THE SKIN EDIT · INGREDIENT FOCUS
Retinol vs Retinal vs Retinoid vs Tretinoin: What the Strengths Actually Mean
Retinol, retinal, retinoid, tretinoin. The names sound similar enough that they are often used interchangeably, but they are not the same thing.
The percentages make the comparison even more confusing. A 1% retinol is not automatically stronger than a 0.025% tretinoin, because they are different molecules and the skin processes them differently.
The mistake I see most often is choosing the highest number and assuming it will deliver the best result. With retinoids, the best strength is the one that is appropriate for your skin and that you can use consistently.
What is the difference between retinol, retinal, a retinoid and tretinoin?
Retinoid is the umbrella term for a family of vitamin A compounds. Retinyl palmitate, retinol, retinal and tretinoin are all retinoids, but they differ in how much conversion they require before the skin can use them as retinoic acid.
The simplest way to understand the relationship is:
- Retinyl palmitate → Retinol → Retinal → Retinoic acid
Tretinoin is retinoic acid, so it is already in the biologically active form. Retinal, also called retinaldehyde, is one conversion step away. Retinol is two steps away, while retinyl palmitate requires further conversion.
Those conversion steps vary from person to person. The formulation also affects how stable the ingredient remains, how effectively it reaches the skin and how well it is tolerated.
This is why the percentages cannot be compared directly. A 1% retinol is not forty times stronger than a 0.025% tretinoin. They are different ingredients with different levels of biological activity.
Retinol, retinal and retinyl palmitate are commonly found in cosmetic skincare and available over the counter. Tretinoin, by contrast, is a prescription only medicine in the UK.
What does the percentage on a retinol product actually mean?
The percentage tells you how much of that particular ingredient is present in the formulation. It does not place every retinoid on one universal strength scale, and it tells you nothing about stability, delivery or how your skin will tolerate it.
A percentage also tells you nothing about:
- How stable the ingredient remains in its packaging
- How effectively the formulation delivers it into the skin
- Which supporting ingredients are included
- How frequently the product is used
- How well your skin tolerates it
- Whether the finished product has been clinically tested
Two retinol products containing the same percentage may therefore behave very differently.
Packaging matters too. Retinol is unstable when exposed to light and air, so an opaque, air limiting container is generally preferable to a clear jar that is repeatedly opened.
Is a stronger retinoid always better?
No. A stronger retinoid may cause more irritation without producing a meaningfully better result for every patient. The objective is not to use the strongest product possible. It is to use an effective retinoid consistently.
In one 48 week study of photoaged skin, 0.025% and 0.1% tretinoin produced similar improvements, while the higher concentration caused significantly more redness and scaling. This does not mean there is never a reason to prescribe above 0.025%. It shows that increasing the concentration does not automatically guarantee a better long term result. Reference.
The appropriate strength depends on what is being treated, the formulation, previous retinoid use and how the skin responds. Some patients may benefit from a higher concentration, while others achieve excellent results at a lower strength.
Redness, burning and peeling are not proof that a retinoid is working. A lower strength used consistently may achieve more than a stronger product that repeatedly causes inflammation and has to be stopped.
The better question is not, "Which retinoid is strongest?" It is, "Which strength is appropriate for my concern and sustainable for my skin?"
What strength of retinoid should a beginner start on?
I do not choose a starting retinoid from the percentage alone. I look at the person’s skin, sensitivity, current routine, previous retinoid use and what we are actually trying to treat.
Someone with sensitive skin, rosacea, eczema, a disrupted barrier or no previous retinoid experience needs a more cautious starting point. Someone who already tolerates a well formulated retinal or retinol may be able to begin differently.
Frequency matters as much as concentration. I would generally rather start with a lower strength used consistently, then increase the strength gradually if needed and well tolerated, than begin too aggressively and cause dermatitis.
For a cosmetic retinoid, starting twice a week is often reasonable. If the skin remains comfortable, the frequency can be increased gradually. A prescription retinoid should be used according to the instructions provided by the prescriber.
I would not routinely start someone who has never used a retinoid on the highest available concentration of tretinoin. A high percentage is not an achievement, and peeling is not the aim.
