Peptides to Take With a GLP-1: The Evidence

The Short Answer

People ask this question for one of two reasons. Either they are watching the scale move and the mirror get worse, or they have read that GLP-1 weight loss takes muscle with it and they want to get ahead of the problem. Both are reasonable. What is not reasonable is the answer the internet gives, which is a list of four or five peptides presented as a package, with no ranking, no evidence grading, and no acknowledgment that nobody has run the study.

So here is the part that most pages will not put in the first paragraph. There is no published randomized trial of any peptide in this article taken alongside semaglutide or tirzepatide. Not one. Everything below is mechanism reasoning, borrowed from trials in other populations, applied to a situation nobody has studied head-on. That does not make the reasoning worthless. It does mean the honest way to present it is in tiers, with the confidence level attached, rather than as a stack you buy all at once.

It is also worth knowing that the premise itself is contested. Body composition substudies of GLP-1 therapy do report that a meaningful share of the weight lost is lean tissue, but published estimates span a wide range, and a 2024 JAMA viewpoint from Conte, Hall, and Klein argued that the clinical relevance of that loss is genuinely unsettled. Losing lean mass alongside fat is what happens in most weight loss. Whether it costs you function, or is simply the tissue that supported a larger body, is a separate question from whether the number looks alarming.

Conte C, Hall KD, Klein S. "Is Weight Loss-Induced Muscle Mass Loss Clinically Relevant?" JAMA, 2024. PMID 38829659. View study

The Three Tiers at a Glance

Tier 1: Protein and Resistance Training

This is the tier with actual randomized human evidence, and it is the one every vendor page treats as a throwaway line before the product list. Reverse that order.

Longland and colleagues put young men in a steep caloric deficit with hard training and randomized them to higher or lower protein. The higher-protein group gained lean mass and lost more fat while eating at a deficit, which is the exact outcome anyone on a GLP-1 is trying to buy. That is a controlled human trial with a body composition endpoint. No peptide in this article has anything comparable.

Longland TM, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM. "Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial." Am J Clin Nutr, 2016. PMID 26817506. View study

The general case is older and broader. Weinheimer and colleagues reviewed energy restriction with and without exercise in middle-aged and older adults and found that adding exercise consistently shifted the composition of the weight lost. Cava, Yeat, and Mittendorfer later pulled the mechanistic literature together into a single practical conclusion: protein and resistance exercise are the two levers that reliably protect muscle during weight loss.

Weinheimer EM, Sands LP, Campbell WW. "A systematic review of the separate and combined effects of energy restriction and exercise on fat-free mass in middle-aged and older adults." Nutr Rev, 2010. PMID 20591106. View study

Cava E, Yeat NC, Mittendorfer B. "Preserving Healthy Muscle during Weight Loss." Adv Nutr, 2017. PMID 28507015. View study

The closest thing to a direct test comes from Lundgren and colleagues in the New England Journal of Medicine. They took adults through a low-calorie diet, then randomized them to exercise alone, a GLP-1 receptor agonist alone, both together, or placebo, and followed body composition for a year. The combination group did better than either single arm. This is not a peptide study, and it used liraglutide rather than the drugs most people are asking about, but it is the best available human answer to the question of what to add to a GLP-1. The answer was exercise.

Lundgren JR, Janus C, Jensen SBK, et al. "Healthy Weight Loss Maintenance with Exercise, Liraglutide, or Both Combined." N Engl J Med, 2021. PMID 33951361. View study

For the deeper version of the muscle-loss problem itself, including who is most affected and why, see muscle loss on a GLP-1 Read nextHow to Keep Muscle While Taking Ozempic, Wegovy, or MounjaroUp to 40% of weight lost on GLP-1 medications is lean muscle. Here is what the research actually shows, why it happens, and which growth hormone peptides providers prescribe to preserve lean mass during a caloric deficit.Read article . For a protocol-depth walkthrough of how the GH-axis peptides get sequenced during and after a course, see the muscle preservation stack guide Read nextPeptides to Preserve Muscle on GLP-1: The Stack ProtocolA protocol-depth read on Tesamorelin, CJC-1295/Ipamorelin, BPC-157, MOTS-c, and NAD+ for adults who lost (or are losing) lean mass on Ozempic, Wegovy, Mounjaro, or Zepbound.Read article . This page is the decision layer above both.

