Underarm shaving: avoiding irritation and ingrown hairs

Have you ever found yourself rushing to the bathroom, razor in hand, five minutes before heading out, only to emerge with an irritated armpit? If so, you're clearly not alone. Shaving your underarms seems harmless, but it's probably the most poorly treated area in your entire grooming routine.

An area rarely taken seriously

We think about it quickly after showering, often without really paying attention to what we're doing. Yet the armpit combines almost everything skin can hate: it's thin, it creases when you move your arm, it rubs against clothes, and it sweats more than the rest of the body. In short, it's the worst place to improvise a quick shave.

In 2026, we still deserve a routine that doesn't end with a grimace in the mirror every time we raise our arm.

What a classic razor really does to this skin

A classic blade isn't designed for an area that moves so much. The result: cuts, small red bumps, and a feeling of tightness that lasts all day. And the worst time to discover it is, of course, just before going out.

"I tried the billy on my armpits a bit out of curiosity at first, not just for intimate areas. Zero cuts, zero redness the next day, whereas usually I always had some irritation somewhere." — Jerome D.

The myth that has persisted for years

You've probably heard this before: "shaving makes hair grow back thicker and coarser." Frankly, that's false, and it's been proven for a long time. The razor cuts the hair at its base; it doesn't affect its root or its thickness. The impression of coarser hair simply comes from the fact that a freshly cut hair has a blunt end, so it feels different to the touch for the first few days. Nothing more.

Another persistent myth: "shaving clogs pores." Again, no, a razor only removes visible hair; it doesn't obstruct anything. What actually clogs pores are deodorant residue or poorly rinsed sweat, not the act of shaving itself.

Why ingrown hairs specifically appear there

Ingrown hairs are easy to understand once you know the mechanism. When a razor cuts hair precisely at skin level, the regrowth can take a wrong turn and grow inwards instead of emerging normally. Under the arms, the skin that creases and rubs constantly exacerbates the phenomenon.

This brings us to a point we want to make clear, because it's often misunderstood: the ceramic blade of the billy protects against cuts, but it doesn't shave completely smooth. It deliberately leaves half a millimeter of hair. This is not a flaw; it's precisely what allows the hair to grow back over the skin rather than burrowing into it. Perfectly smooth skin and skin without ingrown hairs are two goals that don't always go together, and billy has clearly chosen the latter.

Razor, waxing, or trimmer: what really changes under the arms

Waxing removes hair with the root, so regrowth is slower, but the underarm area is particularly sensitive to this type of removal, with a higher risk of redness and small bumps than elsewhere on the body. A classic razor is faster, but this is precisely where cuts and ingrown hairs most often occur, because the blade comes into direct contact with the skin.

Even though it was initially designed for intimate areas, a trimmer like billy sits somewhere in between. It's as fast as a razor, without the risk of cuts, but also doesn't pull out the root like waxing would. It's the logical compromise when you're looking to maintain a delicate area without a complicated protocol.

How often to take care of it

There's no universal rule; it mostly depends on your individual hair growth rate and the style you want to maintain. Generally, once or twice a week is ample for a well-maintained area that's never prickly. If you notice recurring irritation, it's often a sign that you're going over it too often or too close, not that you need a more aggressive tool.

The routine that changes everything, without taking ten minutes

Gently stretch the skin with your free hand, shave in the direction of hair growth, and avoid going over the same spot five times hoping for a closer result. On a waterproof area like this, you can absolutely do it in the shower; the skin is more pliable and pores are open.

And because the billy is waterproof, you don't even need to get out of the shower to take care of it. Shave, rinse, dry, done.

The connection with perspiration, which is never explained enough

Irritated skin sweats differently. Sweat glands are close to micro-lesions caused by a classic razor, which often accentuates the feeling of discomfort and more noticeable sweat in the hours that follow. Unaggravated skin, on the other hand, returns to its normal function almost immediately after using the trimmer.

The detail that truly makes a difference afterward

Here's something that isn't said enough: with a classic razor, you generally have to wait before applying deodorant, giving the irritated skin time to calm down. With billy, since there are no cuts or irritation, you can apply your deodorant immediately afterward, without waiting and without a burning sensation. For someone who only has five minutes in the morning, this fundamentally changes the routine.

And if you prefer to keep some length

No one said that the only valid option is "shave everything." The travel mode and guards of the billy also allow you to simply maintain, trim, and keep a style rather than completely removing hair. Your body, your style, including under your arms.

The entire green, blue, or yellow range works in exactly the same way, with a ceramic blade designed to last, to be changed every 3 to 6 months depending on your usage.

To go further

If you want to delve into the topic for other sensitive areas, we also have resources to guide you: the men's intimate trimmer and the women's intimate trimmer address the same concerns, just on a different part of the body.

Key takeaway

An irritated armpit is never inevitable; it's almost always a question of the tool. Change the tool, and the morning routine stops being a dreaded moment.

Frequently Asked Questions

Does shaving underarms hurt more than elsewhere?
Not in itself, but the skin there is thinner and more mobile, so irritation is more frequent with a poorly adapted classic razor.

Does shaving really make hair grow back thicker?
No, that's a myth. Regrown hair just has a blunt end to the touch, which gives this impression without the actual thickness having changed.

Why do I only get ingrown hairs under my arms?
Because it's an area that creases and rubs constantly, which encourages hair to grow inwards when it's cut too short.

How often should this area be shaved?
Once or twice a week is usually sufficient, depending on individual hair growth rate.

Can billy be used in the shower for this area?
Yes, it's waterproof, which makes it one of the most convenient times to use it.

Do I have to wait before applying deodorant afterward?
With a classic razor, often yes, due to irritation. With billy, the absence of cuts and irritation allows for immediate application.