If you're dealing with hair loss, you'll sooner or later come across ketoconazole shampoo. On Reddit, in forums, sometimes even from a dermatologist. It's presented as a simple, inexpensive addition to your routine. But is that really true?
We'll take an honest look at what it is, how it works, and what the research actually says about it.
What is ketoconazole?
Ketoconazole is an antifungal agent primarily known from Nizoral, a shampoo originally intended for dandruff and seborrheic dermatitis. It works by damaging the cell wall of fungi, causing them to die.
Nothing to do with hair loss, you might think. However, in the 1990s, it was already found that people using the shampoo for dandruff sometimes reported less hair loss. This caught the attention of researchers.
How might it help with hair loss?
Researchers describe two mechanisms.
The first is its anti-inflammatory action. On an affected scalp, you often see mild, chronic inflammation around the hair follicles. This contributes to the accelerated death of these follicles. Ketoconazole appears to inhibit this inflammation, even when no fungal infection is present.
The second mechanism is slightly more speculative. Ketoconazole may inhibit the enzyme 5-alpha-reductase. This enzyme is precisely what finasteride also targets: it converts testosterone into DHT, the hormone that gradually shrinks hair follicles in hereditary hair loss. Studies suggest that a 2% ketoconazole shampoo can reduce scalp DHT concentration by approximately 12 to 16 percent after four weeks. That's small compared to finasteride, but it's not insignificant.
What does the research say?
Here it gets nuanced. There is research, but it is limited in scope.
The most well-known study dates back to 1998 and compared a 2% ketoconazole shampoo with 2% minoxidil in men with androgenetic alopecia. The outcome: both groups showed comparable improvement in hair density, hair thickness, and the ratio of actively growing hairs. This is remarkable for a shampoo.
A more recent analysis showed that daily use of 2% ketoconazole shampoo led to an average of 18 percent more hairs after six months. No significant effect was found with the 1% version.
That's the point: concentration matters. The over-the-counter version (such as Nizoral 1%) probably has little effect on hair loss. For an effect, you need 2%, which in the Netherlands and Belgium is only available by prescription or through a GP.
At the same time: these are small studies. The 1998 study had only a limited number of participants. Larger, randomized studies are still lacking. A 2025 publication in the journal JEADV Clinical Practice concluded that ketoconazole is promising as an adjunctive therapy for hair loss, but more research is needed for definitive recommendations.
What can't you expect from it?
Ketoconazole shampoo is not a miracle cure. A few things to keep in mind:
It probably doesn't actively stop hair loss on its own. It has no direct effect on the genetic sensitivity of your hair follicles to DHT, unlike finasteride.
It doesn't work for everyone. People with seborrheic dermatitis or scalp inflammation seem to benefit more than people with a healthy scalp and purely hereditary baldness.
And: it's a shampoo. You wash it off. The contact time on the scalp is short, which makes it difficult for an active ingredient to work deeply. For this reason, some specialists advise leaving the shampoo on for a few minutes before rinsing.
For whom does it work best?
Based on the available research, ketoconazole shampoo appears to be most effective for men who meet two conditions: they have hereditary hair loss AND they have an affected scalp. Think of dandruff, flakes, an oily or itchy scalp, or seborrheic dermatitis.
In this group, ketoconazole does two things at once. It treats the underlying fungal problem, thus reducing the chronic irritation that can accelerate loss. This is useful regardless of whether you use other remedies.
For men with a completely healthy scalp and purely genetic hair loss, the effect is less predictable. The DHT-inhibiting mechanism probably also works for them, but the inflammation you would be addressing is minimal or absent. This reduces its added value.
Unsure whether your hair loss is hereditary or something else? Then first read this article about the causes of hair loss. It makes quite a difference for the approach.
Is it worth trying then?
As an addition to an existing routine: yes, possibly. Especially if you also suffer from dandruff, a flaky scalp, or an itchy feeling, because for those, it is proven effective anyway.
As a standalone solution for hereditary hair loss: expectations must be realistic. It probably won't bring your hair back. Whether it slows down hair loss depends on the cause and severity.
The risk is low. The side effects of ketoconazole shampoo are limited, and so are the costs. If you want to try it, choose the 2% variant and use it two to three times a week. Leave it on for two to three minutes before rinsing it off.
Combining with a hair serum
A shampoo works differently than a serum. A shampoo cleanses and treats the scalp for a short time. A serum stays on and can keep active ingredients in contact with the hair follicles for longer.
If you want to actively do something about hair loss, a combination makes more sense than either one separately. The shampoo provides a clean, anti-inflammatory scalp. A serum with proven active ingredients like Redensyl or Procapil can then do its job better.
The Hairborn Growth Serum is specially developed for men with early hair loss and contains a combination of ingredients that support hair follicles without the side effects of medication. If you are considering expanding your routine, that is a logical next step alongside a ketoconazole shampoo.
Summary
Ketoconazole shampoo has a scientific basis, but the evidence is limited. It probably works best as a supplement, not as the sole measure. Make sure you use the 2% variant, use it consistently, and don't expect a quick turnaround. A healthy scalp is a good foundation for whatever else is in your routine.