The ESK blog

The Long (And Controversial) Journey Of Vitamin A – Your “Must Have” Skincare Ingredient

20 July 2021

Dr Ginni Mansberg

Originally published: July 20th 2021 | Updated: May 20th 2026

Vitamin A was first tested in the 1940’s for use in treating acne, but early testing found it to be too irritating. While testing of Vitamin A for acne and a range of other skin conditions continued (and continues to this day) its potential to irritate hampered its usefulness.

So how did a promising yet flawed ingredient go from being too irritating to use, to today’s frontline ingredient recommended for use in anti-aging, acne, and (pustular) Rosacea!?

IT ALL STARTED AS AN ACNE MEDICATION

It all started with Albert Kligman, who is often referred to as the father of modern dermatology. He set out to find a concentration and formulation of Retinoic Acid (a.k.a. Tretinoin – a form of Vitamin A) for the treatment of acne, that could be tolerated. His experiments with Vitamin A (amongst other things) on prisoners at Holmesburg Prison is both the biggest blight on his career but also led to the development of a Retin-A. Licensed by Johnson and Johnson in 1967, Retin-A found an “acceptable” trade-off between irritation and effectiveness of Retinoic Acid and it is still used today under prescription for the treatment of acne!

…WHICH SEEMED TO REDUCE SKIN AGING

Not long after the release of Retin-A, mature users of the medication started (quite excitedly) to report general improvements in their skin including a reduction in wrinkles, roughness and pigmentation. They came in for an acne treatment and ended up looking years younger! Remember that back in the 60’s there were no effective anti-aging treatments…

These reports prompted Kligman and others to start trials on Retinoic Acid for treatment of premature skin aging. The success of these new trials resulted in Vitamin A being identified not only as the frontline ingredient for treatment of acne but for skin aging too. And in 1995, Tretinoin was approved by the FDA as a medication for reducing wrinkles, pigmentation and hyperpigmentation.

But while Kligman’s formulation reduced the irritation of Retinoic Acid, for many it is still too irritating. This led Kligman and others to look for alternate forms of Vitamin A, which were well tolerated and still effective.

BRIEF INTERLUDE: THE DIETARY JOURNEY OF VITAMIN A

Vitamin A is used in our bodies for a number of functions including vision, cell growth and differentiation and plays a critical role in the maintenance of a number of organs including the heart, lungs and kidneys. Its role in cell differentiation and growth is what makes it such an effective ingredient in the skin.

We consume Vitamin A in our diets from a number of sources (eg. liver, sweet potatoes, carrots, cheese, fish and sweet melon). These forms of Vitamin A are converted to Retinol and Retinyl esters which are stored in our bodies.

In order to convert the stored forms of Vitamin A into the two forms of Vitamin A which are actively used in our bodies, Retinyl esters are converted first into Retinol. Retinol is then oxidised into Retinal (used amongst other things in vision) which is then oxidised into Retinoic Acid.

CAN WE HACK THE DIETARY PATH OF VITAMIN A TO FIND AN EFFECTIVE AND GENTLE FORM?

Retinol

Since the 1960’s, researchers have been looking for alternate forms of Vitamin A that would be effective and gentle. Since Retinol is stored in the body and is converted into Retinoic Acid, it was both easily analysed and studied. From the mid 1980’s, when formulation techniques improved to increase its stability it started to be used in commercial products. The problem? The two-stage conversion of Retinol to Retinoic acid means that it needs to be used in concentrations of at least 10 times those of Retinoic acid to get results! And while the irritation of Retinol at these higher concentrations again starts to become an issue, we still just don’t have great evidence for its effectiveness. However, its widespread availability and use in commercial products has seen it becoming ever more popular in recent times.

Retinal

In the late 1990’s, as the knowledge of the Vitamin A conversion chain became better understood, the ability to synthesize chemicals improved (remember unlike Retinol, Retinal is not stored in the body), and the search for an effective and non-irritating form of Vitamin A continued, trials on Retinal started. Since then, the evidence has shown that due to its efficient conversion to Retinoic Acid and possibly also in part to its own properties, it is the most effective and best tolerated form of Vitamin A. However as things stand, due probably to its expense, difficulty to sourcing and stabilise, it is still very rare to find Retinal in skin care products.

