Performance Medicine Peptide therapy
Peptide therapy in Philadelphia, explained by a physician.
30 peptides people ask about, from BPC-157 to semaglutide: what each one is, what people take it for, and what the research actually shows. No hype, no stacks.
- 30 peptides, in plain language
- A five-part series by Dr. Asare Christian
- King of Prussia · video across Pennsylvania
Peptide library
Which one are you curious about?
Healing and recovery
Growth hormone
Weight and metabolism
Brain, mood and sleep
Skin and longevity
Hormones and sexual health
Immune
Often grouped with peptides
Tap a peptide to see what it is, what people take it for, and how far the research has come. Then find out whether it is right for you: that part takes a physician.
"Peptide" is a chemistry word, not an evidence category. Insulin is a peptide. So are the GLP-1 medicines. So is a vial sold online as "research use only".
BPC-157
- What it is
- A synthetic peptide derived from a protein found in gastric juice.
- Taken for
- Tendon, ligament, joint and gut healing. On social media, a near-miracle.
- Research
- Interesting effects on tissue repair in animal and cell models. Only a handful of very small human studies; no large controlled human trials.
TB-500 Thymosin beta-4
- What it is
- The active fragment of thymosin beta-4, a naturally occurring protein involved in cell migration and repair.
- Taken for
- Injury healing and recovery.
- Research
- Promotes cell migration, new blood vessels and tissue repair in animal and cell models. No completed controlled human trials. Detected in athlete samples, which says how widely it circulates.
GHK-Cu Copper tripeptide
- What it is
- A naturally occurring copper-binding tripeptide, best known from skin care.
- Taken for
- Skin, hair and wound healing; increasingly sold injectable.
- Research
- Laboratory research plus small human studies on skin appearance and wound repair, almost all topical. The injectable evidence is much thinner.
LL-37
- What it is
- The human body's own antimicrobial peptide, part of the innate immune system.
- Taken for
- Infections, biofilms, inflammation.
- Research
- Well studied in the laboratory as an antimicrobial and immune signal. Also implicated in driving inflammation in conditions such as psoriasis. No human trials of injecting it.
CJC-1295
- What it is
- A modified growth-hormone-releasing hormone analog, usually paired with ipamorelin.
- Taken for
- A "growth hormone alternative": body composition, recovery, sleep.
- Research
- Placebo-controlled dose studies in healthy adults show sustained rises in growth hormone and IGF-1 for days after injection. Whether that improves body composition, healing or aging, and whether long-term use is safe for that purpose, has not been shown.
Ipamorelin
- What it is
- A selective growth-hormone secretagogue: it prompts the pituitary to release growth hormone with less effect on cortisol and hunger than older releasers.
- Taken for
- Lean mass, recovery, sleep, "anti-aging".
- Research
- Raises growth hormone in humans. Developed as a medicine for post-surgical bowel recovery; that trial program did not succeed. No outcome trials for the fitness uses it is sold for.
Sermorelin
- What it is
- A fragment of growth-hormone-releasing hormone, used in the 1990s to diagnose growth hormone deficiency in children.
- Taken for
- Growth hormone support for body composition, recovery and aging.
- Research
- Increases the body's own growth hormone release. Little evidence that treatment improves body composition, recovery or aging measures in adults. Generally regarded as well tolerated in the published literature.
Tesamorelin EGRIFTA
- What it is
- A growth-hormone-releasing hormone analog, available as a prescription medicine.
- Taken for
- Visceral fat, body recomposition, anti-aging.
- Research
- In randomized trials of adults with HIV-associated abdominal fat, 15 to 20 percent less visceral fat over 6 to 12 months. That is the population it was studied in; it is heavily marketed well beyond it.
GHRP-2 / GHRP-6 / Hexarelin
- What it is
- Older growth-hormone-releasing peptides that act on the ghrelin receptor.
- Taken for
- Growth hormone, muscle, appetite.
- Research
- Reliably raise growth hormone in humans, and raise hunger and cortisol along with it. Used as diagnostic tools; no outcome trials for body composition or aging.
IGF-1 LR3
- What it is
- A modified, longer-acting version of insulin-like growth factor 1.
- Taken for
- Muscle growth and recovery.
- Research
- Animal and cell research. No human trials of the modified form; IGF-1 itself can lower blood sugar and is tied to growth pathways that matter for cancer risk.