Tier 2: Real Mechanism, Thin Human Data

Everything in this tier has a mechanism you can trace and at least some human or animal data supporting that mechanism. What none of them has is a trial in the population asking the question. Read this section as "here is why someone would reason their way to this," not as "here is what works."

The GH-axis peptides

Growth hormone and IGF-1 are the two signals most directly involved in holding onto lean tissue, and both fall during a caloric deficit and again with age. The oldest relevant human evidence is not about peptides at all. Snyder, Clemmons, and Underwood gave growth hormone to obese adults on a restricted diet for eleven weeks in 1988 and found improved nitrogen balance and a shift in what kind of tissue was being lost. That study is the origin of the entire idea, and it used recombinant growth hormone, not a releasing peptide.

Snyder DK, Clemmons DR, Underwood LE. "Treatment of obese, diet-restricted subjects with growth hormone for 11 weeks: effects on anabolism, lipolysis, and body composition." J Clin Endocrinol Metab, 1988. PMID 3379136. View study

Sermorelin Explore PeRxSermorelinThe Growth Hormone OptimizerView peptide is the first 29 amino acids of growth hormone releasing hormone. Rather than supplying growth hormone, it asks the pituitary to release its own in the normal pulsatile pattern. Khorram and colleagues gave a GHRH(1-29) analog to older men and women for months and measured endocrine and body composition changes, which is the human anchor for the class. Again, note the population: age-advanced adults, not people in a pharmacologically driven caloric deficit.

Khorram O, Laughlin GA, Yen SS. "Endocrine and metabolic effects of long-term administration of [Nle27]growth hormone-releasing hormone-(1-29)-NH2 in age-advanced men and women." J Clin Endocrinol Metab, 1997. PMID 9141536. View study

Tesamorelin Explore PeRxTesamorelinMetabolic Optimization PeptideView peptide is the one with a full FDA approval behind it, for HIV-associated lipodystrophy, and it is approved for that indication and not for weight management or muscle preservation. Falutz and colleagues published the pivotal work in the New England Journal of Medicine in 2007 and a pooled phase 3 analysis in 2010, showing visceral fat reduction with lean mass maintained. That is a real, replicated, human body composition result. It is also a result in people with a specific fat redistribution syndrome, which is a different physiology from a person losing forty pounds on tirzepatide. The mechanism transfers. The evidence does not automatically come with it.

Falutz J, Allas S, Blot K, et al. "Metabolic effects of a growth hormone-releasing factor in patients with HIV." N Engl J Med, 2007. PMID 18057338. View study

Falutz J, Mamputu JC, Potvin D, et al. "Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in human immunodeficiency virus-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data." J Clin Endocrinol Metab, 2010. PMID 20554713. View study

CJC-1295/Ipamorelin Explore PeRxCJC-1295/IpamorelinPulsatile Growth Hormone ReleaseView peptide pairs a long-acting GHRH analog with a selective secretagogue that works through a different pituitary receptor. Teichman and colleagues showed in healthy adults that CJC-1295 produces sustained elevation of growth hormone and IGF-1, and Raun and colleagues characterized ipamorelin as selective, meaning it triggers growth hormone release without the cortisol and prolactin rise seen with older secretagogues. Both are real human and preclinical pharmacology papers. Neither measured body composition during weight loss, and neither involved a GLP-1.

