Are there side effects from fillers?
A side-effect list is only as useful as the product name attached to it.
Yes, but read the product's own list
Yes, the sources below discuss risks, so side effects are a question to take seriously. This page does not list them from memory. It shows where to read the documented ones and what to ask so the answer is tied to a specific product.
Reading a side-effect list field by field
A claim that a filler is "safe" or "gentle" is a label, not a specification. The comparison that matters is field by field: the product name, what its documentation lists as possible side effects, and how that list is worded. If one product's list is long and another's is short, check whether the shorter one is actually shorter or just less specific.
The FDA soft tissue filler page is the regulator's own description of these devices. The ASPS page on dermal fillers gives a plastic surgery society's version to compare against it. For the removal side, the Journal of Clinical and Aesthetic Dermatology paper on dissolving hyaluronic acid filler is the one to read.
Take the product name to the appointment
Ask the provider for the product's name and for the written side-effect information that comes with it. Ask what to do and whom to contact if something looks wrong after treatment. Keep the product name so you can check it against the sources above.
Why your clinician has the last word on side effects
We compare product documentation rather than give medical advice, so a licensed clinician who knows your health history is the right person to say which side effects apply to you.