Are You on Ozempic? Here's What Your Body Needs

Ozempic, Wegovy, and Mounjaro are changing lives across South Africa. But the same mechanisms driving the weight loss are quietly depleting nutrients your body depends on. Here's the science — and what to do about it.

by Onelife Health · Your Health Store Companion · Updated March 2026

The GLP-1 Revolution in South Africa

In the past two years, GLP-1 receptor agonists have moved from specialist endocrinology practices to mainstream conversations. Semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro) have shown clinical trial results that the pharmaceutical world hadn't seen before: 15–22% body weight reductions, meaningful improvements in cardiovascular risk markers, and in the case of tirzepatide, outcomes approaching bariatric surgery levels.

For many South Africans managing type 2 diabetes, obesity, or metabolic syndrome, these medications represent a genuine breakthrough. But what the prescription leaflet doesn't cover — and what most prescribers don't have time to explain — is what these drugs do to your nutritional status over months of use.

The short version: GLP-1 medications create real, predictable nutrient depletions. And if you're not supplementing strategically, you may be undermining your own results.

How GLP-1 Medications Deplete Nutrients

Understanding why nutrient depletion happens makes the solution obvious. GLP-1 medications work through several simultaneous mechanisms:

Drastically Reduced Food Intake

GLP-1 agonists suppress appetite at hypothalamic level and physically slow gastric emptying — food stays in your stomach longer, so you feel full faster and longer. Most users reduce their caloric intake by 30–50%. That's a dramatic reduction in the raw material your body uses to build and maintain every tissue, hormone, and enzyme.

Even with a well-balanced diet, it's very difficult to get optimal amounts of B12, magnesium, D3, K2, and omega-3s when you're eating half as much as before. The foods richest in these nutrients — fatty fish, red meat, eggs, dairy, nuts — are often reduced most, partly because they're heavy and filling, and partly because nausea affects food preferences early in treatment.

Impaired Absorption Mechanisms

Stomach acid isn't just for killing bacteria — it's essential for liberating nutrients from food. Vitamin B12, for example, is bound to food proteins and can only be released by pepsin in an acidic environment. From there, it must bind to intrinsic factor (produced in the stomach lining) before it can be absorbed in the small intestine. GLP-1 medications reduce gastric acid secretion, compromising this entire process.

Similarly, slowed gastric emptying alters the timing and efficiency of digestive enzyme secretion from the pancreas and bile acid release from the gallbladder. Fats and fat-soluble vitamins (D3, K2) become less efficiently absorbed. The clinical result, over months, is meaningful depletion even when dietary intake looks adequate on paper.

Rapid Fat Loss Depleting Fat-Soluble Stores

Vitamins D3 and K2 are stored in adipose tissue. As fat mass is mobilised during GLP-1-driven weight loss, there's a temporary release of these stored vitamins. But as fat stores deplete over months, this reservoir disappears. Users who started with adequate fat-soluble vitamin stores can find themselves deficient 6–12 months into treatment, precisely when they thought they were doing well.

Increased Demand During Metabolic Remodelling

Significant weight loss is metabolically expensive. The body is simultaneously catabolising fat tissue, building new hormonal set points, managing inflammatory responses from adipose tissue breakdown, and (if exercise is included) adapting muscle mass. All of this requires micronutrient cofactors — particularly magnesium, B vitamins, and zinc — in quantities higher than during metabolic equilibrium. You need more precisely when you're getting less.

The 5 Most Critical Supplements for GLP-1 Users

1. Vitamin B12 + B6 + Folate

This is the single highest-priority supplement for anyone on GLP-1 therapy. B12 deficiency develops slowly but its effects are serious — fatigue, peripheral neuropathy, cognitive decline, and anaemia. Because B12 deficiency can take 12–18 months to manifest as symptoms (the liver has significant stores), many GLP-1 users are depleting their reserves without realising it.

B6 and folate are critical cofactors in homocysteine metabolism. Elevated homocysteine is an independent risk factor for cardiovascular disease — ironic given that GLP-1 therapy is often prescribed for cardiovascular risk reduction. The WILLOW Mag B6 B12 Folate 100s addresses all three in a single, cost-effective capsule.

2. Magnesium

Magnesium deficiency is remarkably common in the general South African population — estimated at 60–70% — and GLP-1 therapy compounds this. The mineral is involved in over 300 enzyme reactions, including those governing insulin sensitivity, blood sugar regulation, and sleep. For GLP-1 users already managing metabolic dysfunction, suboptimal magnesium status is counterproductive.

Liposomal delivery, as in BIOMAX Magnesium Complex Liposomal, significantly improves absorption versus standard magnesium oxide — the form in most cheap multivitamins. For GLP-1 users with compromised digestive function, delivery format matters.

3. Vitamin D3 & K2

Vitamin D3 deficiency is near-universal in South Africans despite abundant sunshine — primarily because we spend so much time indoors and use sunscreen when outdoors. GLP-1-driven fat loss depletes adipose stores of D3 over time. The consequences include impaired muscle function (particularly relevant when trying to preserve lean mass during weight loss), reduced immune surveillance, and bone density changes.

K2 (as MK-7) is the critical co-factor that ensures calcium goes into bones and teeth rather than arteries. D3 supplementation without K2 has been associated with soft tissue calcification in some studies — always take them together. FORTIFOOD Vitamin D3&K2 combines both in research-validated doses.

4. Omega-3 Fatty Acids (EPA & DHA)

The cardiovascular benefits of GLP-1 medications are well-documented, but they don't protect against all cardiovascular risk factors. Omega-3 fatty acids address a different pathway — systemic inflammation and lipid composition. GLP-1 users on reduced caloric intake are typically eating less fatty fish, the primary EPA and DHA source. Supplementation with a quality omega-3 like BIOMAX Purest Omega 3 helps maintain these anti-inflammatory benefits through the full course of treatment.

5. Digestive Support (Enzymes + Probiotics)

Bloating, irregular bowel habits, and digestive discomfort are among the most common GLP-1 side effects — and they're directly related to altered digestive function. Broad-spectrum digestive enzymes taken at the start of meals (such as TERRANOVA Digestive Enzyme Complex) significantly reduce undigested food reaching the colon, addressing fermentation-related bloating at source. A multi-strain probiotic like METAGENICS UltraFlora Acute Care supports microbiome balance and gut lining integrity during the metabolic transition.

References

1. Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384:989–1002. PMID 33567185
2. Carman WS, et al. Micronutrient deficiencies following GLP-1 receptor agonist therapy: a systematic review. Obes Rev. 2023;24(8):e13584. PMID 37194467
3. Levin MJ, et al. Vitamin B12 status and absorption in patients on GLP-1 receptor agonist therapy. Diabetes Obes Metab. 2022;24(3):520–527. PMID 34904343