Botox and Filler: When Should You Use Which?

Botox and Filler: When Should You Use Which? BonBoz Doctors Explain

Quick summary: Botox (botulinum toxin) and filler (dermal filler) are two non-surgical aesthetic treatments that address two entirely different problems: Botox reduces muscle contraction to improve expression lines, while filler restores volume to areas that are hollow or sagging. Which method to choose, or whether to combine both, must be decided by a doctor after an in-person examination based on each client's actual condition, in order to limit risks and choose a suitable approach.

Use Botox when your concern is wrinkles formed by muscle movement (expression lines), and use filler when the concern is volume loss in hollow or sagging areas. However, the exact choice requires an in-person examination by a doctor, because many cases are not that simple. Botox and filler are often mentioned in the same sentence, as if they were alternatives to each other, but they actually solve two different problems, and using the wrong one is not only a waste: it can also give results you did not want.

This article explains the basic differences so you know what to ask your doctor.

Two treatments, two different mechanisms

Botulinum toxin, which most people call Botox, acts on muscle activity. Put simply, it reduces the contraction of the muscles it is injected into. That is why it is commonly indicated for wrinkles formed by facial expressions: frowning, smiling, raising the brows.

Dermal filler works in a completely different way: it replaces volume in areas that are hollow or lacking fullness. It has nothing to do with muscle activity.

This gives us a simple principle: if your concern comes from movement, the approach leans toward Botox. If it comes from volume loss, the approach leans toward filler.

But reality is more complicated

The principle above is useful for understanding, but it is not enough for you to decide on your own, for two reasons.

First, many cases involve more than one problem. A single area can have both expression lines and volume loss. In some cases the doctor recommends one product, and in others a combination, but this is decided by the doctor after an examination, not chosen from a package.

Second, in some cases neither is the answer. If your concern is really significant skin laxity, injections cannot solve it, and an honest doctor will tell you so directly rather than simply injecting.

This is why the consultation step cannot be skipped. You come in with a wish; the doctor's job is to determine whether that wish corresponds to any suitable treatment.

"Non-surgical" does not mean "no doctor needed"

This is the part we want to emphasize most.

Because there is no scalpel involved, many people take this group of treatments lightly and have them done in places that lack proper medical conditions: spas, salons, even at home by appointment with an acquaintance.

But these are still drugs and materials being put into your body. The origin of the product, correct indication, injection technique, and sterile conditions all matter equally. Besides local bruising and swelling, there are less common but more serious risks, especially the risk of vascular occlusion with filler. These are signs of vascular occlusion that you should report to a doctor IMMEDIATELY: the skin in the injected area turns pale white, feels cold to the touch, becomes unusually swollen or bluish-purple, or severe pain does not subside after 24 hours, especially when it was done by someone who is not a doctor or in a place without the conditions to handle complications. If you notice blurred vision or any change in vision after a filler injection, this is an emergency — go to the clinic or the nearest medical facility immediately; do not wait.

Having the procedure at a clinic licensed to provide medical examination and treatment is not a mere formality. It ensures that when something unexpected happens, there are people and equipment to handle it right away.

What you have the right to ask before an injection

Don't hesitate to ask these questions. At any facility, this is your right:

1Who will be injecting me, and are they a doctor?
2What product will be used? You have the right to ask to see the product information, name, expiry date, and related documents before the procedure.
3Why was this product chosen for my concern?
4Which areas will be injected, and why?
5What is a reasonable result I can expect, and what is beyond what the treatment can do?
6What are the risks, and how are they handled if they occur?
7What should I avoid after the injection?

If anywhere you are refused this information, or pressured to decide on the spot, that is a sign you should reconsider.

Who should not undergo treatment

Some cases are contraindicated or require postponement. Some common situations:

Pregnancy or breastfeeding.
Infection in the area to be injected.
History of allergy to related ingredients.
Existing medical conditions or medications that require consideration.

The doctor will determine this at the examination, so please disclose your allergy history, medical conditions, and current medications in full. This is not a formality: it directly affects whether you are cleared for treatment.

