Parts 1 and 2 of this series covered the recovery, repair, longevity, and cellular health compounds most relevant to men over 40 building a serious optimization protocol. This article covers the performance and body composition end of the peptide landscape — compounds that target energy systems, metabolic efficiency, fat metabolism, and physical output.

A few of these compounds sit at the cutting edge of what’s being researched and used in advanced protocols. The evidence base is compelling but in some cases earlier-stage than the compounds covered in Parts 1 and 2. The tiering framework applies throughout. The N=1 principle applies to everything in this category more than anywhere else — individual metabolic response to these compounds varies, and the only way to know how they work for you specifically is to run them carefully, monitor honestly, and evaluate over an appropriate timeframe.

The goal this article is written for is not dramatic transformation. It is maintenance and optimization under load — sustaining low body fat, high training output, and metabolic efficiency over time. That is a more sophisticated and more honest application of these compounds than the typical body composition framing suggests.

The Metabolic Stack: What These Compounds Actually Do

The performance and body composition peptides and compounds in this article work primarily through metabolic pathways — energy production, fat oxidation, mitochondrial efficiency, glucose regulation, and the hormonal signals that govern body composition. They are not stimulants. They are not shortcuts. They are precision tools that, when layered on top of a solid foundation of training, nutrition, sleep, and stress management, support the body’s ability to perform and maintain optimal composition under sustained load.

The man who benefits most from this category is not the man trying to lose 30 pounds. It is the man who has already done that work, who trains consistently and eats well, and who is looking to maintain elite body composition and high performance output as he ages — without the metabolic slowdown that most men accept as inevitable after 40.

5-Amino-1MQ: NNMT Inhibition and Metabolic Efficiency

5-Amino-1MQ is a small molecule NNMT inhibitor — NNMT being nicotinamide N-methyltransferase, an enzyme that plays a significant role in metabolic regulation. When NNMT is overexpressed, it depletes SAM (S-adenosylmethionine) and NAD+ precursors, slowing metabolism and promoting fat storage. Inhibiting NNMT reverses that process.

The practical effects of NNMT inhibition: improved metabolic rate, enhanced fat oxidation, better body composition maintenance, and improved insulin sensitivity. Research has shown meaningful reductions in fat mass and improvements in metabolic markers in animal models. Human real-world use reports are consistent with those mechanisms — improved energy, better training performance, and body composition maintenance that outperforms what training and nutrition alone produce at the same effort level.

Importantly, 5-Amino-1MQ also appears to support NAD+ availability by reducing the drain on precursors — which has broader implications for cellular energy production and the mitochondrial function that everything downstream of performance depends on. It stacks well with SLU-PP-332 for this reason, with complementary mechanisms that together support energy system efficiency from multiple angles.

Tier: Emerging with strong mechanistic data. Animal research strong. Human real-world use growing with consistent reports.

SLU-PP-332: ERR Agonism and the Exercise Mimetic

SLU-PP-332 is an agonist of the estrogen-related receptor (ERR) family — nuclear receptors that regulate mitochondrial biogenesis, oxidative metabolism, and energy homeostasis. ERR agonism essentially tells the body to produce more mitochondria and use them more efficiently — a process that normally requires sustained aerobic exercise to stimulate.

The exercise mimetic framing is accurate but needs context. SLU-PP-332 does not replace training. What it does is amplify the mitochondrial and metabolic adaptations that training produces — making the same training load more effective at the cellular level. For men already training hard, that amplification translates to better energy output, faster recovery between sessions, improved fat oxidation, and body composition maintenance that holds up better over time.

Running it alongside 5-Amino-1MQ creates a stack that hits NNMT inhibition and ERR agonism simultaneously — two different but complementary pathways both pointing toward improved metabolic efficiency, better fat utilization, and sustained energy. The combination is one of the more interesting cutting-edge stacks being run in advanced protocols right now.

Tier: Cutting edge / research-stage. Mechanistic data compelling. Human trials limited but real-world use building.

