Leaving apple cider vinegar (ACV) in your hair overnight is a popular home remedy, but it’s worth knowing that long exposure can irritate your scalp and dry out hair, especially if the vinegar is not diluted.
What ACV may do for hair when used properly:
- Remove buildup: Its acidity may help loosen residue from styling products, oils, and hard-water minerals.
- Make hair feel smoother: Lowering the hair’s pH temporarily can help the hair cuticle lie flatter, which may make hair feel shinier.
- Help with scalp concerns: Some people find diluted ACV rinses reduce feelings of oiliness or scalp buildup. However, it is not a proven treatment for dandruff or scalp infections.
Why leaving it overnight can be risky:
- Undiluted vinegar is acidic and may cause burning, redness, itching, or irritation.
- Frequent or prolonged use may contribute to dryness and breakage, especially for color-treated, curly, or already dry hair.
- It can sting if it gets into cuts or irritated skin.
A gentler approach:
- Mix about 1–2 tablespoons of apple cider vinegar with 1 cup (240 ml) of water.
- Apply after shampooing.
- Leave for a few minutes.
- Rinse thoroughly.
If you tried leaving it overnight and your hair feels great, that doesn’t necessarily mean it is causing harm—but it’s better not to make overnight ACV treatments a regular habit.
If you tell me your hair type (oily scalp, dry hair, curly, dyed, thinning, dandruff, etc.), I can suggest a safer routine.