There is no fixed timetable for stepping up. I increase frequency or strength when the skin is comfortable, not simply because a certain number of weeks has passed. Change one variable at a time so that you know what the skin is responding to.
How should you apply a retinoid?
Use a small amount on clean, dry skin at night and introduce it gradually. Applying more product will not make the long term result arrive faster, but it can make irritation more likely.
For many facial retinoids, a pea sized amount is enough for the whole face. However, follow the directions supplied with your specific product or prescription.
Avoid applying it to broken or inflamed skin. Be cautious around the eyelids, corners of the nose and corners of the mouth, where irritation is more common.
Keep the rest of the routine simple. Use a plain, ceramide rich moisturiser, a hydrating serum if needed and avoid layering exfoliating acids with your retinoid on the same evening when you are starting or if your skin is sensitive.
Apply a broad spectrum SPF every morning. Retinoids help address some visible effects of photoageing, but they do not prevent ultraviolet damage or replace sunscreen.
How long does a retinoid take to work?
Retinoids work in months rather than days. Acne and texture may begin to improve over approximately eight to twelve weeks, while pigmentation, fine lines and photoageing generally take several months. The first few weeks are mainly about establishing tolerance.
At four weeks, I am not expecting a transformation. I am looking at whether the patient can use the product consistently without significant irritation. Some people notice early changes in oiliness, congestion or texture, but it is too soon to judge the final result.
By twelve weeks, I would hope to see early improvement in the concern being treated, particularly acne, blocked pores or uneven texture.
At six months, changes in pigmentation, fine lines and overall photoageing are easier to assess. Collagen remodelling is gradual, which is why consistency matters more than chasing quick peeling.
If there is no meaningful improvement after an adequate trial, it is often best to reassess the diagnosis, adherence, formulation, application and surrounding routine, rather than simply keep increasing the strength.
Sometimes the retinoid is not the problem. Sometimes it was never the right treatment for the concern in the first place.
What is retinisation, and how long does it last?
Retinisation is the adjustment period that can occur when the skin is introduced to a retinoid. Mild dryness, tightness or flaking may develop during the first few weeks, but significant burning, swelling or cracking is not a normal goal.
Retinisation is not inevitable and should not be treated as proof that a product is effective. Starting gradually and supporting the skin barrier can make the process much more manageable.
Mild flaking that improves with moisturiser and less frequent application is different from a reaction that is painful, intensely red, swollen, blistered, crusted or persistently worsening. Those are reasons to stop and seek advice.
What to do if irritation develops
- Reduce the frequency or pause temporarily
- Stop exfoliating acids, scrubs and other irritating products
- Use a plain moisturiser and gentle cleanser
- Do not apply the retinoid to broken or inflamed skin
- Contact your prescriber if the product was prescribed
A moisturiser sandwich can also help temporarily. This means applying moisturiser, then the retinoid, followed by another layer of moisturiser once the retinoid has settled.
If you need to rely on sandwiching indefinitely, the strength, formulation or frequency may need reviewing.
Is peeling part of the retinoid process?
Some mild dryness or flaking can occur when starting a retinoid, but significant peeling, soreness or inflammation is not a desirable endpoint and does not mean the treatment is working better.
Irritation can impair the skin barrier and make the routine harder to continue. In skin that is prone to pigmentation, inflammation may also make uneven pigmentation worse.
The term "purging" is overused too. Acne can temporarily appear worse when an effective acne treatment is introduced, but not every breakout is a purge.
A new rash, persistent burning, marked redness or breakouts in unusual areas may indicate irritation or an unsuitable product rather than a necessary adjustment phase.
Do you need a prescription for tretinoin in the UK?
Yes. Retinol, retinal and retinyl esters are commonly available in cosmetic skincare, but tretinoin is a prescription only medicine in the UK and should be prescribed after an appropriate assessment.
Prescription treatment may be useful when there is a clear clinical indication, such as acne or photoageing, and cosmetic products have not provided enough benefit. It also allows the strength, formulation and surrounding routine to be selected and adjusted more precisely.
