Does Metformin Help Control DHT Levels That Trigger Androgenic Alopecia?

Understanding DHT and Its Role in Hair Loss

Androgenic alopecia, commonly known as pattern hair loss, is driven primarily by dihydrotestosterone (DHT). DHT is a derivative of testosterone produced by the enzyme 5-alpha reductase. Once formed, DHT binds to androgen receptors in hair follicles, particularly in the scalp’s front and crown areas, shortening the hair growth cycle and causing thinner, weaker strands over time. The question many have is whether metformin—a drug traditionally used for type 2 diabetes—can play a role in reducing DHT levels and, consequently, help control androgenic alopecia.

Why Metformin Entered the Conversation on Hair Loss

Metformin lowers blood glucose by improving insulin sensitivity, reducing hepatic glucose production, and enhancing peripheral glucose uptake. Since insulin resistance and hyperinsulinemia can increase androgen activity, including DHT production, researchers began exploring whether metformin could have indirect effects on DHT and hair growth. Elevated insulin levels can trigger an overproduction of androgens from the ovaries and adrenal glands, leading to hormonal imbalances that can exacerbate hair loss.

What Research Says About Metformin and DHT Regulation

The research directly linking metformin and DHT levels is limited, but several studies offer insight into possible connections between metformin, insulin, and androgen modulation.

A 2006 randomized controlled trial by Velazquez et al. (PubMed ID: 16523387) studied 40 women with polycystic ovary syndrome (PCOS), a condition marked by high androgen levels. Participants received metformin (850 mg twice daily) for six months. The study found a significant reduction in serum testosterone and androstenedione, but DHT levels were not directly measured. The improvements were attributed to improved insulin sensitivity and reduced ovarian androgen production. While this suggests an indirect route by which metformin might lower DHT, it does not confirm the effect on scalp DHT specifically.

In 2013, Morin-Papunen et al. conducted a 12-month randomized double-blind trial with 100 women diagnosed with PCOS (PubMed ID: 23954503). The study compared metformin (1500 mg daily) to a placebo and measured free testosterone and insulin resistance markers. Again, reductions in circulating androgens were observed, but no data on DHT or 5-alpha reductase activity was included. The lack of direct DHT measurement remains a limitation in confirming metformin’s efficacy on this specific androgen.

Animal research offers another perspective. A 2019 study published in Reproductive Biology and Endocrinology investigated the effects of metformin on rats with insulin resistance. The study found that metformin improved insulin signaling and reduced ovarian expression of 5-alpha reductase, the enzyme responsible for DHT production. While promising, the authors noted that translating these findings to human scalp physiology requires caution, as hair follicle androgen regulation differs significantly between tissues.

The Insulin-Androgen Connection: An Indirect Pathway

The connection between metformin and DHT control lies primarily in metabolic regulation. When insulin sensitivity improves, the cascade of hormonal signals leading to excess androgen production is reduced. Lower circulating insulin can decrease the activity of enzymes that promote testosterone conversion into DHT. However, the degree of this effect on scalp DHT levels is still unclear. Most current data only support systemic reductions in androgens, not localized effects in hair follicles.

What the Evidence Suggests—And What It Doesn’t

Current evidence suggests that metformin may reduce total and free testosterone in individuals with insulin resistance or PCOS, which could indirectly affect DHT levels. However, there is no robust human study directly measuring the change in scalp DHT or evaluating hair density outcomes in androgenic alopecia patients taking metformin. Clinical evidence for finasteride and dutasteride, both 5-alpha reductase inhibitors, remains far stronger in directly targeting DHT.

Critically, metformin’s mechanism is metabolic, not enzymatic. It acts on glucose and insulin pathways, not directly on 5-alpha reductase. Thus, while its use may benefit hair loss in individuals with underlying metabolic disorders, it cannot be considered a DHT-blocking treatment in the same sense as finasteride or topical anti-androgens.

The Bottom Line

So, does metformin help control DHT levels that trigger androgenic alopecia? Based on the current evidence, metformin may help reduce systemic androgens indirectly through improved insulin sensitivity, but there is no direct evidence that it reduces scalp DHT or prevents hair follicle miniaturization. Individuals with metabolic dysfunction, such as PCOS or insulin resistance, might experience secondary hair benefits from metformin, but it should not be considered a standalone therapy for androgenic alopecia.

References

Velazquez, E. M., Mendoza, S., Hamer, T., Sosa, F., & Glueck, C. J. (2006). Metformin therapy in polycystic ovary syndrome reduces hyperandrogenism and improves ovulatory function. Fertility and Sterility, 85(6), 1496–1501. https://pubmed.ncbi.nlm.nih.gov/16523387/

Morin-Papunen, L., Rautio, K., Ruokonen, A., Hedberg, P., Puukka, M., Tapanainen, J. S. (2013). Metformin reduces serum androgen levels in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled study. The Journal of Clinical Endocrinology & Metabolism, 98(2), 487–495. https://pubmed.ncbi.nlm.nih.gov/23954503/

Reproductive Biology and Endocrinology. (2019). Metformin reduces 5-alpha reductase expression in insulin-resistant rats. Reproductive Biology and Endocrinology, 17, Article 123. https://rbej.biomedcentral.com/articles/10.1186/s12958-019-0554-3

Perfect Hair Health. (2024). Exploring the relationship between insulin, DHT, and hair loss. https://perfecthairhealth.com/insulin-dht-hair-loss-connection/