Antiperspirant vs Alum — Comparing Effectiveness and Safety
Antiperspirant or alum — we compare the effectiveness, ingredients and safety of both. See what science says about aluminium salts and potassium alum.
Where does sweat come from and why does it smell?
Sweat produced by the eccrine glands is mainly water with electrolytes — it is odourless in itself. The unpleasant smell arises when skin bacteria break down organic compounds (fatty acids, sterols) — chiefly Staphylococcus hominis and Corynebacterium. Antiperspirants and alum tackle this problem in different ways.
How does an antiperspirant work?
Antiperspirants contain aluminium salts — most often Aluminum Chlorohydrate (ACH), Aluminum Chloride, or Aluminum Zirconium Tetrachlorohydrex GLY. These salts enter the openings of the sweat glands and form a gel-like plug that physically blocks sweat secretion by 20–40% (depending on concentration and form). Their action is therefore antiperspirant — it reduces the production of the secretion itself, not just its smell.
Compare the products available in the antiperspirants category on PurScore.pl, where every product comes with an analysis of its INCI ingredients.
How does alum work?
Potassium alum (Alum, Potassium Alum — K Al(SO₄)₂ · 12H₂O) is a natural mineral. It works differently: it does not block the pores, but instead creates a low-pH environment on the skin that inhibits the growth of the bacteria responsible for odour. So it is effectively a mineral deodorant, not an antiperspirant. Sweating continues as normal — but it produces no smell, because the bacterial flora is temporarily kept in check.
Looking for alum stones and talcs? Take a look at the alum and talc category.
The aluminium question — what does science say?
Concerns about a link between aluminium salts and breast cancer or Alzheimer's disease have circulated online for years. It is worth taking a closer look at the facts, however:
- Breast cancer: In its opinion SCCS/1613/19, the European Scientific Committee on Consumer Safety (SCCS) concluded that, based on the available data, a causal link between aluminium salts in antiperspirants and breast cancer cannot be confirmed. At the same time, the SCCS set maximum safe concentrations: 10.60% for ACH in sprays and 6.25% in creams/sticks.
- Alzheimer's disease: The European Food Safety Authority (EFSA) points out that the main source of aluminium exposure is diet (food, water), not cosmetics. Transdermal absorption of aluminium salts from antiperspirants is negligible (estimated at 0.00048–0.06% of the dose).
- Potassium alum is an ionic molecule that penetrates the skin poorly. The available data suggest it is highly safe, although long-term clinical studies are lacking compared with the aluminium salts used in antiperspirants.
Effectiveness — a practical comparison
| Criterion | Antiperspirant | Alum |
|---|---|---|
| Sweat reduction | Yes (20–40%) | No |
| Odour control | Very good | Good with low activity |
| Duration of action | 24–72 h | 8–12 h |
| Risk of clothing stains | Yes (yellow stains from aluminium salts) | Minimal |
| Skin irritation | Possible (especially after shaving) | Rare |
Who should choose alum?
Alum works well for people with low-to-moderate perspiration, sensitive skin, a tendency to irritation after shaving, and those who choose to avoid synthetic additives. It is not sufficient for excessive sweating (hyperhidrosis) or intense physical exertion.
Are antiperspirants regulated by law?
Yes. In the European Union, antiperspirants are subject to EU Regulation 1223/2009 as cosmetic products. Concentration limits for aluminium salts and safety testing requirements are set by the SCCS. Manufacturers are obliged to maintain a Product Safety Report available to supervisory authorities.
You will find full information on aluminium salts and alum in the PurScore Ingredient Encyclopedia.
The information in this article is for educational purposes. In the case of excessive sweating or skin reactions, consult a dermatologist.
FAQ
Yes, potassium alum (Potassium Alum) contains aluminium, but in an ionic form that penetrates the skin poorly. This is a different form from the aluminium salts used in antiperspirants (e.g. aluminium chlorohydrate).
According to the SCCS opinion (2019), aluminium salts at the permitted concentrations are safe in cosmetics. No link with breast cancer or Alzheimer's disease has been confirmed. People with damaged skin (after shaving) should take care.
Yellow stains result from a reaction between aluminium salts and the proteins in sweat and the fabric fibres, made worse by high temperatures. Using less product and putting clothes on only after the antiperspirant has dried reduces this effect.
During intense physical exertion and heavy sweating, alum usually does not provide enough protection for the whole day. It works better as an everyday option with moderate activity.
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