Over the past decade, peptide therapy has emerged as a dynamic component of regenerative medicine. There is currently strong research interest in the function of peptides, potential opportunities for their use, and how they might be developed into therapeutic treatments.
In this guide, we explain what researchers need to know about peptide therapy, including its potential benefits. We will also discuss the future of peptide therapy, as well as safety concerns and the best types of peptides for various research objectives.
Researchers interested in conducting peptide research can find full details of our preferred vendor at the end of this guide.
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What are Peptides?
Peptides are molecules composed of linear or cyclic strings of amino acids or amino acid residues linked with peptide bonds. Current estimates put the number of natural peptide molecules in excess of 13,000 while the number of artificial peptides is believed to exceed 1 × 1013 .
Broadly speaking, peptides can be categorized according to structure and may be divided into either linear or cyclic molecules. They can also be divided according to their molecular weights as follows :
- Small molecule drugs with high oral bioavailability
- Large molecule peptides with low oral bioavailability
We can also categorize peptides according to length, but this is often complicated by imprecise, flexible definitions and plenty of overlap between different categories. For example, polypeptides generally do not exceed fifty amino acids in length but can be of any length, while proteins (generally over fifty amino acids in length) comprise one or more polypeptides. Shorter peptides are known as oligopeptides and typically contain 2-20 amino acids.
Let us now turn our attention to the question at hand: what is peptide therapy?
What is Peptide Therapy?
Peptide therapy is the practice of using synthetic peptides, or modified natural peptides, in a clinical setting. The main goal of peptide research is to explore how peptides could be used to provide therapeutic care .
What are peptide therapeutics?
Peptide therapeutics are created when peptides, either natural or synthetic, are transformed via solid-phase peptide synthesis into medical products.
The process of creating these products involves making various modifications to peptides, such as adding amino acid side chains or altering the backbones of the peptides to improve their properties. Peptide therapeutics are typically engineered to have a higher bioavailability, longer half-life, and/or increased efficiency compared to the original peptides, and may result in the development of peptide-based drugs .
What are peptide-based drugs?
Peptide-based drugs are compounds that seek to combine the advantages of small molecule drugs with proteins to improve various factors such as bioavailability, efficiency, half-life, and potency .
Small molecule drugs have high oral bioavailability and good metabolic stability but low target selectivity, which increases the likelihood of side effects. Larger molecule drugs are injected (due to low oral bioavailability) and tend to have a much higher potency and target specificity than small molecule drugs, though at the cost of metabolic instability.
Peptide-based drugs seek to marry the advantages of small- and large-molecule drugs, via the development of peptides that have a higher affinity to target proteins than small molecular compounds. Researchers typically develop peptide-based drugs by selecting peptides from peptide libraries or by using the structures of target proteins .
Benefits of Peptide Therapy
Given the inordinately high number of synthetic peptides (1 × 1013), a comprehensive summary of the benefits of peptide therapy is beyond the scope of this guide. However, we can outline the main directions that current peptide research is taking to illuminate some of the most impactful benefits offered by peptide therapy.
Polypeptides including neuropeptide Y, brain-gut peptide, and glucagon-like peptide are currently under investigation as potential treatments for metabolic diseases such as obesity, type 2 diabetes, hypertension, and cardiovascular disease. The specific features and properties of these peptides, including browning of white fat, short half-life, and low toxicity has drawn significant research interest.
Further, some peptides have been shown to modify macronutrient intake, reduce appetite, and regulate energy expenditure, adding to their potential to treat obesity. Additional areas of therapeutic interest include blood sugar and cholesterol regulation, the reduction of adipose tissue, and increased lean muscle mass.
Some peptides have displayed the ability to improve healing in injury recovery settings. For instance, the angiogenic peptide BPC-157 has been shown to improve bone, ligament, and tendon healing in animal models. Other angiogenic peptides such as TB-500 are evidenced to promote cellular regeneration to affect more rapid and efficient injury recovery.
Several peptides have demonstrated anti-inflammatory effects in both in vivo and in vitro studies. For example, TB-500 has been shown to block inflammation and reduce fibrosis, while GHK-Cu has exhibited anti-oxidative and anti-inflammation benefits in mouse models with bleomycin (BLM)-induced pulmonary fibrosis.
Some other peptides, such as the melanocortin agonist melanotan 1 and the telomerase activator epithalon, have also been shown to regulate the inflammatory response. This is achieved through various modalities depending on the peptide, including significant antioxidant effects and cytokine suppression.
There is substantial research interest in the ability of certain peptides to reverse cognitive impairment in various animal models. For example, GHK-Cu has displayed this ability in mouse models and is currently under investigation as a candidate for preclinical and clinical aging studies.
Several peptides, such as MK-677 and tesamorelin, respectively act as growth hormone secretagogues or growth-hormone-releasing hormones. In this capacity, they may offer neuroprotective and neurogenerative benefits. Further, the many clinical impacts of melanocortin agonist melanotan 2 include the treatment of addiction and autism, the latter affected through the modulation of oxytocin levels.
Pain management 
Many peptides have exhibited the ability to alleviate various types of pain and present tremendous opportunities for medicinal application research. For instance, the ghrelin mimetic ipamorelin has been shown to alleviate visceral pain in test subjects with colonic hypersensitivity and is currently at the forefront of peptide therapeutics research in this area.
The one-time FDA-approved peptide sermorelin is currently under investigation as a potential treatment for patients with recurrent glioma. It is one of several peptides that have been shown to enhance immune response.
