List of Peptides and What They Do (2026 Guide)

Peptides are short chains of amino acids—typically between 2 and 50 amino acids linked together. Your body produces thousands of them naturally. They act as signaling molecules, telling cells what to do: build muscle, reduce inflammation, release growth hormone, burn fat. For a broad overview of how these compounds are used clinically, see our peptide therapy guide.

The therapeutic peptide market has exploded over the past decade. Some peptides are FDA-approved drugs with extensive clinical data. Others have strong animal research but no human trials. And some are marketed on hype alone.

This guide covers every major peptide used in clinical and wellness settings as of 2026. For each one, you’ll get: what it does, what the evidence actually shows, its FDA/regulatory status, and how it’s typically used. No fluff, no overselling.

Key Takeaways

• FDA-approved peptides (semaglutide, tirzepatide, tesamorelin) have the strongest evidence—randomized controlled trials with thousands of participants [1, 2]
• Research peptides (BPC-157, TB-500, CJC-1295) have promising animal data but limited or no human clinical trials [3]. Most require reconstitution before use
• The FDA restricted many popular peptides from compounding pharmacies in 2023–2024, placing them on the Category 2 bulk drug substance list [4]
• Evidence level matters. An FDA-approved drug with Phase III trials is in a different universe from a peptide tested only in rat models

Table of Contents

1. GLP-1 Receptor Agonists (Weight Loss)
2. Growth Hormone Secretagogues
3. Healing and Recovery Peptides
4. Anti-Aging and Longevity Peptides
5. Cognitive and Neuroprotective Peptides
6. Sexual Health Peptides
7. Immune-Modulating Peptides
8. How to Read This Guide
9. Side Effects and General Risks
10. FAQ
11. Sources

How to Read This Guide

For each peptide, we list:

• What it does — mechanism of action in plain English
• Evidence level — rated as:
  • ⭐⭐⭐ Strong = FDA-approved, Phase III human trials
  • ⭐⭐ Moderate = Human clinical data exists (Phase I/II or observational)
  • ⭐ Preliminary = Animal/in vitro data only, no published human trials
• FDA status — approved, compounding-restricted (Category 2), or investigational
• Typical use — common dosing context (not a prescription)

---

GLP-1 Receptor Agonists (Weight Loss)

GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after eating. It signals your brain to feel full, slows stomach emptying, and helps regulate blood sugar. Synthetic GLP-1 peptides mimic and amplify this effect.

This is the most well-studied category of therapeutic peptides, with multiple FDA-approved drugs and clinical trials involving tens of thousands of patients.

Semaglutide (Ozempic / Wegovy)

What it does: GLP-1 receptor agonist. Reduces appetite, slows gastric emptying, improves insulin sensitivity. Originally developed for type 2 diabetes, now widely prescribed for weight management.

Evidence level: ⭐⭐⭐ Strong

The STEP trials (Semaglutide Treatment Effect in People with Obesity) showed an average weight loss of 14.9% of body weight at 68 weeks with semaglutide 2.4 mg weekly, compared to 2.4% with placebo [1]. Real-world data from the SHAPE study confirms these results: patients lost an average of 14.1% body weight at one year [5].

FDA status: Approved. Ozempic (for diabetes, 2017), Wegovy (for weight management, 2021).

Typical use: Weekly subcutaneous injection. Starts at 0.25 mg/week, titrated up to 2.4 mg/week over 16–20 weeks.

Tirzepatide (Mounjaro / Zepbound)

What it does: Dual GIP/GLP-1 receptor agonist. Activates both the GLP-1 pathway and the GIP (glucose-dependent insulinotropic polypeptide) pathway, producing greater weight loss and glucose control than GLP-1 alone.

Evidence level: ⭐⭐⭐ Strong

A head-to-head trial published in the New England Journal of Medicine in 2025 found tirzepatide produced 20.2% body weight loss at 72 weeks versus 13.7% for semaglutide (P<0.001) [2]. The SURMOUNT trials showed up to 22.5% weight loss at the highest dose [6].

