Prostaglandin Analogs: The Primary Eyelash Growers
The most widely known and effective medications for promoting eyelash growth belong to a class of compounds called prostaglandin analogs (PGAs). These medications were initially developed to treat ocular conditions, such as glaucoma, but their ability to induce hypertrichosis (excessive hair growth) was a notable side effect. This discovery led to the development of specific formulations for cosmetic use.
Bimatoprost (Latisse)
Bimatoprost, sold under the brand name Latisse, is the only FDA-approved prescription medication specifically for treating hypotrichosis, or having inadequate eyelashes. Its origin traces back to its use as Lumigan, a glaucoma medication used to lower intraocular pressure. Its mechanism of action is primarily understood as prolonging the anagen (growth) phase of the eyelash hair cycle. It is also believed to increase the number of hairs in this growth phase, resulting in longer, thicker, and darker eyelashes. The medication is applied once nightly to the base of the upper eyelashes using a sterile applicator to minimize the risk of side effects and contamination.
Other Prostaglandin Analogs (Off-label Use)
Other PGAs used for glaucoma treatment have also been observed to cause eyelash growth, though they are not FDA-approved for cosmetic purposes. Examples include latanoprost (brand name Xalatan) and travoprost (brand name Travatan). Since these drugs are formulated for intraocular use and not specifically for topical eyelid application, using them off-label for eyelash enhancement carries higher risks of ocular side effects and permanent changes.
How Medications Affect the Eyelash Growth Cycle
The hair growth cycle consists of three main phases: anagen (growth), catagen (transition), and telogen (resting). The relatively short duration of the anagen phase for eyelashes is the reason they don't grow indefinitely long. Prostaglandin analogs promote eyelash growth by targeting the anagen phase in two key ways:
- Prolonging the anagen phase: This allows lashes to grow longer than they normally would before entering the transition phase.
- Increasing the number of hairs: The medication may stimulate more hair follicles to enter the active growth phase.
Additionally, PGAs can enhance melanin production within the follicles, resulting in darker-looking lashes. This mechanism is also responsible for potential pigmentation changes in the skin and iris.
Other Classes of Medications Causing Eyelash Growth
Beyond prostaglandin analogs, other types of medications can also cause changes in eyelash growth, often as an unintended side effect. These are typically associated with systemic treatments for other conditions:
Epidermal Growth Factor Receptor (EGFR) Inhibitors
Certain cancer treatments, such as EGFR inhibitors like cetuximab, panitumumab, erlotinib, and gefitinib, have been reported to cause eyelash trichomegaly. This condition is characterized by thick, rigid, and excessively long eyelashes. It is thought to be a result of the drug's effect on hair follicles.
Janus Kinase (JAK) Inhibitors
Janus Kinase (JAK) inhibitors, including baricitinib and tofacitinib, have shown promise in promoting eyelash and eyebrow regrowth for individuals with alopecia areata. These drugs are potent immunosuppressants that interfere with the inflammatory pathway associated with hair loss in autoimmune conditions.
Other Reported Medications
A variety of other medications have been reported in medical literature to cause eyelash trichomegaly as a rare or less common side effect. These include:
- Minoxidil
- Diazoxide
- Corticosteroids (topical)
- Psoralens
- Zidovudine
- Phenytoin
- Tacrolimus
- Cyclosporine
- Interferon-α2b
Safety Considerations and Side Effects
Any medication that alters hair growth can have unintended side effects, especially around the delicate eye area. With prostaglandin analogs, common adverse effects can include:
- Eye irritation, dryness, or redness
- Itching of the eyes and eyelids
- Darkening of the eyelid skin (often reversible)
- Increased tears
More serious and potentially permanent side effects are also possible, particularly with improper use or long-term application:
- Permanent iris pigmentation changes: PGAs can increase the amount of brown pigment in the iris, which is more noticeable in lighter-colored eyes. This change is considered permanent even after discontinuing the medication.
- Orbital fat atrophy: A rare side effect, this involves the loss of fat around the eyes, leading to a hollowed or sunken appearance. This condition may be irreversible in some cases.
- Hair growth in unwanted areas: Accidental application of the medication to other skin areas can lead to unwanted hair growth. Proper application using the provided sterile applicators and blotting any excess is crucial.
It is essential to consult with an ophthalmologist or a dermatologist before beginning any new eyelash growth treatment to ensure it is appropriate and safe for your specific health needs.
Comparison of Eyelash Growth Treatments
| Feature | Bimatoprost (Latisse) | Off-Label PGAs (e.g., Latanoprost) | OTC Serums with PGAs | Non-PGA Serums |
|---|---|---|---|---|
| FDA Approval | Approved for eyelash hypotrichosis | Not approved for cosmetic use | Not regulated as drugs; efficacy and safety not tested | Not regulated as drugs |
| Primary Purpose | Eyelash growth | Glaucoma treatment | Cosmetic enhancement | Conditioning/Strengthening |
| Mechanism | Prolongs anagen phase | Prolongs anagen phase (as side effect) | Similar to PGAs | Nourishes and conditions lashes |
| Potential Side Effects | Eyelid darkening, irritation, permanent iris color change, orbital fat atrophy | Higher risk of ocular side effects | Less regulated, risks not well-known | Generally milder, less potent |
| Access | Prescription required | Prescription required (for off-label use) | Over-the-counter | Over-the-counter |
Conclusion
Several medications, primarily prostaglandin analogs like the FDA-approved bimatoprost (Latisse), are known to cause eyelashes to grow longer, thicker, and darker by extending the anagen phase of the hair cycle. Other drugs, including some glaucoma medications and cancer therapies, can produce similar effects as a side effect. While these treatments can be highly effective, they come with a range of potential side effects, from minor irritation and temporary eyelid darkening to permanent iris color changes and orbital fat loss. It is crucial to use these potent medications only under the guidance of a healthcare professional to ensure safety and minimize risks, particularly if using an off-label or unregulated product.
For more information on Latisse, consult the American Academy of Ophthalmology's guidance on the product.
