At Opti Laboratories, we frequently consult with clients who have noticed eyebrow or eyelash thinning while on hormone therapies, particularly relating to breast cancer or for menopausal symptoms. The effects on hair, especially on the lashes and brows, are underappreciated. We want to help our clients understand which hormone-related therapies can affect lashes and brows, what to expect and how we can assist.
Most hormones are thought to affect the hair growth cycle but oestrogens, progesterone, androgens and thyroid hormones (which we cover in its own article) play an especially crucial role in hair follicle cycling. The interplay is delicate:
Oestrogen tends to prolong the anagen (growth) phase of hair, supporting fuller and slower-shedding hair. When levels reduce it can lead to female pattern hair loss.
Androgens, like testosterone or DHT, can stimulate hair growth in certain areas that are androgen sensitive areas but can often contribute to follicle miniaturisation of hair in genetically susceptible women.
Eyebrow and eyelash follicles are less androgen sensitive than scalp follicles, but are still affected by hormonal shifts.
Here are the main classes of hormone related treatments and what clinical evidence has found:
| Drug class | Common use | Evidence or reports of lash / brow loss |
|---|---|---|
|
Tamoxifen |
Breast cancer, prevention in high-risk |
In endocrine therapy settings, around 25% of patients report hair thinning or hair loss with tamoxifen or aromatase inhibitors in broader scalp hair analysis. |
|
Anastrozole, letrozole or exemestane |
Hormone-positive breast cancer |
The shift towards androgenic dominance is thought to drive thinning, so oestrogen blocking medications can lead to eyebrow and eyelash thinning or loss. |
|
Hormone replacement therapy (HRT) |
Menopause symptom relief |
The evidence can seem contradictory - some find that HRT can help thicken their hair while others find that it can lead to a degree of thinning |
|
Anti-androgen therapy such as spironolactone, flutamide or cyproterone |
Acne, prostate cancer treatment, transgender health |
Eyelashes and eyebrow growth tend to be less directly impacted but changes can occur |
Will my lashes and brows regrow?
In most cases they will. Hormone driven changes are often responsive to a restoration of a stable hormone profile from either a cessation of therapy, adjustment in dose or even just adjustment by the body. Regrowth may be slower or partial because follicles may adapt to the hormonal change or may be damaged by any associated treatment.
How long before regrowth starts?
It is highly variable and depends on the whole picture. Some people find that recovery starts in months with full regrowth within 12 months, but for some people it can be a few years before a near normal level of brow or lash is achieved.
What should I do if I notice eyelash or eyebrow loss while taking tamoxifen (or any hormonal therapy)?
These treatments are often essential and you should not stop them yourself. If you feel thinning is occurring then talk to the prescribing doctor. They can often review your entire situation and may alter the therapies that you are on.
What can I do to support regrowth?
It is important to have a good, healthy diet as a good foundation for healthy hair growth. It is easier said than done, but minimising stress will also help. Our eyelash growth treatment is bimatoprost based and has been used by many of our clients to help improve the growth in these circumstances.
Hormonal and endocrine therapies often influence eyelash and eyebrow growth, and the thinning may occur subtly or gradually. The good news from our experience is that most of our clients find that they can boost their growth using our growth treatment and serum.
If you are on any of the hormonal therapies mentioned and have noticed lash or brow thinning, do not alter your treatment. Always talk to your doctor and they can often make changes to help.
If you are looking for more help then Opti Laboratories can help you. We provide cosmetic growth options and our experience can help you maximise your lash and brow growth.