Your Hair & Your Health Part II: Medications, GLP-1’s & Testosterone
Last week we talked about how hair loss isn’t just a vanity concern—it can be a harbinger of deeper imbalance.
We touched on stress, thyroid insufficiency, GLP-1 medications, PCOS/PMOS, medication-induced nutrient depletion, and the COVID spike protein.
Today, we’re going a little deeper.
Let’s Talk About Treatments
Minoxidil & Finasteride: What Your Doctor May Not Have Mentioned
When someone comes to me with hair loss, I’m wondering if we’re trying to stimulate new growth or identify why the hair is falling out in the first place.
Minoxidil has become the go-to recommendation for hair loss, handed out so routinely it’s easy to assume it’s both benign and a definitive solution. It isn’t quite either.
Minoxidil is a vasodilator. It works by increasing blood flow to the follicle and prolonging the active growth phase of the hair cycle. It can be very helpful, but it doesn’t address the underlying cause of hair loss.
When it works, it works only while you’re taking it. That’s an important concept to understand before starting treatment. Once you stop, you’re generally back to where you started within a few months because the follicles no longer receive that support and hair falls out.
There’s also an initial shedding phase when starting the medication as older hairs are pushed out to make room for new growth. It can be alarming if you aren’t warned in advance.
Finasteride works differently. It blocks the conversion of testosterone to DHT, the androgen most responsible for follicle miniaturization and pattern hair loss.
It’s used primarily in men and, in some cases, off-label in postmenopausal women. It should not be used in women of childbearing age because of the risk of birth defects.
Young men also deserve a thoughtful conversation about the potential for persistent side effects — including sexual dysfunction, decreased libido, and depression — before starting treatment.
Getting to the Root Cause
Hair loss is rarely caused by one thing.
More often, it’s the result of several factors working together. When I’m evaluating someone with hair loss, there are two places I want to look first: thyroid function and stress.
Could Your Thyroid Be Part of Your Hair Story?
The thyroid is often one of the last things checked, and one of the first things missed.
Hypothyroidism slows nearly every metabolic process in the body, including the hair growth cycle. The result is diffuse thinning, often accompanied by dry skin, fatigue, sluggishness, slowed reflexes, and feeling cold when everyone else seems comfortable.
One of the more telling physical clues is thinning of the outer third of the eyebrow.
If you’re noticing both hair loss and eyebrow thinning, it’s worth asking your provider for a comprehensive thyroid evaluation — not just TSH. I recommend including Free T3, Free T4, and thyroid antibodies along with TSH.
Why Stress Shows Up Months Later
One of the most common questions I hear is:
“Why is my hair falling out now? My stressful period ended months ago.”
The answer is something called telogen effluvium.
Stress-related hair loss usually appears two to three months after the triggering event. By the time you notice extra hair in the shower, the crisis has often passed, making the connection easy to miss.
The body doesn’t distinguish between emotional stress and physical stress. Illness, surgery, rapid weight loss, childbirth, and major emotional events can all trigger the same response.
Chronic stress also keeps cortisol elevated, disrupting the hair growth cycle over time.
Considering Other Contributors
Sometimes the answer isn’t your thyroid or stress history.
Several other contributors deserve consideration, especially if they fit your health history.
GLP-1 Medications and Hair Loss
If you’ve started semaglutide, tirzepatide, or another GLP-1 medication and noticed increased shedding, you’re not imagining it.
The medication itself isn’t thought to be toxic to the hair follicle. The more likely explanation is rapid weight loss and loss of appetite/nausea/less eating adding up to inadequate protein intake.
As we discussed last week, hair is a luxury tissue. When the body is in a calorie deficit and protein intake is too low, it redirects those nutrients to more essential functions. Hair follicles are among the first to lose out.
If you’re taking a GLP-1 medication, getting enough protein becomes even more important.
