The Peptide Playbook

Chapter 1: The Peptide Landscape

Peptides are short chains of amino acids — typically between 2 and 50 — linked together by peptide bonds. If proteins are full sentences, peptides are individual words. Smaller, more specific, and each with a particular job to do.

Your body produces roughly 7,000 different peptides naturally. They act as signaling molecules — tiny chemical messengers that tell specific cells what to do. When you cut your finger, peptides signal cells to start repairing tissue. When you fall asleep, peptides trigger growth hormone release. When your immune system detects an invader, peptides coordinate the response.

The key distinction: peptides don't force a response — they amplify signals your body already uses. They're not foreign chemicals being introduced into your system. They're more like turning up the volume on a conversation your cells are already having.

Why the Information Is So Bad

Here's the problem: the peptide space sits at the intersection of real medical research, biohacker experimentation, and unregulated commerce. That creates an information environment where a legitimate study on BPC-157's effect on tendon healing gets cited alongside a Reddit post about someone injecting research chemicals from an unverified overseas supplier.

The noise-to-signal ratio is terrible. Influencers sell their own peptide lines. Forums treat anecdotes as evidence. Clinics charge premium prices for protocols with minimal clinical backing. And most people have no framework for separating what's real from what's marketing.

This playbook exists to fix that. Every compound in here is rated by evidence tier, backed by published research where it exists, and paired with honest assessments of what we know, what we don't, and what the risks are.

The Regulatory Landscape in 2026

The regulatory situation changed significantly in early 2026. In late 2023, the FDA moved 19 popular peptides to its Category 2 list, effectively banning compounding pharmacies from preparing them. In February 2026, HHS Secretary Robert F. Kennedy Jr. announced that roughly 14 of those peptides would be reclassified back to Category 1 — restoring legal access through licensed compounding pharmacies with a valid prescription.

This is important context. The reclassification doesn't mean these peptides are FDA-approved drugs. It means a doctor can legally prescribe them and a compounding pharmacy can legally prepare them. The evidence quality varies enormously from compound to compound.

How to Use This Playbook

This guide is structured around goals, not compounds. Start with what you're trying to achieve — fat loss, recovery, sleep, cognition, longevity — and find the relevant chapter. Each goal chapter gives you:

1. The compounds that are actually studied for that purpose
2. Evidence tiers so you know how strong the research is
3. Practical protocols with dosing, timing, and cycling
4. Side effect profiles and monitoring requirements
5. Clear stop criteria — when to discontinue and seek medical guidance

Chapter 2: Evidence Tiers Explained

Not all peptides are created equal. Some have decades of human clinical data. Others have promising animal studies and not much else. Treating them all the same is how people get hurt.

Every compound in this playbook is assigned an evidence tier based on the quality and quantity of published research. Here's how the system works:

Tier 1: Strong Human Evidence

Multiple randomized controlled trials (RCTs) in humans. FDA-approved or in late-stage clinical trials. Clear dose-response data. Well-characterized side effect profiles. Examples: semaglutide, tirzepatide, tesamorelin.

Tier 2: Moderate Human Evidence

At least one human clinical trial, though not necessarily a large RCT. Consistent results across multiple studies. Mechanism of action well understood. Side effects documented but long-term data limited. Examples: CJC-1295, ipamorelin, GHK-Cu (topical).

Tier 3: Animal Evidence + Human Case Reports

Extensive animal studies showing consistent effects. Limited human data, mostly case reports or observational studies. Mechanism of action plausible. Safety profile extrapolated from animal data and clinical observation. Examples: BPC-157, TB-500, DSIP.

Tier 4: Preclinical / Experimental

In vitro studies or early animal research only. Mechanism theoretically sound but unproven in humans. No established dosing protocols. Safety profile largely unknown. Examples: Epithalon, MOTS-c, SS-31.

Chapter 3: Goal — Fat Loss

Fat loss is the most popular entry point into peptides, largely driven by the GLP-1 medication revolution. But GLP-1 agonists are just one category. Growth hormone secretagogues and metabolic peptides offer different mechanisms and different risk profiles.

GLP-1 Receptor Agonists

Semaglutide (Ozempic / Wegovy) — Tier 1

Semaglutide is the most well-studied peptide for fat loss, period. The STEP clinical trial program demonstrated average weight loss of 15-17% of body weight over 68 weeks. It works through multiple mechanisms: reducing appetite via hypothalamic signaling, slowing gastric emptying, and improving insulin sensitivity.

