Beukow Nail Fungus Treatment Pen with 25% Undecenoic Acid

The precision pen tip is the standout feature: it lets you apply the treatment directly to a nail and reach its edges without spreading product over a larger area.

The formula contains 25% undecenoic acid, plus tea tree oil, almond oil, and vitamin E. It is intended for damaged or discolored fingernails and toenails.

This is a routine-based product, not a one-step fix. The directions call for twice-daily use, and the listed treatment period is 15 to 30 days, depending on nail thickness.

How to use it

The directions say to gently file the affected nail until it is thin and smooth, then remove the cap, twist the base, and apply the product to the area. The pen format is useful for tracing the nail edge or covering a small affected spot without handling a bottle and brush. For example, you could keep it with your nail-care items and apply it after filing as part of your regular routine.

Consistency is part of the trade-off: twice-daily application takes more follow-through than a product used occasionally. The instructions also recommend washing the area and changing socks and shoes regularly. How manageable is that routine for you? It matters, since the directions tie use to a multiweek period rather than a single application.

Pros

The pen tip offers controlled application, while its compact design makes it easy to carry in a bag or pocket. The listed formula combines undecenoic acid with tea tree oil, almond oil, and vitamin E, the product description says these added ingredients help moisturize dry nails and describes the formula as gentle on nails and skin. That is the product’s claim, not a guarantee that every user will find it non-irritating.

Worth considering if you want a targeted applicator and are comfortable building nail care into your daily routine. It’s not for you if you want a treatment that requires little upkeep, or if you are looking for a quick, one-time application. Filing the nail beforehand is another step to factor in.

Spec sheet

• Format: Nail treatment pen
• Active ingredient: 25% undecenoic acid
• Other listed ingredients: Tea tree oil, almond oil, and vitamin E
• Application: Twice daily
• Listed treatment period: 15 to 30 days, depending on nail thickness
• Pack: 4 pieces
• Intended use: Damaged or discolored fingernails and toenails

When it makes sense

This pen makes the most sense for someone who wants to apply a nail treatment precisely and can stick with the prep and twice-daily schedule. Compared with a less targeted format, the pen is designed to make application around nail edges more controlled and portable. A simpler routine may suit someone who does not want to file the nail or keep up with repeated applications.

The description does not provide details about how long each pen lasts or how results vary by cause of nail discoloration. Without having tried it, those are meaningful unknowns if you are deciding whether this format fits your routine. Choose it for its direct application and stated ingredients, not on the assumption that it will suit every nail concern.