Testosterone in Women: The DHT Connection
Testosterone prescribing in women has increased dramatically over the past several years. While it can be incredibly helpful for libido, energy, mood, and muscle maintenance, this isn’t the case for every woman – and more isn’t necessarily better.
When testosterone levels become too high, or in women with higher 5-alpha reductase activity, testosterone can be converted into DHT, the hormone responsible for androgenic hair loss.
The result can look very similar to male-pattern hair loss: thinning at the crown and temples, often accompanied by acne or unwanted facial and body hair.
If you’re taking testosterone and noticing hair loss, DHT is worth investigating.
Adding minoxidil while continuing testosterone dosing treats the symptom while leaving the cause unaddressed.
The COVID Spike Protein
We’re still learning about the long-term effects of COVID, but post-COVID hair loss has become one of the more common lingering symptoms reported by women. Researchers believe inflammation and changes in the blood vessels that support healthy follicles may play a role.
If your hair loss began or worsened after a COVID infection, it’s another piece of the puzzle worth considering.
Supporting Healthy Hair from Within
Once we’ve looked at the potential causes, the next question becomes:
What does a healthy hair follicle need to thrive?
Some of the most important nutrients include:
-Iron (ferritin, the storage form of iron, below 70 may be a contributor to hair loss)
-Zinc
-Vitamin D
-B vitamins, including folate and B12
-Vitamin C
-And perhaps most importantly… adequate dietary protein
Many of these nutrients are depleted by commonly prescribed medications such as:
-Statins – can deplete CoQ10.
-Oral contraceptives – can deplete B6, folate, zinc, and magnesium.
-Metformin can deplete B12.
-Proton pump inhibitors – can deplete iron, B12, and zinc.
Replacing those nutrients doesn’t solve every case of hair loss, but it can make a meaningful difference when deficiencies are part of the picture.
That’s why my Hair Growth Support collection on Fullscript focuses on professional-grade formulas with transparent ingredient lists, bioavailable forms, and a strong clinical track record.
https://us.fullscript.com/welcome/kanderson-ross/store-start
Topical Hair Support
Nutrition and hormones are where I almost always start, but they’re not the whole story.
There are also topical products that work by inhibiting 5-alpha reductase at the scalp to help slow the conversion of testosterone into DHT.
I’ve been using one myself and recommending it to patients, and the feedback has been encouraging.
If you’d like to learn more about my topical product recommendations, email us at support@drkrista.com.
Your Move
If you’re on testosterone, ask your provider to check your DHT level. If it hasn’t been checked, that’s a good place to start.
If you’re taking a GLP-1 medication, pay close attention to your protein intake. Because appetite is often reduced, many women are unknowingly under-consuming protein.
If you’ve experienced significant stress, illness, surgery, childbirth, or another major life event in the past three to six months, connect those dots before assuming the worst.
And if no one has evaluated your thyroid — or checked your ferritin — that’s another conversation worth having.
Hair loss is rarely random.
Your body is usually trying to tell you something.
Warmly,
Dr. Krista
Fullscript Instructions – To purchase these high quality/physician-grade supplements, you must set up an account by submitting your email address. Then you will see the storefront with a list of “collections” on the left side of the page. Hair Support is in the Collections list with supplements referenced in this and the next article. If you have any trouble, please email support@drkrista.com.
Fullscript Disclosure – Some product links in this newsletter are affiliate links through Fullscript, a professional-grade supplement dispensary. If you purchase through my Fullscript storefront, I may receive a small commission at no additional cost to you. I’m also a market partner for the hair care line mentioned above and earn from sales. I only recommend products I use personally or in my clinical practice. These are not sponsored posts, and my recommendations are not influenced by these affiliate arrangements. Individual results may vary.
Olive Says
I recently had a haircut.
I didn’t ask for it.
My coat is kind of a big deal around here — I’m the family’s support animal, and I take that responsibility seriously.
Although Mom says the support seems to be directed more toward me than from me.
I’m told I’m a beautiful princess.
I was already aware.