Forehead lines and frown lines: Botox dosing, timing, and what actually works

Forehead lines and frown lines (the vertical "11s" between the brows) are the most commonly treated areas with neuromodulators. Despite how common the treatment is, dosing errors and mismatched expectations are frequent. Here's what actually matters.

The two muscle groups involved

Forehead horizontal lines are created by the frontalis muscle — the large muscle that runs vertically up the forehead and contracts when you raise your eyebrows.

Frown lines (glabellar lines / "11s") are created by the corrugator supercilii and procerus muscles — the muscles between and above the brows that contract when you frown or squint.

Understanding the relationship between these muscles is the most critical concept in forehead treatment.

The frontalis-brow relationship

The frontalis muscle (forehead) has a compensatory function: it contracts to elevate the brows. If you weaken the frontalis too much or without treating the depressor muscles (corrugators, procerus, orbicularis), the brow drops — creating the heavy, hooded appearance that patients frequently complain about.

This is why treating the forehead alone without treating the glabella is usually incorrect. The ideal approach:
Treat the glabella (which depresses the brow) with adequate doses
Treat the frontalis conservatively (too aggressive a dose drops the brow)
The net effect: brow position is maintained or elevated slightly, and forehead movement is smoothed without heaviness

Providers who don't understand this relationship, or who treat only the area the patient asks about, frequently create brow drop.

Botox vs. Dysport vs. Xeomin vs. Daxxify

All neuromodulators work by blocking the signal at the neuromuscular junction, but they differ in formulation, onset, spread, and duration:

| Product | Manufacturer | Onset | Duration | Notes |
|---|---|---|---|---|
| Botox (onabotulinumtoxinA) | Allergan/AbbVie | 5–7 days | 3–4 months | Most studied; benchmark product |
| Dysport (abobotulinumtoxinA) | Galderma | 2–4 days | 3–4 months | Spreads more; different unit ratio to Botox |
| Xeomin (incobotulinumtoxinA) | Merz | 5–7 days | 3–4 months | "Naked" toxin (no accessory proteins); less antibody resistance |
| Daxxify (daxibotulinumtoxinA-lanm) | Revance | 5–7 days | 6+ months | Peptide-enhanced formulation; FDA-cleared for longer duration |

Unit equivalence: Dysport units are NOT the same as Botox units. Approximately 2.5–3 Dysport units = 1 Botox unit. Providers pricing by units should clarify which product they're pricing.

Typical dosing for forehead and glabella

These are general ranges — individual anatomy varies significantly.

| Area | Typical Botox dose | Notes |
|---|---|---|
| Glabella (11s) — female | 20–30 units | Higher doses for deep etched lines |
| Glabella (11s) — male | 25–40 units | Stronger muscles in most men |
| Forehead — female | 8–15 units | Lower doses to preserve some movement and avoid brow drop |
| Forehead — male | 10–20 units | Heavier muscles; more units needed |
| Glabella + forehead combined | 30–50 units | Treated together in most approaches |

Red flag: Providers who offer forehead-only treatment with 20+ units without asking about your brow position are likely to create heaviness or brow drop.

When to start and how often to treat

When to start: The best time to start Botox for prevention is when dynamic lines become visible at rest (beginning to become static). For most people this is late 20s to early 30s. Starting earlier than this provides minimal benefit; starting before lines become static prevents them from becoming etched permanently.

Frequency: Every 3–4 months for Botox/Dysport/Xeomin; every 6+ months for Daxxify. The goal is retreating before the lines fully return — most providers recommend treating when movement returns to about 50% rather than waiting for full return.

Does early, consistent Botox reduce how much you need over time? Yes — with consistent use, patients often find they need slightly less over years because the muscle atrophies mildly with disuse.

What Botox cannot fix

Static lines (etched at rest): Deeply etched lines that are visible with the face completely relaxed are in the skin, not in muscle movement. Botox prevents the muscle from deepening them further but doesn't fill them. These require a filler approach (soft filler, like Belotero or diluted Juvederm) placed precisely in the line, or resurfacing (fractional laser, RF microneedling) to stimulate collagen remodeling in the line.

Skin laxity, crepiness, or texture: Botox relaxes muscle — it doesn't improve skin quality. Retinoids, RF microneedling, or laser resurfacing address skin quality.

Horizontal forehead lines in patients with significant brow ptosis: If the brows are already low-positioned, treating the frontalis (which is holding the brows up) drops them further. In this situation, surgical brow lift or Ultherapy brow lift is more appropriate.

Combination approaches for forehead and frown lines

Botox + filler for deep glabellar lines: Botox to stop the movement creating the line, then soft filler to fill the static line. This combination produces better correction of established lines than either alone.

Botox + resurfacing (RF microneedling, fractional laser): For significant skin quality issues and etched lines. The timing matters: most providers recommend doing Botox first and waiting 2–4 weeks before resurfacing.

Botox + brow lift (Ultherapy or surgical): For patients with significant brow ptosis, energy-based brow lifting combined with conservative frontalis Botox addresses both concerns.

What a treatment session is like

Session duration: 10–15 minutes once numbing cream (optional, often not used for small treatments) is applied.

Pain level: Minor. Brief sharp sensation at each injection point; most patients find it very tolerable.

After treatment:
Remain upright for 4 hours
Don't rub or massage the treated area for 24 hours
Expect mild redness at injection points for 30–60 minutes
No strenuous exercise for 24 hours

Follow-up: Most providers offer a 2-week touch-up if results are asymmetric or insufficient. This is standard — small adjustments are common.

Questions to ask your provider

Do you recommend treating my forehead and glabella together, or do you have a reason to treat one area alone?
How many units do you typically use in patients with my muscle strength and line depth?
What's your protocol if I'm unhappy with the result at 2 weeks (heavy brow, uneven movement)?
For my deep static lines, would you recommend filler or resurfacing in addition to Botox?
Should I be treating any other areas (crow's feet, lip lines) at the same time for a balanced result?

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