Crystal Deodorant Singapore: Prices, Picks and the Aluminium Question

Last updated: September 2026.

Your grandmother in Penang probably had a chunk of batu tawas on the bathroom shelf. Crystal deodorant is the same mineral, cut smooth and sold in a stick, and it works the same way: a thin salt film on the skin that reduces the smell without touching the sweat.

Below are four Singapore prices read off the retailers' own pages on 2 Sep 2026, with the cost per gram worked out, and a straight answer to the question the whole category is built on.

The short version

One of those four is ours. If you soak through a shirt rather than simply smell, none of them is the right product and you want the zinc oxide and microsilver option instead.

Is crystal deodorant aluminium free?

No.

Crystal deodorants are alum salts, usually potassium alum and sometimes ammonium alum. Potassium alum is potassium aluminium sulfate, KAl(SO4)2.12H2O. Aluminium is in the name and in the molecule. A product made of it is not aluminium free, whatever the front of the pack says, and "aluminium free" is a common phrase on crystal deodorant packaging and product titles in this market.

Our own 120g stone is made of the same mineral, so this is not a point we can score off anyone. It is just what the chemistry says.

The difference that is real

Conventional antiperspirants use aluminium chlorohydrate or aluminium zirconium tetrachlorohydrex glycine. These react with proteins in the sweat duct to form a gel plug. That is how they cut wetness, and it is why they work for people who soak.

Alum does not do that. It sits on the skin surface and does not plug the duct. Your sweat output is unchanged. What changes is the bacteria.

So if your reason for avoiding conventional antiperspirants is the duct-plugging mechanism, or a preference for a single named mineral over a formulated stick, crystal alum answers that. If your reason is that you want no aluminium in any form, crystal alum does not answer it, and magnesium hydroxide, zinc oxide or sodium bicarbonate formulas are where to look. Our natural deodorant shortlist covers several of those, including ones we do not sell.

How it works

Body odour is not sweat. Fresh eccrine sweat is close to pure water and apocrine sweat is odourless when it leaves the skin. The smell comes from skin bacteria breaking sweat down into short-chain fatty acids and thioalcohols.

Alum interrupts that. The stone dissolves in the moisture on damp skin and leaves a thin, astringent mineral-salt film, and alum inhibits the growth of the organisms responsible. Al-Talib and colleagues exposed four axillary malodour-producing bacteria to potassium aluminium sulfate in a laboratory dish and reported inhibited growth (Journal of Clinical and Health Sciences, 2016). That is a test-tube result rather than a trial on people, and the mechanism behind it is not settled in the literature we could find, so we are not going to explain to you exactly why it happens.

It is a deodorant, not an antiperspirant. It works on the smell. It does nothing about the wet.

What crystal deodorant costs in Singapore

Prices below were read from each retailer's own page on 2 Sep 2026. Cost per gram uses the price shown that day and the weight the seller publishes. We checked the first page of Google Singapore for "crystal deodorant" on 30 Aug 2026 and found no priced comparison across sellers, which is why this table exists.

At the prices actually charged that day, the most expensive gram in the table costs about 4.7 times the cheapest. Compare list prices instead and the gap widens to about 6.3 times. Every entry is the same active mineral.

One of the five rows is promotional and will move: the Corpore Sano discount cycles, and its list price is S$28.45. Salt of the Earth ran a S$14.35 offer that ended on 31 Aug 2026, so the S$16.90 above is the standing price again. Bamboo Straw Girl's blocks are handmade and the seller states the weight varies between 95 and 110g, which is why that row carries a range rather than a single figure.

Two more sellers turn up in the Singapore results and are not in the table because we could not read a price. CRYSTAL, the long-running US brand, is sold through iHerb SG, which does not display a figure before checkout. The Green Collective lists crystal stones but its site returned no price to us on the day.

The four picks in detail

1. Efreshme Pure Crystal Deodorant, 120g, S$8.99

Ours, so weigh it accordingly. Pure mineral salts, unscented, no fragrance and no preservatives. At S$0.075 per gram it is the cheapest of the four priced options in the table, using the 120g weight published on our product page.

It will not keep you dry. Our product page carries a "24 Hour Odor Protection" line, and that is a marketing claim about smell that we have not put through an independent wear test. Read it as a claim about odour, not about sweat. Available on our website, S$8.99.

