Celimax Retinal Shot vs Retinol Shot: Everything You Need to Know About The Vita-A Retinal Booster & Retinol Serum

If you've been looking for a Korean retinoid, chances are you've come across two very similar-looking Celimax products:

Celimax The Vita-A Retinal Shot Tightening Booster

and

Celimax The Vita-A Retinol Shot Tightening Serum

Retinal. Retinol. Shot. Tightening.

The names are similar enough that one obvious question comes up:

What's the difference—and which Celimax Vita-A product should you use?

The answer is more important than it might seem.

Both products belong to Celimax's Vita-A line and target concerns such as wrinkles, visible pores, skin texture and loss of firmness. But they use different forms of vitamin A, have different strengths and are not necessarily intended for the same stage of your retinoid routine.

And yes—Celimax actually says they can be used together.

Here's everything you need to know.

Celimax Retinol Shot vs Retinal Shot: Quick Comparison

The easiest way to think about the pair is:

RETINOL SHOT = your starting treatment

RETINAL SHOT = your more intensive treatment

And if you're planning to use both:

Start with Retinol Shot first → build tolerance → introduce Retinal Shot later.

Celimax specifically recommends using the Retinol Shot Serum for approximately two weeks to allow the skin to adjust before combining it with the Retinal Shot Booster.

First: What Is the Difference Between Retinol and Retinal?

Both belong to the vitamin A family of skincare ingredients.

But they aren't identical.

To understand the difference, you need to know what happens after a topical retinoid is applied.

Retinol ultimately needs to be converted into retinoic acid, the biologically active form that interacts with retinoid receptors in the skin.

The simplified pathway is:

Retinol → Retinal → Retinoic Acid

That means retinal—also called retinaldehyde—is one conversion step closer to retinoic acid than retinol.

This is one reason retinal products are generally considered particularly interesting for people who already have some experience with cosmetic retinoids.

But don't automatically interpret that as:

“retinal is always better than retinol.”

Formulation, concentration, stability, delivery system and your skin's tolerance all matter.

What Is Celimax The Vita-A Retinol Shot Tightening Serum?

The Celimax The Vita-A Retinol Shot Tightening Serum is a 30 mL retinol serum developed around:

• Pure retinol

• A-Shot™ micro-particle technology

• Peptide complex

Celimax specifically emphasizes that the formula contains pure retinol rather than simply relying on a retinol derivative.

The serum is positioned around several visible signs of aging, including:

• Enlarged-looking pores

• Fine lines and wrinkles

• Skin firmness

• Skin density

• Facial elasticity

• Uneven-looking texture

Celimax conducted human application testing on the serum involving 20 adults, evaluating measures including pore number, depth, area and volume, as well as skin density, forehead wrinkles, eye-area wrinkles, nasolabial lines and facial lifting.

Individual results can vary.

What Is A-Shot™ Technology?

This is what makes Celimax's Retinol Shot different from a conventional retinol serum.

The formula contains Celimax's A-Shot™ micro-particle technology.

Celimax describes these as very fine micro-sized particles designed to help the formula interact closely with the skin and support delivery of the skincare ingredients.

The brand states that the Retinol Shot Serum contains approximately 162,000 A-Shot™ particles.

These particles are also why you may experience an unusual sensation when applying the product.

Why Does Celimax Retinol Shot Tingle?

This is one of the most important things to know before purchasing it.

A tingling or prickling sensation can occur.

Celimax explains that the sensation is associated with its microscopic A-Shot™ particles.

The brand says these particles naturally shed along with dead skin cells.

So if you apply the serum and think:

“Why does this feel prickly?”

that doesn't necessarily mean something has gone wrong.

However, there is an important difference between:

temporary mild prickling

and

significant irritation.

Persistent burning, intense redness, itching or peeling should not simply be ignored because the product is called a “Shot.”

Reduce the amount or frequency if your skin becomes irritated.

What Does Celimax Retinol Shot Tightening Serum Do?

Its primary targets are:

Fine lines and wrinkles

Retinol is one of the best-known cosmetic ingredients for addressing visible signs of aging.

Visible pores

Pores can become more noticeable because of several factors including oil production, congestion and loss of elasticity around the pore.

Improving overall texture and firmness can therefore help pores appear more refined.

Firmness

The formula is positioned around tighter, firmer-looking skin.

