Dark, velvety patches on the back of the neck or under the arms are often mistaken for tanning, pigmentation, or poor hygiene. However, doctors are now urging people to pay closer attention to these skin
changes. The condition, known as Acanthosis Nigricans, is usually harmless on its own but can serve as an early warning sign of underlying metabolic issues.
The topic recently gained attention after Dr Sunita Sayammagaru shared an observation from her daily commute. While travelling by metro, she noted that a large number of people around her showed signs of Acanthosis Nigricans on the back of their necks.
Doctor Points Out Reason For Dark Neck
Dr Sunita Sayammagaru wrote on X, “More than 50% of people in my compartment have Acanthosis Nigricans – those dark hyperpigmented velvety patches on the back of the neck, armpits, groin folds, in the folds of skin on the abdomen….” She wrote that when she looked at them, she realised why they had dark necks.
Travelling by Metro train and am leisurely observing everyone…
More than 50% of people in my compartment have Acanthosis Nigricans – those dark hyperpigmented velvety patches on the back of the neck, armpits, groin folds, in the folds of skin on the abdomen….
Obviously, I… pic.twitter.com/yzCaKIEdSB
— Sunita Sayammagaru 🇮🇳🇬🇧 (@drsunita02) January 11, 2026
She wrote, “Even the people who look slim from behind have it, and lo and behold, when I see them from the front, they have a good potbelly/paunch…not surprising. Acanthosis is one of the first signs of insulin resistance, which is the precursor of diabetes and other metabolic disorders.”
Echoing her views, Dr Sayajirao Gaikwad also addressed the common misconception around dark necks and underarms. In a follow-up tweet, he wrote, “Acanthosis Nigricans, the dark velvety skin on the neck or underarms, isn’t about poor hygiene. It’s one of the clearest external signs of insulin resistance. When cells resist insulin, the body produces more of it. Excess insulin overstimulates skin cells and pigments leading to thickened, darkened patches. This is not just cosmetic. It’s an early red flag for prediabetes, type 2 diabetes, PCOS, fatty liver, and metabolic syndrome.”
Dark Neck Isn’t Dirt
It’s Insulin ResistanceAcanthosis Nigricans, the dark velvety skin on the neck or underarms, isn’t about poor hygiene.
It’s one of the clearest external signs of insulin resistance.When cells resist insulin, the body produces more of it.
Excess insulin… https://t.co/XPBlx7jQQA— Dr.Sayajirao Gaikwad (@DietDrsayajirao) January 11, 2026
Dr Sayajirao suggested these lifestyle changes to reduce the dark spots and control insulin.
• A strict low-carb diet
• Higher protein, healthy fats
• Weight loss (even 5–10% matters)
• Resistance training & proper sleep
What Is Insulin Resistance?
Insulin resistance occurs when the body does not react effectively to insulin, causing the pancreas to produce more. Over time, this imbalance can lead to conditions such as type 2 diabetes, hormonal disorders, and other metabolic issues. Because the skin changes are visible long before blood tests show abnormalities, doctors say it should not be ignored.
