Volume Three — Understanding Skin Ingredients
Article 2:  Vitamin A

Vitamin A Explained: Retinol, Retinal & Prescription Retinoids

“Vitamin A can be one of the most effective ingredients in skincare — but the best result doesn’t always come from using the strongest version.”

Vitamin A is one of the most researched ingredient families in modern skincare.

It can help improve:

• Fine lines and photoageing
• Uneven skin texture
• Acne and congestion
• Pigmentation
• Skin-cell turnover
• Collagen support
  

However the term Vitamin A covers several different ingredients — from relatively gentle cosmetic retinol through to prescription medications such as tretinoin.

And this distinction matters.

Some forms are easier for the skin to tolerate.

Others work more directly and can produce stronger results — but may also cause significantly more irritation.

The goal isn’t simply to use the strongest Vitamin A available.

It’s to use the most appropriate form, strength and frequency for your skin.

What Is Vitamin A?

Vitamin A is a group of related compounds known as retinoids.

In skincare, retinoids influence how skin cells grow, differentiate and renew themselves.

They interact with retinoic acid receptors within the skin and can affect processes involved in:

• Cell turnover
• Sebum and follicular function
•  Pigmentation
• Collagen production and degradation
• Skin texture and thickness

This is why Vitamin A can be useful across both acne and healthy-ageing skincare.

Topical tretinoin in particular has a long history of evidence for acne and photoageing. 

The Vitamin A Family

Not every form of Vitamin A acts at the same strength.

A useful way to think about it is as a conversion pathway:

Retinyl Esters → Retinol → Retinal (Retinaldehyde) → Retinoic Acid

Retinoic acid is the form that directly interacts with retinoid receptors.

The further away an ingredient sits from retinoic acid, the more conversion steps the skin needs to perform.

That generally means:

• potentially gentler activity
• slower results
• better tolerability for some people
• It does not mean weaker forms are useless.
  

For many people, tolerability and consistency matter more than theoretical potency.

Retinol

Retinol is probably the best-known cosmetic form of Vitamin A.

Before it can act as retinoic acid, the skin must convert:

Retinol → Retinal → Retinoic Acid

Retinol may help with:

• Fine lines
• Texture
• Pigmentation
• Mild congestion
• Healthy ageing
  

Because it requires conversion, it is generally less potent and often better tolerated than prescription tretinoin.

That makes it a useful starting point for many people who are new to Vitamin A.

Clinical studies have shown that well-formulated topical retinol can improve features of photoageing with relatively good tolerability, although irritation can still occur. 

Retinal — Also Called Retinaldehyde

Retinal sits one step closer to retinoic acid:

Retinal → Retinoic Acid

It is increasingly popular because it can provide stronger Vitamin A activity than retinol while often remaining more tolerable than prescription retinoids.

It may be useful for:

• Healthy ageing
• Fine lines
• Pigmentation
• Acne-prone skin
• Uneven texture
  

For someone who has outgrown a low-strength retinol but doesn’t necessarily need a prescription retinoid, retinal can be a useful middle ground.

What Is Tretinoin?

Tretinoin is retinoic acid itself.

Unlike retinol or retinal, it doesn’t need to be converted by the skin before binding to retinoid receptors.

That is one reason it is more potent.

Tretinoin is a prescription medication in many countries and has decades of evidence for treating acne and photoaged skin. Studies consistently show improvements in features such as fine wrinkling, mottled pigmentation, roughness and other signs of photodamage. 

But potency comes with a trade-off.

Tretinoin is also significantly more likely to cause irritation.

Why Does Tretinoin Cause So Much Sensitivity?

The common early reaction to topical retinoids is sometimes called retinoid dermatitis or “retinisation”.

Symptoms can include:

• Redness
• Dryness
• Tightness
• Peeling
• Scaling
• Burning
• Stinging
• Itching
  

These local reactions are especially common during the early stages of treatment. 

Tretinoin changes epidermal cell turnover and differentiation relatively quickly.

For skin that isn’t accustomed to retinoids, that increased biological activity can temporarily disrupt the outer barrier faster than the skin adapts.

The result is increased dryness, irritation and sensitivity.

This is not proof that the product is “working better”.

Severe irritation is not the goal.

In fact, persistent inflammation can make it harder to use the medication consistently and may worsen problems such as post-inflammatory pigmentation in susceptible skin.

Does Tretinoin Make Your Skin More Sensitive to the Sun?

Sun protection is particularly important when using topical retinoids.

Tretinoin-treated skin can be more vulnerable to irritation from sunlight and environmental extremes, especially while the skin is adjusting.

Official product information recommends minimising unnecessary UV exposure and using protective clothing and sunscreen. 

That doesn’t mean tretinoin permanently “thins” healthy skin in the simplistic way sometimes claimed online.

But during the adjustment period, the outer skin can become dry, irritated and more reactive.

Daily SPF is non-negotiable.

