Iron + Zinc

Here's the scale of the problem: when you're eating a lot less on a GLP-1, you can quietly run low on minerals you need for more than just your hair. Research shows nearly 20% of people on these medications develop at least one nutritional deficiency within the first year — meaning a mineral or vitamin level that's dropped low enough to matter. Among those eating fewer than 1,200 calories a day (a genuinely low intake that makes it hard to get enough from food alone), about 18% were low in iron and 12% were low in zinc. These two minerals get most of the attention for hair health, but they also do quieter jobs around the body — helping turn food into energy and keeping your immune system working.

If your zinc is genuinely low, your clinician may suggest a repletion dose — meaning a higher, targeted amount taken for a while to bring your stores back up. A common range is 25–50 mg of elemental zinc a day (the word "elemental" just means the actual zinc in the pill, not the weight of the whole compound), and this is meant to help the cells that build your hair shaft — keratinocytes — do their job properly. One friendly safety note: zinc and copper compete with each other, so taking high zinc for a long time can quietly drag your copper down. That matters because even a "subclinical" gap — where your stores are slipping but you're not yet anemic, meaning your blood counts haven't dropped to the point of a formal diagnosis — can still raise the chance of diffuse shedding, where hair thins evenly across your scalp, especially during the peak weight-loss phase.