Journal
Formulation, clinical evidence and protocols, from the people who develop them.
Measured retinoid content frequently departs from the declared figure, and a large fraction is lost within months. Across 12 commercial cosmetics followed for six months, content...
A label percentage describes how much active is in the container, not how much is free to move into skin. Permeation is driven by thermodynamic activity...
Reported penetration depth falls as hyaluronic acid molecular weight rises: about 100 um at 20-50 kDa, about 50 um at 100-300 kDa, and stratum corneum only...
Human skin carries carboxylesterases, but the proportion of an applied ester that arrives hydrolysed varied about 39-fold across four human skin membrane preparations. The measured figures,...
Yes, and the ceiling is set by a transporter rather than by the jar. Ascorbate enters cells through sodium-dependent carriers whose transport is saturable, with reported...
Measured skin levels give a qualified answer: in part, and essentially only when the peptide carries a lipid chain. In full-thickness mouse skin the pentapeptide KTTKS...
TEWL measures outward water vapour flux in g·m−2·h−1, not how much of an applied substance gets in. Pooled values run from 2.3 on breast skin to...
Follicular openings cover about 0.1% of the skin surface, yet plugging half the follicles in excised skin cut the permeation of hydrophilic model compounds by roughly...
Because only the undissociated free acid acts as the permeant, and pH decides how much of it exists. Glycolic acid has a pKa of about 3.83:...
No. In ex vivo human skin, oleic acid and oleyl alcohol at 0.75% delivered almost identical amounts of diclofenac over 24 hours, yet only oleic acid...
Healthy adult skin measures roughly pH 4.0–6.0, and that acidity is a product of barrier metabolism rather than a condition imposed on it. Lipid processing contributes...
Skin penetration is measured in vitro in a two-chamber diffusion cell, under fixed conditions: 32 ± 1 °C, split-thickness human skin of 200–500 µm, 85–115 %...