AND THAT’S HOW…

From a beginning of frustration and irritation, through a validation process which has us squirming in our chairs, to unanticipated user feedback leading to new lines of investigation. Vitamin A first identified as an ingredient of interest in the 1940’s has finally made it to the top of the online skin care ingredient searches. Though while that search term is “Retinol”, we’re predicting that the skin care industry will catch up to the evidence and start searching for “Retinal”.

SHOP OUR RETINAL NIGHT CREAMS WITH NIACINAMIDE (VITAMIN B3)

ULTIMATE A

Reduce wrinkles, fine lines and hyperpigmentation. Improves skin barrier function. Retinal at 0.06%, Niacinamide, for use on all skin types.

Ultimate A

Ultimate A Night Cream contains 0.06% Retinal, the most gentle and effective form of Vitamin A, paired with Niacinamide to help maintain skin barrier function and support brighter, firmer and more even looking skin tone and texture. Well suited even for the most irritable skin.

Key features:

0.06% Retinal to support a brighter, smoother and firmer skin texture
Niacinamide to support skin barrier function and a more even looking skin tone
Gentle formulation suitable for nightly use

Usage: Apply at night after cleansing (and serum if being used) as part of your evening skincare routine.

ULTIMATE A+

Reduce wrinkles, fine lines and hyperpigmentation. Improves skin barrier function. Retinal at 0.1%, Niacinamide and Glycolic Acid for use on thicker, oilier or acne prone skin. Higher concentration of Retinal and Glycolic Acid combine for better results in managing acne.

Ultimate A+

Building on the proven performance of Ultimate A, Ultimate A+ Night Cream is designed for those looking to refine texture and tone or support skin prone to congestion. With 0.1% Retinal (the next-generation form of Vitamin A), Niacinamide, and 2% Glycolic Acid, this formula delivers visible improvements while remaining gentle and well tolerated.

This unique combination supports smoother-looking skin, helps refine the appearance of pores and uneven tone, and promotes a more hydrated, balanced complexion.

Featuring:

Potent yet gentle formulation suitable for daily use
Helps improve the appearance of uneven tone and texture
Supports firmer, more supple-looking skin
Formulated with evidence-based ingredients known to enhance skin clarity

Note: Retinal is not suitable for use during pregnancy.

ULTIMATE A GOLD

Reduce wrinkles, fine lines and hyperpigmentation. Improves skin barrier function. Retinal at 0.1%, Niacinamide and PHAs for use on dry, sensitive, pigmented or mature skin.

Ultimate A Gold

Ultimate A Gold: the most effective and gentle ingredients that evidence based cosmeceutical skincare has to offer, in one revolutionary formula.

The game-changing night cream developed in partnership with Selma Blair - combines our most potent hero ingredients to effectively and gently tackle the most common skin concerns – in one product.

Tackling the signs of aging skin including fine lines, skin elasticity, impaired barrier function, hydration, dullness and uneven skin tone. it is our most powerful product yet and yet it’s still ridiculously well tolerated.

Wake up to skin that's supple, smoother, and softer.

For the most irritable of skin, Ultimate A may be a better option, particularly when starting to use Retinal based products

*Ultimate A Gold (Retinal) may transfer onto white or light-coloured fabrics. For best results, we recommend using darker clothing or surfaces to avoid visible marks.

Shop ESK Retinal Collection

References

Frequently Asked Questions

Find answers to common questions about our product

Yes, the two concerns overlap significantly. Retinal accelerates cell turnover, helping shift pigmented cells out of the skin faster. L-Ascorbic Acid (Vitamin C) helps neutralise the UV signal that triggers excess melanin production. Glycolic Acid, Lactic Acid as well as PHAs (Polyhydroxy acids) support surface renewal, improving uneven skin tone over time. Combining these actives with daily SPF gives you an approach that addresses both aging and discolouration simultaneously, which is why ESK's anti-aging products are also core to its pigmentation routines.