FDA status: Approved. Mounjaro (for diabetes, 2022), Zepbound (for weight management, 2023).

Typical use: Weekly subcutaneous injection. Starts at 2.5 mg/week, titrated to 5, 10, or 15 mg/week.

Retatrutide

What it does: Triple agonist—hits GLP-1, GIP, and glucagon receptors simultaneously. The glucagon component adds direct fat-burning effects that the other GLP-1s don’t have.

Evidence level: ⭐⭐ Moderate

Phase II trial data showed 24.2% mean body weight reduction at 48 weeks with the 12 mg dose—the largest weight loss ever recorded for any anti-obesity medication in clinical trials [7]. Phase III trials are ongoing.

FDA status: Investigational. Not yet approved. Expected FDA submission in 2026.

Typical use: Weekly subcutaneous injection in clinical trials. Dose-ranging from 1 mg to 12 mg.

Survodutide

What it does: Dual GLP-1/glucagon receptor agonist. Similar concept to retatrutide but without the GIP component. Shows particular promise for fatty liver disease (MASH/NAFLD).

Evidence level: ⭐⭐ Moderate

Phase II data showed up to 18.7% weight loss at 46 weeks and significant reductions in liver fat [8]. Phase III trials ongoing for both obesity and MASH.

FDA status: Investigational.

Typical use: Weekly injection in clinical trials.

---

Growth Hormone Secretagogues

These peptides stimulate your pituitary gland to produce and release more of your own growth hormone (GH). They don’t contain growth hormone—they signal your body to make more of it.

The appeal: increased GH supports muscle recovery, fat metabolism, sleep quality, and skin health. The trade-off: the regulatory environment is complicated, and most of these lack large human trials.

Sermorelin

What it does: Growth hormone-releasing hormone (GHRH) analog. Mimics the natural GHRH signal, prompting the pituitary to release GH in a pulsatile (natural) pattern.

Evidence level: ⭐⭐ Moderate

Sermorelin was FDA-approved in 1997 for the diagnosis and treatment of GH deficiency in children (brand name Geref). Clinical studies showed it increased IGF-1 levels and improved growth velocity in GH-deficient children [9]. It was voluntarily withdrawn from the market by the manufacturer for commercial reasons (not safety), and is now available through compounding pharmacies.

FDA status: Previously FDA-approved (withdrawn for commercial reasons). Currently compoundable under 503A regulations.

Typical use: 200–300 mcg subcutaneous injection before bed, 5 days on / 2 days off.

CJC-1295

What it does: Modified GHRH analog with a much longer half-life than sermorelin. The DAC (Drug Affinity Complex) version binds to albumin, extending the half-life to 6–8 days. The non-DAC version lasts about 30 minutes and is typically paired with ipamorelin.

Evidence level: ⭐⭐ Moderate

A study by Teichman et al. (2006) showed that CJC-1295 with DAC increased mean GH levels by 2–10 fold and IGF-1 levels by 1.5–3 fold after a single injection, with effects lasting 6–14 days [10]. These were dose-dependent increases in healthy adults aged 21–61.

FDA status: Category 2 (restricted from compounding as of 2023). The FDA is reviewing CJC-1295 for potential reclassification [4].

Typical use: CJC-1295 no DAC: 100–300 mcg combined with ipamorelin, injected before bed. CJC-1295 with DAC: 2 mg once or twice weekly.

Ipamorelin

What it does: Growth hormone secretagogue that works through the ghrelin receptor (GHS-R). Unlike GHRP-6 or GHRP-2, ipamorelin selectively stimulates GH release without significantly raising cortisol or prolactin [11].

Evidence level: ⭐⭐ Moderate

Clinical studies in post-surgical patients showed ipamorelin improved bowel recovery time and was well-tolerated. A Phase II trial for postoperative ileus demonstrated safety across multiple dosing levels [11]. It’s considered one of the “cleanest” GH secretagogues due to its selective action.

FDA status: Under PCAC review (as of October 2024) for potential inclusion on the 503A allowed list [4]. Currently in regulatory limbo.