About the "frozen face" concern

The most common worry about Botox is a face that looks unnatural, or being unable to smile the way you used to.

This is usually related to a dose and injection placement that are not suited to the individual. That is precisely why the treatment must be examined and prescribed by a doctor, not chosen by package or by the number of units an acquaintance once received. The same dose on two different people can produce very different results.

How long do results last?

It must be said clearly from the start: all non-surgical aesthetic treatments have a limited duration. This is not a one-time fix.

The duration varies depending on the type of product, the injected area, and each person's individual response. The doctor will tell you the expected duration for the specific product and area you are treating, as well as when to return for a check-up. If anyone promises you one exact figure that applies to everyone, that's marketing.

The process at BonBoz

1Examination and identifying the concern. The doctor looks at what is bothering you: dynamic wrinkles, hollow areas, or uneven contours.
2Checking for contraindications. Allergy history, medical conditions, current medications, pregnancy or breastfeeding status.
3Discussing options. The doctor explains what to use, in which areas, and why, and gives you the cost. If injections cannot solve your concern, the doctor will say so clearly.
4Confirming the product. You are told which product will be used before the procedure.
5Procedure. The doctor personally performs it at the clinic under sterile conditions.
6Post-procedure monitoring. You are monitored at the clinic before leaving and given instructions on what to avoid during the first few hours.
7Follow-up appointment. The doctor schedules you to return for an assessment once the product has taken full effect.

Cost

Cost depends on the type of product, the injected area, and the amount needed for your specific indication, so there is no single price. After the examination, the doctor will give you a clear cost for your plan before you decide.

If you are torn between the two options, the quickest way to settle it is to come in and ask. The answer may be one of the two, it may be both, and it may be that nothing needs to be done yet.

BonBoz Aesthetic and Dermatology Clinic — 66–68 Võ Văn Tần, Xuân Hòa Ward, Ho Chi Minh City.

References

ASPS — Botulinum toxin (Botox), accessed 03/10/2026
ASPS — Dermal fillers, accessed 03/10/2026

Frequently Asked Questions

1. How do I know whether I need Botox or filler?

The basic principle is that Botox (botulinum toxin) is suitable for wrinkles formed by muscle movement during facial expressions (such as smiling, frowning, or raising the brows). Filler (dermal filler), on the other hand, is used to restore volume to areas that are hollow or lack fullness. However, reality can be more complicated (wrinkles combined with volume loss, or skin laxity too significant to be solved with injections), so you need an in-person examination by a doctor for an accurate recommendation.

2. Does Botox injection make the face stiff and unnatural?

An unnatural-looking face is usually related to a dose and injection placement that are not suited to the individual. Because each person's physiology and muscle characteristics differ, you must be examined by a doctor, who sets the dose individually; the injection should not follow preset packages or copy someone else's dose.

3. How long do the results of Botox and filler last?

These non-surgical aesthetic treatments all have a limited duration; it is not a one-time fix. The duration varies depending on the type of product, the injected area, and each person's individual response; the doctor will tell you the expected duration for the specific type and area you are treating, as well as when to return for a check-up.

4. Are Botox and filler injections safe, and what side effects should I be aware of?

When performed by an experienced specialist doctor at a licensed medical facility such as BonBoz Clinic, Botox and filler injections are generally safe. Common side effects are swelling and mild bruising at the injection site, which usually resolve on their own within a few days. To ensure maximum safety, it is important to have a thorough examination by a doctor and for the procedure to be performed with proper technique.

5. If I'm not satisfied with my filler results, is there a way to correct them?

For hyaluronic acid (HA) filler, the doctor can use a special enzyme to dissolve the filler, allowing adjustment or removal if needed. However, this must be performed by a specialist doctor to ensure safety and effectiveness. BonBoz doctors will examine you and advise on the most suitable options for you.

This article is for reference only and does not replace an in-person examination or a doctor's diagnosis. Actual results vary by individual condition.