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The following supplements have the strongest evidence base for GLP-1 users. Evidence grades reflect the quality and quantity of human clinical trial data.

Tier 1 — Strong evidence

Creatine monohydrate

Dose: 5g daily. Evidence: Strong

The most well-studied supplement for lean mass preservation during caloric restriction. Extensive RCT evidence. Raises serum creatinine — inform your prescriber.

HMB (β-Hydroxy β-methylbutyrate)

Dose: 3g daily, split across meals. Evidence: Moderate–Strong

Anti-catabolic. Reduces muscle protein breakdown during caloric deficit. Less well-known than creatine but has solid mechanistic and trial support.

Tier 2 — Moderate evidence

Leucine enrichment

Target: 2.5–3g per meal. Evidence: Moderate

Primary amino acid trigger for muscle protein synthesis via mTORC1. GLP-1-induced meal suppression often drops leucine per meal below the activation threshold.

Magnesium glycinate

Dose: 200–400mg before bed. Evidence: Moderate

Reduced food volume on GLP-1 commonly produces subclinical magnesium deficiency. Glycinate form has best absorption and least GI irritation.

Where to buy

We disclose our affiliation with LeanLoss.com, which carries the full mainstream stack (creatine, HMB, magnesium glycinate) in clean formulations with third-party testing. We recommend them because we know the sourcing — not only because they're an affiliate.