Retinal

Why it is here

One conversion step away from retinoic acid, which is why it acts faster than retinol. The rare active where the interesting version and the evidenced version are the same molecule.

Topical vitamin A has to become retinoic acid before it does anything, and each conversion step loses material. Retinol converts to retinal, then retinal converts to retinoic acid. Starting one step later shortens the chain. In human skin, retinaldehyde induces cellular retinoic acid binding protein type 2 and increases epidermal thickness and proliferation markers in a dose-dependent way, which is the biochemical signature of a working retinoid.

The receipts

1. At week 18 both 0.05 percent retinaldehyde and 0.05 percent retinoic acid significantly reduced wrinkle and roughness features by optical profilometry, with no significant change in the vehicle group; retinaldehyde was well tolerated throughout while retinoic acid caused more local irritation and affected compliance.

   Profilometric evaluation of photodamage after topical retinaldehyde and retinoic acid treatment. Journal of the American Academy of Dermatology, 1998. RCT, n = 125 patients (40 retinoic acid, 40 retinaldehyde, 45 vehicle). PMID 9843009

2. Over 24 weeks both concentrations significantly increased dermal density by high-frequency ultrasonography and improved elasticity by cutometry, with wrinkle reduction on Antera 3D imaging particularly at 0.1 percent, and minimal adverse effects reported.

   Comparative evaluation of topical stabilized retinaldehyde 0.1% vs. 0.05% on skin biophysical and biomechanical parameters. Skin Research and Technology, 2026. split-face, n = 56 women aged 30 to 58. PMID 41729119

3. Retinaldehyde produced dose-dependent increases in epidermal thickness, keratin 14 and Ki67-positive cells; the 1 percent preparation was tolerated by up to 70 percent of subjects, while 0.1 percent and 0.05 percent on facial skin were well tolerated and allowed prolonged use for up to three years.

   Topical retinaldehyde on human skin: biologic effects and tolerance. Journal of Investigative Dermatology, 1994. cohort, n = 229 patients across the tolerance studies. PMID 7798613

In practice

Typical use

0.05 to 0.1 percent. Coming of Age uses 0.1 percent, the higher of the two levels compared head to head in the 2026 split-face study and the level with the more pronounced wrinkle result there. Start two or three nights a week and build up.

Pairs with

Squalane, Niacinamide, Ceramides, Palmitoyl Pentapeptide-4

Keep apart from

l-ascorbic-acid in the same routine step: no chemical catastrophe, but a pH 3 serum and a retinoid on the same skin at the same time is how people talk themselves out of using either. Vitamin C morning, retinal night.. Strong exfoliating acids and benzoyl peroxide on the same night: compounding irritation with no evidence of compounding benefit. Alternate nights.. Pregnancy: topical retinoids are conventionally avoided during pregnancy and breastfeeding. This is a precaution, not a demonstrated harm at cosmetic levels, and it is your doctor's call, not ours.

Cautions

Expect dryness, flaking and some redness in the first few weeks. Retinoids increase photosensitivity, so daily sunscreen is not optional. Avoid during pregnancy and breastfeeding by convention. Retinal degrades in light and air, so packaging matters more than it does for most ingredients.

Questions people ask