Mochi Labs: Bloodwork That Fits Into Your Treatment

Why Bloodwork Can Be Useful During GLP-1 Treatment

Bloodwork is not required during GLP-1 treatment, and labs are not a condition of treatment through Mochi Health. Our existing guide on which labs to monitor says the same thing. Bloodwork is simply a way to see more than what the scale shows, for people who want those metrics.

GLP-1 treatment is not static, and neither is your body while it is underway. While weight is the most visible measure of progress, it is also the least informative about what is happening beneath the surface.

Nutrient Levels Can Drift

GLP-1 medications work partly by reducing appetite, which means many people eat considerably less than they did before, and sometimes with less variety. A narrative review of nutritional deficiencies during GLP-1 therapy describes appetite suppression, delayed gastric emptying, and altered absorption as plausible routes to shortfalls in specific nutrients (1).

A retrospective study of adults prescribed GLP-1 receptor agonists, most of whom had type 2 diabetes, found vitamin D deficiency was the most common abnormality. This was found in 7.5% of patients at six months and 13.6% at twelve months, with thiamine, other B vitamins, and several minerals also appearing (1,2).

Bariatric surgery care already has established monitoring protocols, and a 2025 review set those alongside GLP-1 treatment. It notes that protocols from the British Obesity and Metabolic Surgery Society, and the American Society for Metabolic and Bariatric Surgery call for routine nutrient monitoring after surgery, and argues that a comparable approach could reasonably be adapted for patients on GLP-1 medications (3).

Thyroid and Metabolic Markers

Thyroid function affects weight and energy, and thyroid conditions are common. The National Institute of Diabetes and Digestive and Kidney Diseases puts hypothyroidism at nearly 5 in 100 Americans aged 12 and over, and notes that most cases are mild or have few obvious symptoms (7). That combination is common and easy to miss, which is why it is worth confirming with bloodwork rather than assuming.

Blood sugar and cholesterol are standard measures of cardiometabolic health, and having a baseline is what makes any later change interpretable. Testing gives you and your provider a before and after rather than a guess. Our guide to which labs to monitor on GLP-1s covers the individual markers in depth, and a companion piece on thyroid function and GLP-1s covers that relationship specifically.

What the Scale Cannot Show You

Weight loss is not selective. A 2024 review of body composition during GLP-1-based treatment found wide variation in how much of the weight lost is lean mass, from roughly 15% to as much as 40–60% across the studies it examined. The authors concluded that the change in skeletal muscle appears to be adaptive, in line with what would be expected given age, disease status, and the amount of weight lost (4). One editorial makes the point that caloric restriction on its own produces comparable lean mass loss, so this is not unique to these medications (5).

Either way, body composition is the part of this you can influence while treatment continues, and the response is behavioral rather than pharmacological. A joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society sets out nutritional priorities during GLP-1 therapy, including protein adequacy alongside resistance training (6). Our guide to why protein intake matters goes into the practical side.