TLDR Darkened knuckles can be an early sign of insulin resistance.
In a 2018 study involving 294 young adults aged 18 to 23, researchers discovered that Acanthosis Nigricans (AN) on the knuckles is a significant indicator of insulin resistance (IR). The study included 149 individuals with AN and 145 controls. Those with AN had higher fasting insulin levels (13.45 µU/mL vs. 8.59 µU/mL) and Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) index values (2.86 vs. 1.78) compared to controls, indicating that AN could serve as an early marker for IR. The presence of AN in the knuckles was found to have a sensitivity of 72% and a specificity of 62% for predicting IR. The study concluded that AN in the knuckles is an accessible, straightforward, and sensitive clinical sign for predicting IR, which could be beneficial for early intervention, even in individuals with a normal body mass index (BMI).
9 citations,
October 2014 in “Experimental and Clinical Endocrinology & Diabetes” Knuckle Acanthosis Nigricans is common in Latin American youth and may indicate early insulin resistance, especially in those with normal weight.
50 citations,
October 2009 in “Clinical Endocrinology” Hair loss in young men linked to higher risk of insulin resistance and metabolic issues.
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21 citations,
December 2007 in “Primary Care” Early diagnosis and treatment of PCOS is crucial to reduce emotional distress and health risks.
43 citations,
May 1988 in “British Journal of Dermatology” Patients with acanthosis nigricans often have insulin resistance and signs of increased male hormones, but treatment targeting these male hormones is generally ineffective.
The conclusion is that there's a link between high testosterone levels, insulin resistance, and certain skin conditions, regardless of obesity.
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11 citations,
January 2012 in “International Journal of Endocrinology” Insulin resistance is found in 20% of Thai women with PCOS, with age, waist size, skin changes, and abnormal blood fats increasing the risk.
71 citations,
January 2015 in “The Scientific World Journal” Insulin resistance may contribute to various skin diseases and treating it could improve skin health and prevent more serious conditions.