Tirzepatide (Mounjaro / Zepbound) — Tier 1

Tirzepatide is a dual GIP/GLP-1 receptor agonist. The SURMOUNT trials showed average weight loss of 20-26% of body weight — significantly more than semaglutide. The dual mechanism appears to provide stronger appetite suppression with potentially better preservation of lean mass.

Growth Hormone Secretagogues for Fat Loss

CJC-1295 + Ipamorelin — Tier 2

This combination is the most widely prescribed GH secretagogue stack. CJC-1295 (with DAC) is a growth hormone releasing hormone (GHRH) analog that extends GH release duration. Ipamorelin is a selective growth hormone secretagogue that stimulates pulsatile GH release without significantly raising cortisol or prolactin.

Together, they amplify your natural growth hormone pulses rather than providing a constant exogenous supply. The fat loss mechanism is indirect: elevated GH promotes lipolysis (fat breakdown), improves body composition over time, and supports recovery from training.

5-Amino-1MQ — Tier 3

5-Amino-1MQ is a selective inhibitor of nicotinamide N-methyltransferase (NNMT). It is actually a small molecule, not a peptide, but is commonly grouped with peptides in this space. Animal studies show 30-40% reductions in fat cell size without changes in caloric intake by increasing NAD+ levels and shifting cellular metabolism toward fat oxidation. However, human clinical data remains very limited. Commonly discussed research dosages range from 50-150 mg/day orally.

Chapter 4: Goal — Recovery & Healing

This is the category that put peptides on the map in fitness communities. The “Wolverine Stack” (BPC-157 + TB-500) became the most searched peptide protocol online in 2025-2026, driven by anecdotal reports of dramatically accelerated healing from injuries that normally take months to resolve.

Before diving into specific compounds, understand how recovery works at the biological level. Healing follows a three-phase cascade: inflammation (hours 0-72), proliferation (days 3-21), and remodeling (weeks to months). Recovery is rate-limited by blood flow, signaling, and raw materials. Peptides theoretically intervene in the signaling layer — amplifying the messages that coordinate this entire cascade.

BPC-157 (Body Protection Compound) — Tier 3

BPC-157 is a 15-amino-acid sequence derived from human gastric juice. It has an extensive body of animal research — hundreds of studies showing effects on tendon, ligament, muscle, gut, and nerve tissue healing. A 2025 systematic review in orthopaedic sports medicine confirmed consistent positive outcomes in preclinical models.

The caveat: no completed human randomized controlled trials as of March 2026. The evidence is strong for what it is (consistent animal data + clinical observation), but it remains Tier 3 because we lack the controlled human data that would elevate it.

TB-500 (Thymosin Beta-4 Fragment) — Tier 3

TB-500 is a synthetic fragment of thymosin beta-4, a naturally occurring protein involved in wound healing and tissue repair. Research has demonstrated it promotes cell migration, angiogenesis (new blood vessel formation), and reduces inflammation. It works on a systemic level, unlike BPC-157 which may have more localized effects.

The Wolverine Stack: BPC-157 + TB-500

The combination of BPC-157 and TB-500 is the most popular peptide stack in the recovery space. The rationale: BPC-157 works more locally on tissue repair signaling, while TB-500 works systemically on cell migration, inflammation reduction, and angiogenesis. Together, they theoretically address recovery from multiple angles.

GHK-Cu (Copper Peptide) — Tier 3

GHK-Cu is a naturally occurring tripeptide with strong affinity for copper ions. Research shows it promotes collagen synthesis, wound healing, and has anti-inflammatory properties. Unlike most peptides in this guide, GHK-Cu has significant topical evidence — it's been studied for skin healing, scar reduction, and hair growth in human trials when applied topically.

Injectable GHK-Cu has less human data but is commonly used in regenerative medicine protocols. Typical injectable dosing ranges from 1-3 mg daily, subcutaneously, in 4-6 week cycles.

Chapter 5: Goal — Sleep & Cognition

Sleep peptides and nootropic peptides are a smaller but growing category. The appeal is straightforward: better sleep quality directly impacts recovery, hormone production, and cognitive function. And for men over 35 dealing with the dual pressures of demanding careers and declining sleep architecture, these compounds are getting serious attention.

DSIP (Delta Sleep-Inducing Peptide) — Tier 3

DSIP is a naturally occurring neuropeptide discovered in 1977. It was identified from cerebral venous blood during induced sleep in rabbits, and subsequent research showed it promotes delta wave (deep) sleep — the restorative sleep phase where growth hormone is primarily released.