Prescription does not automatically mean better for everyone. Someone doing well with a cosmetic retinal or retinol does not need to move to tretinoin simply because it is more direct.
Tretinoin can cause significant irritation and is not appropriate for everyone. Medical history, skin conditions, pregnancy plans, current products and previous reactions all need to be considered.
Why should you not buy tretinoin online without a prescription?
Buying prescription strength tretinoin from an unregulated overseas website removes the assessment and follow up that make prescribing safer. You may not know whether the product is genuine, stable, correctly labelled or appropriate for your skin.
Possible problems include:
- Counterfeit or incorrectly labelled products
- Poor storage during manufacture or delivery
- A concentration different from the one advertised
- No assessment of pregnancy or pregnancy plans
- No review of skin conditions, medication or other active products
- No support if a significant reaction develops
A prescription is not simply permission to buy a stronger cream. It is a clinical decision about whether the treatment is suitable and how it should be used safely.
Who should not use a retinoid?
Topical retinoids should not be used during pregnancy or while planning a pregnancy. This includes prescription tretinoin and cosmetic vitamin A derivatives such as retinol and retinal.
Absorption from topical products is low, but UK guidance recommends avoiding topical retinoids during pregnancy as a precaution because risk cannot be completely excluded.
If you become pregnant while using a topical retinoid, stop using it and speak to your doctor or prescriber. Do not panic, but do ask for individual advice.
When treatment may need to be avoided, postponed or modified
- You have an allergy to the product or one of its ingredients
- You have active eczema, dermatitis or significantly broken skin
- You are experiencing a severe rosacea flare
- Your skin barrier is markedly compromised
- You have previously had a significant reaction to a retinoid
- You have an upcoming or recent procedure and the treating clinician has advised a pause
Sensitive skin, rosacea and eczema do not always rule retinoids out permanently, but they change how cautiously I approach them. The barrier should be settled first, and a lower strength, different formulation or less frequent application may be needed.
If you are breastfeeding, discuss the specific product and treatment area with an appropriate healthcare professional before use.
Should you stop using your retinoid before a facial treatment or procedure?
Sometimes, but there is no universal stopping period for every treatment. The advice depends on the procedure, the retinoid and the condition of your skin.
Peels, laser treatments, microneedling, waxing and other procedures can irritate the skin. Continuing a retinoid too close to some treatments may increase sensitivity and interfere with recovery.
Follow the instructions of the clinician performing the procedure. Tell them exactly which product you use, how often you apply it and whether the skin is already irritated.
Do not assume that every treatment requires the same pause before and after.
What do I prescribe, and why?
When prescription treatment is appropriate, I prefer being able to select the strength, formulation and surrounding routine for the individual rather than giving everyone the same product at the same concentration.
A single active ingredient may be appropriate when the treatment goal is straightforward. A bespoke compounded formula can earn its place when carefully selected ingredients allow us to address several connected concerns while keeping the routine manageable.
The advantage is not that compounded automatically means stronger or better. It is that the prescription can be tailored to the patient’s skin, concern, tolerance and treatment history and then adjusted as the skin changes.
What I think is overhyped is the pursuit of the highest possible percentage. I also see too much emphasis on peeling, as though irritation proves potency.
The objective is not to make the skin shed. It is to achieve a useful clinical result while keeping the barrier healthy enough for consistent treatment.
I only provide prescription treatment after an appropriate consultation and individual assessment at my clinic in central London.
Which retinoid should you choose?
Start with the concern rather than the percentage. Your skin type, sensitivity, acne history, pigmentation, current routine, pregnancy plans and previous response to retinoids matter more than choosing the largest number on the label.
Retinol may suit someone introducing a cosmetic vitamin A product who wants a gradual and potentially more tolerable starting point.
Retinal may suit someone looking for a more direct cosmetic retinoid while remaining outside prescription treatment.
Tretinoin may be appropriate when there is a clear clinical indication and the patient has been individually assessed, understands the risks and can be monitored appropriately.
Retinyl palmitate is a gentler vitamin A derivative found in some cosmetic products, but it requires more conversion and generally has less convincing clinical evidence than tretinoin.
