How long do dermal fillers last?
A duration claim means little until you know which product and which area it describes.
Why no month count appears here
This page does not print a number of months. The sources it reads do not support one figure for every filler, and a single figure would claim more than a product-by-product comparison can back. The useful question is which product is being used and what its own documentation says about duration.
Duration claims and their conditions
Reading footnotes first, the thing to watch for is a duration printed without its conditions. When two fillers are compared, line up the same fields for each: the product name, the area treated, where the duration claim comes from, and whether it describes a typical result or a best case. Where a claim outruns those fields, treat it as marketing until a source says otherwise.
The FDA dermal fillers page is a plain place to start for how the agency describes these devices, and the ASPS page on dermal filler types covers how products under the label differ. A second reference to hold next to a clinic's own wording is the ASPS page on dermal fillers. The hyaluronidase guideline for aesthetic medicine is worth reading as well, because it covers the case where a filler is dissolved instead of left alone.
Fields to request about a duration claim
Before booking, write down the product name and ask where its duration claim comes from. Ask what "lasts" means in that claim, and whether the answer changes for the area you want treated. Put the answers from different providers side by side and note where they differ.
Last check: which product the duration is quoted for
This publication compares product wording and cannot predict how any filler will behave for you, so a licensed clinician who has examined you is the right source for that.