Typical use: 100–300 mcg subcutaneous injection, often combined with CJC-1295, 1–3x daily (typically before bed). See our full CJC-1295 + ipamorelin stack guide for detailed protocols.

Tesamorelin (Egrifta)

What it does: GHRH analog specifically approved for reducing visceral fat (abdominal fat around organs) in HIV-positive patients with lipodystrophy.

Evidence level: ⭐⭐⭐ Strong

Two Phase III trials (LIPO-010 and LIPO-011) showed tesamorelin reduced trunk fat by approximately 15–18% compared to placebo over 26 weeks, while also increasing IGF-1 levels [12].

FDA status: FDA-approved (Egrifta, 2010) for HIV-associated lipodystrophy. Off-label use for anti-aging and body composition is common but not FDA-sanctioned.

Typical use: 2 mg subcutaneous injection daily.

GHRP-2 and GHRP-6

What they do: Growth hormone-releasing peptides that act on the ghrelin receptor. GHRP-6 strongly stimulates appetite. GHRP-2 is slightly more selective for GH release with less appetite stimulation.

Evidence level: ⭐⭐ Moderate

Human studies exist showing significant GH elevation. GHRP-6 can increase GH levels by 3–6 fold, but it also raises cortisol and prolactin more than ipamorelin [13]. GHRP-2 shows similar GH stimulation with a slightly cleaner side effect profile.

FDA status: Not approved. Category 2 (restricted from compounding).

Typical use: 100–300 mcg subcutaneous, 2–3x daily, often combined with a GHRH analog.

MK-677 (Ibutamoren)

What it does: Technically not a peptide—it’s a small molecule ghrelin receptor agonist. Taken orally (not injected). Increases GH and IGF-1 levels for up to 24 hours per dose.

Evidence level: ⭐⭐ Moderate

A 2-year study in 65 healthy older adults showed MK-677 increased IGF-1 levels to those of young adults and improved body composition, though it also raised fasting glucose and insulin [14]. A separate study showed it increased GH pulsatility without suppressing the body’s natural GH regulation.

FDA status: Under PCAC review (October 2024). Not currently FDA-approved. Available through some compounding pharmacies.

Typical use: 10–25 mg orally, once daily before bed. Often cycled (8 weeks on, 4 weeks off) to manage insulin sensitivity.

---

Healing and Recovery Peptides

These peptides target tissue repair, inflammation, and injury recovery. They’re among the most popular in sports medicine and longevity circles—and the most frustrating in terms of evidence, because most data comes from animal models.

BPC-157 (Body Protection Compound-157)

What it does: A 15-amino-acid peptide derived from a protein found in human gastric juice. In animal models, it promotes angiogenesis (new blood vessel formation) by activating the VEGFR2 receptor and the Akt-eNOS nitric oxide pathway [3]. It accelerates healing of tendons, ligaments, muscle, gut lining, and bone in rats and mice.

Evidence level: ⭐ Preliminary

A 2025 systematic review in the Orthopaedic Journal of Sports Medicine analyzed all available BPC-157 research and found zero completed human clinical trials [15]. All positive data comes from rodent studies. The results are impressive in animals—faster tendon healing, reduced inflammation, gut protection—but we simply don’t have human data yet.

That said, the anecdotal reports from human users are extensive and largely positive, particularly for tendon and joint injuries. The gap between animal data and human experience is unusually large here.

FDA status: Category 2 (restricted from compounding, classified as having “safety concerns”) [4]. No FDA approval. Several lawsuits are challenging this classification.

Typical use: 250–500 mcg subcutaneous, 1–2x daily, injected near the injury site. Also used orally for gut healing (some evidence that BPC-157 survives gastric acid given its origin in gastric juice). Often combined with TB-500 in the wolverine peptide stack.

TB-500 (Thymosin Beta-4 Fragment)

What it does: A fragment of thymosin beta-4, a naturally occurring 43-amino-acid peptide involved in cell migration, wound healing, and anti-inflammation. TB-500 promotes actin regulation, which is the protein that drives cell movement into wound sites [16].

