Nizoral Shampoo and Hair Loss: An In-Depth Guide

  • Medically reviewed by: Dr. Anil Simhadri
  • Written by: William Slator
  • Last updated: 18/01/2024

If you ask the man on the street to tell you the most popular shampoo against men’s hair loss, he will probably mention a popular shampoo marketed specifically for hair loss.

But ask a member of the hair loss community what shampoo he uses, and there’s a good chance it will be Nizoral shampoo or a generic version. Curiously, Nizoral is sold for the treatment of dandruff, not hair loss.

What is the evidence for Nizoral against hair loss? Why has it become so popular, and does the data support its popularity? Read on to find out.


What is Nizoral Shampoo?

Nizoral shampoo is an over-the-counter product that has been on the market for decades. The patent has expired, and you can find generic versions for a fraction of the price.

The structure of a ketoconazole molecule

The active ingredient of Nizoral shampoo is ketoconazole, an antifungal chemical. Ketoconazole is also available as a pill for systemic treatment.

The shampoo is sold for the treatment of dandruff, fungal infections like tinea capitis, and seborrheic dermatitis (1, 2, 3, 4).

Nizoral is not intended to be a daily-use shampoo, and should only be used as directed. Typically, the initial period of treatment requires using Nizoral shampoo twice a week for one month. You can reduce this to a single-use every other week if the issue remains chronic.

Aside from dandruff, there is some research suggesting the active ingredient in Nizoral shampoo may help inhibit the production of DHT. This hormone is the underlying cause of hair loss and thinning hair (5, 6).

A woman pouring nizoral shampoo into her palm

This may make Nizoral a treatment option for men and women with Androgenetic Alopecia (AGA). We will discuss Nizoral and AGA below, but first a brief review of its action against dandruff.

How Does Nizoral Work Against Dandruff?

Scientists believe dandruff is caused – at least in part – by the fungus Malassezia.

By bringing Malassezia under control, Nizoral and other ketoconazole shampoos alleviate the symptoms of dandruff.

Ketoconazole impairs the body’s ability to synthesize ergosterol, which is a vital component of the cell membranes of fungi (7). It also inhibits the growth of dermatophytes and yeasts by reducing the permeability of their cell membrane (8).

Results Against Dandruff & Seborrheic Dermatitis

There is no doubt that ketoconazole is effective against fungal conditions like dandruff and seborrheic dermatitis.

This is what it’s sold for, and it’s been on the market for so long that the evidence is indisputable.

One study, for example, found that after 2 to 4 weeks, close to 90% of subjects with dandruff or seborrheic dermatitis, had an excellent response to ketoconazole shampoo (9).

In another study published by the British Medical Journal of Clinical Evidence, the effectiveness of a ketoconazole scalp preparation was compared to a placebo (10). The results showed a statistically significant difference in the reduction of scalp symptoms such as itching, redness, and dandruff over four weeks for people with seborrheic dermatitis.

Typically the shampoo is used twice a week in the active phase, and then once every week – or every two weeks – to prevent dandruff from coming back.

Its Effectiveness Against Androgenetic Alopecia

The effectiveness of ketoconazole against dandruff is not in dispute. We know it works. Where things get interesting – and more controversial – is when it comes to hair loss.

As I said in the introduction, ketoconazole shampoos are among the most popular shampoos in the hair loss community.

Even though they are not sold for hair loss, and are not recommended for frequent long-term use. Nevertheless, many balding men have thrown away everything else and use only ketoconazole as their daily shampoo.

The makers of Nizoral don’t advertise it as a treatment for pattern hair loss, as this would be illegal. What they do suggest is that it may help with hair loss associated with dandruff.

The language on the product website is a bit grey, and one can’t help but wonder if this is on purpose (11):

If you have dandruff and hair loss, Nizoral® may be able to help.

Nizoral® is different from other OTC dandruff shampoos. Only Nizoral® contains ketoconazole 1%, a clinically proven, powerful, anti-dandruff ingredient.

It controls fungus growth and once the fungus is controlled, so are your dandruff symptoms. Plus, a clinical study showed that when the active ingredient in Nizoral® was used regularly it controlled dandruff and then was shown over time to help control hair loss associated with dandruff.

