These are the two most common cosmetic injections, and they get mixed up constantly — including by people who have already had one.
They are not versions of the same thing. Botox is a muscle relaxer. Filler is a volume replacer. They are aimed at two different causes of the same complaint: "my face looks tired."
This page sorts out which lines belong to which, what the research shows about how long each lasts, and where the two overlap.
These two barely overlap. Both act only in the dermis row and below, and even there by opposite routes: Botox works on the muscle underneath the skin by switching it off, while filler works underneath by adding physical bulk. Neither touches barrier, pore, pigment, or antioxidant function — which is exactly why neither improves skin quality.
Frown lines between the brows | Botox | Strong
The classic use, and the best studied. In a randomized placebo-controlled trial of 355 people, about 65% met the strict combined success standard at 4 weeks, compared with none on placebo (Aesthet Surg J, 2022). Effects started at around 3 days.
Forehead lines and crow's feet | Botox | Strong
Same principle — these are movement lines. Filler in the forehead is uncommon and carries higher risk.
Flat or hollow cheeks | Fillers | Strong
There is no muscle to relax here. The issue is lost fat and bone support, and only volume replaces volume.
Deep smile folds | Fillers | Strong
The folds running from nose to mouth are creases held open by gravity and lost cheek support. Botox does nothing for them.
Thin lips | Fillers | Strong
Volume, plus shape. A small amount of Botox can flip the upper lip outward slightly, but it does not add fullness.
Under-eye hollows | Fillers, with caution | Mixed
It works, but this is the most technique-sensitive area on the face, with the highest rate of lumps, prolonged swelling, and blue-gray discoloration. Choose the injector, not the product.
Lines that are there when your face is still | Fillers | Consensus
Once a movement line has been etched in for years, relaxing the muscle softens it but does not erase it. Etched lines usually need filler, resurfacing, or both.
Jawline and chin definition | Fillers | Moderate
Structural work. Botox can slim a heavy jaw muscle, which is a different goal entirely.
How long it lasts | Fillers | Moderate
Botox typically fades over 3–4 months — in the trial above, average time to a repeat treatment was about 127 days. Hyaluronic acid fillers commonly last 6–18 months depending on the product and the area (J Cosmet Dermatol, 2015).
Reversibility | Fillers | Consensus
Hyaluronic acid filler can be dissolved with an enzyme injection if you do not like the result. Botox cannot be reversed — you wait it out, which takes 3–4 months.
Most people who want a full result end up using both. They fix different problems and they do not interfere with each other.
A common combination:
- Botox in the upper third — forehead, between the brows, crow's feet.
- Filler in the middle and lower thirds — cheeks, folds, chin, lips.
Order matters a little. Many injectors do Botox first and filler about 2 weeks later, once the muscle has relaxed — because relaxed muscles change how much filler a crease actually needs.
Start with one if you are new. Botox is the lower-commitment entry point: cheaper per session, and if you hate it, it is gone in a few months on its own.
Neither one is a skin treatment. If your complaint is tone, texture, pores, or dullness, the answer is sunscreen, a retinoid, or a resurfacing procedure — not an injection.