Prescription Retinoids Aren’t Just Tretinoin

There are several prescription topical retinoids.

Tretinoin

One of the oldest and most studied.

Commonly used for:

• Acne
• Photoageing
  

It is highly effective, but irritation can be significant.

Adapalene

A newer-generation retinoid commonly used for acne.

It has selective activity at retinoid receptors and is generally considered more tolerable than tretinoin for many acne patients.

Clinical comparisons have found lower irritation with adapalene than with tretinoin. 

Tazarotene

A potent prescription retinoid used for conditions including acne and, in some formulations, photoageing.

It can be very effective but may also cause:

• Dryness
• Redness
• Peeling
• Burning
• Increased environmental sensitivity
  

Tazarotene is among the more irritating topical retinoids for some users.

Trifarotene

A newer topical retinoid with selectivity for the retinoic acid receptor gamma.

It is primarily used for acne, including acne involving the face and trunk.

Like other topical retinoids, irritation can occur, particularly when beginning treatment. 

Prescription Doesn’t Automatically Mean Better

This is important.

Someone in their 40s may see another person using prescription tretinoin and assume:

“If tretinoin is stronger than retinol, I should be using tretinoin too.”

Not necessarily.

A prescription retinoid may be entirely appropriate for one person and unnecessarily irritating for another.

The best Vitamin A depends on:

• Skin condition
• Barrier health
• Sensitivity
• Acne severity
• Pigmentation risk
• Other skincare products
• Professional treatments
• Lifestyle
• Pregnancy status
• Ability to use it consistently
  

A product you can tolerate four nights per week may ultimately give you a better result than a stronger product that leaves your skin chronically inflamed and can only be used occasionally.

Who May Need to Be Particularly Careful?

Vitamin A should be approached cautiously in people with:

• Very sensitive skin
• Active eczema
• Rosacea-prone or highly reactive skin
• A compromised skin barrier
• Perioral dermatitis
• Recent aggressive procedures
• Significant dryness
•  Multiple strong actives already in the routine
  

Tretinoin has specifically been reported to cause severe irritation on eczematous skin and should be used cautiously in that setting. 

In these cases, restoring barrier stability may need to come before introducing Vitamin A.

Vitamin A & Pregnancy

Topical retinoids are generally avoided during pregnancy and when trying to conceive.

Although systemic absorption from topical products is much lower than with oral retinoids, topical retinoids such as tretinoin and adapalene are generally not recommended during pregnancy as a precaution. 

Oral isotretinoin is very different and is strongly teratogenic and strictly contraindicated during pregnancy. 

Anyone who is pregnant, planning pregnancy or breastfeeding should discuss retinoid use with their treating doctor.

What About Oral Isotretinoin?

Oral isotretinoin — often known by brand names historically including Roaccutane — is not simply a stronger skincare retinoid.

It is a systemic prescription medication used primarily for severe or treatment-resistant acne.

It can dramatically reduce sebaceous gland activity and acne formation, but it also has important potential adverse effects and strict pregnancy-prevention requirements.

Oral isotretinoin should always be medically supervised.

It should never be grouped with topical cosmetic retinol as though they are simply different strengths of the same skincare product.

 

Does Peeling Mean Vitamin A Is Working?

No. This is one of the most persistent myths surrounding retinoids.

Some dryness or mild flaking may occur when starting treatment.

However:

More peeling does not equal more collage.

More redness does not equal better results.

Burning does not mean the product is working harder.

The aim should be effective biological stimulation without maintaining chronic inflammation or barrier damage.

How Should Vitamin A Be Introduced?

For many people, slowly.

A sensible approach may involve:

1.  Begin with a low or moderate strength.
2. Use it two nights per week initially.
3. Increase frequency gradually if tolerated.
4. Apply to dry skin.
5. Use a supportive moisturiser.
6. Avoid adding several new actives simultaneously.
7. Wear SPF every morning.

Someone using prescription tretinoin should follow the instructions of their prescribing practitioner rather than creating their own schedule from social media.

What About the “Sandwich Method”?

Some people (including us at The Skin Code) recommend to apply:

Moisturiser → Retinoid → Moisturiser 

or

Retinoid mixed in with Moisturiser - this is what we recommend at The Skin Code for some of our Retinoid products.

This can reduce irritation by buffering the retinoid.

It may be particularly useful when beginning treatment or for drier skin.

Whether it is appropriate depends on the specific prescription or formulation, so medical directions should take priority for prescription products.

What Ingredients Work Well Alongside Vitamin A?

Ceramides - these support barrier function and help reduce moisture loss.

Niacinamide - Can help support barrier function and improve tolerability for many skins.

Hyaluronic Acid - Supports hydration.

Peptides - Can complement a healthy-ageing routine without necessarily increasing exfoliation.

Antioxidants - Often used separately in the morning.

