What questions should I bring to a hair loss appointment?

When it started and what happened two to four months before that; whether it is shedding, thinning or both; the pattern; where you are hormonally; your medications and supplements; family history; and what you are actually eating.

Why does the two-to-four month question matter so much?

Because a shed lags its trigger by about that long. The event that explains it is usually sitting in that window, not in the week the shedding started.

What does the visual assessment involve?

A short structured look at part width, density distribution and hair calibre — two minutes that often narrows the diagnosis more than any single lab test.

How I Evaluate Hair Loss: The Questions and Labs I Wish Every Woman Brought to Her Doctor

2026年8月17日

By Dr. Susan Lin, MD | MD HAIR | La Cañada Ventures, Inc.

Every week, a woman tells me some version of the same story. She noticed the shedding months ago — the drain, the brush, the widening part. She finally worked up the courage to mention it at her annual visit. Her doctor glanced at her scalp, ordered a basic blood count and a TSH, and called her a week later with the words that end more hair-loss evaluations than any other sentence in medicine:

“Your labs are normal.”

And that was it. No follow-up plan. No further questions. Just normal labs and a shrug — while her hair kept falling.

I am board-certified in Obstetrics & Gynecology and in Anti-Aging Medicine (A4M), and I have spent my career listening to women describe symptoms that were dismissed too quickly. Hair loss may be the most dismissed of all. So in this article, I want to hand you my own evaluation method — the exact history questions, the visual assessment, and the comprehensive lab panel I believe every woman experiencing hair loss deserves. Bring it to your appointment. Use it as your checklist. Because a thorough hair-loss workup is not exotic medicine; it is simply complete medicine, and you are allowed to ask for it.

The History: Where the Diagnosis Usually Hides

Before I look at a single lab value, I ask questions. In hair loss, the history does most of the diagnostic heavy lifting — and these are the questions that matter most.

1. When did it start — and what happened 2–4 months before that?

Hair follicles respond to systemic stress on a delay. In telogen effluvium — the diffuse shedding that follows a physiologic shock — hairs shift into the resting phase at the time of the insult, but they don't actually fall until roughly two to four months later. So the question is never just “when did the shedding start?” It's “what happened in the window before it started?” Childbirth. Surgery. A high fever or significant illness. Rapid weight loss or a new restrictive diet. A major emotional event. Starting or stopping a medication — including starting or stopping hormonal contraception. When a woman tells me her shedding began in March, I am most interested in her November through January.

2. Is it shedding, thinning, or both?

These are different processes. Shedding — hairs coming out in volume, visible in the drain and brush — points toward telogen effluvium. Gradual thinning — a widening part, a shrinking ponytail, with no dramatic fall — points toward female pattern hair loss, where follicles progressively miniaturize and produce finer, shorter hairs. Many women in midlife have both at once, and each component deserves its own workup.

3. What is the pattern?

Diffuse loss across the whole scalp suggests a systemic driver — thyroid, iron, nutrition, medication, hormonal shift. Loss concentrated at the crown and part line, with relative preservation at the back of the head, suggests pattern hair loss. Loss at the temples and hairline edges raises the question of traction from tight styling. Discrete round patches, or areas where the scalp itself looks shiny and scarred, belong in a dermatologist's office promptly — more on that below.

4. Where are you in your hormonal life?

As an OB/GYN, this is where I live. Postpartum? Perimenopausal cycle changes? Recently stopped an oral contraceptive? Irregular cycles, acne, and unwanted facial hair that might suggest polycystic ovary syndrome (PCOS)? Each life stage and hormonal context produces its own hair-loss signature, and the story often makes the diagnosis before the labs do.

5. What medications and supplements do you take?

Retinoids, some antidepressants, beta-blockers, anticoagulants, some anticonvulsants — the list of medications associated with hair shedding is long, and patients are rarely told. Excess vitamin A and even high-dose supplements can contribute. I ask for the full list, including everything bought over the counter.

6. Who else in your family has thinning hair?

Female pattern hair loss runs in families — and not only through the mother's side, as folklore insists. A mother, aunt, or grandmother with visible thinning raises the likelihood of a genetic, androgen-sensitive component. It doesn't seal the diagnosis, but it shifts the odds.

7. What are you actually eating?

Not what the intake form says — what a real week looks like. Protein intake matters enormously; hair is keratin, and keratin is protein. Restrictive dieting, bariatric surgery, long-term veganism without attention to iron and zinc, and disordered eating patterns all show up on the scalp. Hair is metabolically expensive tissue, and the body will always defund it first.