Evidence level: ⭐ Preliminary

Like BPC-157, the evidence is almost entirely preclinical. Animal studies show accelerated healing of skin wounds, corneal injuries, and cardiac tissue. Thymosin beta-4 (the parent molecule) has been studied in human trials for corneal wound healing (RegeneRx Biopharmaceuticals), where it showed benefit [16]. TB-500 specifically has not undergone human clinical trials.

FDA status: Category 2 (restricted from compounding). Thymosin beta-4 remains under investigation by RegeneRx.

Typical use: Loading: 2–5 mg subcutaneous twice weekly for 4–6 weeks. Maintenance: 2 mg once weekly. Often combined with BPC-157 (the “Wolverine stack”).

GHK-Cu (Copper Peptide)

What it does: A tripeptide (glycyl-L-histidyl-L-lysine) bound to copper. Naturally present in human plasma, saliva, and urine. Promotes collagen synthesis, fibroblast activity, and wound healing. Also has anti-inflammatory and antioxidant properties [17].

Evidence level: ⭐⭐ Moderate

Human studies exist, primarily for topical skin applications. Studies show GHK-Cu stimulates collagen production, improves skin elasticity, and promotes wound closure. It’s one of the better-studied peptides in dermatology [17]. Injectable use has less clinical data.

FDA status: Category 1 (approved for compounding with certain limitations, as of September 2023) [4]. This makes it one of the few peptides that cleared the FDA’s safety review.

Typical use: Topical: serums and creams (0.1–1% concentration). Injectable: 1–2 mg subcutaneous daily. Often used for skin rejuvenation and hair growth.

---

Anti-Aging and Longevity Peptides

MOTS-c (Mitochondrial ORF of the 12S rRNA Type-C)

What it does: A mitochondria-derived peptide that regulates metabolic homeostasis. It activates AMPK (the cell’s energy sensor), improves insulin sensitivity, and enhances exercise capacity. Think of it as a metabolic tune-up at the cellular level [18].

Evidence level: ⭐ Preliminary

Published data is primarily from mouse models, where MOTS-c prevented age-related and diet-induced obesity, improved glucose metabolism, and enhanced physical performance [18]. Human clinical trials are not yet published, though several are reportedly underway.

FDA status: Not approved. Not currently on the Category 2 list, but regulatory status is evolving.

Typical use: 5–10 mg subcutaneous, 3–5x per week.

SS-31 (Elamipretide)

What it does: Targets the inner mitochondrial membrane, specifically binding to cardiolipin. This stabilizes electron transport chain function and reduces oxidative stress at the source [19].

Evidence level: ⭐⭐ Moderate

Elamipretide has been through multiple human clinical trials. It’s been tested in patients with mitochondrial myopathy (the MMPOWER trials), heart failure (the PROGRESS-HF trial), and Barth syndrome. Results have been mixed—it showed statistically significant improvements in some endpoints but narrowly missed primary endpoints in others [19].

FDA status: Investigational. Stealth BioTherapeutics holds the license. Not yet approved but actively in Phase III development.

Typical use: 40 mg subcutaneous daily (clinical trial dosing). Availability through compounding pharmacies varies.

Epitalon (Epithalon)

What it does: A synthetic version of epithalamin, a peptide produced by the pineal gland. Claimed to activate telomerase, the enzyme that lengthens telomeres (the protective caps on chromosomes that shorten with age) [20].

Evidence level: ⭐ Preliminary

The telomerase activation data comes primarily from the lab of Vladimir Khavinson in Russia, published in Russian journals with limited independent replication. A few Western studies have confirmed telomerase activation in cell cultures, but no peer-reviewed, controlled human trials demonstrate anti-aging effects [20].

FDA status: Not approved. Not scheduled for FDA review.

Typical use: 5–10 mg subcutaneous daily for 10–20 day cycles, repeated every 4–6 months.

AOD-9604

What it does: A modified fragment (amino acids 177–191) of human growth hormone. It was designed to retain GH’s fat-burning properties without the muscle-building or blood sugar effects [21].

