As an expert in skincare ingredients, I can provide some guidance on the order of application for peptide serum and hyaluronic acid. Generally, it is recommended to apply products in order of their consistency, starting with the thinnest and ending with the thickest.

In this case, hyaluronic acid is typically a lightweight, water-based product that is easily absorbed. Therefore, it is often recommended to apply hyaluronic acid before other serums or moisturizers. By applying it first, you can ensure that the hyaluronic acid penetrates the skin and provides hydration.

Peptide serums, on the other hand, are usually thicker and more concentrated. They contain peptides, which are small chains of amino acids that can have various benefits for the skin, such as promoting collagen production and improving elasticity. Since peptides are often found in thicker serums or creams, they are usually applied after hyaluronic acid.

To summarize, you would typically apply hyaluronic acid first, allowing it to absorb into the skin, and then follow it with the peptide serum. It's important to note that everyone's skin is unique, so it's always a good idea to consult with a dermatologist or skincare professional for personalized recommendations based on your specific needs and concerns.