Hair Loss After Weight Loss

Of the many unique root causes of hair loss, this one has many women baffled: weight loss and hair loss?

After following the general advice to eat less and work out more, investing so much time, effort, and money into habits that they are told will make them healthy, how could they be experiencing hair loss after weight loss?


Woman running along the water in a park


Many of the clients that I work with come to me after trying to get into better shape. They’d set specific weight loss goals, start a new diet and sign up for a gym membership. At first, many of them saw results; they started to lose weight, were down a few pant sizes, and felt a renewed sense of energy.


But, after a few months, their weight loss plateaued. They used to be losing a few pounds a month, but now their weight remained steady; or in some cases even began to start to creep back up. They talked to their trainers and were typically told that they needed to be stricter with their diets and get to the gym more frequently.


Despite of all of their extra effort to lose those last few pounds, nothing seemed to be working.


Worse, they started noticing that it was taking them longer to recover from workouts. It felt like they were excessively sore and tired all the time. They’d wake up in the morning exhausted despite getting enough sleep the night before. Their periods became more irregular. They lost their libido. They became more constipated. They’re skin became dry or even developed rashes in some cases.


Worst of all, they started to notice that their hair was thinning.


When they’d go to their doctors to have their thyroids tested, they were told that everything was normal. Their TSH (thyroid stimulating hormone) was within range.


Why do some women experience hair loss after weight loss?


Under-eating and over-training is a serious issue and a large contributing factor to a host of issues, including hair loss. Unfortunately, a lot of the messaging we receive about being healthy and fit pushes us to under-eat and over-train. Following misinformed advice like this can lead to us losing weight and losing hair.


A lot of times when women start a fitness routine where they are under-eating and over-training, they’ll tell me that they feel great. But this only lasts for a period of time. Eventually women start feeling very fatigued, having trouble falling asleep and staying asleep. As more time goes by and they push their bodies even harder, they start to notice hormonal changes, maybe even developing an irregular period, exhibiting signs of hypothyroid (even with a normal TSH). Sometimes the last symptom that they notice is hair loss and visible thinning of their hair.


A lot of the work that I do with these clients is to help them learn better habits that are going to support their HPA-axis, their adrenal health. It’s also a re-education on what types of movement to prioritize and how much and when we need to eat to fuel our bodies, support our activity levels, but also to regrow healthy hair.


Our hair is made up of protein (a protein called keratin) and we need there to be adequate protein in our diet to support hair growth, especially when it has already started to thin. If we’re under-eating total calories, it’s going to be difficult (even impossible) to be meeting our needs for macronutrients like protein, and also micronutrients like iron and zinc that are also important for hair growth.


Woman's hand chopping vegetables and herbs


Another Link Between Weight Loss and Hair Loss: Thyroid.


I really want to emphasize something that I hinted at a minute ago: It’s possible to have low thyroid while also having normal TSH. This is especially true I find when I have a client who is under-eating.


Read: Thyroid Hormone and Your Hair


It’s something called famine response hypothyroid, or sometimes also hypothyroidism caused by pituitary dysfunction. If your doctor is only testing TSH, you may not even know that this thyroid pattern is impacting your hair. That’s why I encourage all of my clients to work with their doctors to obtain a full thyroid panel, including TSH, free T4 and T3, reverse T3, and thyroid autoimmune markers.


When we under-eat (whether that’s for weight loss, time constraints, lack of appetite, disordered eating, etc.) it has a negative impact on our thyroid gland. It can cause inflammation and limit nutrients that are needed to produce thyroid hormone (T4) and convert it to the active form (T3) that our hair needs.


If all you’re having tested is TSH, you may miss signs of famine response hypothyroid, which includes low free T4 and/or T3, and sometimes also high reverse T3. All of these together can manifest as symptoms of hypothyroid, including hair loss.


Symptoms of hypothyroid:

  • thinning hair⠀
  • fatigue or being tired a lot⠀
  • cold hands and feet ⠀
  • unintentional weight gain⠀
  • weight loss resistance⠀
  • constipation or stools that are hard to pass⠀
  • low or depressed mood⠀
  • dry skin⠀
  • dandruff⠀
  • low libido⠀
  • high cholesterol⠀

Is there any way to avoid hair loss after weight loss?


You might be wondering if there is any way to lose weight without losing your hair. The answer is yes! But it requires taking a wider lens than simply reducing calories and hitting the gym extra hard – which we now know can be counterproductive, especially if we care about our hair.


If you’re ready to take the next step and learn how I can help you feel your best, schedule our first call here.


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