PDRN / Polynucleotides – Emerging regenerative ingredients that may support tissue repair, hydration and skin resilience. They can be particularly interesting in mature or compromised skin, but they should complement—not replace—good barrier support and appropriate Vitamin A use. 

Exosomes – Cell-derived signalling vesicles being investigated for their ability to support repair, collagen-related pathways and recovery. Early clinical and preclinical data are encouraging, but evidence is still evolving and formulations vary considerably. 

The key is not to turn every routine into an ingredient cocktail.

Vitamin A, barrier-supportive ingredients and regenerative technologies can work well within the same overall skin strategy—but they should be introduced according to what the skin actually needs.

 

What About Exfoliating Acids?

AHAs and BHAs can absolutely coexist with Vitamin A in some routines.

But combining:

• Strong retinoids
• Glycolic acid
• Salicylic acid
• Strong Vitamin C
• Frequent professional exfoliation can quickly overwhelm susceptible skin.
  

There is no prize for fitting every active into seven days.

If the barrier is becoming dry, tight, red or persistently irritated, the routine needs reassessment.

Retinol vs Retinal vs Tretinoin

RETINOL

Best suited to:
Beginners, mild ageing concerns, people wanting gradual Vitamin A introduction.

Advantages: 
Generally more tolerable.

Limitations:
 Requires conversion within the skin and may work more gradually.

RETINAL

Best suited to:
People wanting stronger Vitamin A activity without immediately moving to prescription treatment.
Advantages:
Only one conversion step from retinoic acid.
Limitations:
Can still irritate sensitive skin.

TRETINOIN

Best suited to:
Appropriate medically assessed acne or photoageing patients.
Advantages:
Extensive evidence and direct retinoic-acid activity.
Limitations:
Higher potential for dryness, irritation and retinoid dermatitis.
Prescription guidance is required.

Frequently Asked Questions

Should everyone use Vitamin A?

No.

Vitamin A is highly effective, but skincare should never become a checklist where everyone is expected to use the same ingredient.

Some people will benefit enormously.

Others may do better with different strategies, particularly if their barrier is chronically reactive.

Is tretinoin better than retinol?

It is more potent and has stronger clinical evidence, but that doesn’t automatically make it better for every individual.

The best product is the one that delivers meaningful improvement while remaining tolerable enough to use consistently.

Can I use tretinoin forever?

Many people use topical retinoids long term under appropriate medical supervision.

The routine may still need to change over time depending on skin health, environment, hormonal changes and other treatments.

Can Vitamin A thin my skin?

This is frequently misunderstood.

Topical retinoids can temporarily cause peeling and irritation in the outermost skin layers, which can make the skin feel fragile.

Long-term tretinoin research, however, demonstrates beneficial changes associated with photoaged skin, including effects on epidermal structure and collagen rather than progressive destructive thinning. (PubMed⁠)

Can I use Vitamin A after professional treatments?

Not necessarily immediately.

Retinoids are often temporarily stopped around treatments that significantly disrupt or irritate the skin.

Timing depends on the procedure and the individual skin.

Follow the advice of the practitioner performing your treatment.

The Skin Code Perspective™

Vitamin A deserves its reputation as one of skincare’s most valuable ingredient families.

But we’ve also seen what happens when people believe stronger must mean better.

A chronically red, flaky and uncomfortable skin barrier isn’t the price you should have to pay for healthy ageing.

At The Skin Code, we look at:

1. What your skin is trying to achieve
2. How resilient your barrier currently is
3. What other treatments and active ingredients your using
4. How much Vitamin A your skin can realistically tolerate

Then we decide which form of Vitamin A is most appropriate for your skin.

For one person that may be retinol. For another, retinal. And for someone with a medical indication, their doctor may recommend tretinoin or another prescription retinoid.

The goal isn’t maximum strength. It’s maximum benefit with the least unnecessary irritation.

Key Takeaways

✓ Vitamin A is one of the most evidence-supported ingredient families in skincare.
✓ Retinol, retinal and tretinoin are not the same.
✓ Prescription retinoids are more potent but generally carry greater irritation potential.
✓ Tretinoin can cause dryness, redness, peeling, burning and stinging, particularly during early treatment. (FDA Access Data⁠)
✓ Irritation isn’t proof that a retinoid is working better.
✓ Not every skin needs prescription-strength Vitamin A.
✓ Barrier health and tolerability matter.
✓ Topical retinoids are generally avoided during pregnancy. 
✓ SPF should accompany any Vitamin A routine.

Continue Your Ingredient Journey

Vitamin A demonstrates something we’ll see repeatedly throughout Volume Three: An ingredient can have excellent science behind it and still not be appropriate for every skin.

Next, we’ll explore another skincare heavyweight:

Vitamin C Explained: What It Does & Why the Formulation Matters

We’ll look at the different forms of Vitamin C, antioxidant protection, pigmentation and collagen support — and why two products labelled “Vitamin C” can behave very differently on the skin.