Performance Medicine Peptide therapy
Peptide therapy in Philadelphia, explained by a physician.
29 peptides people ask about, from BPC-157 to semaglutide, plus 2 compounds often mistaken for them: what each one is and what people take it for, in plain language.
- 29 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 and what people take it for. Whether one is right for you is a question for a physician.
"Peptide" is a chemistry word: a short chain of amino acids. Insulin is a peptide. So are the GLP-1 medicines.
BPC-157
- What it is
- A synthetic peptide derived from a protein found in gastric juice.
- Taken for
- Tendon, ligament, joint and gut healing.
TB-500 Thymosin beta-4 fragment
- What it is
- A synthetic peptide based on a short region of thymosin beta-4, a naturally occurring protein involved in cell migration and repair.
- Taken for
- Injury healing and recovery.
GHK-Cu Copper tripeptide
- What it is
- A small copper-binding peptide found naturally in blood plasma, saliva and urine, with levels that fall with age. Best known from skin care.
- Taken for
- Skin, hair and wound healing.
LL-37
- What it is
- The human body's own antimicrobial peptide, part of the innate immune system.
- Taken for
- Infections, biofilms, inflammation.
CJC-1295
- What it is
- A modified version of growth-hormone-releasing hormone, built to last longer in the body.
- Taken for
- Body composition, recovery and sleep. Often paired with ipamorelin.
Ipamorelin
- What it is
- A growth hormone secretagogue: a peptide that acts on the ghrelin receptor to prompt the pituitary to release growth hormone.
- Taken for
- Lean mass, recovery, sleep and healthy aging.
Sermorelin
- What it is
- A fragment of growth-hormone-releasing hormone, once used to test growth hormone release and to treat growth hormone deficiency in children.
- Taken for
- Growth hormone support for body composition, recovery and aging.
Tesamorelin EGRIFTA
- What it is
- A lab-made version of growth-hormone-releasing hormone, the signal that tells the pituitary to release growth hormone.
- Taken for
- Visceral fat, body composition and aging.
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.
IGF-1 LR3
- What it is
- A modified version of insulin-like growth factor 1, changed so it binds less to the proteins that normally carry and restrain IGF-1.
- Taken for
- Muscle growth and recovery.
Semaglutide / Tirzepatide GLP-1 class
- What it is
- Peptide medicines modeled on gut hormones: semaglutide acts on the GLP-1 receptor, tirzepatide on both the GIP and GLP-1 receptors.
- Taken for
- Weight and blood sugar.
Retatrutide
- What it is
- A next-generation metabolic peptide that acts on three hormone receptors at once: GLP-1, GIP and glucagon. It is a different peptide from cagrilintide, which acts on the amylin receptor.
- Taken for
- Weight loss.
Cagrilintide
- What it is
- A long-acting, lab-made version of amylin, a hormone released alongside insulin after meals that helps signal fullness. It is a different peptide from retatrutide, and is studied mainly together with semaglutide.
- Taken for
- Weight loss, usually in combination with semaglutide.
AOD-9604
- What it is
- A modified fragment of human growth hormone, developed as a fat-loss drug.
- Taken for
- Fat loss without growth hormone's other effects.
MOTS-c
- What it is
- A peptide encoded in the mitochondrial genome, first described in 2015.
- Taken for
- Metabolism and exercise performance.
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.
DSIP Delta sleep-inducing peptide
- What it is
- A peptide first isolated in 1977 from the blood of rabbits, studied as a possible sleep signal.
- Taken for
- Deeper sleep, stress.
Dihexa
- What it is
- A small synthetic peptide derived from angiotensin IV, developed in a university laboratory.
- Taken for
- Memory and focus.
Epitalon Epithalon
- What it is
- A synthetic four-amino-acid peptide modeled on a pineal gland extract.
- Taken for
- Longevity, telomeres, sleep.
Glutathione
- What it is
- One of the body's main antioxidants, a tripeptide made in nearly every cell, especially the liver. Sold as capsules, injections and IV drips.
- Taken for
- Skin brightening, antioxidant support and energy.
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.
Humanin
- What it is
- A mitochondrial-derived peptide, studied for roles in cellular protection and aging.
- Taken for
- Longevity.
SS-31 / Elamipretide FORZINITY
- What it is
- A mitochondria-targeted peptide, first studied in the lab as SS-31. Under the name elamipretide it is used for Barth syndrome, a rare genetic disease.
- Taken for
- Mitochondrial health and aging.
PT-141 Bremelanotide
- What it is
- A melanocortin receptor agonist, developed as a medicine for low sexual desire in premenopausal women.
- Taken for
- Libido and arousal, in both sexes.
Melanotan II
- What it is
- A synthetic analog of alpha-MSH, the hormone that signals skin pigment cells.
- Taken for
- Tanning without sun, libido.
Kisspeptin
- What it is
- A natural hormone that switches on the reproductive axis.
- Taken for
- Testosterone, fertility, desire.
Gonadorelin / HCG
- What it is
- Gonadorelin is a synthetic copy of GnRH, the brain signal that starts the reproductive hormone chain. HCG is a pregnancy hormone that acts like LH on the testes. Both are used alongside testosterone therapy.
- Taken for
- Keeping natural testosterone and fertility going during testosterone therapy.
Thymosin alpha-1 Zadaxin
- What it is
- An immune-modulating peptide first isolated from the thymus gland.
- Taken for
- Immune support and resilience.
KPV
- What it is
- A three-amino-acid fragment of alpha-MSH, a natural hormone involved in inflammation and pigmentation.
- Taken for
- Gut healing and skin inflammation.
MK-677 Ibutamoren
- What it is
- Not a peptide: an oral small molecule that mimics ghrelin and raises growth hormone.
- Taken for
- Muscle, sleep 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.
Something else
Bring the name and where it came from. It is a good conversation to have with a physician.
Updated October 2026.
"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
- Where does it come from? Purity, sterility and identity can vary from one source to the next.
- What else could explain it? Fatigue, slow recovery and weight change often have causes worth finding first.
- How will you know it is working? Agree on a measurable target and a review date first.
The peptide series
Read Dr. Christian on peptides, in order.
Five articles, about twenty-five minutes. What peptides are, why self-sourcing goes wrong, peptide by peptide, what changed this year, and how peptide medicine is practiced here.
Questions
What people ask about peptides
Are peptides the same as supplements?
No. Supplements provide raw materials: vitamins, minerals, amino acids. Peptides are signaling molecules: short chains of amino acids that act on pathways already in the body. Sleep, nutrition, inflammation and hormones all shape how those signals are received.
What does "research use only" mean on a peptide sold online?
That the product is not made or labeled for use in people, so its purity, sterility and dose have not been checked for that use.
What is BPC-157?
A synthetic peptide derived from a protein found in gastric juice, and one of the peptides people ask about most. More on BPC-157.
Which peptides do people ask about most?
BPC-157, TB-500, CJC-1295 and ipamorelin, sermorelin, tesamorelin, GHK-Cu, and the GLP-1 medicines semaglutide and tirzepatide. Each has its own page in the library above.
Why do peptides need monitoring?
Because peptides act on growth, immune and metabolic pathways. Baseline labs and follow-up give a physician a way to see how your body is responding.
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.