Evidence level: ⭐⭐ Moderate

AOD-9604 went through Phase IIb human trials for obesity in the early 2000s. Results were underwhelming—modest fat loss that didn’t reach statistical significance in the primary endpoint [21]. It was subsequently abandoned as a pharmaceutical candidate. It’s had more commercial success as a nutraceutical/supplement ingredient (granted GRAS status by the FDA for oral use in 2019, which is not the same as drug approval).

FDA status: GRAS for oral use. Category 2 for injectable compounding [4]. No drug approval.

Typical use: 250–500 mcg subcutaneous daily. Also available as an oral supplement.

---

Cognitive and Neuroprotective Peptides

Semax

What it does: A synthetic analog of ACTH (4-10) developed in Russia. It’s a nootropic that increases brain-derived neurotrophic factor (BDNF) expression and modulates serotonin and dopamine metabolism [22].

Evidence level: ⭐⭐ Moderate

Approved in Russia as a prescription medication for stroke recovery, cognitive disorders, and optic nerve disease. Russian clinical trials show improvements in cognitive function post-stroke and in patients with cognitive decline. However, these studies are not held to the same standards as FDA clinical trials, and independent Western replication is limited [22].

FDA status: Not approved in the US or EU. Not available through US compounding pharmacies.

Typical use: 200–600 mcg intranasal, 1–2x daily. Nasal spray is the standard delivery method.

Selank

What it does: A synthetic peptide based on tuftsin (an immune-modulating peptide) with anxiolytic (anti-anxiety) and nootropic properties. Modulates GABA, serotonin, and dopamine systems [23].

Evidence level: ⭐⭐ Moderate

Like Semax, Selank is approved in Russia and has Russian clinical data supporting its use for generalized anxiety disorder. It shows comparable efficacy to benzodiazepines in some Russian trials, without sedation or dependence [23]. Western clinical trials are absent.

FDA status: Not approved in the US or EU.

Typical use: 250–500 mcg intranasal, 1–3x daily.

Dihexa

What it does: An angiotensin IV analog that acts as a hepatocyte growth factor (HGF) modulator. In animal models, it improved cognitive function at doses millions of times lower than BDNF [24].

Evidence level: ⭐ Preliminary

Only animal and in vitro data exists. The potency claims are attention-grabbing—Dihexa was approximately 10 million times more potent than BDNF at promoting synaptic connectivity in rat hippocampal neurons [24]. But potency in a petri dish doesn’t automatically translate to safe, effective human use. No human trials have been published.

FDA status: Not approved. Investigational only.

Typical use: 10–20 mg orally or subcutaneously. Dosing protocols are not well-established.

---

Sexual Health Peptides

PT-141 (Bremelanotide / Vyleesi)

What it does: Melanocortin receptor agonist (MC3R and MC4R). Unlike Viagra or Cialis, which work on blood flow, PT-141 acts on the brain’s arousal pathways. It was discovered accidentally during melanocortin research when subjects reported spontaneous sexual arousal [25].

Evidence level: ⭐⭐⭐ Strong

PT-141 (as bremelanotide) was FDA-approved in 2019 under the brand name Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women. In the RECONNECT trials, 25% of women on bremelanotide had a meaningful increase in sexual desire versus 17% on placebo [25].

FDA status: Approved (Vyleesi, 2019) for HSDD in premenopausal women. Off-label use in men is common but not FDA-sanctioned.

Typical use: 1.75 mg subcutaneous injection, taken 45 minutes before anticipated sexual activity. Maximum: once per 24 hours, no more than 8 doses per month.

Melanotan II

What it does: Non-selective melanocortin receptor agonist. Stimulates melanogenesis (tanning), reduces appetite, and increases sexual arousal. PT-141 was actually derived from Melanotan II research.

Evidence level: ⭐⭐ Moderate

Human studies exist showing effective skin darkening and sexual arousal effects. However, its non-selective action on multiple melanocortin receptors produces more side effects than PT-141, including nausea, facial flushing, and potential effects on moles and pigmented lesions [26]. There are case reports of melanoma development in Melanotan II users, though causation hasn’t been established.

