Skin Tags and Dark Neck Patches: Signs of Insulin Resistance
Two visible skin changes associated with insulin resistance — often noticed long before anyone runs a blood test.
Some of the earliest visible signs of insulin resistance are on the skin, and they're frequently treated as cosmetic rather than informative.
Acanthosis nigricans
Velvety, darkened, slightly thickened patches of skin — most commonly at the back of the neck, in the armpits, in the groin, or under the breasts.
People often assume it's dirt that won't wash off, or a tan, and try to scrub it. It isn't either.
It's associated with high circulating insulin, which stimulates skin cell proliferation and pigmentation. It's one of the more recognized cutaneous markers of insulin resistance, and it can appear well before glucose readings change — because insulin rises first while glucose is still being held normal.
Skin tags
Small, soft, skin-colored growths, usually in the same locations — neck, armpits, under the breasts, eyelids.
Extremely common and usually harmless. But multiple skin tags, particularly appearing over a short period, are associated with insulin resistance through a similar mechanism.
One skin tag means little. A crop of them is worth mentioning.
What to do about it
Mention it. Not to a dermatologist for removal — to your doctor, alongside a request for glucose testing. Say specifically: I've noticed these, I understand they can be associated with insulin resistance, could we check?
Ask about fasting insulin as well as glucose, if they'll run it. These signs can appear while glucose is still normal precisely because insulin is doing the work of keeping it there.
Don't try to treat the skin. Removing skin tags or bleaching patches addresses the appearance and not the cause, and both tend to return.
What improves them
The darkening often lightens as insulin resistance improves, though slowly — months rather than weeks, and not always completely.
Skin tags don't generally disappear, but new ones stop appearing.
Other skin signs worth knowing
Slow-healing wounds or cuts that take longer than they used to.
Recurrent skin infections, boils or fungal infections in skin folds.
Very dry, itchy skin, particularly on the lower legs.
None of these individually proves anything. All of them are on the list of things that should prompt a check, and all get explained away routinely.
Try this week: if you have velvety darkened patches or a crop of skin tags, ask for a glucose test and mention the skin specifically.
Education, not medical advice. Skin changes should be assessed by your doctor.