In summary, the makers of Nizoral sell it as a product for dandruff, and hair loss related to dandruff. Men with pattern baldness use it as a baldness treatment, even if they don’t have any dandruff. Some doctors will also prescribe it off-label to their balding patients.

Is there any hard scientific evidence to support its use as a hair loss treatment?

Animal Research

There have been two animal studies on topical ketoconazole for hair growth, both with mice.

The first one looked at hair regrowth (12). The researchers shaved the backs of mice and applied 2% ketoconazole solution or a vehicle solution – the equivalent of a placebo.

The ketoconazole-treated mice had significantly faster regrowth.

You can see here what the ketoconazole-treated mice looked like after 21 days, compared to the control mice (the bottom row is ketoconazole).

The second mouse study was very similar (13). However, in addition to the ketoconazole and control groups, it had two more groups of mice. One was treated with minoxidil 5%, and the other with minoxidil plus tretinoin.

After being shaved, all 3 active treatment groups showed significantly more regrowth after 3 weeks, compared to the control.

And they all had a significantly larger average hair diameter.

The authors concluded that ketoconazole was effective in stimulating hair growth and increasing hair diameter, though not as effective as minoxidil.

The Clinical Evidence

We have a couple of studies with balding men who used ketoconazole shampoo as a hair loss treatment.

Uncontrolled Case Studies

The first was a small, open-label study with 6 Japanese men (14). The men were 23 to 51 years old, with hair loss grades II to IV.

They used a 2% ketoconazole lotion almost daily, immediately after using their own unmedicated shampoos. Treatment lasted from six to twelve months. Three of the six men showed various degrees of hair growth. The remaining three had no regrowth.

Controlled Trials

The second human study is not only the biggest one but also of the highest methodological quality (15).

Interestingly, two of the three authors were affiliated with the Janssen/Johnson and Johnson conglomerate. Jannsen was the company that discovered and marketed ketoconazole, and they make the branded Nizoral product.

Versus Placebo

Thirty-nine men with grade III AGA took part. 27 were treated with Nizoral and 12 with an unmedicated shampoo. There was also a control group of 22 men without AGA, of whom half got the Nizoral and the other half the unmedicated shampoo.

The paper doesn’t specify if treatments were randomly assigned or not. At any rate, the treatment lasted 21 months.

The main variable the researchers measured was the so-called Pilary Index or PI. You get this by multiplying the percentage of hairs in the anagen phase, with the average hair shaft diameter.

This handy metric captures two aspects of hair density: how many hairs are actively growing, and how thick they are. You can see in this graph how the PI in the ketoconazole group crept up during these 21 months:

The black boxes in this graph are the medians for the ketoconazole group and the white ones for control.

There was a steady increase in PI over the first 15 months for the Nizoral group, after which it plateaued. On the other hand, the control group had a very slow but steady decline in PI, just as expected.

Hair transplant vs hair plugs

Versus Minoxidil

Given these very encouraging results, the researchers did a second study, which they published in the same paper. This was a direct comparison between the 2% ketoconazole shampoo, and once-daily minoxidil, used in combination with an unmedicated shampoo.

There were 4 men in each group, aged 24 to 29, with grade III AGA. The men had a punch biopsy taken from the vertex at the start of the study, and again after 6 months. From this, the researchers calculated their hair densities.

At 6 months, the hair density increased by 18% in the ketoconazole group, versus 11% in the minoxidil group. Both treatments yielded a 7% increase in hair shaft diameter.

If anything the ketoconazole slightly outperformed minoxidil. In all fairness, however, the men applied the minoxidil once daily, which is not the optimal frequency.

The liquid and the foam versions of rogaine
In one study, Nizoral shampoo yielded comparable regrowth to minoxidil in balding men.

In the conclusion of the paper, the authors state that both of their studies showed an unequivocal effect of ketoconazole shampoo against androgenetic alopecia.

The medication improved hair density and diameter. It also had a favorable impact on the follicles’ hair growth cycle, by increasing the proportion that was in anagen.

The authors wrap up the paper by calling for a larger study to replicate these findings, find the ideal dosage, and evaluate any possible side effects of long-term usage. For reasons that we might never find out, they never carried out this follow-up study.

Possible Mechanisms of Action

On balance, the available evidence does suggest that ketoconazole might work against hair loss in some men.

