What Supplements to Take on a GLP-1: The South African Guide (2026)

By Precious, One Life Health Consultant · June 2026 · 6 min read

You've started semaglutide or tirzepatide. The appetite is finally quiet, the scale is moving — and you're eating half of what you used to. Here's the conversation we have at the counter almost every day now: the medication does the weight work, but nobody told you what it does to your nutrition.

This is the guide we'd walk you through in store. What actually depletes, what we'd supplement, what we'd skip, and the one thing almost everyone on a GLP-1 underestimates — muscle loss.

The short version

• Eat protein first, every meal. 1.6g+ per kg of goal body weight. This is the single biggest lever.
• Creatine, daily. 3–5g of monohydrate — the most evidence-backed muscle-preservation supplement that exists.
• B12 and magnesium are the two most common depletions on GLP-1s. Cover both.
• Omega-3 — appetite suppression crowds out oily fish first.
• Resistance training twice a week. Without it, up to 40% of GLP-1 weight loss can be lean mass.

Why GLP-1s create nutritional blind spots

GLP-1 receptor agonists work by slowing gastric emptying and quieting appetite signals. That's the point — but it has three side effects on nutrition:

1. You simply eat less of everything. Less food means less B12, less magnesium, less omega-3, less protein — not because you're choosing badly, but because the volume isn't there.

2. Slowed gastric emptying changes absorption. B12 in particular needs stomach acid and intrinsic factor to absorb — both are affected when gastric activity slows down.

3. Rapid weight loss takes muscle with it. Studies on semaglutide show a meaningful portion of total weight lost can be lean mass if protein and resistance training aren't protected. Losing muscle drops your metabolic rate — which sets up the rebound nobody wants.

The supplements we'd actually suggest

Creatine monohydrate — the muscle anchor

If we could only recommend one supplement to a GLP-1 user, this is it. Creatine monohydrate at 3–5g daily helps preserve lean mass and strength during caloric restriction — and the evidence base is the deepest in sports nutrition. No loading phase needed. Mix it in water or your morning drink, every day, including rest days.

From our shelf: NATROCEUTICS Creatine Monohydrate Bioactive (240g).

Vitamin B12 (with magnesium) — the depletion cover

Fatigue, brain fog, tingling fingers — these get blamed on the medication, but they're often B12 running low. Combine that with magnesium (involved in 300+ reactions, including the muscle cramps and poor sleep many GLP-1 users report) and you've covered the two most common gaps. A combination product like Willow's Mag B6 B12 Folate handles both in one.

Omega-3 — the crowded-out essential

When your appetite shrinks, oily fish is usually the first thing to go. A clean, tested omega-3 keeps the cardiovascular and anti-inflammatory base covered — and supports the joints that are suddenly carrying less weight but moving more.

Collagen — the skin elasticity play

Fast weight loss challenges skin elasticity. A complete collagen (types I, II and III) at 10g+ daily, given a real 12 weeks, supports the skin remodelling that has to happen as your body changes shape. Pair it with vitamin C — your body can't synthesise collagen without it.

Digestive enzymes and probiotics — if your gut is struggling

Slowed gastric emptying changes the whole digestive environment. If you're dealing with bloating, reflux or constipation on your GLP-1, digestive enzymes with meals and a daily multi-strain probiotic are where we'd start. If symptoms are severe, talk to your prescriber — dose timing can sometimes be adjusted.

What we'd skip

"Fat burners" and thermogenics — you're already in a strong caloric deficit; stacking stimulants on top adds risk without meaningful benefit. Appetite suppressants — the medication is already doing this job. Mega-dose anything — more is not better when your gut is processing slowly.

One important honesty note

Supplements support a GLP-1 journey — they don't replace medical supervision. Tell your prescribing doctor everything you're taking. If you experience persistent vomiting, severe abdominal pain, or signs of gallbladder issues, that's a doctor conversation, not a supplement conversation.

Your One Life shortcut

We've built this twice over:

• The GLP-1 Companion protocol — the muscle, energy and skin stack (creatine + Mag B12 + collagen + omega-3) at 10% off with DISPENSARY10.
• The GLP-1 Support collection — three ready-made bundles (Essentials from R884, Complete, Premium) covering the foundational depletions, each with a free Vivid Health gift.

Not sure which fits where you are in your journey? WhatsApp me — tell me what you're on and how far in you are, and I'll narrow it down. Free, no pressure. Or pop into Centurion, Glen Village or Edenvale.

This article is for information only and is not medical advice. Always consult your prescribing doctor before adding supplements to GLP-1 therapy.

From the apothecary shelf

Three products we'd hand a customer asking for a starting point. Not a paid placement — these are what we actually take, recommend, or keep at the front of the shelf.