Minoxidil Topical Solution or Foam. Minoxidil is a medication that increases new hair growth in cases of hereditary hair loss. You can apply this topical solution or foam on your scalp to promote hair growth. 

Formulations

The original topical minoxidil formulations include concentrations of 5% (recommended for men) and 2% (recommended for women, to decrease the possibility of facial hair growth). It is recommended that patients apply it twice a day to the scalp. These formulations still exist today, though women may have better results if they use the 5% concentration once a day. The most common side effects of the topical application are skin irritation, redness, and dryness. This is due to the presence of propylene glycol in the formula. Propylene glycol has a greasy feeling to it, and it can be a skin irritant.
To decrease this side effect, a foam formulation was developed, and it is overall better accepted by patients. It has no propylene glycol, so it is less greasy and less irritating. It is available in a 5% concentration for men and women. Another advantage of the foam preparation is that the foam melts when in contact with body heat, so most of the product reaches the skin. When the liquid formulation is used, a lot of it is wasted because it stays on the hair instead of reaching the scalp, where it needs to be.

In recent years, there has been a significant increase in the prescription of the oral formulation of minoxidil. When taken by mouth, minoxidil is usually more effective than when used topically, though side effects such as dizziness, tachycardia (fast heart rate), and increased facial and body hair tend to be more pronounced than when used topically.

Effectiveness

There is a plethora of review articles documenting the effectiveness and safety of both topical and oral minoxidil, and it continues to be a useful tool in the medical management of many types of hair loss, including genetic and auto-immune forms.