Teichman SL, Neale A, Lawrence B, Gagnon C, Castaigne JP, Frohman LA. "Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults." J Clin Endocrinol Metab, 2006. PMID 16352683. View study

Raun K, Hansen BS, Johansen NL, et al. "Ipamorelin, the first selective growth hormone secretagogue." Eur J Endocrinol, 1998. PMID 9849822. View study

MOTS-c

MOTS-c Explore PeRxMOTS-cThe Mitochondrial PeptideView peptide is a peptide encoded in mitochondrial DNA, identified by Lee and colleagues in 2015. In mice and in cell culture it activates AMPK, improves insulin sensitivity, and blunts diet-induced obesity, which is the reason it appears on every GLP-1 stack list. The problem is that the sentence you just read describes the entire evidence base. The original paper is a rodent and cell study. There is no human trial showing that injected MOTS-c changes body composition, in a deficit or otherwise.

Lee C, Zeng J, Drew BG, et al. "The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance." Cell Metab, 2015. PMID 25738459. View study

NAD+

NAD+ Explore PeRxNAD+The Cellular Energy CoenzymeView peptide is a coenzyme, not a peptide, and it gets grouped in because clinics that sell peptides also sell it. Massudi and colleagues documented that tissue NAD+ declines with age in humans, which is a real finding and the basis for the whole category. The gap is on the intervention side. Elhassan and colleagues gave aged human muscle a NAD+ precursor and could measure changes in the muscle NAD+ metabolome, but that study used oral nicotinamide riboside. The human evidence sits on oral precursors. PeRx ships NAD+ as a subcutaneous injection, and the injectable form does not inherit the oral trials.

Massudi H, Grant R, Braidy N, Guest J, Farnsworth B, Guillemin GJ. "Age-associated changes in oxidative stress and NAD+ metabolism in human tissue." PLoS One, 2012. PMID 22848760. View study

Elhassan YS, Kluckova K, Fletcher RS, et al. "Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD+ Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures." Cell Rep, 2019. PMID 31412242. View study

BPC-157

BPC-157 Explore PeRxBPC-157The Body Protection CompoundView peptide shows up on GLP-1 lists for two different reasons, and they deserve different answers. The gut reason is that GLP-1s slow gastric emptying and a lot of people feel it, and BPC-157 has three decades of rodent work on gastrointestinal healing behind it, summarized by Sikiric and colleagues. The training reason is that people coming back to the gym after a year of low food intake find their tendons are not ready, and the same rodent literature covers soft tissue. Both are coherent stories. Both rest on animal studies. There is no human trial of BPC-157 for GLP-1 side effects or for anything else at scale.

Sikiric P, Rucman R, Turkovic B, et al. "Stable Gastric Pentadecapeptide BPC 157, Robert’s Stomach Cytoprotection/Adaptive Cytoprotection/Organoprotection, and Selye’s Stress Coping Response: Progress, Achievements, and the Future." Gut Liver, 2020. PMID 31158953. View study

The longer version of that argument, including what the rodent gut data does and does not support, is in BPC-157 with semaglutide or tirzepatide Read nextCan You Take BPC-157 With a GLP-1?There is no documented pharmacological interaction between BPC-157 and semaglutide or tirzepatide. There is also no human study that has given anyone both and watched what happened. Those two sentences sound alike and mean very different things, and almost nobody writing about this online tells you the difference.Read article .

Tier 3: Marketed Hard, Backed by Almost Nothing

This is the tier that separates a clinic from a storefront, because a storefront has no reason to write it.

5-amino-1MQ is an inhibitor of nicotinamide N-methyltransferase. Neelakantan and colleagues showed that NNMT inhibitors reversed diet-induced obesity in mice, which is a genuinely interesting result and the whole of what is publicly known. There is no human efficacy trial. It is also an orally dosed small molecule, not a peptide, which is worth noticing when you find it in a section labeled "peptide stack."

Neelakantan H, Vance V, Wetzel MD, et al. "Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice." Biochem Pharmacol, 2018. PMID 29155147. View study

SLU-PP-332 is sold as exercise in a vial. Billon and colleagues developed it as a synthetic agonist of the estrogen-related receptors and showed it reproduces parts of an acute aerobic exercise response in mice. It is a small molecule, not a peptide, it has never been given to humans in a published trial, and it is not approved anywhere for anything. Selling it to someone whose actual problem is that they stopped lifting is close to the purest form of this category.

