Healthy Living

Learn All About Nizoral Shampoo Adverse Effects

Nizoral shampoo is the brand name for a popular shampoo treatment for dandruff—and hair loss. The Nizoral formula contains ketoconazole, a potent and systematic anti-fungal medication. Due to its potency, Nizoral with ketoconazole concentration of one percent can be purchased at most drug stores over the counter. Nizoral with a concentration of two percent ketoconazole needs to be prescribed by a physician before you can purchase it.

That being said, Nizoral shampoo that can treat a variety of fungal infections, both topically and orally. The medication can be used to effectively treat fungal skin infections like seborrheic dermatitis, yeast infections, and pityrosporum ovale, to name a few.

How Does Ketoconazole Work?

Ketoconazole, the main active ingredient in Nizoral shampoo, eliminates fungi by meddling with their cell membranes. It works by stopping the fungi from producing an essential component of cell membranes called ergosterol. When that production stops, holes appear in the cell membrane. The cells can’t survive with these holes and die off, eliminating the fungus and ending the infection.

Given that process, it stands to reason that other cells could be negatively affected, too, except those cells are important to our well-being and comfort. As such, there are some side effects related to the use of Nizoral shampoo, though they are rare. Below are some of those adverse effects.

Hair Changes 

According to a statement released by, there is a very small percentage of people who experience some changes to their hair when they use Nizoral shampoo. One effect that throws people off-guard is a change in hair texture. This isn’t necessarily a negative side effect, but it’s disconcerting to have your hair look and feel one way your entire life, and then have it change the texture. Another mild side effect of Nizoral shampoo is excessive dryness or oiliness of the hair, as the product affects the sebaceous glands on your head (the same follicles that hair grows from!).  

A less desirable side effect concerning hair is discoloration. The discoloration isn’t a given, but it’s more likely to happen to those who have chemically damaged hair or gray hair. Those who have a chemically induced permanent wave may lose the wavy or curly effect.

Skin Side Effects

Although not common, some undesirable effects on the skin side may occur. Of those potential side effects, the ones that are reported by users include the development of eczema, pimples, dryness, burning sensations, stinging, and itching of the scalp.

Nizoral shampoo is only intended for topical use and shouldn’t come in contact with your eyes (as is the case with most products). Nizoral can cause severe irritation to your eyes and should be rinsed excessively with water should it come in contact with your eyes. Call poison control as soon as you can if this could occur.

According to, research indicates that irritation caused by ketoconazole two percent strength shampoo is far less severe than the irritation caused by shampoos with selenium sulfide at a concentration of two point five percent, like the Selsun Blue.

Nizoral ShampooAllergic Reactions

Allergic reactions are a possibility at almost all times, and the potential for an allergic reaction to Nizoral shampoo is no exception. Some reports from show that allergic reactions or severe hypersensitivity were experienced by a few users. This reaction may be caused by the ketoconazole ingredient or any other ingredient in the shampoo. If you’re concerned about having an allergic reaction, discuss using this medication with your doctor before use.

Some of the signs associated with an allergic reaction include shortness of breath, dermatitis, severe swelling, and hives. If someone experiences such side effects, he or she should seek instant medical attention as a life-threatening shock reaction called anaphylaxis can develop.

Pregnancy Considerations

The U.S. FDA (Food and Drug Administration) classified the Nizoral shampoo as Pregnancy Category C. What does that mean? The animal studies carried out indicate that when applied topically, the product doesn’t cause any harm to the fetus. However, there is very little human research on the subject, confirming that the same can be said for humans.

During the studies involving pregnant rats, birth defects were noted in rats that consumed large amounts of ketoconazole orally. Since Nizoral shampoo isn’t ingested, one might safely assume that applying the shampoo topically is a safe bet.

That being said, pregnant women should use their best judgment and only use Nizoral shampoo if they believe that the potential benefits outweigh the risks.

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