Latanoprost is a prescription eye drop most commonly used to treat open-angle glaucoma and ocular hypertension, which are conditions that lead to increased pressure inside the eye. By increasing the outflow of fluid from the eye, it helps protect the optic nerve and preserve vision. However, since its introduction, clinicians and patients have noted an unintended side effect: increased hair growth, particularly of the eyelashes. This observation led to investigations into how and why this occurs and if it could affect other areas, including the face. The answer is yes, unwanted facial hair growth can occur, but it is typically a localized side effect caused by improper application rather than a systemic issue.
The Connection Between Latanoprost and Hair Growth
Latanoprost is a type of medication called a prostaglandin analog. These drugs mimic the effects of natural prostaglandins in the body, which are involved in various physiological processes, including regulating the hair growth cycle. For hair follicles, latanoprost can influence the cycle by prolonging the anagen (growth) phase and stimulating follicles that are in the telogen (resting) phase. This leads to longer, thicker, and more numerous hairs.
The initial and most common manifestation of this effect is eyelash hypertrichosis. Patients using latanoprost in their eyes for glaucoma treatment often notice a change in the appearance of their eyelashes, which can become denser, longer, and darker. The effect is most noticeable and dramatic in the eyelashes because of the direct and repeated topical application of the medication to the area.
Why Facial Hair Growth Can Occur
While the primary cosmetic side effect is eyelash enhancement, unwanted hair growth on the face can also happen. This is not a systemic side effect caused by the drug entering the bloodstream and affecting hair follicles all over the body. Instead, it is a localized reaction that occurs when the medication inadvertently makes contact with the surrounding skin.
This can happen in several ways:
- Overflow: If excess eye drops spill out of the eye, they can run down the cheek or eyelid, affecting the vellus (fine, light) hairs in that area.
- Residual Droplets: The active ingredient can be transferred from the fingers to other parts of the face after administering the drops.
- Inadvertent Application: In some cases, patients may unintentionally apply the drops to the skin near the eye, such as the upper cheek, inner canthus (corner of the eye), or eyelids.
Case reports have documented hypertrichosis affecting the vellus hairs of the malar (cheekbone) area and other facial regions following the use of ophthalmic latanoprost. However, this effect is much less common and typically less pronounced than the eyelash changes.
Latanoprost vs. Bimatoprost: Effects on Hair
Latanoprost is not the only prostaglandin analog known for its hair-growth effects. Bimatoprost is another drug in this class, and the comparison between them is relevant for understanding hypertrichosis. Bimatoprost is the active ingredient in Latisse, a product specifically approved by the FDA for the cosmetic enhancement of eyelashes. While latanoprost is primarily a glaucoma treatment with hypertrichosis as a side effect, bimatoprost is available in a formulation for targeted eyelash growth.
| Feature | Latanoprost (e.g., Xalatan) | Bimatoprost (e.g., Lumigan, Latisse) |
|---|---|---|
| Primary Use | Ophthalmic solution to reduce intraocular pressure in glaucoma and ocular hypertension patients. | Ophthalmic solution for glaucoma (Lumigan) and topical solution for eyelash hypotrichosis (Latisse). |
| Efficacy for IOP | Very effective. | Potentially provides a greater reduction in IOP than latanoprost, though both are highly effective. |
| Eyelash Hypertrichosis | Common side effect, often desired by patients, but not the primary purpose. | More commonly and often more effectively associated with eyelash growth, especially the Latisse formulation. |
| Onset of Hypertrichosis | Slower onset; studies suggest bimatoprost may cause hypertrichosis sooner and more extensively. | Earlier and more extensive hypertrichosis often observed. |
| Reversibility | Eyelash and periorbital hypertrichosis are generally reversible upon discontinuation. | Generally reversible upon discontinuation. |
How to Manage Unwanted Facial Hair Growth
If you are using latanoprost and are concerned about unwanted facial hair, there are several steps you can take to minimize the risk.
- Use Proper Technique: Apply the drops carefully, ensuring they land directly in the eye and do not overflow onto the skin. Proper drop instillation training can help.
- Wipe Excess Immediately: Use a clean tissue or cotton pad to wipe away any excess medication that runs down your face immediately after application.
- Wash Hands: Wash your hands thoroughly after administering the drops to prevent transferring the medication to other facial areas.
- Address Symptoms with Your Doctor: If you notice unwanted facial hair growth, discuss it with your ophthalmologist or dermatologist. The benefit of controlling glaucoma may outweigh the cosmetic side effect, but other treatment options may be available.
- Consider Alternatives: If the side effect is particularly bothersome and you are a candidate for alternative treatments, your doctor may switch you to a different class of medication that does not cause hypertrichosis.
Conclusion: Weighing the Benefits and Risks
Does latanoprost cause facial hair growth? Yes, it can, but it is typically a localized, reversible side effect that occurs when the medication comes into contact with the skin. The more common and pronounced hair growth effect is on the eyelashes. For most patients, the therapeutic benefits of latanoprost in managing serious eye conditions like glaucoma far outweigh the potential for unwanted, reversible facial hair growth. However, patients who are concerned about this cosmetic side effect should speak openly with their healthcare provider. By practicing careful application and wiping away excess drops, the risk of unwanted facial hair can be significantly minimized. The hair-stimulating properties of prostaglandin analogs are a fascinating area of pharmacology, but for treating widespread hair loss, other established treatments are typically used. A good resource for understanding the mechanism of action for latanoprost and other drugs is the NCBI Bookshelf, which offers detailed, peer-reviewed information like the StatPearls entry on latanoprost..
