Retinaldehyde after fifty: what the studies actually measured

Retinaldehyde after fifty: what the studies actually measured

The short version

  • Retinaldehyde, or retinal, is vitamin A sold without a prescription. Measured changes are modest: skin texture moved about 12 to 13 per cent over three months.
  • Its strongest suit is comfort, not power. It irritates less than prescription retinoic acid, on small numbers.
  • No trial we found establishes that retinal is ten times stronger than retinol. One 23 person split face study favoured it (Kim, 2021).
  • A 2021 review found the positive trials on over the counter vitamin A should not inform clinical decisions and work better as advertising (Spierings, 2021).
  • Most trials publish no age range, and the nearest evidence in old skin used retinol, on forearms (Kafi, 2007). We sell some of these products.

The trial that made the reputation

In 1998, 125 people with facial photodamage used 0.05 per cent retinaldehyde cream, 0.05 per cent retinoic acid cream, or the cream base alone.

Both actives reduced wrinkle and roughness measures at week 18, less so at week 44. The 45 person vehicle group showed no significant change (Creidi, 1998). That inactive arm is what makes it worth reading.

The abstract reports no head to head test against retinoic acid, so we will not say retinaldehyde matched it. It carries no funding statement, and a co-author is listed at the Pierre Fabre Research Institute on another retinaldehyde paper (Vienne, 1999). Pierre Fabre sells retinaldehyde.

Retinal against retinol

The ten times more potent line even appears in papers that never measured it. What exists is one eight week comparison: 23 Korean volunteers used retinaldehyde on one side of the face and retinol on the other.

Both sides improved, the retinaldehyde side more on the objective measures apart from dermal density (Kim, 2021). No inactive arm, and the delivery system was part of what was tested. A direction, not a multiple.

How far the measurements move

In 2018, 40 Korean women used 0.1 or 0.05 per cent retinaldehyde cream twice daily for three months (Kwon, 2018).

  • Texture improved 13.7 and 12.6 per cent
  • Barrier water loss fell 14.5 and 17.9 per cent, hydration rose 10.2 and 6.0 per cent
  • Only 0.1 per cent moved the melanin index, by 6.5 per cent
  • No significant difference between the concentrations

Both arms were active, so that is change over three months of use, not the ingredient on its own. No age range is given.

What matters if you are over fifty

Almost none of these trials were run in older skin. The nearest useful evidence changes both ingredient and body part.

36 residents of senior citizens' facilities, mean age 87, had 0.4 per cent retinol lotion on one forearm and vehicle on the other for 24 weeks. Fine wrinkling improved on the retinol arm and barely moved on the other, with the biochemistry from biopsy subgroups of six and four people (Kafi, 2007).

Retinol, not retinaldehyde. Forearm, not face. It does establish that skin in its eighties still responds to a topical retinoid.

The mechanism is smaller than it sounds

Retinaldehyde is said to convert inside the skin into retinoic acid. Cultured keratinocytes did that, but in live animals most went into retinyl esters, a storage form, delivering little retinoic acid (Sorg, 1999).

Collagen has genuinely been measured, in human skin explants given UVA damage then two weeks of 0.05 per cent retinaldehyde cream, after which collagen and elastic fibres matched unexposed skin (Boisnic, 1999). That is skin in a dish, with no blood supply. Both come from a 1999 supplement on retinaldehyde, and neither carries a funding statement.

The least flattering paper

A 2021 systematic review looked for randomised, double blind, vehicle controlled trials of over the counter vitamin A for facial ageing and found nine. Four showed no significant difference from the vehicle, and the other five gave weak evidence of a mild effect on fine lines only, all with major flaws (Spierings, 2021).

The author declares no conflicts. Those nine are described as retinol products, so we cannot tell you a retinaldehyde trial was among them.

What the tolerance claim rests on

Retinol, retinaldehyde and retinoic acid were compared by patch test and in use over 44 weeks. Retinol and retinaldehyde had equally low irritation potential, and retinoic acid produced redness in 44 per cent, scaling in 35 per cent and burning or itching in 29 per cent in the first four weeks (Fluhr, 1999).

Six people were in the patch test, 355 in the long term arm. The abstract does not give retinaldehyde's own percentages, so we will not quote them.

What to actually do

  • Start at the lower concentration, two or three nights a week, and build up only if your skin stays comfortable.
  • Judge it at three months, not three weeks.
  • Wear sunscreen daily. Every facial trial here enrolled photodamaged skin.
  • Stop if your skin is persistently red, sore or peeling. That is not a sign it is working.
  • Talk to your doctor first if you are pregnant or trying to be, on prescription medication, or have a skin condition under care.

Nothing here treats a condition or changes skin structure in a way you should count on. Bring your products into our Parnell room if you want a second opinion.

The Verdo team

Frequently asked questions

Is retinal really ten times stronger than retinol?
No published trial we could find establishes that ratio. It is repeated in marketing and in the background sections of papers that never measured it. The one direct comparison put retinaldehyde against retinol on opposite sides of the face in 23 people for eight weeks, and the retinaldehyde side did better on the objective measures apart from dermal density, which is a direction rather than a multiple.
Will it do anything on skin in its sixties or seventies?
The retinaldehyde trials mostly publish no age range, so we cannot answer that from them. The nearest evidence used retinol on the forearms of 36 people with a mean age of 87, where fine wrinkling improved against a vehicle treated arm over 24 weeks. That shows older skin still responds to a topical retinoid, not what retinaldehyde will do to your face.
Should I use this or ask my doctor for prescription retinoic acid?
That is a decision for your doctor, not for a skincare page. What the comparison data shows is a tolerance difference: over 44 weeks in 355 people, retinoic acid produced redness in 44 per cent, scaling in 35 per cent and burning or itching in 29 per cent during the first four weeks, and retinaldehyde was described as better tolerated. Tolerance matters because a product you abandon does nothing.
How long before I see anything?
Judge it at three months, not three weeks. The published trials ran from eight weeks to forty four weeks, and texture measures moved by around 12 to 13 per cent over three months in the two concentration trial. In the longest study the measured reduction was more pronounced at week 18 than at week 44.
Does it rebuild collagen?
Collagen has genuinely been measured with retinaldehyde, but in human skin explants kept alive in organ culture rather than on anyone's face. Those samples had UVA damage induced, then two weeks of 0.05 per cent cream, after which collagen and elastic fibres matched unexposed skin. That is skin in a dish with no blood supply, and nothing we sell is intended to change skin structure.
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