# Peptide body lotion, from the base up > peptide body lotion, from the base up — A closer look at peptide body lotion: GHK-Cu, collagen experiments, skin penetration and the cream base that deserves equal billing. **The whole formulation** I give the lotion equal billing. An interesting ingredient still has to make sense in the cream around it. ### [Collagen](/collagen) The cell-culture finding that makes GHK-Cu worth the attention. ### [Skin delivery](/skin-delivery) Copper passing through skin, copper remaining there, and a demanding barrier. ### [Cream results](/cream-evidence) Collagen responders, skin outcomes and the finished formulation. ## The peptide and the cream base The word peptide gets the attention. Lotion sounds like the accommodating substance around it, something to spread the interesting ingredient over a larger patch of skin. I think that division gives the cream base far too little credit. The [review of topically applied GHK](https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/) puts poor passage through the stratum corneum, the outer skin barrier, at the centre of the problem. The formulation has a job to do before a result in cells becomes relevant to a cream. That is the attraction of this particular name. Peptide body lotion asks about a whole preparation and the skin it meets. Ingredient reputation carries little weight beside the work needed to carry it through that encounter. A cream can look wonderfully ordinary while presenting a rather demanding research question. GHK-Cu is the focus here because the [topical literature includes both skin outcomes and delivery research](https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/). It gives the lotion half of the name something substantial to argue with. ## Collagen in the culture dish There is a good reason to take the peptide seriously. In [human fibroblast cultures, GHK-Cu stimulated collagen synthesis without changing cell number](https://pubmed.ncbi.nlm.nih.gov/3169264/). Fibroblasts are the cells doing the collagen-making work in that experiment. The separation between production and cell number makes this a more interesting finding than a vague claim about renewal: the experiment detected a change in what the cells made. I give that observation considerable weight as a reason for further investigation. Its precision is also its boundary. The material was in cell-culture medium, so the cells encountered it under conditions very different from a lotion sitting on skin. There is no cream base in that result to evaluate. The [collagen essay](/collagen) stays with this experiment and the surrounding tissue-remodelling research. The biology is interesting enough to deserve a proper description before anyone asks it to carry a cosmetic claim. ## Copper in a skin experiment The next paper brings skin into the picture. A [human-skin penetration experiment measured copper passing through tissue and copper retained in it](https://pmc.ncbi.nlm.nih.gov/articles/PMC3016279/). These were experiments on skin outside the body, with results reported by skin layer. That setting matters to the interpretation. The reported substance is copper. I read those quantities as copper quantities; substituting the amount of intact peptide would answer a different question. Even without that substitution, the distinction between passage and retention is useful. Material arriving in tissue and material passing through it are separate observations. This is where the lotion stops being background scenery for me. The [skin-delivery page](/skin-delivery) looks at those measurements alongside the formulation problem described in the topical review. It is a closer fit to the everyday object in this site's name than a long list of possible biological effects. ## Results for a finished lotion There are human skin results to consider. The [skin-regeneration review describes placebo-controlled improvements in laxity, clarity, fine lines, wrinkle depth and density](https://pmc.ncbi.nlm.nih.gov/articles/PMC4508379/). Those are distinct outcomes, with more texture than the single word anti-ageing allows. A useful claim names the skin outcome assessed for its particular formulation. A cosmetic claim convinces me when it stays close to the preparation and measurement behind it. A result for collagen production, a result for wrinkle depth and a report about skin density each deserve their own wording. Combining them into a general assurance about a body lotion spends the evidence too freely. The [cream-results essay](/cream-evidence) examines the frequently repeated collagen percentages and the question they leave me with: how would the actual finished body lotion perform against its own base? I would gladly trade a page of ingredient praise for that comparison. It would give the ordinary word lotion the attention it has earned. --- I follow peptide body lotion from copper chemistry to the cream base here, and these notes on published research offer no medical advice.