The Two-Minute Visual Assessment

Next, I look — systematically, not casually. You can do most of this at home in a mirror.

Part width. I look at the part down the center of the scalp and compare its width front to back. In pattern hair loss, the part is often wider toward the front and crown — sometimes described as a “Christmas tree” pattern — while the back of the scalp stays denser.
The temples and hairline. Recession or wispy miniaturized hairs at the temples can reflect androgen-driven loss; broken hairs and thinning concentrated where tension is applied point to traction.
Texture change. I ask women to feel a single strand from the crown and one from the nape. In miniaturization, new growth at the top comes in finer, shorter, and sometimes lighter — the follicle is still working, but producing a diminished hair.
The outer third of the eyebrows. Thinning of the lateral eyebrows is a classic clinical clue associated with thyroid dysfunction. It is not diagnostic on its own, but when I see it alongside fatigue, cold intolerance, or cycle changes, the thyroid panel moves to the top of my list.
The scalp itself. Redness, scale, itching, tenderness, or — most importantly — areas where follicular openings have disappeared and the skin looks smooth and shiny. That last finding suggests scarring, and it changes the urgency of everything.

The Lab Panel I Wish Every Woman Requested

Here is the panel I believe constitutes a complete first-pass hair-loss workup. Screenshot it, print it, bring it with you.

Full thyroid panel — TSH, Free T4, Free T3, and anti-TPO antibodies. A TSH alone is not a thyroid evaluation. Thyroid hormone acts directly on the human hair follicle, influencing the growth cycle and pigmentation (van Beek et al., 2008). Free T3 is the active hormone at the tissue level, and anti-TPO antibodies can identify autoimmune thyroid disease years before TSH drifts out of range.
Serum ferritin — not just hemoglobin. This is the single most common gap I see. A woman can have a perfectly normal hemoglobin and profoundly depleted iron stores. Ferritin reflects the iron reserve available to metabolically demanding tissue like the follicle, and the dermatology literature has long discussed iron deficiency as a potential contributor to hair loss in women, with many clinicians targeting a ferritin above approximately 70 ng/mL in this setting (Trost et al., 2006) — far above the lab cutoff of 12–15 ng/mL that merely rules out anemia.
Vitamin D (25-OH). The vitamin D receptor plays a role in hair follicle cycling, and deficiency is common and correctable (Amor et al., 2010; Almohanna et al., 2019).
Zinc. A required cofactor for the rapid cell division inside the follicle; deficiency is an established, reversible contributor to shedding (Almohanna et al., 2019).
Fasting insulin and fasting glucose. Insulin resistance drives androgen production — particularly relevant in PCOS — and a fasting glucose alone can look reassuring while fasting insulin is already elevated.
DHEA-S and free testosterone. These map the androgen terrain. Elevated levels support an androgen-driven pattern; normal levels with a pattern-loss picture suggest follicle-level androgen sensitivity rather than androgen excess.
Estradiol and progesterone, timed to your cycle if you are still cycling — typically drawn in the luteal phase (about a week before an expected period) for progesterone to be interpretable. Random, untimed sex-hormone levels in a cycling woman are close to uninterpretable, and a great deal of confusion comes from exactly that.

Why “Your Labs Are Normal” Is Often an Incomplete Answer

Two problems hide inside that sentence.

First, “normal” often means “we only checked two things.” A CBC and a TSH will miss low ferritin, low vitamin D, low zinc, early autoimmune thyroid disease, insulin resistance, and every androgen abnormality on the list above. The labs were normal because the revealing labs were never drawn.

Second, laboratory reference ranges are built to flag disease, not to identify the optimal environment for hair growth. A ferritin of 18 ng/mL is “normal” — it rules out iron-deficiency anemia. It is also, in my clinical opinion and in the view of many physicians who treat hair loss, meaningfully below where a woman regrowing hair wants to be. The follicle is one of the most rapidly dividing tissues in the body, and it is among the first to suffer when reserves run low and among the last to recover. “Not diseased” and “well supplied” are different standards. You are entitled to ask which one your results actually meet — and to request your numbers, not just the verdict.

