Written by a cosmetic doctor

Botox vs Dermal Fillers: Which Do You Actually Need?

They do close to opposite things. One relaxes muscle, the other restores volume — and choosing the wrong one is the most common mistake people make before booking.

Dr Nadja Haub · Australasian Professional Diploma in Aesthetic Medicine

People often arrive at a consultation having decided which treatment they want, and it's frequently the wrong one for what's bothering them.

That's not a failure on their part. The two treatments get discussed as though they're interchangeable options on the same menu, when in fact they address quite different problems. Knowing the difference means you'll ask better questions and be harder to sell something you don't need.

If the problem is caused by movement, toxin is the tool. If it's caused by something having deflated or descended, filler is the tool. Almost everything else follows from that.

What botulinum toxin does

Botox®, Dysport® and Xeomin® are brands of botulinum toxin type A. Injected in small, precisely placed doses, the medicine temporarily reduces a muscle's ability to contract by blocking the nerve signal that tells it to fire.

Less contraction means the skin over that muscle creases less. Over time, lines that appeared only on movement become less pronounced at rest.

In New Zealand it's an approved prescription medicine for three areas of the upper face: frown lines between the eyebrows, horizontal forehead lines, and crow's feet at the outer corners of the eyes.

It cannot add volume. If your concern is hollowness, flatness or sagging, relaxing a muscle won't address it — and in some cases will make it slightly more noticeable.

What dermal fillers do

Dermal fillers are injectable gels, usually hyaluronic acid, placed under the skin to restore volume, support structure or refine contour.

They address a different problem entirely: the gradual loss of fat, bone and collagen that changes facial shape with age. Cheeks flatten, the mid-face descends, folds deepen because the tissue above them has lost its support.

Filler cannot stop a muscle contracting. Placing volume into a line caused purely by movement tends to produce a poor result — the line still forms, and now there's product sitting in it.

The test you can do in a mirror

This is the single most useful thing in this article.

Look at the line that's bothering you with your face completely relaxed. Then make the expression that creates it — frown, raise your brows, smile.

Most people over about forty have a mix, which is why the honest answer is often "some of both, in different places."

Side by side

That last row matters more than people realise. If you dislike a toxin result you wait it out, typically a few weeks for the worst of it. Hyaluronic acid filler can be dissolved with an enzyme, usually within days. Different kinds of reassurance, but both worth knowing.

Why they're often used together

The upper face tends to be a movement problem. The mid and lower face tend to be a volume and support problem. Treating one and ignoring the other can produce an oddly unbalanced result — a smooth forehead above a face that still reads as tired.

A sensible plan often relaxes selectively in the upper face and restores support where it's been lost, using as little of each as achieves the goal. That's a judgement made by looking at your face, not by picking from a list.

Which should you start with?

If you're new to this and unsure, starting with botulinum toxin in a single area is reasonable. It's lower cost, it's temporary, the effect is predictable, and it tells you a great deal about how you feel seeing your own face slightly changed. Plenty of people discover that a subtle softening is all they ever wanted.

Filler is a bigger commitment — longer lasting, more technically demanding, and more consequential when it's placed badly. It's worth being confident in your injector before you go there.

The risks are different too

Botulinum toxin. Small bumps at the injection sites that settle within an hour or two, redness, occasional bruising, sometimes headache. Less commonly, the medicine affects a muscle that wasn't the target — a temporarily heavy brow or a lower-sitting eyelid. It resolves as the effect wears off, though that can mean several weeks.

Dermal filler. Swelling and bruising are common and can last several days. Lumps or asymmetry can usually be corrected. The serious risk, though rare, is vascular occlusion — filler entering or compressing a blood vessel, which needs immediate recognition and treatment. This is the main reason to care about your injector's anatomical training and whether they can manage a complication on the spot.

Anyone experiencing side effects after either treatment should see their doctor.

What a good consultation looks like

Whoever you see should be watching how your face moves, not just how it sits at rest. They should be willing to tell you that the treatment you asked for isn't the right one — and to say when the honest answer is that no injectable will fix what's bothering you.

They should also explain the trade-offs rather than only the benefits, and give you a total cost before anything is injected.

Frequently asked questions

Written by Dr Nadja Haub, cosmetic doctor and founder of Satini Cosmetic Clinic, Christchurch. Dr Haub holds the Australasian Professional Diploma in Aesthetic Medicine and teaches botulinum toxin and dermal filler technique to other doctors and nurses. This article is general information and is not a substitute for individual medical advice.