselves, helping to slow oil production and keep pores clear.
CHOOSING VITAMIN A CREAMS
If you decide to try an over-the-counter vitamin A treatment, look for retinol on the ingredient list rather than retinyl palmitate, a weaker version of the vitamin. Retinol isn’t as potent as prescription-strength retinoic acid, so results may take longer to see, but it’s also less irritating to sensitive skin. Unfortunately, it’s common for vitamin A creams to cause redness, sensitivity and dry, flaky skin until you become acclimated. To minimize these side effects, start by applying just a pea-sized amount to your face every other night or every two nights for several weeks; follow with a plain, unscented moisturizer. Gradually increase your usage to nightly.
Vitamin A is a fat-soluble vitamin that has several important functions in the body.
•    It helps cells reproduce normally, a process called cellular differentiation.
•    It is essential for good vision. The first sign of a vitamin A deficiency is often poor sight at night.
•    It is needed for the proper development of an embryo and fetus.
Vitamin A helps keep skin and mucous membranes that line the nose, sinuses, and mouth healthy. It also plays a role in:
•    Immune system function
•    Growth
•    Bone formation
•    Reproduction
•    Wound healing
Vitamin A comes from two sources. One group, called retinoids, comes from animal sources and includes retinol. The other group, called carotenoids, comes from plants and includes beta-carotene. The body converts beta-carotene to vitamin A. Major carotenoids, including lycopene, lutein, and zeaxantuin, have important biological properties, including antioxidant and photoprotective activities.
It is rare in the developed world to have a serious deficiency of vitamin A. Symptoms include:
•    Dry eyes
•    Night blindness
•    Diarrhea
•    Skin problems
A nutrient that the body needs in small amounts to function and stay healthy. Vitamin A helps in vision, bone growth, reproduction, growth of epithelium (cells that line the internal and external surfaces of the body), and fighting infections. It is fat-soluble (can dissolve in fats and oils). Vitamin A is found in liver, egg yolks, and whole milk dairy products from animals and in fish oils. It can also be made in the body from a substance found in some fruits and vegetables, such as cantaloupes, carrots, spinach, and sweet potatoes. Vitamin A is being studied in the prevention and treatment of some types of cancer. Also called retinol.
Vitamin A is a fat soluble vitamin that is required for a number of bodily functions. This vitamin is needed to maintain good vision and a healthy immune system, as well as being essential for growth and development.
Vitamin A describes a group of compounds that include retinol, retinoic acid, retinal, and a number of provitamin A carotenoids such as beta-carotene. All types of vitamin A contain a beta-ionone ring with an isoprenoid chain attached which is referred to as the retinyl group. Both structures are required for vitamin activity.

Functions of Vitamin A
In the eyes, retinal is combined with a protein called opsin to give rhodopsin, an essential light absorbing molecule needed for color vision and seeing in dim light.
Another form of Vitamin A, retinoic acid, is a key hormone-like growth factor for epithelial cells and other cell types in the body.
Sources of Vitamin A
Vitamin A is found in both plant and animal food sources. The form of vitamin A absorbed when animal sources are consumed is retinyl palmitate, which gets converted into an alcohol called retinol. Retinol acts as a storage form of vitamin A, which can be converted to and from retinal, the active aldehyde form of the molecule. One of the richest animal sources of Vitamin A is liver.
Plant sources of Vitamin A include orange and yellow fruits and vegetables such as carrots, pumpkin, sweet potato, apricots and mangoes. The orange/yellow pigment occurs due to the presence of provitamin A carotenoids such as beta-carotene. These compounds need to be converted into vitamin A or retinol in the body before they can be used.
Vitamin A is the name of a group of fat-soluble retinoids, including retinol, retinal, and retinyl esters [1-3]. Vitamin A is involved in immune function, vision, reproduction, and cellular communication [1,4,5]. Vitamin A is critical for vision as an essential component of rhodopsin, a protein that absorbs light in the retinal receptors, and because it supports the normal differentiation and functioning of the conjunctival membranes and cornea [2-4]. Vitamin A also supports cell growth and differentiation, playing a critical role in the normal formation and maintenance of the heart, lungs, kidneys, and other organs [2].
Two forms of vitamin A are available in the human diet: preformed vitamin A (retinol and its esterified form, retinyl ester) and provitamin A carotenoids [1-5]. Preformed vitamin A is found in foods from animal sources, including dairy products, fish, and meat (especially liver). By far the most important provitamin A carotenoid is beta-carotene; other provitamin A carotenoids are alpha-carotene and beta-cryptoxanthin. The body converts these plant pigments into vitamin A. Both provitamin A and preformed vitamin A must be metabolized intracellularly to retinal and retinoic acid, the active forms of vitamin A, to support the vitamin’s important biological functions [2,3]. Other carotenoids found in food, such as lycopene, lutein, and zeaxanthin, are not converted into vitamin A.
Carotenoids are a class of more than 750 naturally occurring pigments synthesized by plants, algae, and photosynthetic bacteria (1). These richly colored molecules are the sources of the yellow, orange, and red colors of many plants. Fruit and vegetables provide most of the 40 to 50 carotenoids found in the human diet. α-Carotene, β-carotene, β-cryptoxanthin, lutein, zeaxanthin, and lycopene are the most common dietary carotenoids (1). α-Carotene, β-carotene and β-cryptoxanthin are provitamin A carotenoids, meaning they can be converted by the body to retinol. Lutein, zeaxanthin, and lycopene are nonprovitamin A carotenoids because they cannot be converted to retinol.

IUPAC
(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraen-1-ol

(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraen-1-ol

Retinol

retinol
TRADE
Retinol