A drug used to treat male baldness could also help women with thinning hair, an Italian study suggests.
Women are often embarrassed if they have thinning hair
Up to half of women experience some hair thinning during their lifetime.
The researchers said the Archives of Dermatology findings showed finasteride could be used for those who could not use the standard lotion treatment.
But after the study involving 37 women, UK experts said more work was needed to prove the drug - which can be toxic in pregnancy - had benefits for women.
Women who experience loss or thinning of hair can feel embarrassed and be anxious that they do not have the "crowning glory" they would wish for - or that they feel they should have.
It tends to be less obvious than male pattern baldness - resulting in thinning across the scalp rather than a male "monk's tonsure" pattern.
Hormonal changes, such as those which occur after pregnancy or stopping taking contraception, are a common cause of hair loss in women.
A common drug used to treat the condition is minoxidil, which is applied to the scalp to encourage hair regrowth.
However, some women are allergic to the lotion, or do not like having to apply it to their scalp twice a day.
The Italian researchers used finasteride, which is available in the UK to treat male baldness.
It works by blocking the conversion of the male hormone testosterone to dihydrotestosterone - high levels of which are linked to baldness.
The hair follicles are then not affected by this hormone, and can enlarge back to normal.
In the study 37 women aged 19 to 50, who had experienced hair loss, were given gave 2.5 milligrams of finasteride and the contraceptive pill.
Women had to take the pill because finasteride is known to cause birth defects, so cannot be given if women are pregnant or if there is a chance they might conceive.
A contraceptive was given that reduced levels of male hormones which could also affect the rate of hair loss.
Researchers photographed patients' heads and assessed their hair density using a high-definition video technique called computerised light videodermoscopy.
They were examined at the beginning of the study and after they had taken the two medications for 12 months.
After a year, 23 patients (62% of those studied) were seen to have improved after the treatment.
No difference was seen in 13 patients, and one patient was found to have worsened.
The difference reflects that seen with other baldness treatments, where women with so-called "Christmas tree" baldness patterns - where there is hair loss down the middle of the top of the head - see more benefit from treatment than others.
The women themselves thought the treatment had been even more successful than the photos showed.
Twenty-nine patients felt their condition had improved while eight said theirs had stabilised.
None reported that it had worsened.
Professor Antonella Tosti, who led the research, said: "This drug would not be a first line treatment.
"But it could be used for women who aren't able to use the lotion or who are allergic to it."
She added that people often preferred taking a pill for something, rather than using a cream.
The researchers plan to carry out further research to see if the treatment might help post-menopausal women - who would also not need to take the pill.
But Dr Nigel Hunt, of the Alopecia UK, said more research was needed which compared women on finasteride with women who were not treated.
"There isn't very good evidence that any form of medication has an impact on alopecia.
"We would need to be certain it was going to be of benefit - particularly because of the potential damage to foetuses."