How to Advocate for Yourself in a 15-Minute Appointment

I have practiced medicine for 35 years. I know exactly what a 15-minute visit can and cannot hold. Here is how to make it work for you:

Bring your history in writing. One page: when the shedding started, what happened in the 2–4 months prior, your pattern, your cycle status, your medications and supplements, your family history. You have just saved eight minutes of the visit.
Bring photographs. Your part, your hairline, your ponytail — same lighting, same angle, dated. Objective change over time is the most persuasive evidence you can offer.
Bring the lab list above and ask directly: “Would you be willing to order these? If not, could you note in my chart which ones you're declining?” That second sentence is respectful, and it is remarkably clarifying.
Ask for your actual values. “Normal” is not a number. Request a copy of your results and know your ferritin, your Free T3, your vitamin D.
Ask for the referral if you need it. If your physician is not comfortable with a full hair-loss workup, a referral to dermatology or endocrinology is a reasonable and standard request.

None of this is adversarial. Most physicians respond well to an organized, specific patient. You are not being difficult — you are being a good historian, which is the most valuable thing a patient can be.

When to See a Dermatologist — Promptly

Most diffuse hair loss can begin its workup with a primary care physician or gynecologist. But some presentations should go straight to a dermatologist, and quickly:

Patchy loss — discrete round or oval bare patches, which raise the question of alopecia areata, an autoimmune process.
Any sign of scarring — smooth, shiny areas where the follicular openings have vanished, or redness, scale, and tenderness around the hairline. Scarring alopecias destroy follicles permanently, and the hair that is lost does not return. Early diagnosis — sometimes requiring a scalp biopsy — protects what remains.
Rapid, dramatic onset — handfuls of hair over days to weeks, or shedding accompanied by systemic symptoms.

With scarring processes especially, time is follicle. Do not wait months for these.

The Bottom Line

Hair loss in women is a legitimate medical complaint that deserves a legitimate medical evaluation: a structured history, a systematic look at the scalp, and a lab panel that goes well beyond a CBC and TSH. “Your labs are normal” is only meaningful if the right labs were drawn — and interpreted against the standard of a well-supplied follicle, not merely the absence of disease. You do not need to be a physician to get this workup. You need a list, a one-page history, and the willingness to ask. I hope this article serves as all three.

Dr. Susan Lin's Clinical Perspective

“In 35 years of medicine, I've learned hair loss is never vanity — it's identity. And yet it remains one of the most under-evaluated complaints in women's health. The pattern I see over and over is a woman dismissed with a normal hemoglobin and a normal TSH — two tests that cannot see low ferritin, low Free T3, thyroid autoimmunity, insulin resistance, or an androgen-sensitive follicle. The fix is not exotic. It is a complete history, a careful look at the scalp, and a complete panel, interpreted with the follicle's actual needs in mind. When a woman walks in with her timeline written down and her lab list in hand, the quality of her care changes that day.”

— Dr. Susan Lin, MD, Physician Formulator, MD HAIR

Mechanism Spotlight: Why Ferritin — Not Hemoglobin — Is the Number That Matters

Hemoglobin measures the iron already committed to your red blood cells. Ferritin measures the iron held in reserve — the supply line. The hair follicle matrix is among the most rapidly proliferating cell populations in the human body, and that proliferation is iron-dependent: iron is a cofactor for ribonucleotide reductase, the rate-limiting enzyme of DNA synthesis. When reserves fall, the body triages — it protects oxygen transport (hemoglobin) and quietly defunds non-essential, high-turnover tissue like the follicle. This is why a woman can be months into significant shedding while her hemoglobin remains pristine. It is also why the standard lab range fails her: a ferritin of 15 ng/mL rules out anemia, but the dermatology literature and clinical practice in hair loss commonly target reserves above roughly 70 ng/mL before considering iron optimized for regrowth (Trost et al., 2006). If you ask for only one addition to a basic panel, ask for ferritin — and ask for the number.

MD HAIR Product Recommendation

Start with the 60-Second Hair Quiz

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References

Dr. Susan Lin, MD is the physician formulator behind MD HAIR, a line of drug-free, hormone-free, clinically informed hair care products by La Cañada Ventures, Inc., San Mateo, CA. MD HAIR products are cosmetics and supplements; they are not intended to diagnose, treat, cure, or prevent any disease. Because there are no clinical data in pregnant or breastfeeding women, we do not advocate using MD HAIR products during pregnancy or lactation. Individual results vary. This article is for educational purposes only and does not constitute medical advice. Always work with your own physician on the evaluation and management of hair loss. MD Nutri Hair™ is a dietary supplement. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Explore more physician-written guides at mdhair.com/pages/hormonal-hair-loss