Clinical Studies

Medik8 is a cosmeceutical skincare brand. As such, we use only the best active ingredients in our formulations. We use clinical studies from trusted, ethical sources to validate what we do.


Study - Synthesis and in vitro biological activity of retinyl retinoate, a novel hybrid retinoid derivative.
H. Kim et al, Bioorganic & Medicinal Chemistry, 2008, 16, pp 6387-6393

A novel vitamin A hybrid is synthesised via a condensation reaction between retinol and retinoic acid to form retinyl retinoate. Retinyl retinoate is proven to be photostable. In parameters looking at retinoic acid activity (such as CRABP2 induction and collagen synthesis) retinyl retinoate showed higher biological activity than retinol. The biological effects of retinyl retinoate is caused by the molecule itself, not by splitting down into its constituent parts.

Key result - Retinyl retinoate can be used during the day time as it is photostable, and it is more powerful than retinol. Retinyl retinoate is directly biologically active, and does not need to be broken down into retinol and retinoic acid to work in the skin.

Study - Retinyl retinoate, a novel hybrid vitamin derivative, improves photoaged skin: a double-blind, randomized-controlled trial
H. Kim et al, Skin Research and Technology, 2011, 17, pp 380–385

A prospective double blind, in vivo clinical study on 11 Korean women using 0.06% retinyl retinoate for 12 weeks. A statistically significant improvement in facial wrinkles and roughness were seen during the study, and were found to improve 22% more than that of a 0.075% retinol cream.

Key result - Retinyl retinoate is able to reduce the appearance of wrinkles and rough skin, and is more powerful than retinol.

Study - Improvement in skin wrinkles from the use of photostable retinyl retinoate: a randomized controlled trial H. Kim et al, British Journal of Dermatology, 2010, 162, pp 497-502

An in vivo study of 46 Korean women with periorbital wrinkles. One study compared 0.06% retinyl retinoate with a placebo cream over 12 weeks, applying twice daily. Another study compared 0.06% retinyl retinoate with 0.075% retinol cream, applying twice daily. The retinyl retinoate treated wrinkles improved as compared with wrinkles treated with retinol or placebo. Significant improvements were seen in average roughness. No side effects were seen with retinyl retinoate.

Key result - Retinyl retinoate applied twice daily was significantly more effective than retinol. Retinyl retinoate is gentle on the skin.

Study - Novel anti-wrinkle effect of cosmeceutical product with new retinyl retinoate microsphere using biodegradable polymer
H. Kim et al, Skin Research and Technology, 2012, 18, pp 70–76

An in vivo study on 44 Korean women over 12 weeks. All patients used a cream containing 0.06% retinyl retinoate for 12 weeks. Half of the women used a cream that encapsulated the retinyl retinoate into a polymer encapsulation system. The encapsulation helped penetration and produced more significant changes in visual wrinkle grades than the non-encapsulated retinyl retinoate.

Key result - Encapsulating retinyl retinoate boosts penetration and power.

Study - Retinyl Retinoate, a Retinoid Derivative Improves Acne Vulgaris in Double-blind, Vehicle-controlled Clinical Study
B Kim et al, Tissue Engineering and Regenerative Medicine, 2013, 10(5), pp 260-265

An in vivo study on 15 patients with acne vulgaris, using 0.05% retinyl retinoate over 8 weeks on half of their face. On the other half a placebo cream was applied. The cream with retinyl retinoate showed a significant decrease in both inflammatory and non-inflammatory lesions, and a reduction in sebum production.

Key result - Retinyl retinoate can be used as a mild, long term approach for blemish-prone skin.


Study - Retinol and retinal metabolism. Relationship to the state of differentiation of cultured human keratinocytes.
G Siegenthaler et al, Biochemical Journal, 1990, 268(2), pp 371-378

An in vitro study using cultured keratinocytes (epidermal skin cells) to observe how quickly retinol and retinaldehyde metabolised into retinoic acid (the bioactive form of vitamin A). Rate of formation of retinoic acid (pmol/h per mg of protein):
Retinol: 4.49
Retinaldehyde: 51.6 (11x faster)

Key result - Retinaldehyde converts to retinoic acid 11x faster than retinol. Faster conversion = faster results.

Study - Topical retinaldehyde on human skin: biological effects and tolerance
J Saurat et al, Journal of Investigative Dermatology, 1994, 103(6), pp 770-774

An in vivo study on 229 patients on keratome biopsies obtained after 4 day exposure to types of vitamin A in the same vehicle cream. Types used were retinol, retinoic acid and retinaldehyde. The study measured retinoic acid activity using CRABP2 protein induction (a hallmark of retinoic acid activity). Retinaldehyde is found to induce CRABP 2 to a similar extent to retinoic acid, and much more than retinol.

Key results - Retinaldehyde is more biologically active than retinol = better results.

Study - The antibacterial activity of topical retinoids: the case of retinaldehyde.
M Pechere et al, Dermatology, 2002, 205(2), pp 153-158

In vitro study exposing retinaldehyde, retinol and retinoic acid to different strains of bacteria. Retinaldehyde was the only type of vitamin A tested which showed significant, direct antibacterial action against gram-positive bacteria such as P. acnes.

Key result - Retinaldehyde is the only type of vitamin A tested which has direct antibacterial action, making it ideal for use on blemish-prone skins.

Study - Profilometric evaluation of photodamage after topical retinaldehyde and retinoic acid treatment.
P Creidi et al, Journal of American Academy of Dermatology, 1998, 39(6), pp 360-365

In vivo study on 125 patients over the course of 18 weeks. 40 patients used 0.05% retinoic acid, 40 patients used 0.05% retinaldehyde, 45 patients used a placebo cream. Both vitamin A creams produced a significant reduction in wrinkles and roughness, and no statistically significant differences were found between the retinoic acid and retinaldehyde groups. Retinaldehyde was much better tolerated than retinoic acid.

Key result - Retinaldehyde provides the results of retinoic acid, without the irritation.

Study - Repair of UVA-induced elastic fiber and collagen damage by 0.05% retinaldehyde cream in an ex vivo human skin model. S Boisnic et al, Dermatology, 1999, 199(Suppl 1), pp 43-48

An ex vivo study using human skin explants which had been subjected to UVA exposure to stimulate photoaging. 0.05% retinaldehyde cream was then applied for 2 weeks and the results compared to non-treated skin explants. In the retinaldehyde skin explants, collagen and elastin fibers were restored to the level of non-photodamaged skin.

Key result - Retinaldehyde can help to repair collagen and elastin damage induced by UVA exposure.