There are four main types of hair loss:

  • Alopecia areata. Considered an autoimmune disease, though researchers have yet to discover the antibodies involved. Characterized by small hair follicles and slower hair growth.
  • Telogen Effluvium. While some 80% of hair follicles are typically in the growth phase at any one time, 20% or so are in the telogen, or the resting phase. This means hair tends to fall out, and this phase is the reason why it’s normal to lose 50-100 hairs per day. Telogen Effluvium occurs when a much higher percentage of hair enters the telogen phase at once than normal. This is thought to be due to stress, occurring 6 weeks to three months after a stressful event. It’s generally self-limited.
  • Androgenic alopecia (male pattern hair loss). High testosterone levels, or high levels of other hormones in the androgen family are responsible for this one. Most often, the problem is that testosterone converts to dihydrotestosterone, or DHT. DHT causes hair follicles to shrink, usually in patterns involving a receding hairline or in one centralized location. Women can have this pattern as well as men, but usually if they do, it indicates high levels of androgens, often due to PCOS.
  • Female Pattern Hair Loss. This is characterized by more diffuse all over thinning. More often than not, the cause is either hypothyroidism or low ferritin.


Sometimes the cause becomes obvious from the case history: there was a major illness, an accident, pregnancy, or death in the family. Perhaps there’s a past medical history of other autoimmune conditions. Maybe there are a bunch of other hypothyroid symptoms (constipation, fatigue, weight gain, dry skin, cold extremities). For a man, perhaps there’s a family history of male pattern hair loss; for a woman, perhaps she has other symptoms of androgen excess, such as acne or oily skin, irregular periods, or abnormal hair growth.

Depending on the conversation, here are some tests that might be appropriate:

  • Ferritin
  • A full thyroid panel: TSH, fT3, fT4, reverse T3, Anti-TPO, Anti-thyroglobulin
  • Androgens: free and total testosterone, DHT
  • For a woman, a PCOS workup: LH and FSH, androgens, estradiol and progesterone, insulin, HbA1c
  • Salivary cortisol testing — was there a major stressor? The adrenals will likely show it.
  • ANA with reflex: this is a grab bag for autoimmunity, to see if there are any other autoimmune conditions involved, though this will not necessarily be positive even if the cause is alopecia areata.
  • Micronutrient testing (see below.)


Regardless of the type of hair loss, deficiency in some of these micronutrients might be to blame.

  • Iron. I have to give this one top billing, because it’s the nutrient most often responsible for female pattern hair loss. Specifically it’s deficiency in ferritin, or the storage form of iron, that’s to blame. I wrote here on why ferritin tends to be chronically low in some people. It’s not enough just to supplement with iron to get the ferritin up— you need to know why it was low in the first place and treat that.
  • Vitamin D. There’s definitely a connection between low Vitamin D and autoimmunity, so it’s not surprising that Vitamin D deficiency is especially associated with alopecia areata. This study shows that topical treatment of Vitamin D in alopecia areata cases can be effective, while this study shows that as severity of alopecia areata cases goes up, Vitamin D concentration goes down. But this study also shows a definite correlation between low vitamin D and tellogen effluvium, as well.
  • Zinc. Zinc is one of the most ubiquitous micronutrients in the body, necessary for a wide variety of enzymatic reactions. It also helps follicles recover and protects against shrinkage. So it’s not surprising that this study found zinc deficiency plays a key role particularly in alopecia areata and in tellogen effluvium. This study, too, correlates tellogen effluvium with low levels of zinc.
  • Biotin. This B vitamin seems to be the one everyone knows about for hair loss—most of my hair loss patients come in already on a biotin supplement. This study shows that biotin can improve the strength and diameter of hair. Most patients come in on too little to do any good, though—the dose should be 10,000 mcg daily.
  • Fish Oil & Antioxidants. I’m lumping these together because that’s what researchers did in this study: a combination of fish oil and antioxidants showed significant improvements over a 6 month period in hair loss, hair diameter and density. Fish oil is one of those nutrients I think everyone should be on anyway. Antioxidants are another: this class of micronutrients include all those that quench free radicals, speculated to be part of the cause of cellular aging. Antioxidants include Vitamin C, selenium, Vitamin E, CoQ10, Alpha Lipoid Acid, N-Acetyl Cysteine, and resveratrol, to name a few. They work synergistically and are protective not only against age-related hair graying and hair loss, but also against most chronic Western diseases.


In some cases, the cause of hair loss is obvious. If it’s not, I’d definitely recommend a good work-up, including the nutrients listed above (except for fish oil and antioxidants—it’s possible to run levels on these, but only through specialty labs. Besides, you should be taking them anyway.) If you decide to try the nutrients listed above without testing, a few guidelines:

  1. Don’t take iron unless you’ve had levels tested. Too much iron becomes a pro-oxidant instead of an anti-oxidant, which is bad news.
  2. Don’t take more than 30 mg of zinc for any length of time; you can set yourself up for a copper imbalance. And you’ll probably want to take it with food, since it’s likely to make you nauseous otherwise!
  3. It’s possible to overdose on Vitamin D, so don’t go crazy unless you’ve had your levels tested and a doctor told you how much to take! A safe maintenance dose is 2000 IU daily.