GW-501516: PPARδ Activation and Endurance Metabolism

GW-501516, also known as Cardarine, is a PPARδ (peroxisome proliferator-activated receptor delta) agonist. PPARδ regulates fatty acid oxidation, mitochondrial function, and glucose metabolism in skeletal muscle. Activating it shifts the body toward preferential fat burning as a fuel source, improves endurance capacity, and supports metabolic efficiency under sustained exercise load.

The effects that users consistently report: significantly improved endurance and cardiovascular output, enhanced fat oxidation particularly during training, and body composition improvements driven by the shift toward fat as primary fuel. For men running high cardio volumes alongside resistance training, the applications are directly relevant.

The honest note: GW-501516 was discontinued in pharmaceutical development due to tumor promotion findings in animal studies at high doses over extended periods. This is a compound that requires informed decision-making, conservative dosing, and provider involvement. It is included here because it is widely used in advanced protocols and deserves honest treatment rather than either uncritical promotion or blanket dismissal. The risk profile in real-world human use at reasonable doses and cycle lengths is not well-established either way — men considering it should understand that uncertainty going in.

Tier: Cutting edge / research-stage. Strong performance data. Honest risk uncertainty noted.

SR-9011: Rev-erb Agonism and Circadian Metabolism

SR-9011 is a Rev-erb agonist — Rev-erb being a nuclear receptor that regulates circadian rhythm, metabolism, and inflammation. Rev-erb agonism has shown effects on fat mass reduction, improved metabolic rate, enhanced mitochondrial function, and reduced inflammation. It also interacts with circadian biology in ways that affect energy availability throughout the day and sleep quality at night.

Stacked with GW-501516, SR-9011 adds Rev-erb agonism to PPARδ activation — hitting metabolic efficiency from two distinct regulatory angles simultaneously. The combination produces effects on endurance, fat oxidation, body composition, and energy that are reported as additive by men running both. The circadian regulation component is a meaningful secondary benefit — better metabolic timing means better energy distribution across training and recovery windows.

SR-9011 has a short half-life that requires more frequent dosing than some compounds to maintain consistent receptor engagement. Timing relative to training and sleep matters more here than with most compounds in this article.

Tier: Cutting edge / research-stage. Compelling mechanistic and animal data. Human trial data limited.

MOTS-C: Performance Applications

MOTS-C was covered in full in Part 2 for its longevity and cellular health mechanisms. Its performance applications deserve a specific mention here.

The AMPK activation that MOTS-C produces — the same pathway activated by exercise and caloric restriction — has direct performance implications: improved glucose uptake in muscle tissue, enhanced fatty acid oxidation, and better mitochondrial efficiency under exercise load. For women in particular, MOTS-C has shown strong effects on metabolic performance and body composition maintenance, with real-world reports consistent with the research. The performance benefits apply to men as well, particularly for men focused on metabolic efficiency and body composition maintenance under sustained training load.

If performance and body composition are primary goals alongside the longevity applications, MOTS-C is worth considering as part of this stack rather than purely in the cellular health context. See Part 2 for the full treatment.

Melanotan II: Libido, Tanning, and an Honest Assessment

Melanotan II is a synthetic analogue of alpha-melanocyte stimulating hormone that activates melanocortin receptors. Its effects are significant and in some cases dramatic: deep tanning through melanin stimulation, substantial libido enhancement, appetite suppression, and some evidence of improved erectile function. It is used by both men and women for these applications.

The honest assessment covers both sides. The libido effects are real and reported as intense — sometimes uncomfortably so at higher doses. The tanning effect is genuine and substantial. The appetite suppression is a meaningful secondary benefit for body composition management. These are not trivial or marginal effects.

The honest caveats: long-term effects on skin, including questions around melanoma risk with sustained use, are not fully established. Nausea is a common initial side effect. Dose management matters significantly — the intensity of effects scales with dose in ways that require careful titration. Men considering MT-2 should understand these uncertainties clearly and approach it with provider involvement and conservative starting points.

This is included here as an honest field report on a compound widely used in advanced protocols. Personal validation is limited to awareness and research rather than direct use. The N=1 principle applies fully.