Mature and menopausal skin faces a dual challenge: accelerated collagen loss (driven by falling oestrogen) and a disrupted skin barrier which causes increased sensitivity and dryness. A strong routine includes a gentle cleanser, Vitamin C serum in the morning, a ceramide-rich moisturiser to support barrier function, retinal skincare product at night, and an SPF daily. ESK has dedicated collections for both Menopausal and Perimenopausal skin with products matched to these specific needs.

Yes, but choosing the right products for your skin is important. Sensitive skin doesn't mean you can't use evidence-based anti-ageing ingredients, it just means you may need to start with gentler formulations. For vitamin A, retinal (retinaldehyde) is generally better tolerated than retinol while still delivering excellent anti-ageing benefits. Many people can use retinal more comfortably, although those with very sensitive skin should still introduce it gradually. For vitamin C, L-ascorbic acid is the gold standard for improving photodamaged skin, but because it's formulated at a low pH, it can sometimes cause temporary stinging or irritation in sensitive skin. If your skin is more reactive, it might be better to avoid Vitamin C serums. The key to success is matching your skincare to your skin's current tolerance, not using the strongest products from day one. The ESK Skin Quiz can help identify the best anti-ageing routine for your skin type, sensitivity and experience with active ingredients.

The three ingredient groups with the strongest evidence for anti-aging are cell regulators, antioxidants and chemical exfoliants - in that order. In the cell regulator category, Vitamin A is by far the most studied and most effective ingredient across all anti-aging actives. Retinal (Retinaldehyde) is the form ESK uses because it is both highly effective (10-20x's more effective than Retinol) and non-irritating, even for sensitive skin. In the antioxidant category, L-Ascorbic Acid (Vitamin C) and Niacinamide (Vitamin B3) have the strongest evidence. For exfoliation, Glycolic Acid and Lactic Acid have the best clinical support. And the emerging evidence for Polyhydroxy acids make them a great option for sensitive skin. Daily broad-spectrum SPF sits above all of these: UV exposure is the primary driver of premature skin aging, and no active ingredient can outwork unprotected sun exposure.

Skin ageing is driven by two main processes: chronological ageing (the natural ageing process) and premature ageing, also known as photoageing.

Chronological ageing happens naturally over time as the skin produces less collagen, elastin and hyaluronic acid, and its ability to repair and renew itself slows. This leads to thinner, drier skin, fine lines and a gradual loss of firmness.

Premature ageing is caused by external factors, particularly cumulative UV exposure, which is responsible for up to 80% of visible facial ageing. UV damage breaks down collagen and elastin, leading to deeper wrinkles, rough texture, uneven pigmentation and loss of elasticity. Smoking, air pollution, poor sleep and diet can also contribute to premature skin ageing.

While we can't stop chronological ageing, we can slow and even improve many of the visible signs of UV skin damage. Most evidence-based skincare ingredients, including sunscreen, vitamin A (retinal), vitamin C and niacinamide, work by helping to prevent or repair the effects of photoageing.

The only form of Vitamin C with strong clinical evidence for anti-aging is L-Ascorbic Acid. Most brands use bonded derivatives like Magnesium Ascorbyl Phosphate and still call it Vitamin C on the label. But there is no evidence those alternatives actually work. The challenge with L-Ascorbic Acid is stability: it degrades when exposed to light and air. ESK formulates its Vitamin C products in airless, opaque packaging specifically to maintain stability and ensure the ingredient is still active when it reaches your skin.

Both are forms of Vitamin A but they work differently. Retinol requires a two-step conversion process in the skin before it becomes Retinoic Acid, the active form the skin actually uses. Retinal is one step closer, meaning it converts more efficiently and delivers faster results at lower concentrations. Retinal is also significantly better tolerated than Retinol, making it suitable even for sensitive skin. It is more expensive to produce, which is why most brands stick with Retinol, but the evidence for Retinal is strong and the irritation profile is in a different league. It is the only form of Vitamin A ESK uses.