Retinol and retinal — when to start, and how

The family

One ingredient wearing several names.

Retinoid is the family name for vitamin A and its derivatives. Skin can only use one member of that family directly. Everything else has to be converted inside the skin first, and every conversion loses some of what you applied.

So the products on a shelf are not different ingredients. They are the same one at different distances from being usable. Retinyl esters are furthest away. Retinol is closer. Retinaldehyde — usually sold as retinal, one letter apart and endlessly confused with the other — is closer again. The prescription end of the family needs no conversion at all, which is exactly why it needs a prescription.

What it does is speed up how quickly skin turns over its surface cells and, over much longer, change how the deeper layers behave. It is among the most studied ingredients in skincare. It is also slow, drying at the start, and degraded by light, which is why it is used at night and sold in opaque packaging.

The ladder

Four rungs, and where the real jump is.

Weakest at the top, strongest at the bottom. The gap between the last two rungs is far larger than between the first three.

Retinyl esters: Retinyl palmitate, retinyl propionate and their relatives. Several conversions away from usable, so the weakest of the group by a wide margin. They turn up in moisturisers and in products marketed as gentle. Often there is vitamin A on the label and very little happening on the skin.
Retinol: Two conversions away, and the standard over-the-counter form. Most of the evidence people cite about vitamin A comes from studies of retinol or of the prescription end, not of the esters. Sold roughly between 0.1% and 1%, and the top of that range is where most people get into trouble rather than where most people get results.
Retinaldehyde · retinal: One conversion away. At the same percentage it is stronger than retinol and generally shows change sooner. It is also less common, more expensive, and less stable, which is why it tends to come in airless packaging. Stronger is the selling point, and stronger is not automatically what you want.
The prescription end of the family: No conversion at all — the skin uses it as applied. These are prescription-only medicines in Australia. A doctor decides whether one is appropriate and at what strength, and there is little a skin clinic or a web page can usefully add. If a GP or dermatologist already has you on one, say so at a consultation. It changes what else belongs in a routine considerably.

Percentages do not compare across rungs. A low-percentage retinal is not weaker than a high-percentage retinol, and comparing the two numbers as if they measured the same thing is the most common mistake in a pharmacy aisle.

Honestly

Most people start too strong.

The usual pattern is not subtle. Someone buys the highest strength on the shelf because it seemed like better value, uses it every night for a fortnight, and ends up tight, flaking and stinging. They push on, because they have read that this part is normal. Then they stop entirely and decide retinol does not suit them.

Usually it was the entry point, not the ingredient. A lower strength used consistently for a year does more than a high one used aggressively for three weeks and then abandoned. The waste is the money on the strong bottle and the year that could have been running underneath it.

There is a real distinction underneath all of this, and it has a name.

Retinisation: The adjustment period skin goes through when a retinoid is introduced. Typically dryness, fine flaking around the nose and mouth, a feeling of tightness, and some pinkness. It generally arrives in the first fortnight, is most obvious somewhere in the first month or two, and settles as skin adapts. It is expected rather than a sign something is wrong.
A reaction: Different in kind rather than degree. Burning that does not settle, swelling, weeping or crusting, intense itch, or redness spreading beyond where the product was applied. That is not an adjustment period and pushing through it is not resilience. Stop, and have it looked at — by a GP if it is marked or spreading.
And the part a page cannot do: Tell you which of the two you are having. That needs someone looking at your skin, knowing what else is on it and what it was doing beforehand. Anyone sorting this out for you over the internet is guessing, including us.

Time

Months, not weeks.

Surface texture is usually the first thing anyone notices, and that tends to be a matter of weeks. Everything else is slower. The research people quote about vitamin A generally runs from twelve weeks to a year, and the change accumulates across that period rather than arriving at the end of it.

Skin varies considerably and none of this is certain. Some people see a clear difference. Some see very little and are better served by attention elsewhere. Age, sun history, the rest of the routine and how consistently it is actually used all change the answer, and none of that is knowable from a page.

