Published by Ys Pharma Inc., the company that makes Kadason, a salicylic acid shampoo mentioned in this article. This is not an independent test, and this article has not been medically reviewed. Label details checked October 29, 2026.
Why there are two different approaches
Seborrheic dermatitis on the scalp shows up as flakes, greasy or dry scale, redness, and itch. Two things are going on at once. Skin cells build up and stick together as scale. And the skin reacts to Malassezia, a yeast that normally lives on oily skin.
Most medicated shampoos focus on one of these two things: some control the yeast, and others help reduce scale.[5] Knowing how each one works makes the comparison easier.
How salicylic acid works
Salicylic acid is a keratolytic. In plain terms, it softens the "glue" between dead skin cells so scale can loosen and rinse away.[8]
- U.S. status: Salicylic acid at 1.8% to 3% is an active ingredient allowed under the FDA's OTC monograph for shampoos that control dandruff, seborrheic dermatitis, or psoriasis.[1] Products sold under the monograph follow its ingredient and labeling rules; they are not individually approved by the FDA.
- Labeled uses vary by product: a salicylic acid shampoo may be labeled for dandruff, seborrheic dermatitis, psoriasis, or more than one of these. Check the Uses line.
- Label warnings to know: for external use only; avoid contact with the eyes; stop and ask a doctor if your condition worsens or does not improve after regular use as directed.[2][3]
How ketoconazole works
Ketoconazole is an antifungal. It lowers the amount of Malassezia yeast on the skin.[5]
- U.S. status: Ketoconazole 1% shampoo is sold without a prescription under an FDA-approved new drug application (for example, Nizoral Anti-Dandruff, NDA 020310).[4] Higher-strength ketoconazole products require a prescription.
- OTC labeled use: "controls flaking, scaling and itching associated with dandruff."[4]
- Label warnings to know: do not use on a scalp that is broken or inflamed, or if you are allergic to its ingredients; stop and ask a doctor if a rash appears, or if the condition worsens or does not improve in 2 to 4 weeks; for children under 12, ask a doctor.[4]
Side-by-side comparison
The ingredients
| Compare | Salicylic acidKeratolytic | KetoconazoleAntifungal |
|---|---|---|
| How it works | Loosens and lifts scale | Acts on Malassezia yeast |
| U.S. OTC strength | 1.8%–3% | 1% (higher strengths by prescription) |
| How it's sold OTC | FDA OTC monograph | FDA-approved application (NDA) |
| OTC labeled uses | Dandruff, seborrheic dermatitis and/or psoriasis, depending on the product | Dandruff (flaking, scaling, itching) |
| Seborrheic dermatitis | Can be labeled for symptom relief | Not on the OTC 1% label; ask a doctor about prescription options |
Example products (from U.S. Drug Facts labels)
| Compare | KadasonMedicated Shampoo | NizoralAnti-Dandruff |
|---|---|---|
| Active ingredient | Salicylic acid 1.8% | Ketoconazole 1% |
| Labeled use | Relief of the symptoms of seborrheic dermatitis | Controls flaking, scaling and itching associated with dandruff |
| Directions | At least twice a week, or as directed by a doctor | Every 3–4 days for up to 8 weeks, then only as needed (adults and children 12+) |
| Key warnings | Do not use for prolonged periods without consulting a doctor; avoid the eyes | Do not use on broken or inflamed scalp; stop if a rash appears |
| Pregnant or breastfeeding | Ask a health professional before use | Ask a doctor before use |
Simplified from the U.S. labels cited below, not a head-to-head efficacy result. We did not find a clinical trial that directly compares these two products. Follow the label of the product you use. For more formula details and two other OTC options, see our 4-product label comparison.
Which is better for seborrheic dermatitis?
There is no single answer. Here is what the labels, guidelines and studies actually say.
- Labels: Some salicylic acid shampoos, including Kadason, list seborrheic dermatitis symptom relief as their use. The OTC ketoconazole 1% label lists dandruff.[3][4] This describes how each product is labeled; it does not show that one works better.
- How they work: They target different parts of the problem, scale versus yeast. The American Academy of Dermatology (AAD) notes that different dandruff shampoos work differently and recommends using the one or two your dermatologist includes in your plan.[5]
- Evidence: Most trials of ketoconazole in seborrheic dermatitis studied the 2% strength.[7] Those results can't be assumed to apply to the 1% OTC shampoo. Reviews generally describe salicylic acid as a keratolytic that helps remove scale.[8][9]
If you have been diagnosed with seborrheic dermatitis, or it also affects your face, ears or body, a dermatologist can suggest which shampoo, or which combination, fits your case.
How often should you use each?
Follow the Directions on your product's label. The two ingredients come with different directions.
- Salicylic acid shampoos (monograph wording): "For best results use at least twice a week or as directed by a doctor."[2] This sets a minimum, not a maximum.
- Kadason specifically: the same direction appears on its label, which also says: "Do not use for prolonged periods without consulting a doctor."[3]
- OTC ketoconazole 1% (Nizoral Anti-Dandruff): use every 3–4 days for up to 8 weeks or as directed by a doctor, then only as needed to control dandruff. For children under 12, ask a doctor.[4]
Your hair type can change the routine. The AAD notes that people with straight or wavy hair may use a dandruff shampoo 2 to 3 times a week, while a dermatologist may recommend once a week for curly or tightly coiled hair. It also advises leaving the shampoo on the scalp for the time your dermatologist recommends.[5]
Can you alternate both shampoos?
