Botox and Fillers: When to Use Which? Explained by BonBoz Doctors

Botox should be used when your concern is wrinkles formed by muscle movement (expression lines), and fillers should be used when the issue is a loss of volume in hollow or sagging areas—but the exact choice requires a direct consultation with a doctor, as many cases are not that simple. Botox and fillers are often mentioned in the same breath, as if they were interchangeable options, but they actually address two different issues, and using the wrong one is not just a waste of money—it can also lead to undesirable results.

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

Two different treatments, two different mechanisms

Botulinum toxin—commonly known as Botox—acts on muscle activity. Simply put, it reduces the contraction of the injected muscle group. Therefore, it is typically indicated for wrinkles formed by facial expressions: frowning, smiling, or raising the eyebrows.

Dermal fillers do something completely different: they restore volume to hollow or sunken areas. They have nothing to do with muscle activity.

From this, we can deduce a simple rule of thumb: if your concern stems from movement, the solution leans toward botulinum toxin. If the issue stems from a loss of volume, the solution leans toward dermal fillers.

But reality is more complex than that

While this rule of thumb is helpful for understanding, it is not enough for you to make a decision on your own. This is for two reasons.

First, many cases involve more than one issue. An area can have both expression lines and volume loss. In some cases, the doctor will prescribe one type; in others, a combination—but this is decided by the doctor after an examination, not chosen as a pre-packaged deal.

Second, there are cases where neither is the answer. If your actual issue is significant skin laxity, injections will not solve it—and an honest doctor will tell you that directly instead of proceeding with injections anyway.

This is why the consultation step cannot be skipped. You come in with a goal; the doctor's job is to determine whether that goal aligns with any specific intervention.

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

This is the point we want to emphasize the most.

Because no surgery is involved, many people downplay these procedures and have them done at facilities that lack proper medical qualifications—spas, salons, or even at home through an appointment with an acquaintance.

However, these are still medications and materials being introduced into your body. Product origin, correct indication, injection technique, and sterile conditions are all equally critical. Aside from localized bruising and swelling, there are rare but more serious risks—particularly vascular occlusion with fillers. These are the signs of vascular occlusion that require you to contact a doctor IMMEDIATELY: the skin at the injection site turns pale/white, feels cold to the touch, shows abnormal swelling or bluish discoloration, or causes severe pain that does not subside after 24 hours—especially when performed by a non-doctor or at a facility lacking the necessary equipment to handle complications.

Having the procedure done at a licensed medical clinic is not a mere formality. It ensures that if an unusual situation arises, qualified personnel and proper equipment are immediately available to handle it.

What you have the right to ask before getting injected

You should not hesitate to ask these questions. At any facility, this is your right:

1. 1Who is performing my injection, and are they a doctor?
2. 2What product will be used? You have the right to ask to see the product information, name, expiration date, and relevant documentation before the procedure.
3. 3Why was this specific product chosen for my concern?
4. 4Which areas will be injected, and why?
5. 5What are the realistic results I can expect, and what is beyond its capability?
6. 6What are the risks, and how will they be managed if they occur?
7. 7What should I avoid after the injection?

If a facility refuses to provide this information or pressures you to make an immediate decision, that is a red flag to reconsider.

Who should avoid these procedures

There are contraindications or situations where treatment should be postponed. Some common scenarios include:

• Being pregnant or breastfeeding.
• Having an active infection at the planned injection site.
• Having a history of allergies to any of the ingredients involved.
• Having underlying medical conditions or taking medications that require careful consideration.

The doctor will determine this during the consultation, so please provide a complete history of your allergies, medical conditions, and current medications. This step is not a mere formality—it directly determines whether you are cleared for the procedure.

Regarding the "frozen face" concern

The most common concern regarding botulinum toxin is looking unnatural or being unable to smile as before.

This issue is usually related to improper dosage or injection placement for the individual. This is precisely why the procedure must be evaluated and prescribed by a doctor, rather than chosen as a package deal or based on the number of units an acquaintance received. The same dose on two different people can yield very different results.

How long do the results last?

It must be made clear from the start: non-surgical interventions only offer temporary results. This is not a "one-and-done" procedure.

The duration varies depending on the product type, injection area, and individual physiology. The doctor will provide an estimated timeframe for your specific product and treatment area, along with when you should return for a follow-up. If anyone promises you an exact duration that applies to everyone, that number is purely marketing.

The Process at BonBoz

1. 1Consultation and assessment. The doctor evaluates your concerns—whether they are dynamic wrinkles, hollow areas, or asymmetrical features.
2. 2Screening for contraindications. Reviewing allergy history, medical conditions, current medications, and pregnancy or breastfeeding status.
3. 3Treatment planning. The doctor explains what should be used, in which areas, why, and provides the cost. If injections cannot resolve your issue, the doctor will state so clearly.
4. 4Product confirmation. You will be shown the product to be used before the procedure begins.
5. 5Procedure. The doctor personally performs the injection at the clinic under sterile conditions.
6. 6Post-procedure monitoring. You are monitored at the clinic before leaving and receive instructions on what to avoid during the first few hours.
7. 7Follow-up appointment. The doctor schedules a follow-up to evaluate the results once the treatment has taken full effect.

Cost

The cost depends on the type of product, the injection area, and the amount required for your specific indication—so there is no flat rate. After the examination, the doctor will provide a clear cost estimate for your treatment plan before you make a decision.

If you are torn between the two options, the quickest way to resolve your hesitation is to come in for a consultation and ask. The answer might be one, both, or perhaps that you do not need anything done yet.

BonBoz Aesthetic and Dermatology Clinic — 66–68 Vo Van Tan, Xuan Hoa Ward, HCMC.

Content compiled and reviewed by the medical team at BonBoz Clinic.