Metformin in skin disorders
What is metformin?
It is an oral hypoglycemic agent (lowers blood sugar levels) that lowers hepatic glucose production and increases insulin sensitivity, since it increases the use of glucose by adipocytes and muscles. It is classically used in non-insulin-dependent diabetes (type II) associated with obesity as it improves the prognosis and quality of life of these patients by reducing cardiovascular complications. It has also been shown to reduce blood levels of lipids (triglycerides, free fatty acids and low-density cholesterol (LDL) and platelet aggregation (it has an antiplatelet effect). In some genetic diseases, it also reduces the incidence and mortality of cancer.
What is the use of metformin in dermatology?
Increased insulin sensitivity can improve skin disorders such as acanthosis nigricans, and reducing the overproduction of ovarian androgens improves skin signs of hyperandrogenism, whether or not associated with polycystic ovary syndrome (click here), such as acne, hirsutism (more information here) and hidradenitis suppurativa.
Can metformin be helpful in treating excess hair?
Hirsutism, or excess hair in androgen-dependent hairy areas (moustache, chin, chest, abdomen), is usually related to an excess of the aforementioned hormones (polycystic ovary syndrome in 90% of cases). The treatment of polycystic ovary syndrome (PCOS) with metformin improves insulin sensitivity (decreases body mass index) and endocrinological functioning of the ovary: it reduces the concentration of luteinizing hormone (LH), androstenedione and testosterone, regulates the menstrual cycle, restarts ovulation and reduces the risk of miscarriage in the future.
In comparative studies between oral contraceptives (ethinyl estradiol plus cyproterone acetate) and metformin, it seems that metformin is more effective than the former in the treatment of hirsutism at 6 and 12 months of treatment. The combination has shown better indices in terms of the implementation of the patient’s metabolic profile measured by the thickness of the arterial walls, insulin sensitivity, the amount of body fat and menstrual regularity.
How useful can metformin be in the treatment of acne?
In women with chronic acne in the context of hyperandrogenism secondary to PCOS, metformin has been shown to be effective in improving acne lesions, lowering testosterone levels, regularizing menstrual rhythm, and improving insulin sensitivity.
Therefore, in women with persistent acne and signs of hyperandrogenism, there will be several therapeutic options other than isotretinoin. In these cases, isotretinoin is probably not the best therapeutic option, as it does not treat the hyperandrogenic etiology of acne and can increase blood lipid levels in patients at risk.
What other skin disorders may metformin play a role in?
Positive results have been reported in hidradenitis suppurativa, acanthosis nigricans (which translates insulin resistance), eruptive xanthomas (which are usually associated with hyperlipidemia) and, very anecdotally, in some skin tumours.
REFERENCES
· Ibáñez L, Díaz M, Sebastiani G, Marcos MV, López-Bermejo A, de Zegher F. Oral contraception vs insulin sensitization for 18 months in nonobese adolescents with androgen excess: posttreatment differences in C-reactive protein, intima-media thickness, visceral adiposity, insulin sensitivity, and menstrual regularity. J Clin Endocrinol Metab. 2013 May; 98(5):E902-7.
· Badr D, Kurban M, Abbas O. Metformin in dermatology: an overview. J Eur Acad Dermatol Venereol. 2013 Nov; 27(11):1329-35.