From the Guidelines
Topical minoxidil's main side effects include scalp irritation, dryness, itching, flaking, and redness at the application site, as well as potential systemic absorption causing more serious effects, although the latter is rare with proper application. When considering the use of topical minoxidil, it's essential to weigh these potential side effects against the benefits of treatment, particularly in conditions like alopecia areata, where its efficacy has been studied, albeit with mixed results 1. Some key points to consider about topical minoxidil's side effects include:
- Local irritation is the most common side effect, which can include itching, redness, and dryness of the scalp.
- Systemic side effects, such as dizziness, headaches, and changes in blood pressure, are less common but can occur, especially if the medication is not used as directed.
- The risk of allergic reactions, which can be severe, necessitates careful monitoring and immediate medical attention if symptoms such as severe itching, rash, swelling, or difficulty breathing occur.
- Proper application and adherence to the recommended dosage can help minimize the risk of side effects; for example, applying the solution only to a dry scalp and avoiding broken or irritated skin.
- The solution comes in different concentrations, and the dosage (e.g., 1 mL twice daily for the 5% solution) should be strictly followed to reduce the risk of adverse effects.
- It's worth noting that while the British Association of Dermatologists' guidelines discuss the use of minoxidil in alopecia areata, the focus is on its efficacy rather than side effects 1, highlighting the need for a comprehensive approach to patient education and monitoring.
From the FDA Drug Label
The most common side effects are itching and skin irritation of the treated area of the scalp. Unwanted hair growth on the face and other parts of the body has been reported in women. But it is rare and reversible If scalp irritation continues, stop use and see a doctor Minoxidil topical solution 5% contains alcohol, which will cause burning or irritation of the eyes. Stop use and ask a doctor if
- chest pain, rapid heartbeat, faintness, or dizziness occurs
- sudden, unexplained weight gain occurs
- your hands or feet swell
- scalp irritation or redness occurs
- unwanted facial hair growth occurs
The main side effects of topical minoxidil are:
- Itching
- Skin irritation of the treated area of the scalp
- Unwanted hair growth on the face and other parts of the body (rare and reversible, mostly in women)
- Scalp irritation or redness
- Unwanted facial hair growth
- Chest pain, rapid heartbeat, faintness, or dizziness
- Sudden, unexplained weight gain
- Swelling of hands or feet 2
From the Research
Topical Minoxidil Side Effects
- The most common side effect of topical minoxidil is irritant contact dermatitis, with typical symptoms of itching and scaling 3.
- These symptoms are often a result of an allergic reaction to propylene glycol, or less commonly, to minoxidil itself 3, 4.
- Allergic contact dermatitis to topical minoxidil solution can cause pruritus and scaling of the scalp 4.
- Patch testing can be used to determine the causative allergen, and alternative formulations using other solvents may be effective for patients allergic to propylene glycol 4.
- However, patients found to be allergic to minoxidil are no longer candidates for topical treatment of their alopecia with any preparations of minoxidil 4.
- Other side effects, such as facial swelling, can occur in rare cases 3.
- Combination therapy with low-level light therapy (LLLT) and 5% minoxidil may have a higher effectiveness in improving hair density and hair diameter, with no reported side effects 5, 6.