When we think about the different physical and emotional challenges associated with obesity, hair loss may not come to mind. Yet this is a concern for many people; while obesity is not considered a direct cause of hair loss, people with obesity do have a higher risk of experiencing thinning hair and even balding—for a variety of physiological reasons. “Hair loss in individuals with obesity can have several causes, including hormonal imbalances, chronic inflammation, nutrient deficiencies, or even rapid weight loss,” explains Supriya Rao, a quadruple board-certified physician in internal medicine, gastroenterology, obesity medicine, and lifestyle medicine.
For starters, there are multiple ways in which hormone imbalances commonly associated with obesity can cause hair loss. One is that obesity can lead to increased levels of hormones called androgens, which are involved in hair growth. This can lead to a condition known as androgenetic alopecia, in which all those excess androgens over-stimulate hair follicles, shortening the growth period for individual strands and causing miniaturization—when hair follicles shrink and produce finer, weaker hairs. Research has begun to confirm that people with a higher BMI and body weight are more prone to severe androgenetic alopecia.
There are other hormone-related conditions associated with obesity that can contribute to hair loss, like Type 2 diabetes and polycystic ovary syndrome (PCOS). With Type 2 diabetes, high blood glucose can cause damage to the blood vessels in the scalp, reducing the delivery of oxygen to hair follicles and negatively affecting hair health. Type 2 diabetes is also associated with excess insulin and androgens, both of which can affect hair follicle health and cause miniaturization and eventual hair loss. Similarly, PCOS is associated with elevated levels of androgens (including testosterone) and can commonly lead to female pattern hair loss, where hair thins near the hair part as well as overall.
PCOS—and obesity in general—can also cause insulin resistance, a precursor to Type 2 diabetes, where the body’s cells become less responsive to insulin, a hormone that regulates blood glucose. As with diabetes, this can impair the function of hair follicles. Insulin resistance can also increase levels of a specific androgen called DHT, a sex hormone known to shrink hair follicles and cause thinning hair.
Other health problems associated with obesity can also trigger hair loss. Thyroid problems—including hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid)—are also closely linked to both obesity and hair loss. There’s also an autoimmune condition called alopecia areata in which the body attacks healthy hair follicles, leading to hair loss. While this condition is in part genetic, not a result of obesity, studies suggest that by causing chronic inflammation and immune dysfunction, obesity has the potential to exacerbate autoimmune conditions like alopecia areata.
Further complicating matters when it comes to hair health, people living with obesity often experience elevated levels of stress hormones like cortisol and adrenaline. That’s due to chronic inflammation and stress in the body, as well as increased activity of an enzyme located within fat tissue. High stress-hormone levels have been shown to increase oxidative stress and disrupt the hair growth cycle, prompting hair follicles to prematurely enter a resting phase, which leads to increased shedding and rapid hair loss.
