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Ingredient Beauty Benefits

Skin concerns

Wrinkles

Photoageing and loss of elasticity.

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What it is

Folds that stay in the skin. Lines that appear only when you make an expression and lines that stay at rest are different things.

Why it happens

Collagen in the dermis declines with age, expression muscles fold the same spot over and over on top of that, and ultraviolet light speeds the whole process up.

Where to start

Korea lists only four actives for wrinkle claims — retinol, retinyl palmitate, adenosine and polyethoxylated retinamide. Peptides are not on that list.

There are no numbers and no citations in this box. What has been established, and how far, is below.

For wrinkles, Korea has a fixed list. The functional-cosmetics rule (Annex 4) notifies only four wrinkle actives: retinol (2,500 IU/g), retinyl palmitate (10,000 IU/g), adenosine (0.04%) and polyethoxylated retinamide (0.05–0.2%).

No peptide is on that list. That is not a ban; it means a company must submit data and pass review to carry a functional claim.

Read the concentrations alongside. On the palmitoyl pentapeptide-4 page, the concentration with evidence behind it is 3 ppm — 0.0003%. It is a number that makes 'high concentration' on a label worth rereading.

Evidence level
Strong evidenceUV filter

Sunscreen

An ingredient class — not a single line on an ingredient list

An Australian trial randomised 1,621 people and followed them 4.5 years. Squamous cell tumour incidence was 39% lower (1,115 vs 1,832 per 100,000); basal cell carcinoma showed no difference. This is one of the few entries on this site carrying strong evidence.

Moderate evidenceRetinoid⚠ In pregnancy Do not use

Retinol

Retinol

In a vehicle-controlled trial, 0.4% retinol applied for 24 weeks moved the fine-wrinkle score by −1.64 against −0.08 for vehicle. Thirty-six people, and it was forearms, not faces. In pregnancy, guidance says do not use it.

Moderate evidenceAntioxidant

Niacinamide

Niacinamide

In a 12-week split-face study of 50 people, 5% niacinamide reduced fine lines, yellowing, red blotchiness and pigmented spots. The control was not nothing but the same moisturiser, and the manufacturer paid for the trial.

Moderate evidenceAntioxidant

Vitamin C (ascorbic acid)

Ascorbic Acid

In pig skin, L-ascorbic acid entered only when formulated below pH 3.5, and 20% was the concentration for optimal absorption. Pure ascorbic acid is not among Korea's listed whitening actives; four of its derivatives are.

Moderate evidenceAntioxidant

Bakuchiol

Bakuchiol

In a 12-week double-blind trial of 44 people, bakuchiol 0.5% and retinol 0.5% reduced wrinkle area and hyperpigmentation to a similar degree, with more irritation on the retinol side. With no vehicle arm, the trial cannot say what the improvement on either side was due to.

Moderate evidenceAcid

Glycolic acid (AHA)

Glycolic Acid

In a 22-week, 74-person, vehicle-controlled double-blind trial, 76% of people using 8% glycolic acid cream improved by at least one grade of photodamage (vehicle: 40%). Thirty years on, we found nothing better for this ingredient. And the same molecule did not protect the skin barrier.

Moderate evidencePeptide

Palmitoyl pentapeptide-4 (Matrixyl)

Palmitoyl Pentapeptide-4

In a 12-week, double-blind, split-face trial in 93 people, a moisturiser containing 3 ppm significantly outperformed the same moisturiser without it for fine lines and wrinkles. Three ppm is 0.0003%. It is a number that makes 'high concentration' on a label worth rereading.

Moderate evidenceAcid

Gluconolactone (PHA)

Gluconolactone

A 1997 trial put four acids side by side and then challenged the skin. Sites treated with gluconolactone lost significantly less barrier function than vehicle, than untreated skin, and than glycolic acid. And the Korean AHA warning text does not apply to this ingredient.

Moderate evidencePeptide

Acetyl hexapeptide-8 (Argireline)

Acetyl Hexapeptide-8

In a 60-person placebo-controlled trial, periorbital wrinkles improved significantly. But the placebo group improved 0%, a figure rarely seen in cosmetic trials. And we found no trial comparing this ingredient directly with botulinum toxin.

Moderate evidenceAcid

Lactic acid

Lactic Acid

In a 1983 trial, a 12% lactate lotion, a 5% lactic acid lotion and a plain emollient all three significantly improved xerosis. The difference emerged one to two weeks after treatment stopped. And in the 1996 photodamage trial it beat vehicle on four forearm measures — more than glycolic acid managed in the same trial.

Moderate evidenceRetinoid⚠ In pregnancy Do not use

Retinaldehyde

Retinal

In a randomised double-blind trial comparing 0.1% and 0.05% creams in 40 Korean women over 13 weeks, there was no statistically significant difference between the two concentrations. Note what the trial lacks: there was no vehicle arm — everyone applied retinaldehyde. A comparison against applying nothing is not here.

