Onion juice does have a valid place in traditional practices for managing dandruff, owing mainly to its sulfur content. This sulfur can be helpful to maintain skin health and promote circulation, contributing to healthier scalp conditions. Yet, as with anything, moderation and method matter. Onion juice shouldn’t be left on the scalp for an extended period, especially overnight due to the strong odor and potential irritation. Aim to leave it for about 15–30 minutes before rinsing thoroughly to reduce the chance of lingering smell.
Your description of oily scalp post-application indicates that the juice might not suit your scalp constitution, particularly if pitta dosha is dominant. In Siddha-Ayurvedic terms, maintaining balance is essential, so if over-oiliness results, it could complicate the dandruff situation. Balancing the treatment by combining onion juice with equal parts of aloe vera gel can act to calm the scalp, adding moisture without excess oiliness.
For a more comprehensive approach, ensure your diet and lifestyle support your prakriti as well. Reduce spicy and oily foods if your pitta is aggravated and incorporate cooling practices like consuming more cucumber and green leafy vegetables. Consider external treatments like massaging your scalp with coconut or neem oil, which can have soothing effects. These methods should aid in controlling the dandruff safely.
If the issue persists, consult with a healthcare professional to explore potential underlying issues that require attention. It’s important to ensure the scalp health aligns with overall health needs, diligently looking after both the symptoms and potential underlying causes. Prioritize methods that complement your lifestyle while addressing the discomfort effectively.