Skin texture

Consistent retinoid use can help create a smoother-looking skin surface.

Skin density

Celimax has also conducted human application testing evaluating changes in skin density following use of the serum.

What Is Celimax The Vita-A Retinal Shot Tightening Booster?

The Celimax The Vita-A Retinal Shot Tightening Booster is the more intensive member of the pair.

It contains 0.1% retinal and uses nano-liposomal retinal technology.

Celimax describes the formula as containing 0.00003 mm nano-liposomal retinal alongside its approximately 0.015 mm A-Shot™ micro-particles.

The product is designed around concerns including:

• Wrinkles

• Visible pores

• Loss of elasticity

• Skin firmness

• Aging-related texture changes

Unlike the 30 mL Retinol Shot Serum, the Retinal Shot comes in a concentrated 15 mL format.

Is Celimax Retinal Shot 0.1% Retinal?

Yes.

Celimax currently identifies the Retinal Shot Tightening Booster as containing 0.1% retinal.

This is an important distinction from the Retinol Shot Serum.

It is not simply a more concentrated bottle of the same product.

The two products use different vitamin A forms.

What Does Celimax Retinal Shot Tightening Booster Do?

The Retinal Shot is primarily designed for more intensive care targeting:

• Fine lines

• Wrinkles

• Elasticity

• Visible pores

• Firmness

• Uneven-looking texture

Celimax positions it as a high-performance vitamin A product for people concerned about declining elasticity and the wrinkles and enlarged-looking pores that can accompany it.

Why Is the Retinal Shot Yellow?

Retinal itself naturally has a yellow colour.

So the concentrated yellow appearance of a retinal formula is not automatically a sign that the product has gone bad.

Celimax describes the Retinal Shot Booster as having a concentrated yellow texture.

As with any vitamin A product, however, storage instructions should be followed carefully because retinoids can be sensitive to factors such as light and heat.

Is Celimax Retinal Shot Stronger Than Retinol Shot?

For most shoppers, the Retinal Shot should be considered the more advanced/intensive option.

The main reason is its use of 0.1% retinal.

Retinal sits one conversion step closer to retinoic acid than retinol.

Celimax's own usage strategy also supports this distinction: when customers want to use both products, the brand recommends first using the Retinol Shot Serum for approximately two weeks to establish tolerance before adding the Retinal Shot Booster.

So if you're completely new to retinoids, don't automatically buy the Retinal Shot simply because it sounds stronger.

Stronger isn't necessarily better if your skin cannot tolerate it.

Which Celimax Vita-A Product Should Beginners Use?

For someone new to retinoids, we'd generally start with:

Celimax The Vita-A Retinol Shot Tightening Serum.

Why?

Because Celimax itself recommends establishing tolerance with the Retinol Shot before combining it with Retinal Shot.

That gives you an opportunity to learn how your skin responds to:

• Retinol

• A-Shot™ technology

• The prickling sensation

• Increased skin sensitivity

• Vitamin A skincare generally

Once your skin is comfortable, you can decide whether you actually need the more intensive Retinal Booster.

Who Should Choose Celimax Retinal Shot?

The Retinal Shot makes more sense if:

• You've already used retinol

• Your skin tolerates retinoids well

• Fine lines are a major concern

• You want more intensive firmness care

• You're concerned about enlarged-looking pores associated with loss of elasticity

• You're specifically interested in retinal

• You want to move beyond beginner retinol skincare

Can You Use Celimax Retinol Shot and Retinal Shot Together?

Yes—and this is particularly interesting.

Celimax specifically promotes the two as its THE VITA-A SET.

However:

Do not start both products simultaneously if your skin hasn't already adapted to retinoids.

Celimax recommends:

Step 1: Use Retinol Shot Serum first

Step 2: Allow approximately two weeks for adaptation

Step 3: Gradually introduce Retinal Shot Booster

When the two products were tested together in a human application study involving 21 adults, Celimax reported improvements in measures including eye-area wrinkles, facial lifting and pore parameters.

The brand reports measured changes including:

• Pore depth: -14.80%

• Pore area: -28.74%

• Pore count: -21.79%

The study ran from May 20 to June 4, 2024.

These are brand-reported clinical testing results and individual results can vary.

How Do You Use Retinol Shot and Retinal Shot Together?

Celimax recommends establishing tolerance to the Retinol Serum first.