FDA status: Not approved. The FDA has issued warnings about unregulated Melanotan II products.

Typical use: Loading: 250–500 mcg subcutaneous daily for 2–3 weeks. Maintenance: 250–500 mcg 1–2x weekly.

Kisspeptin-10

What it does: Stimulates GnRH (gonadotropin-releasing hormone) release, which triggers LH and FSH production—the hormones that drive testosterone and estrogen production.

Evidence level: ⭐⭐ Moderate

Human studies (primarily by Waljit Dhillo’s group at Imperial College London) show kisspeptin acutely increases LH and testosterone levels. It’s being studied as a potential fertility treatment and diagnostic tool for reproductive disorders [27]. Under PCAC review for compounding eligibility.

FDA status: Under PCAC review (October 2024) [4]. Not yet approved.

Typical use: Research dosing varies widely. Not yet standardized for clinical use.

---

Immune-Modulating Peptides

Thymosin Alpha-1 (Ta1)

What it does: A 28-amino-acid peptide naturally produced by the thymus gland. Modulates T-cell function and enhances immune surveillance. It has been used extensively in Asia and South America for hepatitis B, hepatitis C, and as an immune adjuvant in cancer treatment [28].

Evidence level: ⭐⭐⭐ Strong

Thymosin alpha-1 is approved in over 35 countries (not the US) for hepatitis B and as an immune modulator. It has extensive clinical trial data showing improved immune response in immunocompromised patients. A meta-analysis of hepatitis B trials showed significantly higher response rates when Ta1 was added to standard therapy [28].

FDA status: Not FDA-approved in the US. Previously available through 503A compounding; the FDA is reviewing its status. Approved and widely used in China, Italy, and several other countries under the brand name Zadaxin.

Typical use: 1.6 mg subcutaneous, 2x weekly.

LL-37

What it does: A cathelicidin-derived antimicrobial peptide. Part of the innate immune system. Has direct antimicrobial activity against bacteria, viruses, and fungi, plus immunomodulatory effects [29].

Evidence level: ⭐ Preliminary

Mostly preclinical data. Animal studies show broad antimicrobial activity and wound-healing promotion. Human clinical trials for specific therapeutic applications are limited. It’s being investigated as a potential treatment for chronic wounds and infections resistant to conventional antibiotics [29].

FDA status: Not approved. Research-stage only.

Typical use: Dosing protocols not well-established. Research contexts use 50–100 mcg subcutaneous.

BPC-157 (Immune Context)

BPC-157 also appears in the immune-modulating category because animal studies show it counteracts immunosuppression and modulates the inflammatory response through the nitric oxide system [3]. See the Healing and Recovery section above for full details.

---

Side Effects and General Risks

Side effect profiles vary enormously between peptides, but some patterns are common:

GLP-1 agonists (semaglutide, tirzepatide): Nausea, vomiting, diarrhea, and constipation are the most common side effects, reported in 30–50% of patients during dose escalation. These typically improve after 4–8 weeks. More serious but rare risks include pancreatitis, gallbladder disease, and potential thyroid tumor risk (observed in rodents but not confirmed in humans) [1, 2].

Growth hormone secretagogues: Water retention, tingling/numbness in extremities, increased hunger (especially GHRP-6 and MK-677), elevated fasting blood glucose, and joint stiffness. MK-677 in particular can worsen insulin sensitivity with prolonged use [14].

Healing peptides (BPC-157, TB-500): Reported side effects in the anecdotal literature are mild—injection site irritation, mild headache, dizziness. However, the absence of human clinical trials means the true side effect profile is unknown [15]. BPC-157’s strong pro-angiogenic effect raises theoretical concerns about promoting blood vessel growth in tumors, though this hasn’t been demonstrated.

General injection risks: Injection site pain, redness, swelling, and very rarely, infection. Using proper sterile technique largely prevents these.

The biggest risk isn’t the peptide—it’s the source. Unregulated peptides from gray-market suppliers may contain impurities, incorrect doses, heavy metals, or the wrong compound entirely. A 2023 analysis found significant content variability in compounded peptide products [30]. If you’re going to use peptides, source them from a licensed compounding pharmacy with third-party testing.