Semaglutide / Tirzepatide GLP-1 class
- What it is
- Peptide medicines that act on gut-hormone receptors. The best-known peptides most people have never thought of as peptides.
- Taken for
- Weight and blood sugar.
- Research
- Large randomized trials for weight management and blood sugar; newer dual agonists in phase 3 trials with deeper weight loss and resolution of fatty liver. Well-known gastrointestinal side effects; long-term data still accumulating.
Retatrutide / Cagrilintide
- What it is
- Next-generation metabolic peptides: a triple gut-hormone agonist and an amylin analog, both still in trials.
- Taken for
- Deeper weight loss than current medicines.
- Research
- Phase 2 results with large weight loss; phase 3 trials under way. Not yet licensed anywhere, which is why anything sold under these names online is not the trial product.
AOD-9604
- What it is
- A fragment of human growth hormone, developed as a fat-loss drug.
- Taken for
- Fat loss without growth hormone's other effects.
- Research
- Human trials for obesity in the 2000s did not show meaningful weight loss and development was stopped. Now sold for the same purpose anyway.
MOTS-c
- What it is
- A peptide encoded in the mitochondrial genome, discovered in 2015.
- Taken for
- Metabolism, exercise performance, "exercise in a vial".
- Research
- Real metabolic effects in mice and correlations with exercise and metabolic states in people. No completed interventional trials of taking it.
Semax / Selank
- What it is
- Two Russian-developed peptides: Semax is an ACTH fragment analog, Selank a tuftsin analog. Usually taken as nasal sprays.
- Taken for
- Focus, memory, anxiety.
- Research
- Decades of clinical use in Russia and small studies there; very little controlled research elsewhere. Pharmacology is plausible; outcomes in Western trials are untested.
DSIP Delta sleep-inducing peptide
- What it is
- A peptide isolated in the 1970s from the brains of sleeping rabbits.
- Taken for
- Deeper sleep, stress.
- Research
- Small human studies from the 1970s and 80s with mixed results, and little modern work. Whether it induces sleep in people at all remains unsettled.
Dihexa
- What it is
- A small synthetic peptide derived from angiotensin IV, developed in a university laboratory.
- Taken for
- Cognition, "nootropic" effects.
- Research
- Improved memory tasks in rats. No human trials of any kind, and its growth-factor mechanism raises safety questions nobody has studied.
Epitalon Epithalon
- What it is
- A synthetic four-amino-acid peptide modeled on a pineal gland extract.
- Taken for
- Longevity, telomeres, sleep.
- Research
- Telomerase activity in cell studies and small Russian studies in older adults from the 1990s and 2000s. No modern controlled trials.
Glutathione
- What it is
- The body's main antioxidant, a tripeptide the liver makes. Sold as capsules, injections and IV drips.
- Taken for
- Skin brightening, "detox", energy.
- Research
- Oral glutathione is poorly absorbed; intravenous use has specific medical roles. Evidence for the wellness and skin uses is small and inconsistent.
Collagen peptides
- What it is
- Hydrolyzed collagen: a protein broken into short chains for absorption. A supplement, not a signaling peptide.
- Taken for
- Skin, joints, hair, nails.
- Research
- Several small randomized trials show modest improvements in skin hydration and joint comfort over months. Mechanism and durability still debated.
Humanin
- What it is
- A mitochondrial-derived peptide, studied for roles in cellular protection and aging.
- Taken for
- Longevity.
- Research
- Circulating levels differ across age groups and health conditions. No human trials of taking it.
SS-31 / Elamipretide FORZINITY
- What it is
- A mitochondria-targeted peptide that circulated for years in longevity communities as SS-31, now a prescription medicine for Barth syndrome.
- Taken for
- Mitochondrial health and anti-aging.
- Research
- Years of human trials in Barth syndrome, an ultra-rare genetic mitochondrial disease. For longevity and general use, unproven. The "SS-31" sold online is not the medicine.
PT-141 Bremelanotide
- What it is
- A melanocortin receptor agonist, available as a prescription medicine for low sexual desire in premenopausal women.
- Taken for
- Libido and arousal, in both sexes.
- Research
- Randomized trials in the population it was licensed for, with modest effects and frequent nausea. Much less data in men.
Melanotan II
- What it is
- A synthetic analog of the pigment hormone alpha-MSH, never developed into a medicine.
- Taken for
- Tanning without sun, libido.
- Research
- Small early human studies, then development stopped. Case reports link it to new and changing moles; dermatologists advise against it.
