Luteolin is a flavonoid found in many plants, which can reduce hair loss by reducing scalp PGD2. It’s another interesting example of an anti-allergy treatment, which translates well as a hair loss treatment.
Cetirizine is a cheap anti-allergy medication. It’s thought to reduce PGD2 when applied to the scalp. In one experiment, 1% cetirizine was applied to the scalps of subjects and ‘significant hair growth’ was reported.
Setipiprant is another example of an anti-allergy medication which was discovered to reduce hair loss. It does this by decreasing scalp PGD2, which is key to stopping hair loss.