FAQ

What peptides are FDA-approved?▼

Several peptides have full FDA approval: semaglutide (Ozempic/Wegovy), tirzepatide (Mounjaro/Zepbound), bremelanotide/PT-141 (Vyleesi), tesamorelin (Egrifta), and various others in non-wellness contexts (insulin, oxytocin, vasopressin, calcitonin). The majority of peptides used in the wellness and anti-aging space are not FDA-approved for those purposes.

Are peptides legal?▼

It’s complicated. FDA-approved peptides prescribed by a doctor are completely legal. Peptides on the Category 1 list can be legally compounded by 503A pharmacies. Category 2 peptides (BPC-157, CJC-1295, TB-500, etc.) are currently restricted from compounding, though this is being challenged in court and reviewed by the FDA’s PCAC committee [4]. Purchasing “research peptides” is a legal gray area—they’re sold for research use only, not human consumption.

Which peptide is best for muscle recovery?▼

BPC-157 and TB-500 are the most commonly used for injury recovery and tissue repair, often combined as the “Wolverine stack.” The evidence is strong in animal models but lacks human clinical trials [3, 15]. For growth hormone-mediated recovery, the CJC-1295/ipamorelin combination is popular. Tesamorelin is the only FDA-approved option that directly increases growth hormone.

Can you take multiple peptides at once?▼

Many protocols combine peptides—CJC-1295 with ipamorelin, BPC-157 with TB-500, etc. There’s limited formal research on peptide interactions, but these combinations are common in clinical practice. The main concern is additive side effects. Always work with a prescribing physician who can monitor your response.

How are peptides administered?▼

Most therapeutic peptides are injected subcutaneously (under the skin) using insulin syringes. Some are available as nasal sprays (Semax, Selank), oral capsules (BPC-157 oral, AOD-9604, MK-677), or topical creams (GHK-Cu). GLP-1 agonists use prefilled auto-injector pens. The route of administration matters—bioavailability varies significantly between injection, oral, and topical delivery.

Sources

1. Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine. 2021;384(11):989-1002. doi:10.1056/NEJMoa2032183

2. Tirzepatide as compared with semaglutide for the treatment of obesity. New England Journal of Medicine. 2025. doi:10.1056/NEJMoa2416394

3. Vukojevic J, Siroglavic M, Kasnik K, et al. Rat periodontal ligament and alveolar bone healing after BPC 157 therapy. Journal of Functional Morphology and Kinesiology. 2022;7(1):1. PMC article on BPC-157 VEGFR2 activation and NO signaling via Akt-eNOS pathway. PMC12567428.

4. FDA. Interim Policy on Compounding Using Bulk Drug Substances Under Section 503A — Category 2 Substances. Updated September 2023. Includes BPC-157, CJC-1295, TB-500, AOD-9604, GHRP-2, GHRP-6.

5. Real-World Weight Loss Observed With Semaglutide and Tirzepatide in Patients with Overweight or Obesity and Without Type 2 Diabetes (SHAPE). Advances in Therapy. 2025. PubMed ID: 40875186.

6. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine. 2022;387(3):205-216. doi:10.1056/NEJMoa2206038

7. Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-hormone-receptor agonist retatrutide for obesity—a phase 2 trial. New England Journal of Medicine. 2023;389(6):514-526. doi:10.1056/NEJMoa2301972

8. Sanyal AJ, Bedossa P, et al. A phase 2 randomized trial of survodutide in MASH and fibrosis. New England Journal of Medicine. 2024;391(4):311-319. doi:10.1056/NEJMoa2401755

9. Prakash A, Goa KL. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs. 1999;12(2):139-157. doi:10.2165/00063030-199912020-00007

10. Teichman SL, Neale A, Lawrence B, et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295. Journal of Clinical Endocrinology & Metabolism. 2006;91(3):799-805. doi:10.1210/jc.2005-1536

11. Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. 1998;139(5):552-561. doi:10.1530/eje.0.1390552

12. Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. New England Journal of Medicine. 2007;357(23):2359-2370. doi:10.1056/NEJMoa072375

13. Bowers CY. Growth hormone-releasing peptide (GHRP). Cellular and Molecular Life Sciences. 1998;54(12):1316-1329. doi:10.1007/s000180050257

14. Nass R, Pezzoli SS, Oliveri MC, et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Annals of Internal Medicine. 2008;149(9):601-611. doi:10.7326/0003-4819-149-9-200811040-00003

15. Vasireddi N, Hahamyan H, Salata MJ, et al. Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. Orthopaedic Journal of Sports Medicine. 2025. doi:10.1177/15563316251355551

16. Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Expert Opinion on Biological Therapy. 2012;12(Suppl 1):S37-S51. doi:10.1517/14712598.2012.687045

17. Pickart L, Vasquez-Soltero JM, Margolina A. GHK peptide as a natural modulator of multiple cellular pathways in skin regeneration. BioMed Research International. 2015;2015:648108. doi:10.1155/2015/648108

18. Lee C, Zeng J, Drew BG, et al. The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis and reduces obesity and insulin resistance. Cell Metabolism. 2015;21(3):443-454. doi:10.1016/j.cmet.2015.02.009

19. Karaa A, Haas R, Goldstein A, et al. Randomized dose-escalation trial of elamipretide in adults with primary mitochondrial myopathy. Neurology. 2018;90(14):e1212-e1221. doi:10.1212/WNL.0000000000005255

20. Khavinson VKh, Bondarev IE, Butyugov AA. Epithalon peptide induces telomerase activity and telomere elongation in human somatic cells. Bulletin of Experimental Biology and Medicine. 2003;135(6):590-592. doi:10.1023/A:1025493705728

21. Heffernan M, Summers RJ, Thorburn A, et al. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. Endocrinology. 2001;142(12):5182-5189. doi:10.1210/endo.142.12.8522

22. Levitskaya NG, Sebentsova EA, Andreeva LA, et al. The neuroprotective effects of Semax in conditions of MPTP-induced lesions of the dopaminergic system. Neuroscience and Behavioral Physiology. 2004;34(4):399-405.

23. Zozulia AA, Neznamov GG, Siuniakov TS, et al. Efficacy and possible mechanisms of action of a new peptide anxiolytic Selank in the therapy of generalized anxiety disorders and neurasthenia. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. 2008;108(4):38-48.

24. Benoist CC, Kawas LH, Zhu M, et al. The procognitive and synaptogenic effects of angiotensin IV-derived peptides are dependent on activation of the hepatocyte growth factor/c-Met system. Journal of Pharmacology and Experimental Therapeutics. 2014;351(2):390-402. doi:10.1124/jpet.114.218735

25. Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials. Obstetrics & Gynecology. 2019;134(5):899-908. doi:10.1097/AOG.0000000000003500

26. Brennan R, Wells JS, Van Hout MC. The injecting use of image and performance-enhancing drugs (IPED) in the general population: a systematic review. Health & Social Care in the Community. 2017;25(5):1459-1531. doi:10.1111/hsc.12326

27. Dhillo WS, Chaudhri OB, Patterson M, et al. Kisspeptin-54 stimulates the hypothalamic-pituitary gonadal axis in human males. Journal of Clinical Endocrinology & Metabolism. 2005;90(12):6609-6615. doi:10.1210/jc.2005-1468

28. Garaci E, Favalli C, Pica F, et al. Thymalfasin (thymosin-alpha 1): past and present. Expert Opinion on Biological Therapy. 2018;18(sup1):19-28. doi:10.1080/14712598.2018.1484450

29. Kahlenberg JM, Kaplan MJ. Little peptide, big effects: the role of LL-37 in inflammation and autoimmune disease. Journal of Immunology. 2013;191(10):4895-4901. doi:10.4049/jimmunol.1302005

30. Almena-Zaldívar E, et al. Content variability in compounded medications. JAMA. 2023. Review of compounding pharmacy quality standards and peptide content analysis.