Once your skin has adapted, a routine can incorporate both products according to your skin's tolerance.

The Retinal Booster is intended for use toward the end of the evening skincare routine, initially applied in a thin layer to areas of concern.

You do not need to immediately cover your entire face with a large amount of retinal.

Gradual introduction is more sensible.

Can You Use Celimax Retinal Shot All Over Your Face?

Eventually, yes, if your skin tolerates it.

Celimax recommends initially using the product according to its retinal adaptation schedule and gradually increasing the amount.

After your skin has adapted, the brand says the product can be applied across the entire face.

This is particularly important with a 0.1% retinal formula.

More product does not automatically produce faster or better results.

How Often Should You Use Celimax Retinal Shot?

Start gradually.

Celimax specifically recommends an adaptation period during the first two weeks.

Even if you experience no irritation after your first application, Celimax advises against immediately increasing the amount or frequency because retinoid reactions can appear later.

Possible adjustment symptoms may include:

• Redness

• Peeling

• Itching

• Warmth

• Stinging

Adjust the frequency and amount according to your skin.

Should You Use Celimax Vita-A Products Morning or Night?

Night is preferable.

Celimax recommends evening use of the Retinal Shot because retinal is sensitive to light and heat.

If a vitamin A product is used during the daytime, sun protection becomes particularly important.

Regardless, daily sunscreen is essential when you're using a retinoid-focused routine.

Sunscreen Is Non-Negotiable

If you're going to invest in retinol or retinal skincare but skip sunscreen, you're undermining your anti-aging routine.

The morning after using Celimax Vita-A products, apply a broad-spectrum sunscreen appropriate for your skin.

This is especially important in Canada even during:

• Winter

• Cloudy weather

• Cold days

UV exposure does not disappear simply because it is -10°C outside.

Celimax Retinol Shot vs Retinal Shot for Wrinkles

Beginner / early fine lines:

Retinol Shot Serum

More established wrinkles / experienced retinoid user:

Retinal Shot Booster

Advanced routine:

Potentially both, once tolerance has been established.

Celimax has conducted wrinkle-related human application testing on both the Retinol Shot and the combination routine.

Which Is Better for Pores?

Both target visible pores.

This makes sense because Celimax isn't treating pores simply as an oil problem.

The Vita-A line also focuses on elasticity and skin structure.

As skin loses firmness, pores can appear more noticeable.

Retinoid skincare can therefore be particularly interesting when your concern is:

visible pores + aging + loss of firmness

rather than only blackheads.

If blackheads and congestion are the primary problem, however, a BHA product may be more directly targeted to that concern.

Which Is Better for Firmness?

Both.

But if you're already an experienced retinoid user and want the more intensive treatment:

Retinal Shot Booster is the more logical choice.

Which Is Better for Mature Skin?

The Retinal Shot may be particularly interesting for mature skin because of its more intensive 0.1% retinal formulation.

But mature skin can also be dry.

If your skin barrier is already compromised, immediately jumping into a strong retinoid routine may cause unnecessary irritation.

Build tolerance and pair the product with appropriate moisturizer.

Which Is Better for Oily Skin?

The Retinol Shot Serum may be easier to incorporate because of its serum format.

Retinoids can also be useful in routines where visible pores and uneven texture are concerns.

However, oily skin is not automatically resistant skin.

You still need to introduce vitamin A gradually.

Which Is Better for Dry Skin?

Either can be used, but dry skin needs additional attention to barrier support.

Consider using:

Gentle cleanser → Retinol/Retinal product → barrier-supporting moisturizer

If your skin becomes excessively dry, flaky or irritated, reduce frequency.

During Canadian winter, this becomes particularly important.

Celimax Vita-A During Canadian Winter

Canadian winter can make retinoid routines significantly more challenging.

Cold outdoor temperatures combined with low humidity and indoor heating can contribute to:

• Dryness

• Tightness

• Flaking

• Barrier discomfort

If you normally use Celimax Retinol Shot three or four times per week during summer, for example, you may find that your skin prefers a lower frequency during January or February.

Listen to your skin rather than following a rigid schedule.

A richer barrier moisturizer may also become necessary.

Celimax Vita-A During Canadian Summer

During warmer, more humid months, lighter moisturizer may be sufficient.

However, UV protection becomes especially important when you're spending more time outdoors.