Ketoconazole likely acts via two distinct biochemical pathways:

One involves ketoconazole’s mild anti-androgenic activity.

Studies in cell cultures, animals, and humans have found that ketoconazole does seem to inhibit the action of androgens, including DHT (16, 17). Albeit mildly.

But there is almost certainly another biochemical pathway that is unrelated to androgens.

Remember the mice studies we discussed earlier? Well, the coats of those mice are so-called androgen insensitive. This means that, unlike the scalp of men, they are not susceptible to the effects of androgens.

To quote the authors of one of the mice studies:

“our study demonstrated that topical KCZ was effective on the androgen‐insensitive coat hairs of mice; its efficacy became rapidly apparent in three weeks of topical application. It is therefore reasonable to offer the hypothesis that the effects of KCZ documented here were the result of the behavior of the substance as an androgen‐independent, biological response modifier.”

Is Nizoral A Viable Daily Shampoo For Balding Men?

The evidence we discussed above is encouraging. At the same time, Nizoral is a shampoo, which is perhaps the most user-friendly baldness treatment there is. After all, we all have to shampoo, so why not use a shampoo that actually fights hair loss?

Having said that, ketoconazole is not all roses. If you’re considering using it for hair loss, there are some things to bear in mind.

Firstly, it’s not the best shampoo out there.

I’m talking about when it comes to doing what shampoo is supposed to do. Which is to make your hair look nice. Clean it will look, no doubt.

But ketoconazole shampoos will kill your volume, and leave your hair looking dull and lifeless. It will also make it dry, brittle, and prone to breakage. If you have longer hair you can also the dry hair shafts to tangle easily.

Your two options are a) to use another shampoo after you’ve applied the ketoconazole and then the conditioner, or b) to just a conditioner afterward, straight after the ketoconazole.

A man with hair loss

Secondly, ketoconazole is not meant for long-term use.

The makers of Nizoral do not sell it as a regular daily shampoo that you can use indefinitely. Nizoral is simply a medication in shampoo form. As such, it is for short-term use, for the treatment of acute dandruff.

For long-term use, most health care specialists would recommend intermittent treatment at most, once every few weeks.

Our recommendation would be to discuss this with your doctor and see if long-term use


Though not particularly expensive per se, Nizoral certainly costs more than regular shampoo.

The cost of Nizoral shampoo will depend on the size of the bottle and the concentration of ketoconazole. On Amazon, for example, you can find a 7oz bottle of 1% for $30.

Generic versions will cost less. They are, however, sold in tiny bottles, and using them will about be 2-3 times more expensive than a regular shampoo.

Possible Side Effects

There are many potential side effects from ketoconazole shampoo. The most common ones include:

  • Skin irritation; itching, stinging, burning
  • Dryness or oiliness of the hair and scalp
  • Headaches

According to the Mayo Clinic, skin irritation is likely to go away after multiple uses (18).

Often, you will be able to manage many of the most common side effects in consultation with a physician.  If you experience any of the more serious side effects, discontinue use immediately and seek medical attention.

Those with the following conditions should consult a physician prior to using Nizoral shampoo:

  • Women who are or want to become pregnant
  • Women who are actively breastfeeding
  • People with asthma or chronic obstructive pulmonary disease
  • Those with some form of cardiac condition
  • People allergic to the ingredients of Nizoral shampoo

Is Nizoral Shampoo Right for You?

Undoubtedly, ketoconazole is an effective treatment for dandruff and seborrheic dermatitis. A short treatment course of a few weeks can make a big difference to the scalp. With proper hair and scalp hygiene care thereafter, you can maintain these good results in the medium and long term.

Whether ketoconazole is an effective treatment against pattern hair loss is a different matter altogether. The available evidence is limited but compelling. 

A recent study also highlighted topical ketoconazole as an effective solution for female pattern hair loss (19).

Though this makes it an attractive proposition for hair loss sufferers, there are some drawbacks. The most important of these are that:

  • it performs poorly as a shampoo
  • costs more
  • you are simply not meant to use it long-term, and certainly not on a daily basis.

If you are not sure whether Nizoral is right for you, consult with your doctor. Together you can discuss the pros and cons and decide if this is a treatment that makes sense for you.

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