The strongest option is not automatically the smartest one.
Retinyl palmitate, retinol, retinal and tretinoin at a glance
| Retinyl palmitate | Retinol | Retinal | Tretinoin | |
|---|---|---|---|---|
| What it is | Cosmetic vitamin A derivative | Cosmetic vitamin A derivative | Cosmetic vitamin A derivative | Prescription only retinoic acid |
| Conversion required | Several steps | Two steps | One step | None |
| Evidence | Limited for visible photoageing | Varies by finished product | Promising but less extensive | Most established for acne and photoageing |
| Tolerability | Generally considered gentle | Often easier to introduce | Varies by strength and formulation | More likely to cause irritation |
| Important point | Usually not directly comparable with stronger retinoids | Formulation and packaging matter | Fewer conversion steps do not guarantee a better product | Higher concentration is not automatically better |
These are broad comparisons rather than guarantees. The formulation, frequency and individual skin response all affect the result.
Where to find us
I see patients at 120 Pall Mall, St James’s, central London SW1Y 5EA, a short walk from Piccadilly Circus, Green Park and Charing Cross.
Patients come to me from across London, throughout the UK and internationally. I build prescription skincare plans around what your skin actually needs rather than a fixed list of products.
Frequently asked questions
Is retinol the same as a retinoid?
Retinol is a retinoid, but not every retinoid is retinol. Retinoid is the umbrella term for the wider family of vitamin A compounds, which includes retinyl palmitate, retinol, retinal and tretinoin.
Is tretinoin stronger than retinol?
Tretinoin is more direct because it is already retinoic acid, the active form, while retinol requires two conversion steps in the skin. Their percentages cannot be compared directly, and the most appropriate option depends on the individual.
Is retinal stronger than retinol?
Retinal is one conversion step from retinoic acid, while retinol is two. This makes retinal more direct in the conversion pathway, but the finished formulation, concentration and stability still determine how a product performs.
Is 1% retinol stronger than 0.025% tretinoin?
The percentages cannot be compared directly because retinol and tretinoin are different molecules. Tretinoin is already biologically active, while retinol must undergo two conversion steps before becoming retinoic acid.
What strength of retinol should a beginner use?
There is no single ideal beginner strength because products containing the same percentage may be formulated differently. Start with a reputable product, introduce it gradually and increase only if the skin remains comfortable.
How long does retinisation last?
Mild dryness or flaking may occur during the first few weeks. It should gradually improve as the skin adapts. Persistent burning, marked redness, swelling, cracking or worsening irritation is not normal retinisation and should be reviewed.
Can you use vitamin C with a retinoid?
Yes, but sensitive skin may not tolerate both in the same routine. I generally place vitamin C in the morning and the retinoid in the evening to keep the routine simple and reduce the risk of irritation.
Is tretinoin available over the counter in the UK?
No. Tretinoin is a prescription only medicine in the UK and should be prescribed after an appropriate assessment. Retinol, retinal and retinyl esters are commonly available in cosmetic skincare without a prescription.
Where is Dr Nabil Jetha’s clinic?
My clinic is at 120 Pall Mall, St James’s, London SW1Y 5EA, in central London. It is a short walk from Piccadilly Circus, Green Park and Charing Cross, and patients come to me from across London, throughout the UK and internationally.
Who is Dr Nabil Jetha?
I am Dr Nabil Jetha, MBBS, BSc (Hons), PGDip (Aesthetics), GMC 7751313, and I practise aesthetic and skin medicine at 120 Pall Mall, St James’s, central London.
You can check my registration on the GMC medical register using reference number 7751313.
If you are unsure which form of vitamin A suits your skin, arrange a consultation and we will start with your concern, tolerance and current routine rather than the percentage on the label.
This article provides general information only and is not a substitute for individual medical advice. Prescription skincare is recommended only after an appropriate consultation and assessment.
Written and edited by Dr Nabil Jetha and his clinic team. Dr Nabil Jetha, MBBS, BSc (Hons), PGDip (Aesthetics), GMC 7751313. Last reviewed October 2026.