If your nostrils flare out when you smile or breathe in hard, Botox can tone down that movement. It relaxes the small muscles that pull the sides of your nose (the alae) outward. If your nose looks wide even with a neutral face, because of a wide base or large nostrils, Botox won't make it narrower; that's a matter of skin and cartilage, and surgery is what changes it.

Many noses have a bit of both, so the first step is figuring out which one is bigger for you. In this article, we'll cover a simple mirror check, what nose Botox can and can't do, how soon it works, what surgery involves and which side effects need a call.

Quick summary

• A nose that widens when you smile can be treated with Botox; a nose that's wide at rest is treated with surgery.

• Mirror check: if the width of your nose changes clearly between a neutral face and a big smile, movement is the main factor.

• Botox starts relaxing the muscle in 2 to 4 days, peaks around day 10 and wears off at about 3 months.

• If one side of your upper lip lifts less when you smile, or an eyelid droops, contact the clinic right away.

Does Your Nose Flare When You Smile, or Is It Wide at Rest?

Two looks in a mirror will tell you a lot. First, with a relaxed face, compare the distance between the outer edges of your nostrils with the distance between the inner corners of your eyes. If your nose is clearly wider than that eye gap, the base itself is wide.

Next, smile broadly without showing your teeth. If your nose looks fine at rest but spreads sideways when you smile, the width is coming from muscle movement. Some noses do both. At a consultation, I look at the balance of your whole face and any difference between the left and right sides first, then sort out which part is driving the width.

Take a photo of each, at rest and smiling, in the same light. You'll want them later, too.

When Can Nose Botox Reduce Nostril Flaring?

Nose Botox works on a nose that flares out when you smile or breathe deeply. It's injected into the muscle that widens the nostrils (the dilator naris) and, in some cases, the muscle that lifts the side of the nose and upper lip. What changes is how the nose moves with expression. The cartilage and the size of the nostrils stay the same.

In a study of 20 people split into a Botox group and a saltwater (saline) group, the Botox group's nostril flaring on smiling dropped from 10.05% to 4.91% of their resting width. Widening at the base dropped from 16.83% to 12.50%. The saline group didn't change. It was a small study, and most other research on nose Botox measured how satisfied people felt rather than measuring the nose, so your own result may differ.

Using Botox on the nose is an off-label use in the US, where it's FDA-approved for lines such as frown lines and crow's feet. Ask your provider which product is being used and where it will go.

How Soon Does Nose Botox Work, and How Long Does It Last?

Botox doesn't work instantly. The muscle typically starts to weaken in 2 to 4 days, and the effect peaks around day 10*. That's the earliest point to judge your result, so compare a smiling photo taken then with the one you took before.

*Based on DermNet guidance on botulinum toxin.

Botox doesn't last forever. After about 3 months, the nerve and muscle reconnect and the flaring gradually returns. To keep the effect, you'd need another round in the same spots. With repeated treatment, the muscle tends to get a little thinner each time, so the gap between sessions can slowly lengthen. Individual results vary.

What Treats a Nose That Looks Wide Even at Rest?

A wide nasal base, large nostrils or bulky nostril wings that show even at rest come down to skin and cartilage, and surgery addresses them. One approach removes a small wedge along the crease where the nostril wing meets the cheek. Another removes tissue from the nostril floor to narrow the base and the nostril opening. Surgeons sometimes combine the two, and this calls for a separate surgical consultation.

In a study of 20 people who had this kind of surgery, the ratio of nose width to the distance between the inner eye corners went from an average of 1.15 to 1.01. The scars looked most raised at 3 months and had faded to barely noticeable by 12 months.

Unlike Botox, surgery can't be undone. If your nose only widens when you smile, it makes sense to rule out movement before considering an incision.

Nose Botox Side Effects: What's Normal and What Needs a Call?

A sting at the injection points, mild swelling, redness and a small bruise are passing reactions to the needle itself. Less movement when you smile, starting somewhere between day 2 and day 10, is the change you're expecting. Contact the clinic right away if nearby muscles seem weaker too, such as:

• One side of your upper lip lifting less, so your smile looks uneven

• Trouble pursing your lips because the upper lip feels weak

• A drooping eyelid or eyebrow

Weakness spreading to nearby muscles happens in fewer than 10% of Botox treatments and can last up to 12 weeks. It wears off with time, and there are ways to ease it in the meantime, so let the clinic know early.

It's better to hold off on Botox in these cases:

• You're pregnant or breastfeeding

• There's a skin infection where the injection would go

• You have a condition that weakens muscles, such as myasthenia gravis

• You've had an allergic reaction to Botox before

• You're taking certain antibiotics (bring a list of your medications)

Fitting Nose Botox Into a Trip to Seoul

Unless you've had sedation that day, there's no need to postpone your flight because of nose Botox.

One visit starts the change rather than finishing it. Since the effect builds over about 10 days, you may be home before you see the full result. Nose Botox doesn't reshape your nose on the spot; it softens how much it moves.

Once you're back home, you can send smiling photos through the consultation button on this page to check how things look. If your smile becomes clearly uneven, or an eyelid droops, see a local doctor first rather than waiting for a reply.

The Bottom Line: Find Out Which Width Is Bigger

Nose Botox results depend on where it goes: only the muscle at the side of the nostril, or also the one running down to the upper lip. That choice decides how much flaring settles and whether your smile changes. Before you decide, ask: "Is my nose wider at rest, or does it widen more when I smile?" That answer tells you whether to start with Botox or surgery.

If you're considering nose Botox, a consultation is where you can find out which approach fits your nose. Beautystone is a clinic in Seoul's Hapjeong area. When you reach out, include a neutral front photo and a smiling front photo in the same light, any nose procedures you've had and your dates in Seoul.

Sources

• Botox vs. saline for nostril flaring on smiling in 20 people (Aesthet Surg J, 2022)

• Review of Botox and device treatments for nose shape (Facial Plast Surg Aesthet Med, 2025)

• Results and scar changes after alar reduction surgery in 20 patients (J Craniofac Surg, 2025)

• Types of alar base reduction surgery and how they're chosen (Clin Plast Surg, 2022)

• How Botox works, how long it lasts, side effects and who should wait (DermNet)