Moderate evidenceAntioxidant

Ferulic acid

Ferulic Acid

In two randomised, double-blind, placebo-controlled trials, the side treated with a vitamin C, E and ferulic acid serum did significantly better than the placebo-serum side on wrinkles and elasticity (at 12 weeks, 23.9% versus 6.8%, P < .001). The designs are among the best in this layer. But what was tested was a serum containing three ingredients, and both sides of the face had a procedure first.

Moderate evidenceAntioxidant

Alpha-lipoic acid

Thioctic Acid

One trial: 33 people applied a 5% cream to one half of the face and its vehicle to the other for 12 weeks. Laser profilometry showed roughness falling 50.8% versus 40.7%, a significant difference (P < .001). The 40.7% on the placebo side has to be read alongside it.

Early researchAntioxidant

Resveratrol

Resveratrol

2025 brought the first study to test this as a sole active. A 134-person, 8-week placebo-controlled trial split oral and topical into four combinations, and wrinkle scores fell significantly only in the arm that was active on both. Meanwhile sebum rose significantly in the arms applying the active cream. Nothing else differed.

Early researchAntioxidant

Astaxanthin

Astaxanthin

This is swallowed. In the 2018 trial (23 people, 10 weeks) the threshold for UV redness rose above placebo, but FUJIFILM supplied both the funding and the authors. In the 2014 trial (44 people, 12 weeks) elasticity and water loss improved, but it was given together with collagen hydrolysate. And in that same trial, UV-induced DNA damage did not differ.

Early researchOther

Hexylresorcinol

Hexylresorcinol

The trial on this ingredient has the design this site keeps wishing for — the control was not a vehicle but niacinamide alone. Randomised, double-blind, split-face, over 12 weeks, the combination beat niacinamide alone significantly on pigment spots (L*), fine lines and skin firmness. But all the authors are at the manufacturer's research arm, and the abstract gives no participant count.

Ingredient dataRetinoid

Retinyl palmitate

Retinyl Palmitate

It is one of four actives notified for wrinkle claims in Korea, and at 10,000 IU/g a product may carry that claim without submitting efficacy data of its own. But we found no human trial that measured this ingredient alone. Both trials we opened are mixtures — one blends it with retinol and retinyl acetate, the other puts it in an oil with antioxidants.

Ingredient dataOther

Adenosine

Adenosine

At 0.04% a product can be filed as a wrinkle-improvement functional cosmetic without submitting data. But the only human trial we found in the published literature had 22 participants, and its comparator was not vehicle but another adenosine formulation.

Ingredient dataAntioxidant

Tocopherol (vitamin E)

Tocopherol

In a 1999 double-blind trial that split each surgical scar in half, vitamin E had no effect or actually made things worse in 90% of cases, and 33% developed contact dermatitis. The authors concluded that its use on surgical wounds should be discouraged. In a six-month trial it absorbed into skin readily but left the lesions unchanged.

Not establishedRetinoid⚠ In pregnancy Do not use

Hydroxypinacolone retinoate

Hydroxypinacolone Retinoate

The human material we found is one 8-week study of a serum containing retinol, HPR, peptides and silybin. And that abstract states neither the number of participants nor a control group. All the authors work at one cosmetics company's research centre. There is no trial of HPR alone on this page.

Not establishedHumectant

Collagen

Collagen

The rule of thumb in the skin-penetration literature is 500 daltons. Collagen is hundreds of times larger. That applying it increases collagen in the dermis has not been established in people.

Not establishedOther

Genistein

Genistein

In two trials of 30 postmenopausal women over 24 weeks, biopsies from the skin in front of the ear showed hyaluronic acid and collagen had risen. But the comparator was estradiol and genistein lost both times, and there was no vehicle-only arm. Neither trial had an endpoint measuring anything visible.

Not establishedPeptide

Copper tripeptide (GHK-Cu)

Copper Tripeptide-1

One randomised trial with 13 completers is all this page has. After CO2 laser resurfacing, one arm used a GHK-Cu product and the other did not. Blinded raters and computer analysis found no difference in erythema, wrinkles or skin quality. Yet the patient questionnaire favoured GHK-Cu significantly (P = .04).

Medicines used for this concern

Medicines are not listed alongside cosmetic ingredients. Dosage and whether a prescription is needed are settled in consultation.

Clinical procedures related to this concern

Procedures are not listed alongside topical ingredients. They are not something you use at home.

Surgery related to this concern

Surgery is not the same as a procedure. Most of it cannot be undone, and this site does not yet grade evidence for this layer — these are not measured with the same ruler as the lists above. Reversibility is shown in place of a grade.