Use sunscreen every morning and reapply appropriately during extended sun exposure.

Can You Use Celimax Retinol Shot With Vitamin C?

Celimax does not recommend using high-concentration vitamin C at the same time as the Retinal Shot.

If you want both in your routine, separating them is the simpler option:

Morning → Vitamin C + sunscreen

Evening → Celimax Vita-A

Or alternate them according to your skin tolerance.

Can You Use Celimax Retinal Shot With AHA or BHA?

Be cautious.

Celimax advises against simultaneously combining its Retinal Shot with exfoliating products.

Using:

retinal + strong AHA/BHA + A-Shot™

in the same routine may simply create more irritation than benefit.

Consider alternating nights.

For example:

Monday → Retinoid

Tuesday → Recovery

Wednesday → BHA

Thursday → Recovery

Friday → Retinoid

Your routine does not need a powerful active every single night.

Can You Use Celimax Retinol Shot With Scrubs?

Celimax specifically advises against combining its Retinal Shot with scrub/exfoliating products at the same time.

This is sensible.

A-Shot™ already creates a prickling sensation, while retinoids themselves require an adaptation period.

Adding aggressive physical exfoliation can unnecessarily increase irritation.

Can You Use Celimax Vita-A With Niacinamide?

Niacinamide can generally fit well into a retinoid routine.

It is frequently used in formulas focused on:

• Barrier support

• Oil balance

• Uneven-looking tone

• Overall skin health

If you're using several serums, however, you don't need to layer everything you own every night.

Can You Use Celimax Vita-A With Peptides?

Peptides can generally complement retinoid-focused skincare.

In fact, Celimax itself highlights a peptide complex as part of its Retinol Shot formula.

This combination is especially relevant to routines focused on:

wrinkles + firmness + elasticity.

Can You Use Celimax Vita-A With PDRN?

Potentially, yes.

PDRN skincare is commonly positioned around hydration, elasticity and recovery-focused care, making it an interesting supporting step alongside a retinoid.

A routine might look like:

Cleanser → PDRN serum → Celimax Vita-A → Moisturizer

depending on the textures and instructions of your specific products.

Can You Use Celimax Retinol Shot With Other Retinol Products?

Usually there is little reason to do so.

Stacking:

retinol serum + another retinol cream + retinal booster

doesn't necessarily mean three times the results.

It may simply mean significantly more irritation.

Choose a retinoid strategy rather than collecting as many vitamin A products as possible.

Does Celimax Retinol Shot Cause Purging?

Retinoids can temporarily change how blemishes appear as the skin adjusts, particularly in acne-prone areas.

However, not every breakout after starting retinol should automatically be called “purging.”

If you develop:

• Persistent irritation

• Widespread redness

• Burning

• Significant itching

• Severe peeling

your skin may be irritated rather than “purging.”

Reduce frequency or stop use until your skin recovers.

Why Does My Skin Peel After Retinal?

Peeling can occur during retinoid adaptation.

Celimax notes that temporary redness, peeling, itching, heat or stinging may occur during the adaptation period.

That does not mean you should simply push through severe irritation.

Reduce:

• Amount

• Frequency

• Other active ingredients

and increase gentle hydration and barrier support.

Can Sensitive Skin Use Celimax Retinol Shot?

Possibly, but with caution.

Remember that you're not only introducing retinol.

You're also introducing Celimax's A-Shot™ technology, which can produce a prickling sensation.

Celimax recommends patch testing first for sensitive skin.

If your skin is extremely reactive, compromised or currently irritated, this may not be the best time to introduce the product.

Can Sensitive Skin Use Celimax Retinal Shot?

Again, potentially—but the Retinal Shot is not where we'd suggest an inexperienced sensitive-skin user begin.

Start with a gentler retinoid strategy and establish tolerance first.

Can You Use Celimax Retinal Shot Around the Eyes?

The eye area is particularly delicate.

Although Celimax's clinical testing includes eye-area wrinkle measurements, avoid getting the product into the eyes and don't assume that more product close to the lash line will produce better results.

Follow the product's application directions and introduce it gradually.

Can You Use Celimax Retinol Shot on the Neck?

Retinoids are sometimes incorporated into neck skincare, but the neck can be surprisingly sensitive.

