Botox is the brand name of a drug made from botulinum toxin type A, which is made by the bacteria Clostridium botulinum.

This is the same toxin responsible for botulism, so the fact it even has a brand name might be considered a fun sign of where we are as a species.

However! It’s certainly popular, so let’s examine the science.

Cosmetic or therapeutic?

Being as it is a paralytic agent, it’s injected into muscles, usually of the face, usually to temporarily reduce the appearance of wrinkles.

• Sometimes this is because people don’t like to have wrinkles
• Sometimes this is because people have strabismus (misaligned eyes) or blepharospasm (twitching eyes) and the same paralysing agent can fix that

The former category is the most common, by far, but the latter category is overrepresented when it comes to reported adverse effects, i.e., people who have it to treat those conditions, are more likely to report problems. There are two main ways we can interpret that, if we want to hypothesize about causality:

1. people who have Botox for therapeutic rather than cosmetic reasons are more likely to experience adverse effects, perhaps because of the underlying condition being treated (actual causality)
2. people who have Botox for cosmetic rather than therapeutic reasons were happier to be having it in the first place, and thus less likely to report adverse effects if experienced (reporting bias)

You can read about the stats behind this, here:

Botulinum toxin type A injections: adverse events reported to the US Food and Drug Administration in therapeutic and cosmetic cases

We may note that in some cases, cosmetic procedures could be considered therapeutic, if it improves someone’s mental health, but even then there is a distinction.

For cosmetic surgery, for example, satisfaction rates vary thus:

• In “type change” (e.g. rhinoplasty), more psychological adjustment is needed, but when it’s all over, the person has a new nose and, statistically speaking, is usually happy with it.
• In “restorative” (e.g. facelift), less psychological adjustment is needed (as it’s just a return to a previous state), so a person will usually be happy quickly, but ultimately it is merely “kicking the can down the road” if the underlying problem is “fear of aging”, for example. In such a case, likely talking therapy would be beneficial—whether in place of, or alongside, cosmetic surgery.

For more details, see: The Many Faces Of Cosmetic Surgery

For Botox, this is of course “restorative”, and thus (per the science, which we link above) is less likely to result in any lasting improvement in mental health.

And what are the risks?

The recorded possible side effects are quite a laundry list:

• difficulty swallowing
• drooping eyelid
• neck weakness
• nausea
• vomiting
• blurred vision
• general or marked weakness
• difficulty chewing
• hoarseness
• edema
• difficulty speaking
• heart palpitations

But, anyone who has ever read the information leaflet that comes with pretty much any medication will note that in order to cover bases, anything that got reported, even if there was no evidence of association, gets listed.

With this in mind, a large review of evidence (with a total n=42,405) found:

❝…in all enrolled facial rejuvenation studies, patients in the BTX-A group had significantly more AEs than those patients in the placebo group (RR = 1.24; 95 % CI 1.07-1.43; p = 0.003).

For crow’s feet lines injection analysis, the BTX-A group did not exhibit any significant increase in AEs compared with the control group (RR = 1.19; 95 % CI 0.96-1.48; p = 0.12), except in injection site hematoma (RR = 2.14; 95 % CI 1.13-4.07; p = 0.02) in the treatment group.

For frown wrinkle injection analysis, AEs were significantly observed in the BTX-A group (RR = 1.47; 95 % CI 1.23-1.77; p < 0.0001), particularly headaches (RR = 1.53; 95 % CI 1.15-2.03; p = 0.003), eyelid ptosis (RR = 5.56; 95 % CI 1.68-18.38; p = 0.005), and heavy eyelids (RR = 6.94; 95 % CI 1.27-37.93; p = 0.03).❞

Source: Adverse Events of Botulinum Toxin Type A in Facial Rejuvenation: A Systematic Review and Meta-Analysis

AE = adverse event

Translating those stats from sciencese, we can summarize in broad terms* as follows:

• In total, the chance of adverse effects was 24% higher than placebo
• For crow’s feet wrinkle treatments, there was no significant increase, except in the case of injection site hematoma (2x increased risk compared to placebo), which is a little unsightly but is temporary and harmless
• For frown line wrinkle treatments, there as a 53% increased chance of headaches, and a 6x increased chance of heavy/drooping eyelids (which is really not too surprising if you inject a paralysing agent into the muscles next to the muscles that hold them up)

*we also rounded and averaged some figures for readability

In general, these risks have been considered acceptable by the medical establishment as a whole, for example:

❝Treatment with Botox is simple, safe and an effective modality for reduction of forehead wrinkles. It offers an alternative management in a cost-effective way when compared to surgical procedures.❞

Read in full: An Evaluation of Use of Botulinum Toxin Type A in the Management of Dynamic Forehead Wrinkles – A Clinical Study

Your own opinion of the acceptability of these risks may vary, of course.

But watch out!

Botox, administered skillfully by a professional, has a very different risk profile to fake Botox and/or administered incorrectly:

CDC | Harmful Reactions Linked to Counterfeit “Botox” or Mishandled Botulinum Toxin Injections

So, take care!