Compounded GLP-1 preparations: trial evidence and limits

Key takeaways

What it is: Unapproved compounded preparation. Injection.
Licensed for: Not approved. Sold through compounding pharmacies and online sellers.
What the trials show: No trial evidence exists for these preparations, because they are not the products that were trialled. Regulators in several jurisdictions have warned about dosing errors and about salt forms — semaglutide sodium and semaglutide acetate — that were never studied in humans.
The catch: This entry exists because the market is large and the risk is real: overdose from unfamiliar concentrations is the specific documented harm. It is not a cheaper version of the licensed drug; it is a different product.
Weight regain after stopping is the rule, not the exception. These are treatments for a chronic condition, not a course you finish.

What the evidence supports

No trial evidence exists for these preparations, because they are not the products that were trialled. Regulators in several jurisdictions have warned about dosing errors and about salt forms — semaglutide sodium and semaglutide acetate — that were never studied in humans. ^[1]

This entry exists because the market is large and the risk is real: overdose from unfamiliar concentrations is the specific documented harm. It is not a cheaper version of the licensed drug; it is a different product.

Compounded GLP-1 preparations is graded popular but weak. The grade describes the quality of the trial evidence, not how well the drug will suit any individual — and the one entry graded "popular but weak" is there precisely because it is widely sold and never trialled. Grades assigned from trial programme and regulatory status.

What happens when you stop

This is the part of the picture most often left out. Withdrawal trials consistently show substantial weight regain within a year of stopping, and cardiometabolic markers drifting back with it ^[2]. That is not a failure of the drug — it is what treating a chronic condition with a drug looks like when the drug is removed.

The practical implication is that the decision to start is a decision about a long horizon, including cost and access over that horizon, rather than about a target weight.

Muscle mass

Rapid weight loss from any cause includes lean tissue, and the incretin trials are no exception. The proportion lost as lean mass appears broadly similar to other rapid-loss methods, but the absolute loss is larger because the total loss is larger. Adequate protein and resistance training are the interventions with evidence behind them, and both are within your control while taking the drug.

Made-up bed in a three-person internal medicine ward room — 玄史生 · CC0 · Wikimedia Commons

Other drugs in this class

Semaglutide — GLP-1 receptor agonist, established
Tirzepatide — Dual GIP / GLP-1 receptor agonist, established
Liraglutide — GLP-1 receptor agonist, established
Dulaglutide — GLP-1 receptor agonist, established
Oral semaglutide — GLP-1 receptor agonist, oral, promising

How much weight do people lose on compounded glp-1 preparations?

What happens if I stop?

Most of the weight returns, typically within a year. Withdrawal trials are consistent on this and it is the single most important thing to understand before starting.

Does it cause muscle loss?

Rapid weight loss from any cause includes lean tissue. Protein intake and resistance training are the mitigations with evidence behind them.

Is a compounded version the same thing?

No. Compounded preparations are not the products that were trialled, dosing errors are documented, and some use salt forms never studied in humans.

References

Every citation below links to the original peer-reviewed record on PubMed or via DOI. Nothing here is a substitute for medical advice.

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Comparison of Clinical Efficacy and Safety of Tirzepatide, Liraglutide and Semaglutide in Patients with Obesity and Without T2D: A Bayesian Network Meta-Analysis of Randomised Controlled Trials Ciudin A, Sapin H, Fan L, et al. · Advances in therapy · 2026 · Meta-analysis DOI PubMed 41820778 Full text
Effectiveness & safety of semaglutide in weight reduction in obese nondiabetic patients: A systematic review and meta-analysis Naz F, Qaiser F, Mumtaz A, et al. · Medicine · 2026 · Meta-analysis DOI PubMed 42536519 Full text
Perioperative management of patients taking glucagon-like peptide 1 receptor agonists: Society for Perioperative Assessment and Quality Improvement (SPAQI) multidisciplinary consensus statement Oprea AD, Ostapenko LJ, Sweitzer B, et al. · British journal of anaesthesia · 2025 · Systematic review DOI PubMed 40379536 Full text
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Efficacy and Safety of Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss Among Adults Without Diabetes : A Systematic Review of Randomized Controlled Trials Moiz A, Filion KB, Toutounchi H, et al. · Annals of internal medicine · 2025 · Systematic review DOI PubMed 39761578
Subcutaneously administered tirzepatide vs semaglutide for adults with type 2 diabetes: a systematic review and network meta-analysis of randomised controlled trials Karagiannis T, Malandris K, Avgerinos I, et al. · Diabetologia · 2024 · Meta-analysis DOI PubMed 38613667 Full text
EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD): Executive Summary Diabetologia · 2024 · Clinical guideline DOI PubMed 38869512 Full text
Long-Term Efficacy and Safety of Once-Weekly Semaglutide for Weight Loss in Patients Without Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Moiz A, Levett JY, Filion KB, et al. · The American journal of cardiology · 2024 · Meta-analysis DOI PubMed 38679221
EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD) Journal of hepatology · 2024 · Clinical guideline DOI PubMed 38851997
A systematic review of the effect of semaglutide on lean mass: insights from clinical trials Bikou A, Dermiki-Gkana F, Penteris M, et al. · Expert opinion on pharmacotherapy · 2024 · Systematic review DOI PubMed 38629387
Comparative effectiveness of GLP-1 receptor agonists on glycaemic control, body weight, and lipid profile for type 2 diabetes: systematic review and network meta-analysis Yao H, Zhang A, Li D, et al. · BMJ (Clinical research ed.) · 2024 · Meta-analysis DOI PubMed 38286487 Full text
Risk of major adverse cardiovascular events and stroke associated with treatment with GLP-1 or the dual GIP/GLP-1 receptor agonist tirzepatide for type 2 diabetes: A systematic review and meta-analysis Stefanou MI, Theodorou A, Malhotra K, et al. · European stroke journal · 2024 · Meta-analysis DOI PubMed 38400569 Full text