Use the directions for the actual formula
Some brands describe a dry-scalp evening application; others allow different timing. Do not transfer one brand’s amount or schedule to another simply because both products use a dropper. A dropperful is not necessarily the same quantity across bottles.
Read whether the product is intended for the scalp or the hair lengths, and whether it is a leave-in formula. Applying a scalp serum mainly to the lengths is a different routine from the one the brand describes.
Keep the first routine understandable
Before adding a product, decide when it will fit around washing and styling. Keep a note of the start date and the other products you use. Introducing several products together makes it difficult to identify which one you like, which one causes an unwanted feeling, or what you would actually repurchase.
Avoid adding a second serum solely because the first has not produced an immediate visible change. Stacking formulas also stacks cost and uncertainty. The routine should have a clear purpose rather than becoming an escalating experiment.
Know what a shopping guide cannot decide
A cosmetic routine is not a diagnosis of thinning. If you are using a prescribed scalp treatment, ask the prescriber about any addition rather than relying on a universal layering order. Follow the product’s precautions and stop using it if irritation develops.
Our comparison notes describe manufacturer directions so you can assess routine fit. We have not tested the dispensers, measured absorption or established a personalised application schedule.
Sources & further reading
Product pages establish brand claims and label facts. They do not independently validate efficacy. Sources checked 14 September 2026.
- The Ordinary: Multi-Peptide Serum for Hair Density — official product and ingredients
- The INKEY List: Caffeine Stimulating Scalp Treatment — official product and ingredients
- Divi: Scalp Serum — official product and ingredients
