Peptides can be unstable when layered with low-pH acids, L-ascorbic acid vitamin C, AHAs, BHAs or certain oxidizing ingredients such as benzoyl peroxide. Apply peptide serums to clean, dry skin and allow them to absorb before applying another product. Oily skin types can often skip a moisturizer afterward because their sebum provides natural occlusion. Using fewer products also reduces the chance of exposing peptides to ingredients or pH conditions that can decrease their stability.

Choose a lightweight, noncomedogenic peptide serum or hydrogel rather than a lipid-rich cream. Oily skin already produces sebum, so it does not need large amounts of oils, butters, waxes or other occlusive lipids. Check the ingredient list for comedogenic ingredients that can contribute to clogged pores. Look for peptides in a water-based formula with lightweight humectants such as glycerin or hyaluronic acid. The goal is anti-aging treatment and hydration without making oily skin feel greasy, sticky or congested.

If you have very oily skin, you usually do not need a moisturizer after your peptide serum. Normal-oily or slightly oily skin may need one when using drying ingredients such as salicylic acid, benzoyl peroxide or retinoids, or whenever skin feels uncomfortable without moisturizer.

After cleansing, it takes time for sebum to spread back over the skin, so temporary tightness immediately after washing does not necessarily mean you need moisturizer. This is especially true in warm, humid climates, where oily skin often needs less occlusion.

Your skin type can also change with the seasons. If your usual skincare routine stops working or your skin becomes noticeably drier or oilier, retake the Baumann Skin Type Quiz so your routine can be adjusted to your current skin type.

Although people love the lightweight feel of peptide serums and the temporary firming effects some peptide formulations can provide, peptides should not be the only anti-aging strategy. Retinoids have much stronger evidence for improving photoaging, fine lines and collagen production. Exosome serums are another promising anti-aging option that support cellular communication and skin rejuvenation. Oily skin types should choose lightweight, noncomedogenic versions of these products and combine them with daily sunscreen, which remains essential for preventing further skin aging.