science

Retinyl palmitate

Retinyl palmitate is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Retinyl palmitate rather than just read about it. In short: Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2. It is the most abundant form of vitamin A storage in animals.

Key takeaways

Retinyl palmitate belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Retinyl palmitate to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Retinyl palmitate from memory before moving on to harder problems.

Reference excerpt

Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2. It is the most abundant form of vitamin A storage in animals. An alternate spelling, retinol palmitate, which violates the -yl organic chemical naming convention for esters, is also frequently seen. In 2021, vitamin A was the 298th most commonly prescribed medication in the United States, with more than 500,000 prescriptions.

Biology Animals use long-chain esters of vitamin A, most abundantly the palmitate form, as a form of vitamin A storage. The storage reaction is catalyzed by LRAT, and the inverse is catalyzed by REH. The esters are also intermediates in the visual cycle: RPE65 isomerizes the retinyl part to 11-cis-retinal.

Uses Vitamin A palmitate is a common vitamin supplement, available in both oral and injectable forms for treatment of vitamin A deficiency, under the brand names Aquasol A, Palmitate A, and many others. It is a constituent of intraocular treatment for dry eyes at a concentration of 138 μg/g (VitA-Pos) by Ursapharm. It is a pre-formed version of vitamin A; therefore, the intake should not exceed the Recommended Dietary Allowance (RDA). Overdosing on preformed Vitamin A forms, such as retinyl palmitate, leads to adverse physiological reactions (hypervitaminosis A). Retinyl palmitate is used as a source of vitamin A added to low-fat milk and other dairy products to replace the vitamin content lost through the removal of milk fat. Palmitate is attached to the alcohol form of vitamin A, retinol, to make vitamin A stable in milk. Retinyl palmitate is also a constituent of some topically applied skin care products. After its absorption into the skin, retinyl palmitate is converted to retinol, and ultimately to retinoic acid (the active form of vitamin A present in Retin-A), though neither its skin absorption nor its conversion is very effective.

Carcinogenicity controversy New York Senator Chuck Schumer has called attention to the fact that high doses of topical retinyl palmitate were shown to accelerate cancer in lab animals, fueling the sunscreen controversy in the popular press. One toxicological analysis determined that "there is no convincing evidence to support the notion that [retinyl palmitate] in sunscreens is carcinogenic." A technical report issued thereafter by the National Toxicology Program concluded that diisopropyl adipate increased the incidence of skin tumors in mice, and the addition of either retinoic acid or retinyl palmitate both exacerbated the rate and frequency of tumors.

Teratogenicity World Health Organization recommendation on Maternal Supplementation During Pregnancy states that "health benefits are expected for the mother and her developing fetus with little risk of detriment to either, from a daily supplement not exceeding 10,000 IU [preformed] vitamin A (3000 μg RE) at any time during pregnancy." Preformed Vitamin A refers to retinyl palmitate and retinyl acetate.

See also Vitamin A Retinyl acetate Vitamin supplement

References

Illustrations

Worked examples

Example 1 — a first encounter with Retinyl palmitate

Start with the simplest possible case. Write down what Retinyl palmitate claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Retinyl palmitate before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Retinyl palmitate ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Retinyl palmitate

In research: Retinyl palmitate appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Retinyl palmitate in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Retinyl palmitate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antioxidants, Cyclohexenes, Orphan drugs, so understanding it makes those chapters shorter.
In everyday life: Look for Retinyl palmitate outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Retinyl palmitate in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Retinyl palmitate means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Retinyl palmitate out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Retinyl palmitate in simple terms?

Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2. It is the most abundant form of vitamin A storage in animals.

Why does Retinyl palmitate matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Retinyl palmitate?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Retinyl palmitate.