If you decide to use the product there:

• Start gradually

• Use a small amount

• Moisturize well

• Stop if persistent irritation occurs

• Apply sunscreen to exposed neck skin

Can Pregnant Women Use Celimax Retinal Shot?

Celimax specifically states that it does not recommend the Retinal Shot during pregnancy or breastfeeding.

The brand notes that skin may also become more sensitive during periods of hormonal change.

If you're pregnant, breastfeeding or trying to conceive, discuss retinoid use with your healthcare professional.

How Long Does Celimax Retinol Take to Work?

Don't judge a retinoid after three applications.

Skincare changes involving:

• Fine lines

• Texture

• Pores

• Firmness

generally require consistent use.

Celimax's own human application testing for the Retinol Shot was conducted over approximately two weeks, but real-world cosmetic results vary and longer consistent use may be needed to evaluate how well the product works for your skin.

Can You Use Celimax Retinol Shot Every Night?

Eventually, some users may tolerate frequent use.

But there is no requirement to use a retinoid every night.

Celimax's Korean guidance suggests approximately 3–4 evening applications per week for several skin types once appropriate.

Your ideal frequency depends on:

• Retinoid experience

• Skin type

• Climate

• Other active products

• Barrier condition

Consistency without irritation is more useful than forcing nightly application.

Do You Apply Celimax Retinol Shot Before or After Moisturizer?

The Retinol Shot is a serum, so it would normally be incorporated before moisturizer.

A straightforward routine is:

Cleanser → Toner → Retinol Shot Serum → Moisturizer

If you're particularly sensitive to retinoids, some people use moisturizer strategically to buffer stronger products, but follow the directions for your specific product and adjust based on tolerance.

Do You Apply Celimax Retinal Shot Before or After Moisturizer?

Celimax describes the Retinal Shot Booster as being used toward the final stage of the evening skincare routine, applying a thin amount to areas of concern.

This is another important difference between the two products:

Retinol Shot = serum step

Retinal Shot = concentrated booster/spot-treatment step

Frequently Asked Questions

What is Celimax Retinol Shot?

Celimax The Vita-A Retinol Shot Tightening Serum is a 30 mL Korean retinol serum formulated with pure retinol, A-Shot™ micro-particle technology and a peptide complex.

It targets visible pores, wrinkles, firmness and uneven-looking texture.

What is Celimax Retinal Shot?

Celimax The Vita-A Retinal Shot Tightening Booster is a concentrated 15 mL treatment containing 0.1% retinal and Celimax's A-Shot™ technology.

It is designed for more intensive wrinkle, pore and elasticity care.

What's the difference between Celimax Retinol Shot and Retinal Shot?

The biggest difference is the vitamin A form.

Retinol Shot → retinol

Retinal Shot → 0.1% retinal

The Retinol Serum is the more logical starting point, while the Retinal Booster provides a more intensive treatment.

Is Celimax Retinal Shot stronger than Retinol Shot?

The Retinal Shot should generally be considered the more advanced option because it contains 0.1% retinal, which sits one conversion step closer to retinoic acid than retinol.

Which Celimax Retinol should beginners use?

Start with the Retinol Shot Tightening Serum rather than immediately combining both products.

Celimax recommends using the Retinol Serum for approximately two weeks before adding the Retinal Booster when using the pair.

Can I use Celimax Retinol Shot and Retinal Shot together?

Yes.

Celimax specifically promotes them together as THE VITA-A SET.

However, establish tolerance with the Retinol Shot first.

Which one do I apply first?

If using both as directed within a routine, the Retinol Shot is the serum step, while the Retinal Shot Booster is used later as a concentrated treatment.

Why does Celimax Retinol Shot tingle?

Both products use A-Shot™ micro-particle technology.

Celimax says these microscopic particles can produce a prickling sensation during application.

Is the tingling normal?

Some temporary prickling can be expected.

Persistent burning, severe redness or significant irritation should not be ignored.

Does Celimax Retinal Shot contain 0.1% retinal?

Yes.

Celimax currently states that the Retinal Shot Booster contains 0.1% retinal.

Is retinal better than retinol?

Not automatically.

Retinal is one conversion step closer to retinoic acid, but the best product is one your skin can use consistently without excessive irritation.

Does Celimax Retinol help pores?

Celimax specifically tested its Retinol Shot Serum for changes in pore number, depth, area and volume.

