Hair and Skin

Testosterone and the related hormones behind skin oil and hair growth, with thyroid, iron stores and the vitamins and minerals hair needs.

Hair loss and adult acne get blamed on genetics or stress, and in a good share of cases the real cause is sitting in the blood and is fixable. Ferritin is first. Dermatologists want it well above the bottom of the lab's normal range before they will rule iron out as the cause of shedding, and iron stores fall long before the blood count shows anything. Thyroid is second, and TSH with free T4 catches both an underactive and an overactive gland, either of which thins hair. Then the androgens. Testosterone, free testosterone, DHEA sulfate and SHBG together show whether pattern loss or jawline acne is being driven by hormones. The free fraction is the one that matters, which is why SHBG is here and why testosterone is run by mass spectrometry with free testosterone measured by equilibrium dialysis rather than calculated. Estradiol adds the other side of that balance. Zinc, copper, vitamin D, B12 and folate are the nutrients whose deficiency shows up in hair and skin first. DHT, the hormone that shrinks hair follicles in pattern loss, is an add-on if you want it.

Blood is drawn at a Quest Diagnostics, Labcorp or BioReference patient service center. Price by laboratory: Quest Diagnostics $239, Labcorp $349 or BioReference $357. Your price depends on your state and the laboratories near you. Enter your ZIP code to see them.

What’s included

• TSH: Thyroid-stimulating hormone, the pituitary hormone that signals the thyroid.
• Free T4: Free (unbound) thyroxine, the main hormone the thyroid releases.
• Iron, TIBC and ferritin: Serum iron, total iron-binding capacity, iron saturation and ferritin, the body's iron-storage protein.
• Vitamin D (25-hydroxy): 25-hydroxyvitamin D, the main form of vitamin D circulating in the blood.
• Zinc: Zinc, an essential mineral, in serum or plasma.
• Vitamin B12 and folate: Vitamin B12; serum folate
• Testosterone, total and free (LC/MS): Total testosterone measured by mass spectrometry, and free (unbound) testosterone measured by equilibrium dialysis.
• DHEA sulfate: DHEA sulfate, a hormone made mainly by the adrenal glands.
• SHBG: Sex hormone-binding globulin, the protein that carries testosterone and estradiol in the blood.
• Complete blood count (CBC): Red cells, white cells with a breakdown by type, and platelets, plus hemoglobin, hematocrit and red-cell size.
• Estradiol (standard): Estradiol, a form of estrogen, measured by a standard immunoassay.
• Copper: Copper, a trace mineral, most of which is carried in the blood by a protein called ceruloplasmin.

Tests you can add

• Dihydrotestosterone (DHT): Dihydrotestosterone, a hormone made from testosterone.
• TPO antibodies: Antibodies to thyroid peroxidase, an enzyme in the thyroid gland.
• Omega-3 and omega-6 fatty acids: Omega-3 (EPA, DPA and DHA) and omega-6 fatty acids in the blood, with their ratios.

Before your draw

No fasting needed.

Book a morning appointment, ideally before 10 a.m. Ask your clinician whether to pause iron or B-vitamin supplements before the draw. If you take biotin (vitamin B7), including in hair, skin and nail supplements or multivitamins, have your blood drawn at least 8 hours after a usual dose, or at least 72 hours after a high dose. If biotin was prescribed, ask your clinician before stopping it.