Kisspeptin
- What it is
- A natural hormone that switches on the reproductive axis.
- Taken for
- Testosterone, fertility, desire.
- Research
- Human physiology studies and early trials in fertility and sexual function. Promising, specific, and far from a general-use product.
Gonadorelin / HCG
- What it is
- Gonadorelin is synthetic GnRH; HCG is a pregnancy hormone. Both are prescription medicines, often used alongside testosterone therapy.
- Taken for
- Keeping natural testosterone and fertility going during testosterone therapy.
- Research
- Well-studied physiology and established medical uses. Their role alongside testosterone therapy is practiced widely and still being refined in trials.
Thymosin alpha-1 Zadaxin
- What it is
- An immune-modulating peptide, available as a medicine in more than 35 countries.
- Taken for
- Immune support and resilience.
- Research
- Human trials for chronic hepatitis B and related liver and immune indications, plus work on immune response in older adults. Weak evidence for the wellness uses it is marketed for in the US.
KPV
- What it is
- A three-amino-acid fragment of alpha-MSH with anti-inflammatory properties.
- Taken for
- Gut healing and skin inflammation.
- Research
- Anti-inflammatory effects in cell and animal models, including models of inflammatory bowel disease. Essentially no published controlled human trials.
MK-677 Ibutamoren
- What it is
- Not a peptide: an oral small molecule that mimics ghrelin and raises growth hormone.
- Taken for
- Muscle, sleep, appetite, "oral growth hormone".
- Research
- Raises growth hormone and IGF-1 in humans. A trial in older adults with hip fracture was stopped early over heart-failure signals. Also raises blood sugar and appetite.
NAD+
- What it is
- Not a peptide: a coenzyme every cell uses for energy metabolism, sold as injections, IV drips and precursors like NMN and NR.
- Taken for
- Energy, longevity, recovery.
- Research
- Precursors raise blood NAD+ levels in humans; clinical outcomes in trials so far are modest and inconsistent. Direct NAD+ infusions have little controlled data.
Something else
The same three questions apply to any peptide: what is it, what has been shown in people, and what is actually in the vial. Bring the name and the source; it is a good conversation to have with a physician.
See the whole library at once
| Peptide | What it is | What the research shows | Stage |
|---|---|---|---|
| BPC-157 | A synthetic peptide derived from a protein found in gastric juice. | Interesting effects on tissue repair in animal and cell models. Only a handful of very small human studies; no large controlled human trials. | Animal and cell studies |
| TB-500 | The active fragment of thymosin beta-4, a naturally occurring protein involved in cell migration and repair. | Promotes cell migration, new blood vessels and tissue repair in animal and cell models. No completed controlled human trials. Detected in athlete samples, which says how widely it circulates. | Animal and cell studies |
| GHK-Cu | A naturally occurring copper-binding tripeptide, best known from skin care. | Laboratory research plus small human studies on skin appearance and wound repair, almost all topical. The injectable evidence is much thinner. | Small human studies, mostly topical |
| LL-37 | The human body's own antimicrobial peptide, part of the innate immune system. | Well studied in the laboratory as an antimicrobial and immune signal. Also implicated in driving inflammation in conditions such as psoriasis. No human trials of injecting it. | Animal and cell studies |
| CJC-1295 | A modified growth-hormone-releasing hormone analog, usually paired with ipamorelin. | Placebo-controlled dose studies in healthy adults show sustained rises in growth hormone and IGF-1 for days after injection. Whether that improves body composition, healing or aging, and whether long-term use is safe for that purpose, has not been shown. | Human data on hormone levels, not outcomes |
| Ipamorelin | A selective growth-hormone secretagogue: it prompts the pituitary to release growth hormone with less effect on cortisol and hunger than older releasers. | Raises growth hormone in humans. Developed as a medicine for post-surgical bowel recovery; that trial program did not succeed. No outcome trials for the fitness uses it is sold for. | Human data on hormone levels, not outcomes |
| Sermorelin | A fragment of growth-hormone-releasing hormone, used in the 1990s to diagnose growth hormone deficiency in children. | Increases the body's own growth hormone release. Little evidence that treatment improves body composition, recovery or aging measures in adults. Generally regarded as well tolerated in the published literature. | Human data on hormone levels, not outcomes |
| Tesamorelin | A growth-hormone-releasing hormone analog, available as a prescription medicine. | In randomized trials of adults with HIV-associated abdominal fat, 15 to 20 percent less visceral fat over 6 to 12 months. That is the population it was studied in; it is heavily marketed well beyond it. | Human trials, one condition |
