Anti-Androgen therapy with Systemic ARP (Androgen Receptor Protein) inhibitors is suitable only for women. Since this class of systematic anti androgens decrease both testosterone and dihydrotestosterone (DHT) they have been seen to hold much promise to stimulate hair re-growth for women. These anti-androgens are contraindicated in men because of the possible adverse effects it can have such as impotence, decreased libido and feminization.
The systemic anti androgens discussed below not only help women who suffer from hirsutism (excessive hairiness) but the also have potential for hair re-growth if used under careful medical advice.
The Anti-Androgens which inhibit only DHT (but not testosterone) are used as hair re-growth treatment in males and have been discussed in the male section of Hair Loss Medication.
Cyproterone acetate is used as an effective treatment for hirsutism and acne. Doctors in Europe also use it as hair regrowth treatment for women. However, no large controlled clinical studies in androgenetic alopecia with cyproterone acetate are available. Limited research on this treatment has shown it to have some effect on stabilization of hair loss although reports on regrowth are quite rare.
Cyproterone acetate 50 to 100 mg/day taken on days 5 to 14 of the menstrual cycle can be used in combination with an oral contraceptive to regulate menstrual cycles and to avoid pregnancy.
It can also have some adverse effects such as depression, nausea, menstrual irregularity, bodyweight gain, breast tenderness and loss of libido. The treatment with this is allowed in women who have passed child bearing age. Women of childbearing age are cautioned to use some other effective birth control method because this anti-androgen has an potential unknown teratogenicity risk if the women becomes pregnant.
Spironolactone is an aldosterone antagonist which has a very mild antiandrogenic effect. It is a competitive inhibitor of ARP (androgen receptor proteins) binding and interfering with the translocation of this complex into the cell nucleus. It also depletes CYP (Cytochrome P) enzyme complex that weakly inhibits androgen biosynthesis in the adrenal glands.
Spironolactone is effective mostly for hirsutism. The drug is less effective in androgenetic alopecia in women, and a dosage of 200 mg/day is usually required. Small open trials have shown some clinical effect in Androgenetic Alopecia, but spironolactone rarely offers the benefit of hair regrowth.
The main adverse effects are menstrual irregularity. Minimal increases in serum potassium levels may occur, but are uncommon. Women of childbearing are warned against using this drug and they must use acceptable birth control methods and be aware there is a risk for feminization of a male fetus, if they become pregnant.
Tretinoin (all-trans retinoic acid) is a biologic response modifier. It is a potent cell mitogen that promotes and regulates epithelial cell growth and differentiation. It promotes angiogenesis and increases percutaneous absorption by affecting the fluidity and the lipid composition of cell membranes.
Tretinoin may have an effect on Androgenetic Alopecia by stimulating the growth of suboptimal hairs and could also act synergistically with minoxidil to produce more dense hair regrowth in women than either compound alone.
Animal studies with topical tretinoin have confirmed the potential of this anti androgen for inducing hair re-growth. Men with Androgenetic Alopecia have shown some hair regrowth when treated for 1 to 2 years with a combination solution of 0.025% tretinoin and 0.5% minoxidil formulated using generic powder forms as reported by some studies.
Precautions for Use
It has been shown that the manufactured formulations of tretinoin (Retin-A®) and minoxidil (Rogaine®), are incompatible and become ineffective if compounded in the same solution. They must either be mixed using generic powder forms or be applied as separate treatments.
Rogaine® must be applied every morning and night and Retin-A® during the day. Even though there seems to be some benefit in using the combination, most patients are not compliant with the need for an extra application during the day, and the additional irritation caused by tretinoin is not always well tolerated.
Chantal Bolduc and Jerry Shapiro, “Management of Androgenetic Alopecia”, Am J Clin Dermatol, 2000 May-Jun; 1 (3)