Human studies from the 1980s and 1990s showed improvements in sleep onset latency and subjective sleep quality in insomniacs. The research is dated but consistent. Typical dosing is 100-300 mcg subcutaneous or intranasal, 30-60 minutes before bed.

Selank — Tier 3

Selank is a synthetic peptide analog of the naturally occurring immunomodulatory peptide tuftsin. It was developed in Russia and has been approved there as an anxiolytic since 2009. Research shows it modulates GABA, serotonin, and dopamine systems without the sedation, dependence, or withdrawal associated with benzodiazepines.

Beyond anxiety reduction, Selank has shown cognitive-enhancing effects: improved memory consolidation, increased BDNF (brain-derived neurotrophic factor) expression, and enhanced focus under stress. Typical dosing is 250-500 mcg intranasal, 1-2x daily.

Semax — Tier 2

Semax is a synthetic peptide derived from ACTH (adrenocorticotropic hormone) fragments 4-10. Also developed in Russia, it has been studied more extensively than Selank, with multiple human trials for cognitive enhancement, stroke recovery, and neuroprotection.

Semax increases BDNF expression, enhances dopaminergic and serotonergic activity, and shows neuroprotective effects. It is administered intranasally at 200-600 mcg, 1-2x daily. Cycles of 10-20 days are typical, with equal time off between cycles.

Chapter 6: Goal — Anti-Aging & Longevity

The longevity peptide category is the most speculative in this playbook. The compounds here have fascinating mechanisms and intriguing preclinical data, but the least human evidence. If you're considering these, go in with eyes open about what we know and what we don't.

Epithalon (Epitalon) — Tier 4

Epithalon is a synthetic tetrapeptide (Ala-Glu-Asp-Gly) studied primarily by Russian researcher Vladimir Khavinson. His work showed that epithalon activates telomerase in human somatic cells, potentially lengthening telomeres — the protective caps on chromosomes that shorten with age. Animal studies in mice and rats showed increased lifespan.

The caveat: telomere biology is far more complex than “longer is better.” Cancer cells also activate telomerase. The long-term implications of artificially stimulating telomerase are not well understood. No randomized controlled trials in humans exist for longevity endpoints.

Common protocol: 5-10 mg subcutaneous, daily for 10-20 days, repeated every 4-6 months.

MOTS-c — Tier 4

MOTS-c is a mitochondrial-derived peptide that was shown to promote metabolic homeostasis and reduce obesity and insulin resistance in mouse studies (published in Cell Metabolism, 2015). It activates AMPK, the cellular energy sensor, and mimics some of the metabolic benefits of exercise.

The research is genuinely exciting at the preclinical level. But we are still far from having human dosing, safety, or efficacy data. This is a “watch this space” compound, not a “start taking this tomorrow” compound.

SS-31 (Elamipretide) — Tier 4

SS-31 is a mitochondria-targeted peptide that concentrates 1000-5000x in the inner mitochondrial membrane. Research by Dr. Hazel Szeto showed it restores mitochondrial bioenergetics and protects against oxidative stress. It has been in clinical trials for mitochondrial diseases (Barth syndrome) and showed some promise, but broader longevity applications remain theoretical.

Chapter 7: Sourcing & Safety

The most important chapter in this playbook. A compound that is 95% pure and properly stored is a completely different product from one that is 60% pure, contaminated with endotoxins, and left unrefrigerated for weeks. The sourcing decision is the single biggest variable in your safety equation.

The Three Sourcing Tiers

Tier A: Licensed Compounding Pharmacies (Recommended)

The safest option. Compounding pharmacies in the U.S. are regulated by state boards of pharmacy and (for 503B outsourcing facilities) by the FDA. They are required to follow current Good Manufacturing Practices (cGMP), test for potency and sterility, and operate under pharmacist oversight. You need a prescription from a licensed physician.

Tier B: Regulated International Pharmacies

Some peptides are available through regulated pharmacies in countries with robust pharmaceutical oversight (e.g., licensed pharmacies in Australia, EU member states). Quality can be high, but legal import status varies by jurisdiction. Research the laws for your location.

Tier C: Research Chemical Vendors

The gray market. These vendors sell peptides labeled “for research purposes only” or “not for human consumption.” Quality varies enormously — from legitimate suppliers with third-party testing to outright fraudulent operations selling mislabeled or contaminated products.

Storage and Reconstitution

Peptides are fragile molecules. Improper storage is one of the most common ways people waste money and introduce safety risks.