| GHRP-2 / GHRP-6 / Hexarelin | Older growth-hormone-releasing peptides that act on the ghrelin receptor. | Reliably raise growth hormone in humans, and raise hunger and cortisol along with it. Used as diagnostic tools; no outcome trials for body composition or aging. | Human data on hormone levels, not outcomes |
| IGF-1 LR3 | A modified, longer-acting version of insulin-like growth factor 1. | Animal and cell research. No human trials of the modified form; IGF-1 itself can lower blood sugar and is tied to growth pathways that matter for cancer risk. | Animal and cell studies |
| Semaglutide / Tirzepatide | Peptide medicines that act on gut-hormone receptors. The best-known peptides most people have never thought of as peptides. | Large randomized trials for weight management and blood sugar; newer dual agonists in phase 3 trials with deeper weight loss and resolution of fatty liver. Well-known gastrointestinal side effects; long-term data still accumulating. | Large human trials |
| Retatrutide / Cagrilintide | Next-generation metabolic peptides: a triple gut-hormone agonist and an amylin analog, both still in trials. | Phase 2 results with large weight loss; phase 3 trials under way. Not yet licensed anywhere, which is why anything sold under these names online is not the trial product. | Late-stage human trials |
| AOD-9604 | A fragment of human growth hormone, developed as a fat-loss drug. | Human trials for obesity in the 2000s did not show meaningful weight loss and development was stopped. Now sold for the same purpose anyway. | Human trials, not successful |
| MOTS-c | A peptide encoded in the mitochondrial genome, discovered in 2015. | Real metabolic effects in mice and correlations with exercise and metabolic states in people. No completed interventional trials of taking it. | Early human research |
| Semax / Selank | Two Russian-developed peptides: Semax is an ACTH fragment analog, Selank a tuftsin analog. Usually taken as nasal sprays. | Decades of clinical use in Russia and small studies there; very little controlled research elsewhere. Pharmacology is plausible; outcomes in Western trials are untested. | Limited human research |
| DSIP | A peptide isolated in the 1970s from the brains of sleeping rabbits. | Small human studies from the 1970s and 80s with mixed results, and little modern work. Whether it induces sleep in people at all remains unsettled. | Older small human studies |
| Dihexa | A small synthetic peptide derived from angiotensin IV, developed in a university laboratory. | Improved memory tasks in rats. No human trials of any kind, and its growth-factor mechanism raises safety questions nobody has studied. | Animal studies only |
| Epitalon | A synthetic four-amino-acid peptide modeled on a pineal gland extract. | Telomerase activity in cell studies and small Russian studies in older adults from the 1990s and 2000s. No modern controlled trials. | Small human studies |
| Glutathione | The body's main antioxidant, a tripeptide the liver makes. Sold as capsules, injections and IV drips. | Oral glutathione is poorly absorbed; intravenous use has specific medical roles. Evidence for the wellness and skin uses is small and inconsistent. | Small human studies |
| Collagen peptides | Hydrolyzed collagen: a protein broken into short chains for absorption. A supplement, not a signaling peptide. | Several small randomized trials show modest improvements in skin hydration and joint comfort over months. Mechanism and durability still debated. | Small human trials |
| Humanin | A mitochondrial-derived peptide, studied for roles in cellular protection and aging. | Circulating levels differ across age groups and health conditions. No human trials of taking it. | Observational research |
| SS-31 / Elamipretide | A mitochondria-targeted peptide that circulated for years in longevity communities as SS-31, now a prescription medicine for Barth syndrome. | Years of human trials in Barth syndrome, an ultra-rare genetic mitochondrial disease. For longevity and general use, unproven. The "SS-31" sold online is not the medicine. | Human trials, one rare disease |
| PT-141 | A melanocortin receptor agonist, available as a prescription medicine for low sexual desire in premenopausal women. | Randomized trials in the population it was licensed for, with modest effects and frequent nausea. Much less data in men. | Human trials, one condition |
| Melanotan II | A synthetic analog of the pigment hormone alpha-MSH, never developed into a medicine. | Small early human studies, then development stopped. Case reports link it to new and changing moles; dermatologists advise against it. | Small human studies, abandoned |
| Kisspeptin | A natural hormone that switches on the reproductive axis. | Human physiology studies and early trials in fertility and sexual function. Promising, specific, and far from a general-use product. | Early human research |
