What Does Ketoconazole Shampoo Do for Your Hair?

Ketoconazole is a broad-spectrum drug that is effective against many fungal species.

It works by inhibiting the production of ergosterol, an organic molecule found in fungus and yeast. This inhibits the fungus and yeast from making normal cell membranes. When the cell membranes are compromised, the growth and reproduction of both organisms are hindered.

Different types of ketoconazole shampoos include:

• Over-the-counter (OTC) ketoconazole shampoo: OTC ketoconazole shampoos contain 1% or less of ketoconazole. The most well-known OTC brand is Nizoral.
• 2% ketoconazole shampoo: A prescription is required to purchase shampoos that contain 2% of ketoconazole. Commonly available brands by prescription include:
  • Ketozal
  • Ketozolin
  • Ket Med

1. Seborrheic dermatitis and dandruff

While sometimes dandruff is caused by dry scalp, other times it is caused by seborrheic dermatitis. Seborrheic dermatitis is an inflammatory disorder that is associated with an overgrowth of Malassezia, a fungus that is found naturally on the skin. This causes a greasy, scaly rash on the scalp, which is often itchy and causes skin flaking and dandruff when scratched.

Due to its antifungal properties, ketoconazole shampoo can help treat seborrheic dermatitis and relieve the flaking, scaling, and itching associated with dandruff.

2. Psoriasis

Ketoconazole shampoo is a common treatment for psoriasis, an inflammatory skin disease that causes skin flaking, skin plaques, and redness. Skin plaques are typically infected with a yeast-like fungus, and psoriasis outbreaks usually necessitate the use of prescription ketoconazole shampoo.

3. Tinea infections

Ketoconazole shampoo can treat tinea infections such as tinea capitis and tinea versicolor.

Tinea capitis is a ringworm-like fungus infection that causes an itchy, uncomfortable rash on the scalp. Severe tinea capitis damages hair follicles and leads to hair shedding.

Tinea versicolor is a skin infection that typically develops on the trunk and shoulders and is caused by the overgrowth of a type of yeast that lives naturally on the skin.

4. Hair loss

Though there is no solid research supporting the use of ketoconazole as a hair loss solution, several studies show that ketoconazole shampoo has the potential to be a possible treatment for male pattern baldness. 

Because men with male pattern baldness have more Malassezia on their heads, ketoconazole may help by destroying excess Malassezia. Ketoconazole shampoos also contain antifungal agents that help kill the yeast, decrease inflammation, and subsequently stop the hair loss associated with male pattern baldness.

In addition, studies show that ketoconazole shampoo boosts individual hair follicle size, which promotes hair growth.

Side effects

Ketoconazole shampoo generally has limited side effects but may cause:

• Blisters or pimples on the scalp
• Burning sensation
• Changes in hair texture
• Dry skin
• Rash
• Skin irritation
• Hair discoloration
• Hair loss (rare; talk to the doctor right away if you notice this side effect)
• Headache
• Itching
• Loss of curls in permed hair
• Oily or dry hair
• Swelling

Allergic reaction

Allergic reactions to ketoconazole shampoo are extremely rare. Seek immediate medical attention if you notice:

• Rashes over the area where ketoconazole is applied
• Difficulty swallowing
• Dizziness
• Hives
• Hoarse voice
• Numbness
• Pain 
• Tingling sensation
• Fainting
• Severe itching, stinging, or irritation
• Swelling of the face, lips, tongue, or throat
• Tight chest
• Trouble breathing
• Wheezing

Interaction with other medications

Talk to your doctor about any medications you are taking to avoid drug interactions. Your doctor can advise whether the medications will interact with ketoconazole.

Ingestion of ketoconazole

Ketoconazole may be harmful if swallowed. If you accidentally consume ketoconazole shampoo, seek immediate medical help.

Dosage, number of applications, and length of treatment depends on the strength of the ketoconazole shampoo used, the condition being treated, and the severity of the symptoms. Ketoconazole shampoo should be used as instructed by the doctor and as indicated on the product label:

• Apply 5-10 mL of ketoconazole shampoo to a wet scalp. 
• Rub gently until it forms a lather, and leave on for 3-7 minutes before rinsing thoroughly with water.
• Avoid contact with the eyes. If shampoo gets in the eyes, rinse well with water.
• To reduce the chance of the fungal infection returning, ketoconazole shampoo should be used for the recommended duration of treatment even if the symptoms seem to have disappeared.
• If a dose is missed, use it as soon as possible, and continue with the regular schedule.
• Store at room temperature and keep it out of reach of children.