Vitamin A is one of the main weapons against aging. It is added to skincare products to treat signs of extrinsic aging. It is also useful in the treatment of acne.

In a nutshell, Vitamin A in their various forms provide several significant benefits for skin:

• Reduces Fine Lines
  
• Increases Skin Thickness
• Reduces Pigmentation
• Improves Skin Texture
• Neutralizes Free Radicals
• Improves Acne

Vitamin A exists in different forms inside the body, and there are different forms of it in skincare products.

Vitamin A in the form of Retinoic Acid (a form found naturally inside cells) has proven efficacy in reversing the signs of extrinsic aging (such as photoaging).

Skincare products utilize synthetically engineered derivatives of Retinoic Acid known as retinoids.

One popular retinoid is Tretinoin, which is Retinoic Acid in synthetic form. Tretinoin is found in prescription strength products, such as Retin-A and Renova. Retin-A was the first Vitamin A prescription product to be approved by the FDA for reducing fine lines, mottled pigmentation, and rough skin texture. Today it is used for the treatment and prevention of photo-aging and acne. Other popular prescription retinoid ingredients include Tazorotene (found in the brand  Tazorac) and Adapalene (found in the brands Differin and Epiduo).

Retinoids are known as skin normalizers because they regulate cellular behavior and increase cell turnover. The latter means they increase the shedding of dead skin cells.

Normalizing this shedding process produces new, healthy skin faster. It also improves acne because of faster shedding of the cells lining pore walls. Retinoids decongest pores by opening up clogged follicles, clearing out the follicular debris, and preventing the formation of new clogs.

In anti-aging skincare, retinoids reduce fine lines and wrinkles by stimulating the production of new skin cells, collagen, and hyaluronic acid, and by inhibiting the production of enzymes that degrade collagen and elastin (MMP enzymes).

Retinoids also help fade dark spots resulting from photoaging, acne scars, and other post-inflammatory hyperpigmentation. In skin lightening products, retinoids speed up the removal of melanin pigment and accelerate the actions of other brightening agents.

There are other forms of Vitamin A used in non-prescription (OTC) skincare products. Let’s take a closer look at the most common forms.

Retinoic Acid (Trans-Retinoic Acid)

Retinoic Acid is the acid form of Vitamin A. It is the active form used directly by the cell. In order words, this is the only form of Vitamin A the body can use.

When the skin absorbs other forms of Vitamin A, the body must convert it into this active form, through a complicated enzymatic process. (See below for a simplified view.)

• Retinoic Acid is by far the strongest form of Vitamin A. But it is only available by prescription.
• Retinoic Acid not only prevents aging but also corrects pre-existing damage.
• Because it is acidic, it is the most irritating form of Vitamin A and can cause redness, peeling, flaking, irritation, dryness, and sun sensitivity.

Tretinoin, a prescription synthetic form of Retinoic Acid, is available in concentrations of 0.025%, 0.05%, and 0.1%.

Retinol

Retinol is the alcohol form of Vitamin A. It has been shown to have the same effects as Retinoic Acid but without the irritation.

Retinol is both an antioxidant and a cell-communicator. As a cell communicator, it tells other cells to produce new skin cells (increase cell turnover) and exfoliates the skin in the process. It also triggers glycosaminoglycan (GAG) production and is one of the few topical ingredients thought to stimulate the proliferation of elastin. The net result is an increase in skin thickness.

Retinol is one of the most usable forms of Vitamin A, absorbing quickly into skin. But Retinol is not active when applied to skin. It is held there until it is needed (more on this below).

How does Retinol compare with other retinoids?

• Biochemically, Retinol accomplishes the same as Retinoic Acid, just at a slower pace.
• Althought Retinol is much weaker than Retinoic Acid, it is also much less irritating.
• Retinol is stronger than Retinyl Palmitate and Retinyl Acetate.

Retinol is unstable in light and tends to oxidize quickly. This is why Retinol is usually recommended for night time use. UV light can degrade Retinol.

Retinol can be drying and irritating if the skin has not been gradually conditioned to it. Some people with very sensitive skin cannot tolerate products with retinol or any retinoids.

It is best to increase the strength of the Retinol concentration gradually over time. This allows skin cells time to develop more Vitamin A receptors, which allows for more uptake of Retinol (the receptors are also depleted by UV).

Retinol is available in concentrations up to 2% in over-the-counter, retail products. You can find higher concentrations in professional products.

