Cosmetic peptides and related research compounds. The biotin 40mg kit is £140 and the Glow 70mg blend, built around the copper peptide GHK-Cu, is £89.99. One safety fact belongs here rather than buried: high amount biotin interferes with many laboratory immunoassays, including thyroid panels and troponin, and can produce falsely high or low results. Both the MHRA and the US FDA have issued communications on this. Keep it away from any bench running immunoassays. Biotin corrects a genuine deficiency, but deficiency is rare on an ordinary diet and evidence of cosmetic benefit in people who are not deficient is weak. Copper peptide preparations are light sensitive and need protective packaging. All supplied for laboratory research use only, not for human or veterinary consumption, with no cosmetic or therapeutic claims made. Read next: supplier checklist, the full range.