Injection Safety

Most peptides are administered via subcutaneous injection — a shallow injection into the fat layer just beneath the skin. This is the same technique used for insulin. Use 29-31 gauge insulin syringes. Rotate injection sites (abdomen, thigh, upper arm). Clean the site with an alcohol swab and let it dry completely before injecting.

Chapter 8: Blood Work & Monitoring

You would not drive a car without a dashboard. Do not use peptides without blood work. Monitoring is how you know whether a protocol is working, whether it's causing harm, and when to adjust.

Baseline Panel (Before Starting Any Peptide)

Get this panel drawn before you start any peptide protocol. These are your reference values. Without a baseline, you cannot know what changed and whether it was the peptide or something else.

GH Secretagogue Monitoring (CJC-1295, Ipamorelin, MK-677)

GLP-1 Agonist Monitoring (Semaglutide, Tirzepatide)

Recovery Peptide Monitoring (BPC-157, TB-500)

Stop Criteria: When to Discontinue

These are non-negotiable. If you experience any of the following, stop the peptide and contact your healthcare provider:

1. Persistent nausea or vomiting that does not improve within 48 hours of dose adjustment
2. Signs of pancreatitis: severe upper abdominal pain radiating to the back
3. Liver enzyme elevation — ALT or AST more than 3x upper limit of normal
4. New or unusual headaches that are persistent or severe
5. Visual changes — any change in vision warrants immediate evaluation
6. Signs of injection site infection: spreading redness, warmth, fever
7. Allergic reaction: hives, swelling, difficulty breathing (seek emergency care)
8. Unexplained fatigue or malaise that worsens over several days

Chapter 9: Stacking & Cycling

Stacking means using multiple peptides simultaneously. Cycling means using them for defined periods with breaks in between. Both concepts are borrowed from performance-enhancing drug culture, but they apply to peptides for practical pharmacological reasons.

Why Cycling Matters

Receptor desensitization is real. When you continuously stimulate the same receptor pathway, your body downregulates those receptors to maintain homeostasis. The result: diminishing returns over time. Cycling — running a peptide for a defined period, then taking time off — allows receptor sensitivity to recover.

Common Stacks by Goal

Recovery Stack

Body Composition Stack

Cognitive Enhancement Stack

Combinations to Avoid

Chapter 10: Quick Reference Cards

Print these pages or save them to your phone. Each card summarizes a single peptide with everything you need at a glance: evidence tier, typical dosing, administration route, cycling protocol, what to monitor, and realistic expectations.

Chapter 11: What's Next

Peptides are a powerful tool, but they are not a foundation. They are the last 5-10% of optimization, layered on top of nutrition, sleep, training, and stress management. If those foundations are not solid, no peptide will compensate.

Here's where to go from here, depending on where you are in your health journey:

If Your Metabolic Health Needs Work

Start with The Metabolic Reset ($7) — our 4-week protocol to stabilize blood sugar, fix insulin resistance, and start losing fat. This is the single most impactful thing you can do before adding any peptide to your regimen. GLP-1 medications work better when metabolic foundations are in place.

If You Don't Understand Your Lab Results

The Blood Work Decoder ($15) gives you optimal ranges (not just “normal”) for every marker your doctor runs. Since blood work is mandatory for safe peptide use, this guide helps you interpret results, understand what each marker means, and know exactly what to do when something is out of range.

If Your Recovery Is the Bottleneck

Before reaching for BPC-157 or TB-500, make sure your recovery foundations are solid. The Recovery Protocol ($27) covers sleep architecture, cortisol management, active recovery protocols, deload programming, and the supplement stack that moves the needle. Fix these first — then add peptides if you still need more.

If You Want the Full System

The Complete Bundle ($59) includes all four guides plus a 90-day integration plan that layers them together in the right order. Month 1 is metabolic foundation. Month 2 adds recovery and nutrition. Month 3 brings in lab work interpretation. Peptides layer on top of all of it.

Free Resources on slimstudio.com

We publish evidence-based articles on peptides, metabolic health, training, and recovery at slimstudio.com/articles. Key reads:

• What Are Peptides? — The beginner's guide that covers fundamentals
• Peptide Stacks: A Beginner's Guide — How to think about combining compounds
• Peptides for Recovery — Deep dive on BPC-157, TB-500, and the Wolverine Stack
• GLP-1 Week by Week — What to expect from semaglutide and tirzepatide
• How to Read Your TRT Labs — Lab interpretation for hormone therapy patients