Dermatology sources do mention rotating shampoos. The AAD says that if a shampoo no longer works as well as it once did, rotating dandruff shampoos may help, and to let your dermatologist know.[5] Mayo Clinic says a provider may suggest rotating between two or more products.[6]
What is less clear is a specific schedule for alternating an OTC salicylic acid shampoo with OTC ketoconazole 1%. The alternating regimen described in a 2015 American Family Physician review paired a prescription steroid shampoo with ketoconazole 2%, not salicylic acid.[8] We did not find a published schedule for these two OTC products.
If you want to use both, ask a dermatologist or pharmacist how to space them, and follow each product's own directions and warnings. Do not use ketoconazole 1% on a broken or inflamed scalp.[4]
What does the clinical evidence show?
| What was studied | What it found | What it does not show |
|---|---|---|
| Ketoconazole alone | A Cochrane review found topical ketoconazole 2% more effective than placebo at clearing seborrheic dermatitis at about 4 weeks. The evidence quality was low, and most trials lasted 5 weeks or less.[7] | It studied 2%, not the 1% OTC shampoo, and did not compare ketoconazole with salicylic acid. |
| Salicylic acid combined with an antifungal | In a 2002 trial, a shampoo with ciclopirox olamine 1.5% and salicylic acid 3% was compared with ketoconazole 2% in 154 people with dandruff (70 also had scalp seborrheic dermatitis). Both improved symptoms over 4 weeks.[10] | It tested a combination product, not salicylic acid alone, at 3% salicylic acid and 2% ketoconazole. |
| Salicylic acid alone | Clinical reviews describe salicylic acid as a keratolytic that helps remove scale and buildup.[8][9] | We did not find a trial directly comparing a salicylic acid–only shampoo with ketoconazole 1%. |
| Different strengths | U.S. OTC strengths are 1.8%–3% salicylic acid and 1% ketoconazole.[1][4] | Study results at one strength cannot be assumed to apply to another. |
Bottom line: the evidence supports the role of each ingredient. It does not show that one OTC shampoo is better than the other.
How to choose
- Check the Uses line. Is the product labeled for seborrheic dermatitis, dandruff, or both?
- Think about what you've tried. If a shampoo has stopped working as well, ask a dermatologist about rotating.[5]
- Check the directions against your routine, including how often you wash and your hair type.
- Read the warnings that apply to you, such as a broken or inflamed scalp, pregnancy or breastfeeding, or use on children.
- Already under a dermatologist's care? Follow their plan.
- Sore, spreading, or not better after regular use? See a dermatologist rather than switching products again.
Where Kadason fits
If, after comparing, you are considering a salicylic acid shampoo, Kadason Medicated Shampoo is one option. Here is what its Drug Facts label states:[3]
- Active ingredient: salicylic acid 1.8%
- Use: for relief of the symptoms of seborrheic dermatitis
- Directions: for best results, use at least twice a week or as directed by a doctor
- Fragrance: none listed in the inactive ingredients
- Size: 8 fl oz (237 mL)
Kadason does not contain ketoconazole, is not an antifungal equivalent, and has not been compared head-to-head with ketoconazole shampoos. It is sold under the FDA's OTC monograph, so it has not been individually approved by the FDA. If your dermatologist has you on an antifungal shampoo, ask them whether and how to alternate the two.
See Kadason's full Drug Facts and ingredients →
Comparing specific products? See our label comparison of four OTC shampoos.
Related reading
- Best Shampoo for Seborrheic Dermatitis: 4 Options Compared
- The Complete Guide to Choosing the Best Seborrheic Dermatitis Shampoo
- Top 10 Shampoos for Managing Seborrheic Dermatitis
- Scalp Psoriasis vs. Seborrheic Dermatitis: How to Tell the Difference
References
- U.S. FDA. 21 CFR 358.710 – Active ingredients for the control of dandruff, seborrheic dermatitis, or psoriasis (eCFR)
- U.S. FDA. 21 CFR 358.750 – Labeling of drug products for the control of dandruff, seborrheic dermatitis, or psoriasis (eCFR)
- DailyMed. Kadason Medicated (salicylic acid) shampoo, NDC 87263-927
- DailyMed. Nizoral (ketoconazole) shampoo 1%, NDC 55505-196
- American Academy of Dermatology. Seborrheic dermatitis: Diagnosis and treatment
- Mayo Clinic. Seborrheic dermatitis – Diagnosis and treatment
- Okokon EO, et al. Topical antifungals for seborrhoeic dermatitis. Cochrane Database Syst Rev. 2015;(5):CD008138.
- Clark GW, Pope SM, Jaboori KA. Diagnosis and treatment of seborrheic dermatitis. Am Fam Physician. 2015;91(3):185-190.
- LeFevre NM, Braudis K, Feigenbaum LS. Seborrheic dermatitis: diagnosis and treatment. Am Fam Physician. 2025;112(2):166-173.
- Squire RA, Goode K. J Dermatolog Treat. 2002;13(2):51-60. PMID 12060502.
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