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Written by Rosalie Orrostieta, MSN, APRN, FNP-C
Medically Reviewed for Accuracy and Safety by Rosalie Orrostieta, MSN, APRN, FNP-C
Last Updated: November 17, 2025
Living here in beautiful Sarasota, we deal with heat and humidity pretty much year-round. That means sleeveless tops, swimsuits, and sundresses are basically our uniform. But I can’t tell you how many times I’ve had a patient sit in my chair, lower their voice, and confess that they feel self-conscious about raising their arms.
They talk about “dark shadows” or “stains” in their underarms that scrubbing just won’t remove.
If this sounds like you, I want you to know two things immediately. First, you are not alone this is one of the most common concerns I treat at Rose Medical Aesthetics. Second, it is rarely a hygiene issue, so please stop scrubbing!
As a Nurse Practitioner, I look at skin through a medical lens. Dark underarms are usually a result of biological factors like hair growth patterns, friction, or specific skin conditions. The good news? We have powerful, science-backed treatments that can brighten this area significantly.
Let’s dive into what’s really happening under your arms and how we fix it.
What Causes Dark Underarms? (Understanding the Root)
Before we can treat the problem, we have to diagnose it. In my practice, I find that patients usually fall into one of three categories. Understanding which one you are is the key to choosing the right treatment.
1. The “Shadow Effect” (It’s Not Pigment!)
This is the most common “aha!” moment I have with patients. Often, the skin itself isn’t actually hyperpigmented. Instead, you have dark, coarse hair growing beneath the surface of the skin.
When you shave, you’re only cutting the hair at the surface. The dark root remains visible underneath the translucent layers of your skin, creating a permanent “5 o’clock shadow.” If you have fair skin and dark hair, this is almost certainly part of your problem. No amount of bleaching cream will fix this because the darkness is under the skin, not on it.
2. Post-Inflammatory Hyperpigmentation (PIH)
Our underarms go through a lot. We shave them, apply chemical deodorants, and then subject them to friction from clothing.
For those with olive to darker skin tones (Fitzpatrick skin types III-VI), this constant irritation triggers the skin’s defense mechanism: melanin production. This is called Post-Inflammatory Hyperpigmentation (PIH). Essentially, your skin is trying to protect itself from the “trauma” of shaving by creating a dark patch.
3. Acanthosis Nigricans
This is where my medical background comes in. Sometimes, the darkening is accompanied by a change in texture. The skin might feel velvety or thicker than usual.
Professional Treatments at Rose Medical Aesthetics
At Rose Medical Aesthetics, we don’t believe in “one-size-fits-all.” We curate a treatment plan based on the root cause we discussed above. Here are the most effective medical treatments we use to brighten underarms.
Laser Hair Removal: The Foundation of Bright Underarms
If you are still shaving your underarms, you are likely fighting a losing battle against darkness.
Shaving is a form of micro-trauma. Every time you drag a razor across that delicate skin, you are scraping off top layers of skin and inviting inflammation. Plus, as I mentioned earlier, shaving leaves the dark root behind.
How We Use It: At Rose Medical Aesthetics, Laser Hair Removal is often step one. We use advanced laser technology that targets the melanin in the hair follicle.
Why It Works for Brightening:
- Eliminates the Shadow: By destroying the hair follicle completely, we remove the dark root. The “shadow” disappears instantly.
- Stops the Trauma: When you stop shaving, you stop the daily irritation. This gives your skin a chance to heal and naturally fade the PIH caused by friction.
I’ve had patients who thought they needed heavy chemical peels, but after 3 or 4 sessions of laser hair removal, 80% of the “darkness” was gone simply because the hair was gone. It is truly a game-changer.
Chemical Peels
For patients where the darkness is true pigmentation (melanin on the skin’s surface), we need to exfoliate. But we need to do it chemically, not physically.
The Secret Ingredient: Glutathione The Perfect Derma Peel is unique because it features Glutathione. In the medical aesthetic world, we call Glutathione the “master antioxidant.” It is incredibly effective at inhibiting melanin production and lightening existing pigment.
What the Process Feels Like: The application takes about 15 minutes in the clinic. It’s not painful usually just a slight tingle. Over the next 7 to 10 days, the old, dark, damaged layers of skin will literally peel away.
It’s oddly satisfying to watch! Once that peeling process finishes, the fresh skin revealed underneath is significantly lighter, smoother, and softer. For deep pigmentation, I usually recommend a series of 2 or 3 peels spaced a month apart.
Microneedling: For Texture and Tone
If your underarms have that “chicken skin” texture or the velvety feel of Acanthosis Nigricans, lasers and peels might not be enough on their own. We need to remodel the tissue.
