Botulinum Toxin and How it Works for Wrinkles

How Botox can improve the appearance of wrinkles

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Botulinum toxin injections are one of the most popular cosmetic procedures and can be used to reduce the appearance of wrinkles.[1] Botulinum toxins are available as onabotulinumtoxinA (Botox®), abobotulinumtoxinA (Dysport®), and incobotulinumtoxinA (Xeomin®). The brands have slight differences among them, but they all contain the type A version of botulinum toxin.

Botulinum toxin is a protein derived from the bacterium Clostridium botulinum. It is a powerful molecule that is dangerous when humans are overexposed. However, scientists have figured out how to use very small amounts for both medical and cosmetic uses. One of the uses is to temporarily decrease the ability of a muscle to contract, thereby improving and decreasing the appearance of wrinkles.


What Does Botulinum Toxin Do?

Normally, a nerve talks to a muscle to tell it when to contract. This communication occurs at what is known as the neuromuscular junction. This is where the nerve releases a signal called acetylcholine that can then activate muscles to contract. Botulinum toxin works by blocking the release of acetylcholine from nerves and the activation of muscle.[1]


How Does Botulinum Toxin Work on Wrinkles?

Facial wrinkles develop due to a combination of factors:

  • Contraction of facial muscles: As facial muscles contract, they repetitively move the skin over and around them, leading to the formation of wrinkles. Botulinum toxin can temporarily improve wrinkles by reducing muscle contraction.
  • Loss of skin hydration: Skin hydration is important as it increases skin’s water and substance. Dry skin leads to more visible lines on the face and increases the appearance of fine wrinkles. Botulinum toxin does not affect skin hydration.
  • Breakdown of collagen on the face: Facial collagen is important to maintain the integrity of the skin. Facial collagen breaks down after chronic exposure to ultraviolet radiation from sunlight,[2,3] cigarette smoke,[4] and pollution.[5] Botulinum toxin does not alter how collagen breaks down.

When botulinum toxin is correctly and accurately injected, specific muscles can be targeted so that they don’t contract as forcefully. This allows wrinkles to relax and become less visible. Depending on the brand of botulinum toxin, it can be approved by the Food & Drug Administration (FDA) for the improvement of wrinkles on the glabella (the location of frown lines) and on sides of the eyes (location of crow’s feet). However, dermatologists and qualified health practitioners may use BT off-label to help improve other wrinkles on the face and elsewhere on the body.


Does Botulinum Toxin Improve All Wrinkles?

No. Botulinum toxin only works by reducing the appearance of wrinkles caused by constant muscle contraction. It does not alter how collagen is produced or broken down in the skin and does not affect skin hydration. Therefore, it works better on dynamic wrinkles rather than static wrinkles. Here is the difference between the two types of wrinkles:

  • Dynamic wrinkles: Wrinkles that may not be visible or are slightly visible when the face is at rest. These wrinkles are more shallow in depth. The wrinkles become visible with facial movement and muscle contraction.
  • Static wrinkles: Wrinkles are clearly visible even when the face is at rest. These wrinkles are deeper in depth. They may become more prominent when the muscles are contracted.


Side Effects of Botulinum Toxin Injections

Botulinum toxin injections can be associated with the following effects:

  • Pain with injection
  • Injection site bruising
  • Headaches
  • Eyelid ptosis (eyelid droop)
  • Heavy eyelids


How Long Does Botulinum Toxin Last?

Botulinum toxin usually takes a week to start working. In other words, if you just had your injections done yesterday, you will not see an effect right away. The effects usually last for two to four months, and the duration of effect can increase with repeated treatment. However, in some people, botulinum toxin can actually become less effective with repeated usage. 

Talk to you local health practitioner or dermatologist to find out more about botulinum toxin.


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  1. Gart MS, Gutowski KA. Overview of Botulinum Toxins for Aesthetic Uses. Clin Plast Surg.2016;43(3):459-471; PMID: 27363760.
  2. Imokawa G, Ishida K. Biological mechanisms underlying the ultraviolet radiation-induced formation of skin wrinkling and sagging I: reduced skin elasticity, highly associated with enhanced dermal elastase activity, triggers wrinkling and sagging. Int J Mol Sci.2015;16(4):7753-7775; PMID: 25856675.
  3. Imokawa G, Nakajima H, Ishida K. Biological mechanisms underlying the ultraviolet radiation-induced formation of skin wrinkling and sagging II: over-expression of neprilysin plays an essential role. Int J Mol Sci.2015;16(4):7776-7795; PMID: 25856676.
  4. Chien AL, Qi J, Cheng N, et al. Perioral wrinkles are associated with female gender, aging, and smoking: Development of a gender-specific photonumeric scale. J Am Acad Dermatol.2016;74(5):924-930; PMID: 26803346.
  5. Li M, Vierkotter A, Schikowski T, et al. Epidemiological evidence that indoor air pollution from cooking with solid fuels accelerates skin aging in Chinese women. J Dermatol Sci.2015;79(2):148-154; PMID: 26055797.