The brand also tested the Retinol + Retinal combination for pore-related improvements.

Individual results vary.

Does Celimax Retinol help wrinkles?

Wrinkle appearance is one of the primary concerns targeted by the Vita-A line.

Celimax conducted human application testing involving forehead, eye-area and nasolabial wrinkles with the Retinol Shot Serum.

Does Celimax Retinal help acne?

The Retinal Shot is primarily marketed around wrinkles, pores, firmness and elasticity rather than as an acne treatment.

People with acne-prone skin may still use retinoid skincare, but this cosmetic product should not be presented as a medical acne treatment.

Can I use Celimax Retinol every day?

Potentially, after your skin has adapted.

You do not need daily use to have a successful retinoid routine.

Can I use Celimax Retinal every day?

Build tolerance gradually rather than immediately using 0.1% retinal every night.

Can I use Celimax Retinol in the morning?

Evening use is preferable for the Vita-A routine.

If using retinoid skincare, daily sun protection is essential.

Can I use Celimax Retinal with vitamin C?

Celimax advises against using its Retinal Shot simultaneously with high-concentration vitamin C.

Consider vitamin C in the morning and retinal at night.

Can I use Celimax Retinal with AHA or BHA?

Celimax advises against simultaneous use with exfoliating ingredients.

Alternating nights is a more conservative strategy.

Can I use Celimax Retinal with niacinamide?

Niacinamide can generally complement a retinoid routine.

Can I use Celimax Retinal with peptides?

Yes. Peptide-focused skincare can complement a routine centered on firmness and wrinkles.

Can I use Celimax Retinal with PDRN?

These ingredients can potentially exist within the same routine, with PDRN skincare serving more of a hydration and recovery-focused role.

Can I use Celimax Retinal while pregnant?

Celimax does not recommend its Retinal Shot during pregnancy or breastfeeding.

Is Celimax Retinal Shot good for beginners?

For someone completely new to vitamin A skincare, we'd start with the Retinol Shot Serum and build tolerance rather than jumping directly into the 0.1% Retinal Booster.

Celimax Retinol Shot vs Retinal Shot: Which One Should You Buy?

Here's the simplest answer.

Choose Celimax Retinol Shot Tightening Serum if:

• You're newer to retinoids

• You want a full-face serum

• Visible pores are a concern

• You're noticing early fine lines

• You want firmer-looking skin

• You want to build retinoid tolerance

• You eventually want to use the full Vita-A routine

Choose Celimax Retinal Shot Tightening Booster if:

• You already use retinol

• You want 0.1% retinal

• Wrinkles are a stronger concern

• You're focused on elasticity

• You want a more intensive treatment

• Your skin already tolerates retinoids

Consider both if:

• You're an experienced retinoid user

• Your skin tolerates the Retinol Shot

• You want Celimax's complete Vita-A routine

• You're willing to introduce the products gradually

Final Verdict: Retinol Shot or Retinal Shot?

Don't choose solely based on which ingredient sounds stronger.

The smartest progression is:

NEW TO RETINOIDS

↓

Celimax Retinol Shot Tightening Serum

↓

Build tolerance

↓

Celimax Retinal Shot Tightening Booster

↓

Use the two strategically if your skin tolerates them

Celimax itself recommends approximately two weeks of Retinol Shot use before introducing the Retinal Shot when combining the pair.

That's an important point because one of the biggest mistakes with retinoids is trying to get results faster by immediately using the strongest possible routine.

With vitamin A skincare:

more irritation does not equal better results.

The Retinol Shot is the more approachable everyday treatment.

The 0.1% Retinal Shot is the more intensive step.

And together, they create one of Celimax's most interesting routines for people focused on:

pores + wrinkles + firmness + skin texture + elasticity.

Where to Buy Celimax Retinol Shot & Retinal Shot in Canada

Canadian shoppers can shop Celimax The Vita-A Retinol Shot Tightening Serum and Celimax The Vita-A Retinal Shot Tightening Booster through THEKSHOP.ca.

When choosing between them, don't automatically reach for retinal because it's the more advanced vitamin A form.

For beginners:

Start with Retinol Shot.

For experienced retinoid users:

Consider Retinal Shot.

For people who want the complete Celimax Vita-A routine:

Build tolerance first, then consider using both.

And whichever option you choose, pair your nighttime vitamin A routine with daily sunscreen.