ACV absolutely has antimicrobial properties so it can be an effective method to ward off scalp infections of some kinds. There have been medical studies attempting to validate the common usage of ACV. At full concentrations, ACV is effective topically against bacteria, yeast, and fungus. However, once diluted it appears to maintain its effectiveness against bacteria down to a 25% concentration but loses effectiveness for yeast and fungi. So, depending on what the cause of the scalp infection is, it may show some effectiveness. For bacteria on the scalp, the infection will appear as a folliculitis, inflamed hair follicles. Yeast will trigger seborrhea which results in itching and flaking. Fungus can attack the hair follicles and cause hair breakage and itching.
If your scalp issues are related to bacteria, it may be somewhat helpful to consider ACV diluted 1 part ACV to 3 parts water to help prevent. However, if your issues are dandruff related you may need to do 1 part ACV to 1 part water as this should be able to retain more effectiveness to the yeast that triggers dandruff.
ACV is slightly acidic. Our hair is also naturally acidic from the oils and sebum from our scalp. Hair products often disrupt the pH balance of our hair. When our hair is normal and in the slightly acidic range, the cuticle is smooth. When we add hair products, many of these attach to our hair by opening the cuticle slightly by making the hair more alkaline. By using ACV, the normal acidity of our hair is restored and the product buildup resolves.
Using ACV occasionally will restore the acidity to the hair follicle. This will smooth out the cuticle and make it less weak. By doing so in moderation you may be able to prevent split ends and breakage.
ACV cannot directly strengthen the hair follicle because its only real function is to restore the pH balance to the hair. By restoring the pH balance the natural strength of the hair follicle will return.
The one downside to ACV is that it inherently lacks oils to accompany it to help restore our hair. It cannot hydrate hair alone- it will need some help from your natural scalp oils or from other oils added. It can restore our natural hair texture however by smoothing out the cuticle. Remember, our hair is not smooth- it’s actually scaly. When these scales lay flat our hair is stronger and shinier. For hair products to attach to our hair they need to open up these scales and rest inside of them!