Tier: Emerging with real-world validation. Risk profile requires honest acknowledgment. Provider involvement recommended.

Glutathione: Antioxidant Support and Stack Synergy

Glutathione is the body’s master antioxidant — a tripeptide that plays a central role in oxidative stress management, immune function, and cellular detoxification. Injectable glutathione produces higher bioavailability than oral forms and is used in advanced protocols for its antioxidant support, metabolic health benefits, and synergy with other compounds in a complex stack.

For men running multiple compounds simultaneously — TRT, peptides, performance compounds — the oxidative load increases meaningfully. Glutathione supports the body’s ability to manage that load while producing its own direct benefits: improved skin health, better immune function, and metabolic support. It is one of the more accessible and lower-risk additions to a Phase 3 protocol.

Tier: Well-documented for antioxidant and immune applications. Injectable form for optimal bioavailability.

Stacking and Sequencing: Principles for This Category

A few practical principles for men approaching the performance and body composition compounds:

Establish the foundation first: The metabolic and performance compounds in this article work best on a body with a solid hormonal and recovery foundation. TRT stable, recovery stack running, training and nutrition dialed in. Adding performance compounds to an unstable foundation produces unpredictable results.

One compound at a time: The N=1 principle is most critical in this category. Add one compound, run it for an appropriate evaluation period, assess individual response, then consider additions. Men who stack multiple cutting-edge compounds simultaneously have no way to attribute effects or side effects to any specific one.

Conservative entry points: Particularly for GW-501516, SR-9011, and MT-2. These compounds produce real effects at meaningful doses and the risk-benefit calculation requires honest individual assessment. Start conservatively and titrate based on response.

Provider involvement: More important in this category than anywhere else in the peptide series. The cutting-edge compounds require protocol design, monitoring, and the kind of clinical experience that prevents the polypharmacy chaos that gives advanced protocols a bad reputation.

FROM THE FIELD

I currently run 5-Amino-1MQ and SLU-PP-332 together, taken with breakfast in the morning. The effects are real but not dramatic in the way a stimulant would be — it’s more that training feels better, energy is consistent through the day, and body composition maintenance at low body fat percentages just holds up better than it might otherwise. These compounds are doing their job under the hood.

Before this stack I ran SLU-PP-332 with GW-501516 and SR-9011. Different mechanism combination, similar overall experience — improved training output, better energy, and body composition that stays lean under sustained load. I switched to the 5-Amino-1MQ combination to try the NNMT inhibition angle specifically. Both stacks work. Both are subtle in how they present.

My body fat is already low. These compounds aren’t doing dramatic transformation work — they’re helping maintain that alongside training, nutrition, and sleep. That’s exactly how they should be used. A man who thinks any of these will produce elite body composition without the foundation doing the real work is going to be disappointed.

MT-2 I haven’t run personally. Melanotan is on my radar and the research is interesting, but I haven’t validated it from my own experience. The reports from people who do run it are consistent with what the mechanism suggests — real effects, real intensity, real need for careful dose management. Worth investigating if the applications are relevant to your goals, with appropriate research and provider involvement first.

The Bottom Line

The performance and body composition compounds in this article represent the cutting edge of what serious optimization looks like in practice. Some have stronger evidence bases than others. All require honest individual evaluation, conservative entry points, and provider involvement for the more complex compounds.

The thread running through all three peptide articles is the same: these are tools that amplify a solid foundation, not substitutes for one. The man running a cutting-edge metabolic stack on top of poor training, inconsistent nutrition, and bad sleep is wasting his time and his money. The man who has built the foundation and added these tools deliberately, with appropriate expectations and honest monitoring, has access to a level of optimization most men never consider.

→ Part 1 of this series: Article 18 — Peptides Part 1: Recovery, Repair, and the Foundation Stack

→ Part 2 of this series: Article 19 — Peptides Part 2: Longevity, Cellular Health, and the Khavinson Framework

→ MOTS-C full treatment: Article 19 — Peptides Part 2

→ Next: Article 21 — GLPs: The Most Misunderstood Weight Loss Tool