| Gonadorelin / HCG | Gonadorelin is synthetic GnRH; HCG is a pregnancy hormone. Both are prescription medicines, often used alongside testosterone therapy. | Well-studied physiology and established medical uses. Their role alongside testosterone therapy is practiced widely and still being refined in trials. | Established medical uses |
| Thymosin alpha-1 | An immune-modulating peptide, available as a medicine in more than 35 countries. | Human trials for chronic hepatitis B and related liver and immune indications, plus work on immune response in older adults. Weak evidence for the wellness uses it is marketed for in the US. | Human trials, specific conditions |
| KPV | A three-amino-acid fragment of alpha-MSH with anti-inflammatory properties. | Anti-inflammatory effects in cell and animal models, including models of inflammatory bowel disease. Essentially no published controlled human trials. | Animal and cell studies |
| MK-677 | Not a peptide: an oral small molecule that mimics ghrelin and raises growth hormone. | Raises growth hormone and IGF-1 in humans. A trial in older adults with hip fracture was stopped early over heart-failure signals. Also raises blood sugar and appetite. | Human trials, safety concerns |
| NAD+ | Not a peptide: a coenzyme every cell uses for energy metabolism, sold as injections, IV drips and precursors like NMN and NR. | Precursors raise blood NAD+ levels in humans; clinical outcomes in trials so far are modest and inconsistent. Direct NAD+ infusions have little controlled data. | Small human trials |
Research moves, and so does this library.
"Peptides are not shortcuts. They are signals. Used without understanding, they can disrupt physiology and delay real progress. Used thoughtfully, within a physician-guided framework, they can support healing, adaptation, and long-term health."
Three questions worth asking about any peptide
- What is actually in the vial? Purity, sterility and even identity vary enormously outside licensed pharmacies.
- What has been shown in people? Mouse studies and biomarker changes are not the same as outcomes in humans like you.
- How will you know it is working? A measurable target and a review date, or it is marketing.
The peptide series
Read Dr. Christian on peptides, in order.
Five articles, about twenty-five minutes. What peptides are, why self-sourcing goes wrong, the evidence peptide by peptide, what changed this year, and how peptide medicine is practiced here.
- 1Peptide therapy: what the evidence actually shows, peptide by peptide
- 2Peptide medicine 2025 to 2026: new approvals, new trial evidence, and the same old hype
- 3Peptides, misinformation, and the risk of doing it yourself
- 4How precision signaling supports cellular health, recovery and longevity
- 5Peptide medicine in Philadelphia, PA
Questions
What people ask about peptides
Are peptides the same as supplements?
No. Supplements provide raw materials: vitamins, minerals, amino acids. Peptides instruct the body to do something; they turn pathways on or off and amplify signals that already exist. That is why they are powerful, and why the internal environment, sleep, nutrition, inflammation and hormones, shapes how a peptide signal is received.
What does "research use only" mean on a peptide sold online?
That it was never made or sold for human use, so nobody verified its purity, sterility, dose, or even that the vial contains what the label says. Contamination, incorrect sequences and degradation are well documented. The risk sits entirely with the buyer.
What is a compounded peptide?
A preparation made by a licensed pharmacy for an individual patient on a physician's prescription, rather than a mass-produced medicine. Which substances a pharmacy may compound is set by federal rules that change over time, which is one reason a physician checks before prescribing.
What is known about BPC-157?
A great deal in animals, very little in people. The animal and cell research on tissue repair is genuinely interesting; the human studies are tiny. More on BPC-157.
Can peptides help tendon or joint injuries?
It is a legitimate area of research, but the most talked-about healing peptides have almost no controlled human data. A physical medicine evaluation of the injury itself, Dr. Christian's specialty, is usually where the useful answers are.
Why do peptides need monitoring?
Because they change physiology. Molecules that stimulate growth, immune or metabolic pathways are biologically powerful, and without baseline labs and follow-up data an adverse effect may go unnoticed until it matters. Dose-sensitive, too: more is not better.
What does peptide therapy cost?
It varies by peptide, dose, sourcing and monitoring. Expected costs are reviewed with you after an evaluation, not quoted before it.
Can this be done by video?
Consultations by video for patients in Pennsylvania at the time of the visit, with labs drawn near you. Everyone else is seen in King of Prussia.
Curious about peptides? Start with a conversation.
Send a request and we confirm within one business day, or call 484-806-1101. Nothing on this page is medical advice.