You started to feel better about the scale, and then you noticed more hair in the brush. It is one of the most unsettling parts of a GLP-1, and one of the most misunderstood. In most cases, it is not the drug. It is how fast the weight came off and what your plate has been missing.

What is actually happening

The usual cause is a pattern called telogen effluvium: a stressor, such as rapid weight loss or a sharp drop in intake, nudges a batch of hairs into their resting phase at the same time. A few months later they shed together. It looks dramatic, but it is a delayed reaction to something that already happened, not ongoing damage.

The nutrients that matter for hair

• Protein. Hair is mostly protein. Too little, and non-essential tissue like hair is first to be deprioritised.
• Iron. Low iron, and low ferritin in particular, is one of the most common drivers of shedding during fast weight loss.
• Zinc. Supports keratin and the hair growth cycle, and is easy to under-eat on smaller portions.

What helps, practically

• Protect your protein. Roughly your body weight in grams a day, every day.
• Lean into iron and zinc. Red meat, shellfish, lentils, spinach, seeds and chickpeas. If you eat little or no meat, these need more attention.
• Ask for a ferritin test. It is the single most useful number for hair, and easy to request.
• Be patient. Regrowth takes months, not weeks. Consistency beats any single product.

When to speak to your prescriber

If shedding is severe, patchy, or comes with other symptoms, that is worth raising with your prescriber or GP rather than treating as a nutrition issue alone. Nutrition supports hair, but it is not a substitute for medical advice.

For most people, though, the plan is calm and clear: enough protein, enough iron and zinc, and a little patience while your hair catches up with the rest of your progress.