What matters when you have your Botulinum toxin (Botox) is the overall number of units that you are given. Practitioners may choose to dilute their Botox with varying amounts of saline, and this will affect how far the Botox diffuses away from the injection site. Personally, when I am treating frown lines between the eyebrows in the frown line (Glabella) region I like to use it in quite a concentrated form (100 units of Botox diluted in 1 ml of saline, giving 10 units per 0.1ml), as I want the Botox diffusion to be quite limited. When I am treating horizontal forehead lines I prefer to use it in a more dilute form (100 units in 2mls of saline) so that I can achieve more diffusion of the botox over a wider area of muscle.
So why does the total number of units that you are given matter so much? Because studies have shown a clear dose-response relationship between the duration of effect and the dosage that you are given. If you are given 20 units of Botox into your glabella frown line region it will last about 16 weeks in 75% percent of clients, whereas if clients are given half that dose it will only last that long 35% of the time, and you will therefore probably be needing more treatment well before the end of four months after your last treatment with this dosage.
So if you are of average build and normal facial muscles mass, and you are having the frown line and your forehead treated with Botox you should probably be getting a total dosage of around 40-50 units. This will reliably achieve an effect that is going to last you for the next four months or so. Clearly if you are exceptionally lean or exceptionally well endowed with facial muscles then the dosage will need to be altered accordingly.
Don’t forget that if your if your doctor is using Dysport (marketed under the name of Azzalure in Europe) then the number of units will be different. It will be about 3 times higher than with Botox or Xeomin as Dysport/Azzalure, unit for unit, is only one third as powerful as Botox. So one unit of Botox is equivalent to around 3 units of Dysport / Azzalure. When given in appropriate dosage studies have shown that Dysport/Azzalure is as effective as Botox. So ask your practitioner about the total dosage they are planning to use. If it’s a lot less or a lot more than the quantities mentioned above for the forehead and frown line areas, ask them why.
I was trained in London at the Royal Free Hospital School of Medicine. I qualified in 1982. I spent many years working as a consultant in paediatric medicine in Middlesbrough. I retired from the NHS in July 2010 and am now working as an aesthetic doctor. I am married and have two children, who are home educated.
Hi,
Thank you for taking the time to read my e-mail.
I have been having botox for the past 5 years, and it used to last for approx 4 months. It now lasts up to 9 weeks roughly, and was enquiring whether due to age/ lifestyle that it would decrease in length of treatment success.
I am 43/ sports therapist so active within my job, I go to the gym roughly 4 times a week, 90 minutes on cardio machines at mid effort.
I drink moderately 1/2 a week.
As the procedure is an expensive treat, have you any advice on how to prolong the treatment, or is my administrator diluting the botox with saline a little to freely?
kind regards
Anon
Thanks for your question. The most probable cause for your botulinum toxin treatment not lasting as long as it used to is that your body as developed a degree of immunity to the type of toxin that you are being injected with. This is known to happen in about 5% – 10% of clients over the years. Often this necessitates increasing the dosage or frequency of the botox or both. Switching to a less immunogenic type of botox (such as Xeomin – also known as Bocotoure) would also be worth trying. In my own clients with this problem I have found that this usually works and the duration gradually stabilizes, although there are reports in the research literature of the occasional treatment failure due to the development of botox resistance.
Good luck.
Mark