Can I use Retin-A tretinoin on my dark armpit?

That's a good question! It depends on what is causing the darkening of the skin. If you have diabetes, you might have a concurrent condition called Acanthosis Nigricans in the armpits. There is a small chance that condition might improve a little with retin-a, but you should see a dermatologist for a proper diagnosis first. If you use the retin-a without really knowing why the armpit is discolored, you might make things worse. Please see an expert, and best of luck!

Thank you for your question. Retin-A may be used on the underarms, but a very common side effect of tretinoin is dryness, redness, and irritation. I highly recommend you consult with a board certified dermatologist to evaluate your skin and to discuss appropriate treatment options. Take care and good luck.