How It Works: We use FDA-cleared devices like SkinPen® or Morpheus8 (Radiofrequency Microneedling). These devices create thousands of microscopic channels in the skin. This triggers a massive surge of collagen and elastin production.
Why I Recommend It: For thickened, dark skin, microneedling helps to normalize the skin structure. As the skin heals, the new tissue is smoother and healthier. When skin is smooth, it reflects light better, which automatically makes it look brighter and less shadowed.
With Morpheus8 specifically, the added heat energy helps to tighten the skin. This is great for mature patients who might have a bit of laxity in the underarm area along with the pigmentation.
Botox for Hyperhidrosis: The Preventative Cure
You might be wondering, “Wait, Rosalie, isn’t Botox for wrinkles?”
Yes, but it is also a miracle worker for sweat. Excessive sweating (Hyperhidrosis) creates a constantly moist environment. This breeds bacteria and increases friction between your arm and your clothes. That friction leads to a specific type of darkening called intertrigo.
By injecting Botox into the underarms, we can temporarily block the chemical signals that stimulate sweat glands.
The Result: Your underarms stay dry. When they are dry, there is less friction. When there is less friction, there is less inflammation and darkening. It’s a preventative measure that changes lives—you can finally wear that silk blouse without worry!
Comparison: Professional Treatments vs. Home Remedies
I know it’s tempting to try a DIY scrub from Pinterest. I’ve seen patients try everything from baking soda to lemon juice. As a medical professional, I have to be honest with you: many of these home remedies do more harm than good.
Lemon juice, for example, is highly acidic and can cause phytophotodermatitis—a reaction that actually burns the skin when exposed to sun, leading to more hyperpigmentation.
Here is a quick breakdown of what you can expect from professional treatments versus at-home attempts:
Laser Hair Removal
- Best For: Dark hair roots, shaving irritation, “5 o’clock shadow.”
- Time to See Results: You’ll see a difference in hair density after 1 session; significant brightening after 2-3 sessions.
Medical Chemical Peels
- Best For: Surface pigmentation, sun damage, melasma.
- Time to See Results: About 7-10 days (after the peeling phase completes).
Microneedling
- Best For: Rough texture, thickened skin, deep pigment.
- Time to See Results: 3-4 weeks as collagen rebuilds.
DIY Lemon/Baking Soda
- Best For: Very mild cases (but high risk of irritation).
- Time to See Results: Inconsistent. often 3-6 months, if at all.
Aftercare & Maintenance: The Rose Medical Protocol
Once we’ve brightened your underarms in the clinic, we want to keep them that way! Maintenance is half the battle. Here is the protocol I give my patients to follow at home.
1. Sun Protection (Yes, really!) It sounds funny, but if you are wearing sleeveless tops, your underarms are getting UV exposure. UV rays stimulate melanin. If you are treating pigmentation, you must protect the area.
2. Medical Grade Skincare Just like you treat your face, you should treat your body. I am a huge advocate for SkinBetter Science products.
- Alto Defense Serum: This is an antioxidant powerhouse that protects against environmental damage.
- Even Tone Correcting Serum: This non-hydroquinone serum is fantastic for keeping pigment at bay between treatments.
3. Switch Your Deodorant If you have sensitive skin, alcohol-heavy deodorants and fragrances are irritants. I recommend switching to a hypoallergenic, aluminum-free option while you are undergoing treatment to minimize inflammation.
Frequently Asked Questions
I get asked these questions all the time in the treatment room, so I wanted to address them here.
Does shaving make underarms darker? Technically, yes. It’s not that the hair grows back darker, but the friction and micro-cuts from the razor cause inflammation. This leads to Post-Inflammatory Hyperpigmentation. This is why I almost always recommend transitioning to laser hair removal.
How many peel sessions do I need? It depends on how deep the pigment is. For a general refresh, one Perfect Derma Peel can do wonders. For darker, long-standing pigmentation, we usually plan for a series of 3 peels.
Is laser safe for darker skin tones? This is a crucial question. At Rose Medical Aesthetics, safety is our priority. We use specific laser wavelengths (like the Nd:YAG) that bypass the melanin in the skin surface and target only the hair follicle. This makes it safe and effective for darker skin tones without causing burns.
Confidence is Waiting
I hope this helps demystify why underarms darken and, more importantly, gives you hope that you don’t have to live with it. You shouldn’t have to hesitate before reaching for something on a high shelf or feel uncomfortable in your favorite summer dress.
Whether it’s the shadow from hair growth or pigmentation from years of shaving, we have the tools to fix it.
If you are in the Sarasota area, come see us at Rose Medical Aesthetics. My team and I would love to sit down with you, take a look at your skin, and build a plan that gets you ready to go sleeveless with total confidence.
Let’s get you glowing!
