Botox injections: advantages and disadvantages.

Originally, botulinum toxin was used exclusively in medicine to manage certain neurological or muscular disorders. The term "botox", which was initially a commercial trademark, gradually became the common name for botulinum toxin injections. This substance, produced by the bacterium Clostridium botulinum, is known for its toxicity at high doses, but also for its therapeutic effects at extremely low doses.

Botulinum toxin must be purified, precisely dosed, and administered under strictly controlled conditions to ensure its safety. Injections should be performed exclusively by trained professionals in appropriately equipped medical facilities.

Approved for aesthetic purposes for the first time in the late 1990s, and practiced in France since the early 2000s, botox is today primarily used to attenuate the expression lines. Its mechanism of action relies on blocking the release of acetylcholine, a neurotransmitter involved in muscle contraction. By preventing this neural transmission, the targeted muscle gradually relaxes, limiting the contractions responsible for the formation or deepening of wrinkles. Injections are most often administered to the glabellar lines, forehead lines, crow’s feet, and nasolabial folds. The effects are not immediate: they generally appear between 3 and 7 days after injection and wane after 4 to 6 months.

Discover our Targeted Skin-Tightening Concentrate, a 'notox' treatment that smoothes expression lines in 5 minutes and is thought to be an alternative to botox.

Today, Botox injections are so widely performed because they offer visible benefits, particularly for expression lines. By acting directly on the muscular activity responsible for repeated facial contractions, botulinum toxin smooths established wrinkles and helps prevent the deepening of those still forming.

Botox injections also have the advantage of being simple and rapid procedures. The procedure typically lasts only a few minutes and requires neither general anesthesia nor extended social downtime. Injections are administered using ultra-fine needles, making the process minimally painful for most patients. Post-procedure effects are generally mild, with occasional slight redness or transient bruising at the injection site.

These characteristics partly explain the success of Botox, which provides progressive aesthetic enhancement through a relatively mild protocol when administered by an experienced professional.

Botox injections are generally considered safe when performed under proper conditions, but they are not without adverse effects. The most frequent complications are mild and transient, arising in the days following injection. They mainly involve the injection site, manifesting as pain, redness, swelling, bruising, or localized tenderness. Headaches or flu-like symptoms may also occur. On the muscular level, excessive or poorly targeted relaxation can result in undesirable aesthetic outcomes, such as facial asymmetry, a frozen appearance, or drooping of the eyelid or eyebrow (ptosis). While many of these reactions typically reverse within a few days to weeks without specific intervention, some require corrective injections.

Cutaneous or allergic reactions have also been reported, although less frequently. These may manifest as diffuse redness, itching, skin eruptions, hives, or facial edema. In very rare cases, delayed hypersensitivity reactions have been described. A case report, in particular, documented a delayed hypersensitivity reaction following botulinum toxin injections. In one female patient, the initial injection performed in July 2019 yielded aesthetic results deemed insufficient after one month (A). A touch-up injection was then administered (B). Four days after this second injection, the patient exhibited marked facial edema accompanied by erythematous lesions, indicating a delayed inflammatory reaction (C). The lesions resolved spontaneously after three weeks.

More rarely, serious complications may be observed following botulinum toxin injections. They are most often linked to excessive diffusion of the toxin beyond the initially targeted injection site, administration of doses that are too high, or an inappropriate injection technique. Because botulinum toxin acts on neuromuscular transmission, even limited systemic diffusion can disrupt essential muscle functions. Such events remain exceptional in aesthetic medicine, but they are well documented in the medical literature.

Among the reported manifestations are general symptoms suggestive of a clinical presentation similar to botulism. Patients may present with diffuse muscle weakness, pronounced fatigue, difficulty swallowing (dysphagia), or difficulty speaking (dysarthria). In the most severe cases, involvement of the respiratory muscles may occur, leading to respiratory distress that requires urgent medical intervention. These effects are more frequently described in therapeutic uses of botulinum toxin, which involve higher doses, but they have also been reported, albeit exceptionally, after cosmetic injections.

Ocular complications represent another rare but specific risk associated with injections performed in the peri‐orbital region. Diffusion of the toxin to the extraocular muscles or the eyelids can lead to a double vision, eyelid ptosis, severe ocular dryness, or incomplete eyelid closure. The latter can expose the cornea to excessive drying, with a risk of irritation or, more rarely, corneal damage. These complications underscore the importance of precise anatomical knowledge and a rigorous technique when administering injections in these sensitive areas.

In exceptionally rare cases, serious infectious or vascular complications have been reported, such as deep soft-tissue infections or localized vascular injury. These events remain extremely uncommon and are often linked to inadequate aseptic conditions. Finally, deaths have been described in the medical literature, primarily in therapeutic settings involving high doses of botulinum toxin, especially in patients with significant comorbidities. In aesthetic medicine, these occurrences remain exceptional, but they require clear patient information and strict adherence to indications and safety protocols.

Botox injections are never a trivial procedure. Given the potential for adverse effects, which can sometimes be severe, it is essential to carefully consider your decision, gather thorough information, and consult only a qualified, experienced healthcare professional who can evaluate the indications and contraindications and ensure the safety of the procedure.

• YIANNAKOPOULOU E. Serious and long-term adverse events associated with the therapeutic and cosmetic use of botulinum toxin. Pharmacology (2015).

• GRECO T. M. & al. Advanced techniques for the use of neurotoxins in non-surgical facial rejuvenation. Aesthetic Plastic Surgery (2020).

• RAHMAN A. & al. A review of complications due to the use of botulinum toxin A for cosmetic indications. Aesthetic Plastic Surgery (2021).

• GOLDUST M. & al. Complications of botulinum toxin A: An update review. Journal of Cosmetic Dermatology (2021).

• SCHIUMA A. T. & al. A systematic review and comparative analysis of botox treatment in aesthetic and therapeutic applications: Advantages, disadvantages, and patient outcomes. Cureus (2024).

• CHEN J. & al. Dysphagia and muscle weakness caused by botulinum toxin poisoning after cosmetic injection: Three case reports and clinical warnings. Dysphagia (2025).

• CAI H. & al. A rare case of delayed-onset hypersensitivity reaction and complete secondary treatment failure following repeated cosmetic botulinum toxin type A injections. Journal of Cosmetic Dermatology (2025).