Drysol is a 20% aluminium chloride hexahydrate solution in alcohol, sold in the US on prescription and on supplier backorder in October 2026. Certain Dri Prescription Strength is a 15% aluminium chloride roll-on you can buy over the counter. Drysol is higher on the label, but the two labels name the salt differently and a higher percentage does not guarantee a better result. For most people the real choice comes down to access and how well your skin tolerates each one.
This comparison is desk research based on Certain Dri's published ingredients and directions, Drysol's drug information, a US wholesaler shortage list, an FDA warning letter and guidance from the International Hyperhidrosis Society (IHS) and the American Academy of Dermatology (AAD). We haven't used either product. It isn't medical advice, and it doesn't give an application schedule: follow the label on your own pack.
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Drysol vs Certain Dri at a glance
| Drysol | Certain Dri Prescription Strength | |
|---|---|---|
| Active ingredient (as labelled) | Aluminium chloride hexahydrate 20% | Aluminium chloride 15% |
| Base | Anhydrous ethanol (alcohol) | Inactive ingredients include water, glycerin and aloe; no alcohol listed |
| US status | Prescription | Over the counter |
| Format | Dab-O-Matic applicator bottle, or solution | Roll-on |
| When to apply, per the label or drug information | Evening, before sleep, on dry skin | At night, on dry underarms |
| Supply, 13 October 2026 | All three packs on supplier backorder | Not on the shortage list we checked |
| Regulatory note | Called an unapproved new drug in a September 2025 FDA warning letter | Not named in that letter |
| Price | Ask your pharmacist | Check the price on Amazon US |
Strength: what the labels tell you, and what they don't
Drysol's 20% is higher than Certain Dri's 15%. Two things stop that being the whole story.
First, the labels describe the active differently. Drysol states aluminium chloride hexahydrate; Certain Dri states aluminium chloride. Treat the numbers as a rough guide, not an exact strength ranking.
Second, more is not always better. The IHS cites a study of 691 people with underarm sweating that tested several concentrations of aluminium chloride and concluded that 15% was as effective as 20% and better tolerated. That study didn't test either of these products, so it doesn't prove Certain Dri matches Drysol. It is a reason not to assume the higher number wins.
The AAD's view points the other way for some people: it says non-prescription antiperspirants are only effective for mild hyperhidrosis, and many people need a prescription version. If a 15% product used correctly for a few weeks hasn't helped, that's your cue to see a doctor rather than try another 15% brand.
Base and irritation
Drysol is dissolved in alcohol, which the IHS describes as anhydrous ethanol. Its drug information lists tingling, mild itching or irritation when it is first applied as the common effects, and says not to apply it to broken, irritated or recently shaved skin. It also says to keep it away from open flames and warns that it may stain clothing and harm metals. Serious allergic reactions are rare, but get urgent help for a rash, swelling of the face, tongue or throat, severe dizziness or trouble breathing.
Certain Dri lists water among its inactive ingredients, along with glycerin, aloe leaf juice and a thickener. Its maker says the formula is "designed to help guard against irritation and burning". That's the brand's claim, which we haven't verified. Its own page also advises against using it after showering or shaving, as that "might cause burning/stinging".
Neither is irritation-free. The IHS names itching and stinging as the most common effects of aluminium chloride treatment, and warns of darkening of the skin after irritation, more often in darker skin tones. If irritation is a problem, the AAD suggests telling your dermatologist; switching to a gel formula is one of the options it lists.
Access, supply and cost
Drysol needs a prescription, from a family doctor, a dermatologist or a telehealth prescriber. A wholesaler shortage list dated 13 October 2026 shows the 35ml and 60ml Dab-O-Matic and the 37.5ml solution all on supplier backorder, with full recovery marked "TBD". In September 2025 the FDA sent its maker, Persōn & Covey, a warning letter stating that Drysol is an unapproved new drug.
That letter isn't a recall. We don't print a Drysol price because we couldn't find a current, dated one from a named pharmacy; your pharmacist can tell you the cash price and whether your plan covers it. More detail is in our Drysol review.
Certain Dri needs no prescription. Its maker sells through retailers rather than publishing a price, and we don't print Amazon prices because they change daily.
Check the formula, pack size, seller and delivery country. Search results may include alternatives.
Check that the listing says Prescription Strength, because other products are sold under the Certain Dri name. Our Certain Dri review covers the range.
Hands and feet
Drysol's drug information covers several areas, including the hands and feet. Certain Dri's directions are for underarms. The IHS notes that palms and soles often need higher aluminium chloride concentrations than underarms, so neither product may be enough for hands. If that's your main problem, ask a doctor about iontophoresis, and see our sweaty hands guide.
Which suits you?
Certain Dri suits a first try at a stronger antiperspirant for underarm sweating, anyone without a prescription, and Drysol users who can't get stock right now.
Drysol suits people who already have a prescription and a pharmacy that can supply it, or whose doctor specifically wants a 20% alcohol-based solution.
Neither may be right if 15% hasn't worked or both irritate. A dermatologist can discuss compounded aluminium chloride, Qbrexza cloths, Sofdra gel and treatments that aren't topical. Our guide to prescription antiperspirants covers each option, how to get it and what the manufacturers' copay offers say.
For other over-the-counter swaps, see SweatBlock vs Certain Dri and the strongest antiperspirants.
In the UK
Neither product is a UK staple, and there's no need to import them. Anhydrol Forte and Driclor are 20% aluminium chloride hexahydrate solutions sold as pharmacy medicines, so a pharmacist can sell them without a prescription after a few questions. That's the same labelled percentage as Drysol. Anhydrol Forte vs Driclor compares the two.
See a doctor, or a GP in the UK, if your sweating is new, happens mainly at night, or comes with other symptoms, because it can point to another condition.
