What are antiperspirants?
Antiperspirants are products designed to reduce sweat or perspiration on the skin. They are available in many formulations including creams, powders, sprays, towels, and roll-ons.
Most commercially available, non-prescription preparations contain low concentrations of aluminium salts such as aluminium chloride, aluminium chlorohydrate, and aluminium zirconium. Aluminium zirconium is thought to be better tolerated by the skin and less likely to cause irritation or aggravation to razor burn.
For individuals who suffer from excessive perspiration (known as hyperhidrosis), a prescription antiperspirant may be a more efficacious option. These agents contain higher concentrations of aluminium chloride or the more potent variant, aluminium hexahydrate.
Recently, topical anticholinergic agents have been introduced which reduce the nervous impulses that stimulate sweat glands to produce sweat. Oral anticholinergic drugs can also be used but are more likely to produce side effects (eg, dry mouth, abdominal aches, difficulty in focusing) than topical agents.
Botulinum toxin and physical or surgical options to reduce sweating are covered in hyperhidrosis.
What is the difference between a deodorant and an antiperspirant?
Deodorants are not antiperspirants; they do not prevent sweating. Their aim is to mask the malodour produced by sweat-metabolising bacteria. An antiperspirant preparation may also contain a deodorant.
How do antiperspirants work?
The mechanism of action depends on the active ingredients within the antiperspirant formulation itself.
Antiperspirants containing metallic salts such as aluminium-based compounds:
- React with mucopolysaccharides on the skin and within the sweat duct leading to damage of the surface epithelia, physical blockage of the sweat glands, and subsequent inability to secrete sweat.
Antiperspirants containing anticholinergic substances such as glycopyrrolate or diphemanil methylsulfate:
- Target cholinergic muscarinic receptors on sweat glands, reducing their activity and thus decreasing sweat production.
How do you use an antiperspirant?
The following routine should be followed nightly for approximately 7–10 days or when a reduction in symptoms is seen; whichever is earlier. The application interval can then be extended, ie, second daily application, third daily application etc; until a maximum duration between treatments is reached.
- Apply to dry skin, after a cool shower before bed — perspiration is limited during sleep and therefore the antiperspirant is more likely to be absorbed and less likely to irritate.
- Wash off the next morning, removing the antiperspirant completely.
- If there is irritation and redness, 1% hydrocortisone cream can be applied in the morning; this may diminish irritation and allow treatment to continue.
For most people, the maximum period between applications that can be reached is one week; however, this varies from person to person. It is generally recommended that patients start at lower concentrations before progressing to higher strengths and/or prescription-only options.
For more information on reducing perspiration, see hyperhidrosis.
Where can antiperspirants be used?
Typically, antiperspirants are used for axillary hyperhidrosis, but can also be used on other areas prone to hyperhidrosis. This includes areas containing two types of glands.
Sweat-producing eccrine glands
- Sweat is a dilute salt solution produced by eccrine sweat glands spontaneously or in response to heat, exercise, and stressful events.
- Eccrine sweat is initially odourless but can start to smell if bacteria get a chance to break down the stale sweat.
- The eccrine glands are distributed over the entire body but are most numerous under the arms and on the palms and soles.
Pheromone-producing apocrine glands
- Located around the breasts axillae and in the groin.
- After puberty, they produce a thick secretion that contains pheromones, the 'personal scent' that most people find unpleasant.
- Bacteria that normally live on the skin break down apocrine sweat and this produces offensive body odour.
- Antiperspirants also help to reduce apocrine sweat production.
Diphemanil methylsulfate powder may also be used to reduce perspiration. It is particularly useful on an amputation stump to reduce irritation by a prosthesis.
What are the risks associated with antiperspirants?
The more efficacious antiperspirants contain higher concentrations of their active agents and therefore are at greater risk of causing side effects.
These side effects include:
- Irritant or allergic contact dermatitis
- More likely if used on areas with thinner, more delicate skin (eg, underarms).
- More likely in individuals with atopy, sensitive skin, or previous history of irritant/contact dermatitis.
- Anticholinergic (antimuscarinic) side-effects with glycopyrrolate or diphemanil methylsulfate, eg, dry mouth and dry eyes and temporary difficulty in focusing when applied to the face
- Facial application should be avoided.
- Cyst formation
- Associated with long-term antiperspirant use due to chronic plugging of the sweat glands and hair follicle.
- Risk of infection and need for antibiotics and drainage.
- Risk can be reduced by washing and exfoliating the area regularly.
- Aluminium-based antiperspirants should be avoided in those with hidradenitis suppurativa.
Topical anticholinergics should not be used in young babies as it has been reported to cause toxicity.
Controversy surrounding antiperspirants
Recently, concern has arisen regarding the potential risk of malignancy with the use of aluminium-containing antiperspirants. Specifically, there has been debate regarding the risk of cancerous changes within breast tissue due to systemic aluminium exposure. However, toxicity related to topical application of aluminium is still controversial as metallic salts have poor systemic absorption.
There has been no scientific evidence to date that has shown a direct correlation between the risk of breast cancer and antiperspirants, which should reassure patients.