On frequency, the general shape is low and infrequent to begin with, then built up only as skin tolerates it. Every night is not the target for everyone and more often is not automatically better — irritated skin does not turn over usefully, it just repairs. What matters is whether you are still using it in a year.

Two things travel with it regardless. Retinoids are broken down by light, so they are used at night. And they increase sun sensitivity, which makes daily sunscreen part of the decision rather than an optional extra alongside it.

What to pair it with is where most home routines come undone, and that genuinely depends on your skin and what it has been through recently. It is a conversation with a nurse, not a rule we can print.

When not

Set aside, and not yet needed.

The whole family is set aside during pregnancy — from the weakest over-the-counter ester through to anything a doctor prescribes. That is not a judgement call made on the day. If you have been using one and have just found out you are pregnant, stop and raise it with your GP or midwife rather than searching for reassurance. It is a common situation and it is theirs to advise on. There is more on what changes in skin in pregnancy.

Breastfeeding is a separate question, and also one for your GP rather than for us.

And if you are in your twenties with skin that is behaving, you probably do not need this yet. Retinol is not a head start you bank. Starting a decade early has no established payoff, and what it commonly buys is an irritated barrier and a drawer of half-used bottles. Daily sunscreen and not over-exfoliating do more for most people at that age than anything on this page.

If you are already using one and it suits you, that is a good reason to keep going and a poor reason to move up a rung. The next rung up is a decision about a problem, not a promotion.

Questions

Asked about retinol.

Answered the way they would be answered in the room.

What is the difference between retinol and retinal?

Both are vitamin A, at different distances from the form skin can use. Retinal, short for retinaldehyde, is one conversion step away. Retinol is two. That makes retinal stronger at the same percentage and generally faster to show change, and it is usually the more expensive and less stable of the two. The one-letter difference in the names is genuinely confusing, and plenty of people buy one believing they bought the other.

Is retinal better than retinol?

Stronger, not better. Whether stronger is what you want depends on how your skin has handled vitamin A before, what else you are using, and how reactive your skin is generally. For someone who has never used a retinoid, the stronger option is the more likely one to be abandoned in the first month. For someone who has used retinol steadily for a year without much happening, it may be the sensible next question. Percentages do not compare across the two.

When should I start using retinol?

There is no age at which it becomes necessary. For most people in their twenties with skin that is behaving, the honest answer is not yet, and daily sunscreen does more. The usual reason to start is a specific thing you want to change in texture, congestion or tone, rather than a birthday. Starting earlier does not bank anything, and the common cost of starting too early is an irritated barrier and money spent on bottles that get abandoned.

How often should a beginner use retinol?

The general shape is low strength, a few nights a week, built up only as skin tolerates it. Every night is not the target for everyone. The most common beginner mistake is the opposite approach: the strongest bottle on the shelf, used nightly, abandoned inside a month. What suits you specifically depends on what else is in your routine and what your skin has been through recently, and that is what an assessment is for.

How long does retinol take to work?

Months rather than weeks. Surface texture is often the first thing people notice and that can be a matter of weeks. Everything else is slower, and the research usually quoted runs from twelve weeks to a year. Skin varies considerably, so some people see a clear difference and some see very little. If nothing at all has changed after several consistent months, the useful question is whether vitamin A was the right thing to be spending the effort on.

Is my skin purging or reacting to retinol?

The adjustment period is called retinisation. It usually looks like dryness, fine flaking, tightness and some pinkness, arriving early and settling as skin adapts. A reaction is different in kind: burning that does not settle, swelling, weeping, intense itch, or redness spreading beyond where you applied it. Pushing through that is not resilience. Which of the two you are having is not something a page can decide, and marked or spreading reactions go to a GP.

Can I use retinol while pregnant?

No. The whole vitamin A family is set aside for the duration of a pregnancy, from the weakest over-the-counter form through to anything a doctor prescribes. That is a firm position rather than a judgement made on the day. If you have been using one and have only just found out you are pregnant, stop and raise it with your GP or midwife rather than searching for reassurance. Breastfeeding is a separate question, and also one for your doctor.

Where this leads