Botox is a purified botulinum toxin type A that temporarily relaxes specific facial muscles to soften expression lines such as frown lines, forehead lines, and crow’s feet. It blocks the nerve signals that tell a muscle to contract, so the overlying skin creases less. Results appear within a few days and typically last 3–4 months.
How does Botox work?
Botox (onabotulinumtoxinA) is injected in tiny amounts into targeted muscles, where it blocks the release of acetylcholine — the messenger that triggers muscle contraction. With the muscle relaxed, dynamic wrinkles (lines that form when you frown, squint, or raise your brows) are smoothed, and the repeated creasing that deepens lines over time is reduced. Botox Cosmetic has been FDA-approved for frown lines since 2002 and used in millions of treatments worldwide.
Botox vs. Dysport: what’s the difference?
Both are botulinum toxin type A neuromodulators and both are FDA-approved to soften glabellar (frown) lines. Practical differences:
- Onset: Dysport often works in 2–3 days; Botox in 5–7 days.
- Spread: Dysport diffuses slightly more (useful for broad areas like the forehead); Botox is often chosen for precise, targeted areas.
- Dosing: Units are not interchangeable — studies use roughly a 2.5:1 Dysport-to-Botox ratio.
- Duration: Both generally last about 3–4 months.
Who is a good candidate?
Generally healthy adults who want to soften dynamic expression lines. Botox is not recommended during pregnancy or breastfeeding, or with certain neuromuscular conditions. A medical-history review confirms whether it is appropriate.
Risks and side effects
Botox and Dysport have strong safety records when administered by trained clinicians. Common, temporary effects include redness, swelling, or bruising at injection sites and mild headache; less commonly, temporary eyelid or brow heaviness. Serious effects are rare.
Results and timeline
Softening usually begins within a few days, with full results around two weeks, lasting about 3–4 months. With consistent maintenance, lines often appear softer over time.
Frequently asked questions
Is Botox safe?
Yes — Botox and Dysport are FDA-approved and used safely in millions of treatments when performed by qualified professionals following FDA guidelines.
How long does Botox last?
Typically 3–4 months, depending on the area, muscle strength, and individual metabolism.
Does Botox hurt?
Most people describe the injections as quick pinches; numbing or ice can be used for comfort.
Will I look “frozen”?
Not when dosed conservatively — a skilled injector softens lines while preserving natural expression.
Physician-reviewed educational overview. At MD Laser & Cosmetics in San Mateo, Botox and Dysport treatments are performed by Dr. Susan Lin, M.D., serving patients within a ~25-mile radius including Burlingame, Foster City, Belmont, San Carlos, Redwood City, Millbrae, Palo Alto and the greater Peninsula. This page is educational and not a substitute for a medical consultation.
References: U.S. FDA · American Academy of Dermatology. For guidance specific to you, consult a physician.