Supplements to Preserve Muscle on GLP-1 Drugs (Ozempic, Wegovy, Mounjaro)

7 min read ·
Bottom Line

GLP-1 drugs are excellent at removing fat, but a large share of the weight you lose is muscle — up to roughly 40% of total weight loss comes from lean tissue, and trial participants have shed about 10% or more of their muscle over a year of treatment. No supplement fixes this on its own: the two interventions with the strongest evidence are eating enough protein (clinicians target roughly 1.6 g per kg of body weight per day) and doing resistance training. Once those are in place, a short list of adjuncts — creatine, HMB, vitamin D, and omega-3 — has modest supporting evidence and is reasonable to add, while exotic "muscle preservation" blends and stand-alone BCAAs are not worth the money.

The GLP-1 receptor agonists — semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) — produce weight loss that used to require surgery. But weight loss by almost any means takes muscle along with fat, and because these drugs suppress appetite so powerfully, many people eat far too little protein to defend their lean mass. The result is a body-composition problem hiding inside a body-weight success: the scale drops, but so does the muscle that supports metabolism, strength, blood-sugar control, and — especially in older adults — independence. The good news is that the defense is well understood, and most of it is not a supplement at all.

How much muscle you actually lose

The numbers are larger than most people expect. A 2024 review in Obesity Reviews concluded that participants receiving incretin-mimetic drugs for obesity lost 10% or more of their muscle mass over the 68-to-72-week trials — an amount the authors compared to roughly 20 years of normal age-related muscle loss, compressed into less than a year and a half [1]. A 2025 review in Current Opinion in Clinical Nutrition and Metabolic Care put it a different way: up to 40% of the total weight lost on a GLP-1 drug can come from fat-free mass rather than fat [2]. Not all fat-free mass is muscle — it includes water and organ tissue — but a meaningful portion is skeletal muscle, and losing it matters for function and for keeping the weight off, since muscle is metabolically active tissue.

The foundation is not a supplement: protein and resistance training

Every serious clinical review of this problem lands on the same two-part answer, and neither part is a pill. The first is adequate protein. A 2025 clinical review in Canadian Family Physician concluded that protein supplementation is effective at preserving muscle mass during drug-induced weight loss, and that resistance training mitigates the loss of both muscle and bone [3]. The second is resistance training itself — lifting weights, bands, or bodyweight work two to three times a week — which is the single most reliable signal telling the body to keep muscle while it sheds fat [1][3]. The ongoing LEAN-PREP randomized trial, which is testing exactly this combination in people starting semaglutide or tirzepatide, targets a protein intake of about 1.6 g per kilogram of body weight per day alongside a thrice-weekly home resistance program [4]. That protein target — well above the bare-minimum 0.8 g/kg — is the number most obesity-medicine clinicians now use.

Where protein supplements fit

Here is the practical problem: 1.6 g/kg/day is a lot of protein — for a 180-pound person, roughly 130 grams — and GLP-1 drugs make you want to eat almost nothing. Hitting that target from whole food while nauseated and full after three bites is genuinely hard, and this is the one place a supplement earns its keep. A whey protein shake delivers 25-30 g of high-quality, leucine-rich protein in a small, easy-to-tolerate volume, which is often more achievable than a chicken breast when appetite is gone. Casein protein is a reasonable slower-digesting alternative, useful before bed. The protein powder is not doing anything magic — it is simply the most reliable way to reach a target that the evidence says protects muscle. Think of it as food, not as a "muscle supplement."

Adjuncts with real (if modest) evidence

Once protein and training are handled, a few supplements have legitimate, if secondary, support specifically in the muscle-during-weight-loss context. The 2025 nutrition-support review names the short list directly: when protein and exercise alone are not enough, branched-chain amino acids, creatine, leucine, omega-3 fatty acids, and vitamin D may be beneficial [2]. Creatine has the best independent track record for supporting strength and training output and is cheap and safe. HMB, a leucine metabolite, has modest evidence for reducing muscle breakdown during catabolic states. Vitamin D matters because deficiency itself impairs muscle function, and it is worth correcting if your level is low. Omega-3 may modestly support the muscle-building response to protein in older adults. None of these is a substitute for the protein-and-training foundation — they are add-ons that may help at the margins.

What to skip

Stand-alone BCAA products are the most common waste of money here. BCAAs are simply three of the amino acids already present — in better proportion — in a complete protein like whey, and supplementing them in isolation does not outperform eating enough total protein. The same goes for proprietary "muscle preservation," "lean support," or "anti-catabolic" blends that repackage creatine, a little leucine, and filler at a premium. There is also no evidence that any supplement lets you skip the resistance training; the muscle-loss problem is driven by the combination of rapid calorie restriction and the absence of a strength stimulus, and only a strength stimulus replaces a strength stimulus. Spend the money on enough protein and a set of resistance bands first; treat everything else as optional.

Related supplements

Sources

  1. Mechanick JI, Butsch WS, Christensen SM, et al. "Strategies for minimizing muscle loss during use of incretin-mimetic drugs for treatment of obesity." Obesity Reviews, 2024;26(1):e13841. PMID 39295512.
  2. Chavez AM, Carrasco Barria R, León-Sanz M. "Nutrition support whilst on glucagon-like peptide-1 based therapy. Is it necessary?" Current Opinion in Clinical Nutrition and Metabolic Care, 2025;28(4):351-357. PMID 40401903.
  3. Bosomworth NJ. "New drugs for weight loss: Why change in body composition matters and why nutrition and exercise remain paramount." Canadian Family Physician, 2025;71(11-12):705-714. PMID 41285626.
  4. Alawadhi AA, Alroudhan D, Alsaeed DJ, et al. "LEAN mass Preservation with Resistance Exercise and Protein during semaglutide and tirzepatide therapy (LEAN-PREP study): a protocol for a randomised controlled trial." BMJ Open, 2026;16(4):e116911. PMID 42020128.
  5. Khan MS, Dawood MH, Handelsman Y, et al. "Fat, muscle, and anti-obesity medications in cardiovascular disease prevention." European Heart Journal, 2026;47(21):2584-2605. PMID 41914150.