2. Bamboo Straw Girl stone, 95 to 110g, from S$14.00

Google put this first in Singapore for "crystal deodorant" when we checked on 30 Aug 2026. Paper-wrapped, no plastic, sold by a local social enterprise that has been shipping this stone since 2015, with 45 reviews on the product page of which 44 are five-star. Options run S$14.00 for the stone alone, S$16.50 with a batik pouch made from offcut fabric, S$20.00 with a standing soap dish, and they sell chipped blocks at a discount rather than bin them.

The listing is titled "Aluminium Free", which is the wording covered above. The explanation further down that same page is careful and correct about what the mineral is and how it differs from antiperspirant salts.

3. Salt of the Earth Classic, 90g, S$16.90

UK brand, pure potassium alum, unscented, sold through the FairPrice marketplace so it lands with a grocery order. FairPrice's own summary describes it as "keeping customers dry and odour-free", and the dry half of that is not something a potassium alum stick delivers. The brand's own description lower on the same page is accurate and says the mineral salts sit on the skin and inhibit odour-causing bacteria.

4. Corpore Sano Crystal Deodorant Aloe Vera, 60g, S$21.34 with the current discount

Australian origin, sold at Watsons SG under product code 76921, described on the listing as dermatologically tested for sensitive skin. Check stock before you make the trip: when we looked on 2 Sep 2026 the online listing had switched to Notify Me and pointed shoppers to physical stores, so it is a walk-in buy rather than a delivery one.

One thing does not add up. The product is named for aloe vera, but the ingredient list Watsons publishes reads "100% pure natural crystal salt", with no aloe in it. A previous version of this guide told you the aloe buffers alum sting on sensitive skin. We are withdrawing that, because we cannot tell from the listing whether there is aloe in the stick at all. If soothing additives are why you are considering it, ask Watsons for the full ingredient list before paying roughly 4.7 times the per-gram price of the cheapest option in the table.

Where crystal deodorant struggles in Singapore

The film needs damp skin to form, and once formed it holds through a normal day. What it does not survive is sustained heavy sweat, which washes it off. If your underarm is running by 11am, the film thins, the bacteria recover and the smell returns in the afternoon.

• Air-conditioned most of the day, outdoors in short bursts: crystal alum is a strong pick and one morning application usually holds.
• Outdoors by default, or a long walk on either end of the commute: expect to reapply at lunch. It takes about thirty seconds at a washroom sink.
• Actually soaking through a shirt: wrong product. You need a real antiperspirant for the wetness, or a stronger antibacterial like a zinc oxide and microsilver cream. Our guide to stopping underarm odour in Singapore works through the decision.

Malaysia: batu tawas and deodorant garam kristal

Reading this from KL, JB or Penang, the local names for the same mineral are batu tawas and deodorant garam kristal, and it sits on pharmacy shelves as a mainstream item rather than an eco-shop curiosity.

The one we priced on the day: Total Image Smelly No More Roll On 60g at Watsons MY, product code 46575, RM16.50 with an 8 percent discount against a usual RM17.90, and RM14.85 for Watsons members. The listing states no alcohol, fragrance, chemicals or oil. Malaysian pharmacy chains also carry it in 120g.

We are not converting any of that to Singapore dollars. Cross-border shipping, the rate on the day and the SST treatment all move independently, so a converted figure would look precise and mean nothing.

How to use a crystal stone correctly

1. Apply to damp skin. Straight out of the shower is ideal. If your skin is dry, run the stone under a tap for three seconds first. The alum needs surface water to dissolve into a film, and on bone-dry skin with a dry stone nothing forms at all.
2. Sweep three to five times per side. No need to grind. A working film is invisible.
3. Air-dry twenty to thirty seconds before dressing. Pulling a shirt over a wet application smears most of it off.
4. Skip it after shaving or waxing. Wait a day. Salt on micro-cuts stings, and this is a common reason people conclude they are allergic when they are not.
5. Dry the stone after every use. A wet stone sitting in a puddle dissolves itself. Wipe it and store it dry.
6. Reapply mid-day if you sweated through it. Rinse, pat dry, reapply.

