The Connection Between Weight Loss and Hair Loss

Hair loss (alopecia) can be experienced by men or women, especially as they age. But can weight loss also cause your hair to thin? To understand the connection between weight loss and hair loss, it's helpful to understand why hair loss occurs.

So why does hair loss happen? There are several common causes.

You've probably heard of male-pattern baldness, but did you know that women can also experience the condition? Female pattern baldness can run in families and it looks slightly different than male-pattern baldness. Women usually experience the condition on the top and crown of the scalp. Women often describe seeing a widening part. You're more likely to experience female-pattern baldness if you have a family history of the condition.

According to the National Institutes of Health, changes in your hormone levels can cause hair thinning. A change in your androgen levels may cause the hair on your head to thin and the hair on your face to feel more coarse. You might notice changes during menopause. Approximately two-thirds of women experience some postmenopausal hair loss.

Low iron can be a cause of hair loss. If you are a vegetarian, if you have heavier than normal periods or if you have a history of anemia, you may experience hair loss from iron deficiency. Some women take iron supplements to reverse the condition, but there is no evidence to support their effectiveness for hair loss. 

Low protein intake may also lead to hair loss, according to some experts. And very low-calorie diets, in general, don't provide enough nutrition to allow your body—including your hair follicles—to function normally.

Harvard health experts explain that it is not unusual to experience hair loss when you are also experiencing unusual stress or anxiety. Unintentional weight loss can also happen during times of physical or mental stress.

Having an overactive thyroid (hyperthyroidism) be the cause of hair loss. In fact, any thyroid patient may experience hair loss. Your physician can run routine tests to see if your thyroid gland is functioning properly.

Weight loss, alone, isn't on this list of hair loss causes. But that doesn't mean you won't experience hair loss when you lose weight. Dieting can be very stressful, exhausting and can lead to nutritional deficiencies that result in hair loss. And many women experience weight gain as they age or during menopause and may go on a diet as a result. The combination of factors may cause your hair to thin.​

If you notice unusual patterns of hair loss, see your doctor. Your healthcare provider can tell you if a related medical condition can be the potential cause of changes to your hair. If not, he or she may be able to refer you to a registered dietitian or a behavioral health specialist if nutrition problems or stress is the cause.

You may also get referred to a dermatologist who can run additional tests to find out why you might be losing hair and what can be done about it.

There are medications that can improve thinning hair. They include:

• Minoxidil. You've probably seen products like Rogaine (minoxidil) advertised on television or in magazines. This medication is widely used and has been shown to be effective in clinical trials. The over-the-counter medication is available in pharmacies.
• Spironolactone. This prescription medication has not been approved by the FDA to help women with thinning hair, but it is a common treatment for hair loss in women because it has been shown to be effective, according to the American Academy of Dermatology.

There are a few other medications that can be used off-label to treat hair loss during weight loss. Your dermatologist can determine if one of them is right for you. Lasers and hair transplantation are also methods used by some women to treat hair loss. But the treatments are not appropriate for everyone and don't always work. You can work with your healthcare provider to see what treatments are most likely to work for you if you experience hair loss during weight loss.