Billon C, Schoepke E, Avdagic A, et al. "Synthetic ERRα/β/γ Agonist Induces an ERRα-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity." ACS Chem Biol, 2023. PMID 36988910. View study

Investigational GLP-1 and amylin analogs sold as research chemicals are the most dangerous item on the list. Some of these compounds are real drug candidates in real manufacturer-run trials. What is being sold online is not the trial drug. It is an unregulated preparation of uncertain identity, purity, and concentration, labeled not for human use so the seller does not have to stand behind it, and there is no dosing literature for the thing in that vial because the thing in that vial has never been characterized.

Why Page One Looks the Way It Does

Run the search yourself and look at who is answering. The results for this question are almost entirely peptide retailers and affiliate sites. That is not a conspiracy, it is an incentive structure, and once you see it the uniformity of the advice stops being mysterious.

A vendor page recommends what the vendor stocks. If the catalog has five items, the article recommends five items, and it recommends them together, because a stack is a larger order than a single vial. Nothing in that model rewards writing "the evidence here is thin" or "you probably only need one of these" or "start with protein and lifting and see where you are in twelve weeks." Those sentences cost money to publish. That is the entire reason the tier three section above exists on this page and not on theirs.

The practical consequence for you is that the recommendation list you have been reading is a function of inventory, not of evidence, and the two lists happen to look identical across sites because the wholesale supply is the same. Treat any stack recommendation that arrives pre-bundled as a merchandising decision until someone shows you the trial.

What to Sort Out Before Adding Anything

A few things are worth settling before any of this becomes a purchase decision.

Whether the foundation is actually in place. Not whether you know about protein and lifting, whether you are doing them. Most people who ask this question have not hit the protein target for a single full week. Adding a peptide to that situation is buying a signal amplifier for a signal that is not being sent.

Whether you are stacking for a reason or by default. Each of the tier two options has a distinct rationale. Growth hormone axis peptides are about lean mass and recovery. MOTS-c and NAD+ are about metabolic and cellular energy. BPC-157 is about tissue tolerance when training resumes. If you cannot say which of those problems you have, you are buying the bundle rather than the answer.

Whether anything on your chart makes this a bad idea. Growth hormone axis peptides are generally avoided with active malignancy, in pregnancy, and with certain pituitary conditions, and growth hormone affects glucose handling in the opposite direction from a GLP-1, which matters more if you have diabetes than if you do not. Every medication you take, including the GLP-1 and anything you bought without a prescription, belongs on the intake form. A licensed provider reviews that list and prescribes accordingly.

Compounded Is Not the Same as Ozempic

One distinction gets blurred constantly in this space, and it is worth being precise about. Ozempic and Wegovy are FDA-approved semaglutide products. Mounjaro and Zepbound are FDA-approved tirzepatide products. Those approvals rest on manufacturer-run trials of those specific products.

A compounded version is prepared by a licensed pharmacy against an individual prescription. It has not been through FDA review for safety or effectiveness, and it is not the approved product. Marketing that implies otherwise is a real legal exposure, not a technicality: a federal court in the Northern District of California has held that blurring the two is plausibly misleading. When you read a claim about how much weight people lost, check which product the study was actually testing, because the answer is almost always the approved one.

The same logic applies one level down to everything in tier two. A trial of tesamorelin in HIV-associated lipodystrophy is evidence about tesamorelin in HIV-associated lipodystrophy. Whether it predicts anything about a person on tirzepatide is a hypothesis. On the practical side, if you are new to self-injection, where to inject semaglutide and tirzepatide Read nextWhere to Inject Semaglutide and TirzepatideBoth are once-weekly subcutaneous injections, and the three standard sites are the same for each. The part that trips people up is not the site. It is that a compounded vial is not a prefilled pen, so you are drawing your own dose and reading it in syringe units. Here is the practical version.Read article covers the site map and why a vial changes how you measure a dose.

Common Questions