Common reasons it looks like it does not work

• Applying to dry skin without wetting the stone. No film, no protection. A common first-timer failure.
• Expecting it to stop sweat. It does not reduce sweat output.
• Switching from an antiperspirant on Monday and judging it by Wednesday. Users commonly report a settling-in period of a week or two after years of antiperspirant use, with week one sometimes worse than baseline. Give it the fortnight.
• Applying over perfumed shower-gel residue. Fragrance oils sit between skin and salt and block the film. Rinse clean first.
• Buying a fragranced crystal stick and blaming the alum. On sensitive skin the added fragrance is usually the culprit. Start unscented for the first month.

Crystal alum against the other natural options

If you smell but rarely soak, crystal alum does the job, and the price table above shows what the same job costs from four different sellers. If you soak, it is the wrong tool whatever the price per gram says. If your objection is aluminium in any form, the middle three rows are where to go.

Who should skip crystal deodorant

• Anyone with clinical hyperhidrosis. This is worth raising with a doctor, since prescription options exist that a deodorant cannot substitute for. Our guide to dermatologist-recommended deodorants in Singapore covers the boundary.
• Anyone in the first week after underarm laser or waxing. Wait for the skin to recover.
• Anyone with a documented alum sensitivity. Move to magnesium hydroxide or zinc oxide.
• Anyone who wants a genuinely aluminium-free product. That is a legitimate preference and this is not that product.

FAQ

Is crystal deodorant aluminium free? No. Crystal deodorants are alum salts, usually potassium alum and sometimes ammonium alum, and both contain aluminium. The real difference from a conventional antiperspirant is mechanical: antiperspirant salts plug the sweat duct to cut wetness, and alum does not.

What does crystal deodorant cost in Singapore? On 2 Sep 2026 the prices we could read ran from S$8.99 for a 120g stone on our own site to S$21.34 for a 60g Corpore Sano stick at Watsons SG on a 25 percent discount. Per gram that is S$0.075 against S$0.356, about 4.7 times, for the same active mineral.

Does crystal deodorant stop sweating? No. It is a deodorant, not an antiperspirant. It leaves a mineral film that inhibits the bacteria producing the smell and does not reduce sweat output. If wetness is your problem, this product class will not solve it.

Does crystal deodorant cause cancer? The National Cancer Institute's position is that there is no conclusive evidence linking underarm antiperspirant or deodorant use to breast cancer. That is a statement about the absence of proof rather than a guarantee.

How long does a crystal stone last? Sellers put it between one and two years with daily use for a block of this size, and Bamboo Straw Girl reports an average of about two years across its customers. Those are seller figures rather than tested ones. Storing the stone dry matters more than its starting size.

Why does my crystal deodorant sting? Almost always because it went on freshly shaved or waxed skin, or skin with a small nick. Wait a day after shaving. If it stings on intact skin you may have a genuine alum sensitivity, in which case switch to magnesium hydroxide or zinc oxide. Garcia-Gavin and colleagues documented a case of true allergic contact dermatitis to an alum stick in 1999, so the reaction is real but uncommon.

What is the difference between batu tawas and crystal deodorant? None, in the active. Batu tawas is the Malay name for raw alum stone sold as a chunk. Crystal deodorant is the same mineral cut smooth and packaged. The difference is presentation and price.

Can I take crystal deodorant on a plane? A solid stone is not treated as a liquid under the usual hand-luggage rules, so it does not come out of your 100ml allowance. A roll-on or spray does. Check your departure airport if you are unsure.

Will it stain my shirts? Pure alum dries clear and does not cause the yellow underarm marks associated with aluminium chlorohydrate antiperspirants.

Can I use it on my feet? Yes, foot-odour bacteria respond to the same mechanism. Keep a separate stone for feet.

Bottom line

If you smell rather than soak, want one thing to last a year, do not want fragrance, and would rather spend under S$10 than over S$20 for the identical mineral, buy the Efreshme Pure Crystal Deodorant. Available on our website, S$8.99. If package-free matters to you more than price per gram, Bamboo Straw Girl is the better buy.

If you want zero aluminium in any form, do not buy any crystal deodorant, ours included. The natural deodorant shortlist has the magnesium and zinc options. For the chemistry on each active we stock, the ingredient library has the detail.