Peptide Therapy Explained
Peptides are short chains of amino acids — the same building blocks your body already uses to signal hormones, repair tissue, and regulate metabolism. Peptide therapy uses precisely-defined sequences to nudge those pathways in a measurable, physician-supervised way. This guide covers what peptides are, how the major families work, what a real clinical protocol looks like, and how safety is governed.
Every protocol PeptidesQ dispenses is written by a licensed physician, filled by a U.S. compounding pharmacy, and monitored through structured intake and follow-up.
What is a peptide?
A peptide is a chain of typically 2–50 amino acids joined by amide bonds. Anything longer becomes a protein. Because peptides are the native language of endocrine and paracrine signaling, they act on specific receptors at low doses — insulin, oxytocin, glucagon, and growth hormone-releasing hormone are all peptides your body makes every day.
Therapeutic peptides are either identical to endogenous sequences or engineered analogues designed for longer half-life, better receptor selectivity, or oral or subcutaneous stability.
How peptide therapy works
- Receptor-level signaling. Peptides bind specific receptors and trigger downstream cascades — GH release, appetite modulation, tissue repair — rather than acting as blunt-force stimulants.
- Physiologic dosing. Doses are typically in the microgram-to-milligram range and cycled to mimic natural pulses.
- Route matters. Most therapeutic peptides are given subcutaneously; oral bioavailability is limited by digestive enzymes.
- Measurable readouts. Response is tracked with the biomarkers relevant to the protocol — IGF-1, HbA1c, hs-CRP, hormones — not vibes.
The major peptide families
Growth hormone axis
Secretagogues that prompt the pituitary to release your own growth hormone in a pulsatile, physiologic pattern — not synthetic HGH replacement.
- CJC-1295 / Ipamorelin. Body composition, recovery, and sleep quality in adults with age-related GH decline.
- Sermorelin. Gentler GHRH analogue often used as a first-line entry into the GH axis.
- Tesamorelin. Targeted reduction of visceral adipose tissue with the strongest clinical evidence in the family.
Metabolic and weight management
Peptides that modulate appetite, gastric emptying, and insulin sensitivity — the category most patients recognize from GLP-1 headlines.
- Semaglutide, tirzepatide. Physician-supervised medical weight loss for members who meet clinical criteria.
- AOD-9604. Lipolytic fragment used adjunctively in body-composition protocols.
- MOTS-c. Mitochondrial-derived peptide studied for metabolic flexibility and insulin sensitivity.
Healing, repair, and recovery
Peptides used to support soft-tissue repair, gut lining integrity, and post-injury recovery — commonly stacked around orthopedic or GI complaints.
- BPC-157. Body Protection Compound derived from gastric juice; used for tendon, ligament, and GI healing support.
- TB-500 (thymosin beta-4 fragment). Cell migration and angiogenesis support during injury recovery courses.
- GHK-Cu. Copper tripeptide used topically and by injection for skin, hair, and wound-repair programs.
Longevity and mitochondrial health
Protocols that target the drivers of biological aging — NAD+ status, mitochondrial output, inflammation, and cellular senescence.
- NAD+ and NAD+ Longevity. Restores the coenzyme central to mitochondrial energy production and DNA repair.
- Epithalon (Epitalon). Studied for telomere and pineal-axis support in longevity stacks.
- Glutathione, methylene blue. Redox and mitochondrial adjuncts commonly layered into longevity plans.
Cognitive and neuroprotective
Peptides and small molecules targeting neuroinflammation, synaptic plasticity, and neurotrophic signaling.
- Dihexa. Angiotensin IV analogue investigated for synaptogenesis and cognitive performance.
- Semax, Selank. Russian-origin neuropeptides studied for focus, mood, and stress resilience.
- DSIP. Delta sleep-inducing peptide used in sleep-architecture and recovery protocols.
Sexual health
Melanocortin-pathway peptides that act centrally rather than through the vascular route classical ED medications target.
- PT-141 (bremelanotide). Central pathway for arousal and desire in both men and women.
- Kisspeptin (research). Upstream regulator of the HPG axis explored for libido and fertility.
Immune modulation
Peptides that upregulate or normalize immune function — particularly relevant in post-viral and chronic-inflammatory workups.
- Thymosin alpha-1. T-cell maturation support with the deepest clinical literature in this family.
- KPV. Alpha-MSH tripeptide fragment studied for gut and systemic inflammation.
Skincare and topical
Cosmeceutical peptides used topically for barrier repair, collagen support, and pigmentation.
- GHK-Cu, Matrixyl, palmitoyl peptides. Included in dermatologist-formulated topicals for collagen and elastin support.
- Melanotan II (medical use only). Melanocortin agonist studied under supervision for photoprotection and specific dermatologic conditions.
Is peptide therapy safe?
Peptide therapy is safe when the protocol is written by a physician who has reviewed your medical history, baseline labs, and current medications, and when the compound is sourced from a licensed U.S. compounding pharmacy. It is not safe when unregulated "research chemicals" are self-administered from grey-market vendors.
Common categorical contraindications include active or recent cancer for GH-axis peptides, severe liver or kidney disease for many injectables, active bleeding disorders for tissue-repair peptides, and pregnancy or breastfeeding across most protocols. Every PeptidesQ intake screens for these before a clinician approves therapy.
For the specific labs your reviewing physician orders, see the biomarker testing guide.
What does a real protocol look like?
- Application and intake. You complete a protocol-specific clinical intake covering history, medications, prior labs, and goals.
- Physician review. A licensed clinician reviews your chart, requests any missing labs, and writes or declines the prescription.
- Compounded and shipped. A U.S. compounding pharmacy fills the order and ships supplies plus injection instructions.
- Follow-up and titration. Response is reviewed at defined intervals and doses are adjusted — or paused — based on labs and how you feel.
Ready to explore a physician-designed protocol?
PeptidesQ membership covers clinical review, U.S. compounded supply, and biomarker-driven titration for every protocol.