For most people, it's generally better to use a shampoo that is closer to the natural pH of the scalp and hair, which is slightly acidic, around 4.5 to 5.5. This acidity helps to maintain the integrity of the hair cuticle, promoting shine, smoothness, and manageability while also supporting a healthy scalp environment.

An alkaline shampoo (one with a higher pH) can disrupt the natural acidic mantle of the scalp and hair. This can lead to cuticle lifting, which may cause dryness, frizz, and increased porosity of the hair shaft, making it more susceptible to damage. Over time, the use of highly alkaline products can lead to scalp irritation and potentially exacerbate conditions like dandruff.

However, there might be specific situations where an alkaline shampoo could be temporarily beneficial. For example, some clarifying shampoos designed to remove heavy product buildup or hard water minerals may have a higher pH to help lift away these deposits effectively. Even in such cases, it's recommended to follow up with a conditioner or a pH-balanced shampoo to restore the natural acidity of the hair and scalp.

In summary, for regular use and maintenance of healthy hair and scalp, an acidic or near-neutral pH shampoo is typically preferred over an alkaline one. It's always a good practice to choose shampoos that are formulated to respect the natural balance of your scalp and hair.