My hair after 14 months in finasteride and 5 months on oral min is stilll thinning

What you’re describing is a multifactorial shedding phase, likely triggered by two overlapping causes:
1- The transition from topical to oral minoxidil, and
2- The recent onset and treatment of hypothyroidism.

Let’s break it down:

There are negative Effects of Thyroid Medication and Hypothyroidism on Hair Growth and I believe this could be one of many possible etiologies affecting you.
You could be suffering Increased Hair Shedding (Temporary Telogen Effluvium):
Here we see that adjusting thyroid hormone levels can shock hair follicles, causing temporary shedding before regrowth stabilizes. Furthermore, You could be sensitive to the Medication.
Some individuals react poorly to levothyroxine or other thyroid medications, experiencing persistent hair loss despite treatment.
Hypothyroidism and its treatment can negatively impact hair growth in different ways. Here’s how it can affect your hair health:
Negative Effects of Hypothyroidism on Hair Growth:
It can preciptate Hair Thinning and Shedding:
Low thyroid hormone levels slow down hair follicle activity, leading to thinning hair or excessive shedding (telogen effluvium).
Based on your history you could have Slowed Hair Growth.
Hair grows in cycles, and an underactive thyroid can prolong the resting phase (telogen), delaying regrowth.You may have Nutrient Deficiencies:
Thyroid conditions can cause deficiencies in iron, biotin, zinc, and vitamin D, which are crucial for hair growth.
An evaluation by a hair expert is suggested including biopsies and bloodwork. Genetic testing is now available to direct your treatment plan.
Good luck.
Jeff Rapaport MD FAAD
Realself Hall of Fame
Castle Connolly Top Doctor

Hair thinning can be distressing, especially when you're actively treating it with medications like finasteride and minoxidil. Here are some considerations that might help clarify your situation:

Medication Effects and Adjustments: Both finasteride and minoxidil can cause initial shedding, which is often a sign that the medications are working as they push older hairs out to make way for new growth. However, if shedding persists, it might be worth discussing with your healthcare provider whether dosage adjustments or alternative treatments are necessary.

Hypothyroidism Impact: Since you've been diagnosed with hypothyroidism, it's important to consider its impact on your hair health. Thyroid imbalances can contribute to hair thinning, and it may take some time for your hair to recover once your thyroid levels are stabilized with treatment.

Time and Patience: Hair growth cycles are slow, and it may take several months to see noticeable improvements once underlying issues are addressed and treatments are optimized.

Consult a Specialist: It might be beneficial to consult with a dermatologist or a trichologist who specializes in hair loss to evaluate your treatment plan and consider factors like your thyroid condition, medication interactions, and overall health.

Lifestyle Factors: Additionally, ensure that you maintain a balanced diet, manage stress, and get adequate sleep, as these factors can also impact hair health.

It's important to continue working closely with your healthcare providers to monitor your condition and adjust treatments as needed. If you have further questions or need more specific guidance, please feel free to ask.

It sounds like you’ve been on quite the journey with hair loss treatments, and there are a few possible factors at play here.
First, your experience with topical minoxidil is not uncommon—many people see good results early on, but if the treatment is stopped or even reduced, there can be a loss of the gains made. Finasteride likely helped stabilize your hair, but shedding after starting is also a common reaction, as the hair cycle resets. Oral minoxidil is stronger in terms of systemic absorption, but it can also cause prolonged shedding in some cases, especially during the first several months. However, six months of shedding is longer than usual, which raises some red flags.
The key piece of new information is your hypothyroidism diagnosis. Thyroid imbalances, especially when untreated or newly treated, can contribute to hair shedding and thinning. Hair loss from hypothyroidism often presents as diffuse thinning rather than recession, and once treatment stabilizes your thyroid levels, your hair may improve, but it can take months to see regrowth.
Given your timeline, it’s possible that both oral minoxidil shedding and thyroid-related shedding are overlapping. You may want to check your latest thyroid levels to ensure your treatment is optimized. Additionally, if the shedding persists, a more in-depth evaluation—such as bloodwork for iron levels, vitamin D, and other potential contributors—could be helpful.
In the meantime, maintaining consistency with your medications is key, as stopping and starting can sometimes trigger more shedding. If your hair is continuing to thin despite treatment, you might also consider alternative therapies, such as PRP or even a hair transplant if your recession is a primary concern.

Hair loss is multifactorial, with hormones being a leading cause. However, before exploring treatments, I recommend ensuring that any underlying medical conditions, such as hypothyroidism, are well managed. It’s important to work with a dermatologist or physician to assess your overall health and make any necessary adjustments to medications, so you’re not working against an unresolved root cause.
Once your health is stabilized, we can optimize your hair restoration journey with advanced modalities like low-level light therapy, medications (including statewide), PRP, etc. While these treatments can be highly effective, addressing the underlying cause of hair loss is essential to achieving the best possible results.