Hair Loss Causes and Blood Tests: What Labs Can and Cannot Show
Quick answer: Hair loss has many causes, and a blood test can only check some of them. Providers commonly look at blood count, iron stores, thyroid function, vitamin D and hormones such as testosterone and DHEA-S. A result outside the normal range is a clue, not a diagnosis, and a normal result does not rule out a scalp or genetic cause.
4 quick facts about hair loss and lab tests
- Pattern thinning that runs in families is common and is linked to hormones and aging.
- Illness, surgery, childbirth, crash dieting or major stress can cause shedding that shows up weeks to months later.
- A history and a scalp exam often find the cause on their own. Blood tests add information when the cause is not clear.
- No blood test shows how your hair will respond to a treatment.
Common causes of hair loss
MedlinePlus lists several groups of causes. Knowing which group fits your story helps decide whether a blood test is useful.
- Aging and family history. Pattern thinning is common, affects men more than women and is linked to hormone changes.
- Shock to the body. Illness, childbirth, surgery, blood loss, severe stress or crash dieting can trigger temporary shedding.
- Medicines. Some antidepressants, blood pressure medicines, birth control pills, retinoids and anti inflammatory drugs can cause hair loss. Never stop a prescription without asking your prescriber.
- Medical conditions. Examples include anemia, thyroid disease, autoimmune conditions, alopecia areata, hormone changes and scalp infections.
- Hair care habits. Tight styles, harsh treatments and frequent heat can damage hair or cause breakage.
Which blood tests do providers look at?
| Marker | Why it is checked |
|---|---|
| CBC | Looks for anemia and other blood count changes. |
| Ferritin, iron and TIBC | Show how much iron your body stores and carries. Low iron can go along with shedding. |
| TSH and free T4 | Check thyroid function. Thyroid disease can go along with hair changes. |
| Vitamin D | Checks your vitamin D level, which is commonly reviewed with hair and nutrition concerns. |
| Total testosterone and DHEA-S | Check androgen hormones, which act on hair follicles. These matter most when thinning comes with irregular periods, acne or extra facial or body hair. |
An older review in American Family Physician on hair loss in women suggests an endocrine workup mainly when a woman has irregular periods, abrupt hair loss, extra hair growth or recurrent acne. It also notes that most women with pattern thinning have normal hormone levels, so a long hormone workup is often unnecessary. That article is from 2003, so ask your provider what is current for you.
What a hair loss blood test cannot show
- It cannot tell you for sure why your hair is thinning.
- It cannot diagnose pattern thinning, alopecia areata or a scalp condition. Those usually need an exam of the hair and scalp.
- It cannot predict whether a treatment will work.
- Results can shift with illness, medicines and supplements. Biotin, for example, can change thyroid and hormone results, so stop it at least 72 hours before your draw.
When to talk with a healthcare provider
MedlinePlus suggests contacting a provider if you have:
- Hair loss in an unusual pattern, or fast loss, especially at a young age.
- Pain, itching, redness, scaling or other scalp changes.
- Acne, facial hair growth or irregular periods.
- Bald spots in the beard or eyebrows.
- Weight gain, muscle weakness, feeling cold or tiredness.
The Hair Loss Panel at Vitality Express Labs
The Hair Loss Panel is $199 and covers CBC, ferritin, iron and TIBC, TSH, free T4, vitamin D, total testosterone and DHEA-S in one blood draw. Order online, visit our Buffalo Grove or Lake Zurich location, and review your results with your own healthcare provider. A doctor’s visit is not required to order. Fasting is generally not required, so follow any instruction given at your visit.
Other tests people check along with hair concerns
- Thyroid Function Test (TSH and Free T4) if thyroid is your main question.
- Comprehensive Thyroid Panel for free T3 and thyroid antibodies.
- Vitamin D Test and Vitamin B12 Test for nutrition questions.
- Anemia Panel for a deeper look at blood count and iron markers.
- Female Hormone Panel when periods are irregular.
Frequently asked questions
Can a blood test show why I am losing hair?
It can show whether markers such as iron, thyroid or hormones are outside the lab’s reference range. It cannot diagnose the cause by itself.
What blood tests are used for hair loss?
Providers commonly review a blood count, ferritin and iron, thyroid tests, vitamin D, and hormones such as testosterone and DHEA-S, depending on your symptoms.
Does low ferritin cause hair loss?
Low iron stores can go along with shedding in some people. Whether it is the cause in your case is a question for your provider.
Do I need to fast?
Fasting is generally not required. Follow any instruction given at your visit.
Can biotin change my results?
Yes. Biotin can change thyroid and hormone test results. Stop biotin and hair, skin and nail supplements at least 72 hours before your draw.
How much does a hair loss blood test cost without insurance?
At Vitality Express Labs, the Hair Loss Panel is $199.
Do I need a doctor’s order?
A doctor’s visit is not required to order this test. Review your results with your own healthcare provider.
Sources
- MedlinePlus, National Library of Medicine. Hair loss.
- Thiedke CC. Alopecia in women. American Family Physician. 2003;67(5):1007 to 1014.
Medically reviewed by Rodion Levin, FNP-C, Founder and Medical Director. This article is for general education. It does not diagnose a condition or replace advice from your healthcare provider.
