Can Minoxidil Cause Greyish Hair?
Yes, minoxidil can cause hair discoloration including greyish changes, though this is not commonly emphasized in official labeling and the evidence is limited but emerging.
Evidence from FDA Labeling
The FDA-approved minoxidil labeling acknowledges that "some people have experienced changes in hair color and/or texture" during treatment 1. However, the official labeling does not specifically detail greyish discoloration as a distinct adverse effect, focusing instead on more common side effects like scalp irritation and unwanted facial hair growth 1.
Clinical Research Evidence
A 2024 observational study from Saudi Arabia provides the most direct evidence for this phenomenon:
- 26% of 453 patients (n=118) reported hair greying while using topical minoxidil 2
- An additional 14.8% (n=67) noticed other color changes 2
- Risk factors for discoloration included:
- Among surveyed dermatologists, 42.1% had observed grey hair after minoxidil use in their patients, though only 17.5% attributed it directly to the medication 2
Historical Context
Earlier literature from 1987 and 2012 noted that minoxidil could cause "increasing growth or darkening of fine body hairs" 3, suggesting the drug's effect on hair pigmentation has been recognized, though primarily in the context of darkening rather than greying 3.
Clinical Implications
- This side effect appears reversible - the FDA labeling notes that "measurable changes disappear within months after discontinuation of treatment" 3
- Monitor patients with risk factors: Those with family history of premature greying or planning long-term use should be counseled about this possibility 2
- The mechanism is unclear but may relate to minoxidil's effects on hair follicle cycling and melanocyte function 2
Caveats
- The primary evidence comes from a single cross-sectional study with self-reported outcomes 2
- The British Association of Dermatologists guidelines (2012) do not mention hair discoloration as an adverse effect of minoxidil 4
- This side effect is not listed among the standard warnings to "stop use and ask a doctor" in FDA labeling 1