Apple cider vinegar (ACV) is sometimes promoted as a home remedy for dandruff, but current scientific evidence does not strongly support its effectiveness. Most claims come from anecdotal reports, which suggest that ACV may help balance scalp pH, encourage the shedding of dead skin cells, and reduce fungal growth. While these ideas are plausible, there is limited research confirming them.

A 2022 review highlighted that ACV might relieve symptoms of a dry scalp, a condition that can resemble dandruff. However, the causes of dry scalp and dandruff differ—dry scalp often stems from irritation or insufficient oil, while dandruff is linked to excess oil production and the overgrowth of Malassezia yeast. Because of these differences, it remains unclear whether ACV can effectively treat either problem. More targeted studies are needed.

What is better established is ACV’s antimicrobial potential. Laboratory studies show that it has antifungal and antibacterial properties, which may contribute to general skin health. Since bacteria such as Staphylococcus can be associated with scalp irritation, and dandruff itself is sometimes mistaken for fungal infections, ACV’s antimicrobial activity could be useful in certain situations.

Still, not all microbes respond equally to ACV. For instance, while undiluted ACV can inhibit the growth of some bacteria, it is less effective against Candida yeast at a 25% concentration. This variability underscores the uncertainty surrounding its application for dandruff and scalp conditions. The effectiveness of ACV may depend on the specific microbes involved and how the vinegar is prepared and applied.

For those who want to try it, dermatologists often recommend diluting ACV to avoid irritation. A common method is mixing two parts ACV with one part water, applying it directly to the scalp, leaving it on for about 15 minutes, and then rinsing with warm water. This can be repeated up to twice weekly, though results may vary from person to person.

Ultimately, ACV should be approached with caution. While it may offer some antimicrobial benefits and temporary relief for scalp dryness, there is no solid evidence that it reliably treats dandruff. Consulting a healthcare professional before trying ACV topically is important, especially for people with sensitive skin or preexisting scalp conditions. If irritation, burning, or unusual reactions occur, it’s best to discontinue use immediately.