Retinyl Palmitate & Retinyl Acetate

Retinyl Palmitate and Retinyl Acetate are the most common ester forms of Vitamin A. They function primaril as antioxidants in skin care products. Both are converted to Retinol inside skin.

• These ester forms are weaker than Retinol but less irritating.
• They have the advantage of being more stable in light and easier to formulate than Retinol.

Retinyl Palmitate makes up about 80% of the Vitamin A in skin. The body stores Vitamin A in this form.

Retinaldehyde (Retinal)

Retinaldehyde (or Retinal) is the aldehyde form of Vitamin A. It is a transitional form of Vitamin A (when Retinol is converted into Retinoic Acid).

This is a less common ingredient.

Beta Carotene

Beta Carotene is a well-known antioxidant. It belongs to the carotenoid group of pigments, which includes lycopene, lutein, zeaxanthin, and astaxanthin. Carotenoids are strong antioxidants and rich in color — orange, red, and yellow especially.

Beta Carotene is NOT Vitamin A. It is a precursor to Vitamin A (retinoic acid), which means that it is converted into Vitamin A in the body. It is sometimes called pro-Vitamin A.

• As an antioxidant, Beta Carotene is very stable and counteracts many free radicals.
• It is oil-soluble, and therefore good for preventing lipid peroxidation.
• Beta Carotene has inherent photoprotective properties. It can reduce redness from UV (erythema).
• Beta Carotene also protects Vitamin C.

Vitamin A undergoes several transformations in the body before it becomes usable (biologically active) to skin cells. Except for Retinoic Acid, all of the above forms of Vitamin A must go through an enzymatic conversion process before it can be made bioavailable in the skin.

Example: How A Carrot is Converted Into A Usable Form of Vitamin A

1. You eat a carrot (which is rich in beta carotene).
2. Your small intestine absorbs the Beta Carotene.
3. Your liver stores it as Retinyl Palmitate.
4. When Vitamin A is needed by cells, Retinyl Palmitate is converted into Retinol and transported through the bloodstream to the skin.
5. When Retinol reaches the dermis/epidermis, it is converted back to Retinyl Palmitate. (This is the only way it can enter skin cells, such as keratinocytes and fibroblasts.)
6. While it crosses the cell membrane of the skin cell, it is converted back to Retinol once more.
7. Once inside the cell, it is finally converted into Retinoic Acid.

Whew. Do you see how many steps it takes to make Vitamin A usable? Isn’t that long and complicated? So the point I want to make is this:

The number one consideration is your skin type.

Is it sensitive? Does it get easily irritated? If so, then you should avoid Retinoic Acid and Retinol, which will be too aggressive for your skin.

If your skin is not overly sensitive or reactive, then consider these options:

• Retinoic Acid is the most effective option for treating extrinsic aging, but it is aggressiveon the skin and available only by prescription. Consult with your dermatologist about whether your skin is suitable for it.
• Retinol is the second most effective. Be aware that the higher the concentration (especially greater than 2%), the greater the chance for irritation. Go easy when you first start using it. Apply it once every few days and gradually work your way up to daily use.
• Retinyl Palmitate and Retinyl Acetate are much weaker than Retinol but the least irritating. They are a safe bet for almost all skin types.

Always Wear Sunscreen If You Use Retinoids In The Daytime – Tretinoin and Retinol make the skin thinner, which may cause photosensitivity when the skin is exposed to the sun.

Make sure you wear sunscreen if you use either one in the daytime and have some exposure to sunlight. Some say retinol should only be used at night. But it is safe to use retinol in the daytime if you’re not outside the whole day in intense sunshine. If you’re mostly indoors, just wear sunscreen over it.

Keep Retinoids Away From Light – Retinoids break down in sunlight. Products containing retinoids should be packaged in opaque containers to protect the retinoids from light, oxygen, and moisture.

If You Are Pregnant, Consult With Your Doctor Before Using Any Retinoids – Excess Vitamin A can cause birth defects or liver toxicity. There are different opinions about whether they can be used on the skin and how much during pregnancy. Some doctors advise against all forms of Vitamin A, while others say to avoid only Retinoic Acid and Retinol. You should follow your doctor’s guidance.

Overuse of Retinoids Can Age Skin – Tretinoin and Retinol thin the skin. Over-use can cause chronic inflammation, which ages skin. Always follow the manufacturer’s instructions on frequency of use.

Vitamin A Can Cause Irritant Contact Dermatitis In Some People – Contact Irritant Dermatitis is a reaction that occurs after exposure to an irritant, which sensitizes skin. (More info on Irritant and Allergic Contact Dermatitis here.)