Additionally, thymosin alpha-1 displays potent immunomodulating and antioxidant effects, regulating T cells to elicit improved immune function in cases of both infection and autoimmune disease.
This small sample of peptide therapy benefits offers an intriguing glimpse into the emerging market of peptide therapeutics. In the next section, we dive into the side effects and safety issues regarding peptide therapy.
Is Peptide Therapy Safe? | Side Effects Breakdown
Researchers interested in peptide therapeutics experimentation may note that peptides are, by and large, available solely as research chemicals. This means that the onus is on researchers to consult relevant literature regarding each peptide before beginning an experiment. Here is a brief overview of the main side effects observed in past peptide research.
Given the novel status of research peptides and peptide therapeutics, most have not undergone extensive human clinical trials to fully evaluate their safety. Researchers are thus strongly advised to consult relevant literature when incorporating peptides into their studies.
Nevertheless, most popularly researched peptides display positive safety profiles in proper clinical settings. Many peptide-based drugs are considered to have low toxicity levels, especially when compared to mainstream pharmaceuticals [5, 22].
Because leading clinicians recognize the great potential of peptides in pharmaceutical advancements, there are constantly emerging improvements in the field. For example, scientists have recently developed a technique for predicting peptide toxicity, involving digital models and highly accurate results. This promises to further counter toxicity in therapeutic peptides, already appreciated for their favorable safety ratings .
Researchers interested in the adverse effects caused by a particular peptide may consult data from clinical trials to gain a clearer picture of that peptide’s overall safety profile.
Likewise, research involving the ghrelin mimetic ipamorelin has shown that this peptide is well-tolerated by test subjects and has not been linked to serious adverse effects .
Some peptide therapeutics have demonstrated significant clinical benefits in trials, giving researchers a clear picture of their tolerability in test subjects. For instance, sermorelin held FDA approval from 1997 to 2008, meaning that it was thoroughly studied in test subjects. It has been found to cause relatively minor side effects such as facial flushing, headaches, swelling, redness, pain, or irritation at the injection site .
Peptide Therapy Cost
The cost of peptide therapy can vary enormously depending on the type, quantity, order volume, and source of the reference materials in question. Here is a brief rundown of peptide therapy costs from our preferred vendor, Peptide Sciences.
- BPC-157: Researchers can expect to pay $59.50 for a single 5mg vial of BPC-157 but can save 8% on bulk orders (10+ vials).
- TB-500: Researchers will pay $165 for a single 10mg vial of TB-500 but can save 13% on bulk orders (10+ vials).
- GHK-Cu: 50mg vials of injectable GHK-Cu cost $70 individually but are eligible for an 11% discount when purchased in bulk.
- Ipamorelin: Researchers can save 9% when they purchase 10 or more 5mg vials of ipamorelin, which cost $46.00 when purchased individually.
- Sermorelin: Single 5mg vials of sermorelin cost $49.50, but researchers can save 10% when they order in bulk.
Hopefully, these example prices offer insight into the cost of peptide therapy. So, where can researchers purchase high-purity peptides?
Where to Buy Peptides Online
Researchers interested in exploring peptide therapeutics will find the most reasonable prices when they shop online. Our preferred vendor is Peptide Sciences, a US-based company that offers fairly-priced peptides delivered within a decent time frame.
Here, specifically, are some of the reasons why we rate them No. 1:
- Guaranteed Purity: Many vendors claim to offer high-purity peptides, but Peptide Sciences is the only company we are aware of that gets all its peptides tested by an independent lab via HPLC-MS quality testing. The results of the third-party tests are posted online.
- Fast Shipping: The logistics of shipping peptides internationally is no easy feat, but Peptide Sciences consistently delivers on its promises. Shipments typically take 2-3 days to the US and 7-10 days to select international destinations. What's more, shipping fees are waived on all US orders over $200.
- Reasonable Prices: Peptide Sciences offers some great deals, especially to researchers who order in bulk. Savings as high as 13 percent are possible on large orders.
- Responsive Customer Service: Researchers can expect their email inquiries to be answered within 1-2 business days by Peptide Sciences’ friendly and competent customer care team.
- Convenient Payment Options: Electronic cheques, credit cards, cryptocurrencies, and third-party platforms like Venmo and Apple/Google Pay are all accepted, giving researchers flexibility and convenience when paying for peptides.
We have yet to find another vendor that can compete with Peptide Sciences on peptide purity, price, or shipping.
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Despite the enormous number of peptides currently under research and the huge variety of directions taken by researchers, many inquiries are focused on a couple of narrow interests. To address those, here is a brief selection of the most frequently asked questions.
Best HGH Peptide Therapy?
HGH (Human Growth Hormone) is produced in the pituitary gland and is instrumental in many physiological functions. From governing physical development to regulating metabolism, cardiovascular health, and body composition into adulthood, it is a topic of close study among clinical researchers for its many benefits [26, 27, 28].
HGH deficiency is observed in both children and adults. In children, the cause of HGH deficiency is largely genetic or unknown, with symptoms such as impaired growth, excess body fat, and late puberty. In adults, deficiency is linked with numerous causes, including brain damage, tumors, and radiation therapy. Symptoms include muscle and bone weakness, fatigue, and adiposity .
Peptides that affect HGH levels have been successfully applied for decades to treat various conditions, including HGH deficiency, renal failure, genetic diseases, and muscle loss due to HIV/AIDS [30, 31]. Additional evidenced benefits of HGH peptide therapy include improved athletic performance, better injury recovery, anti-aging effects, enhanced cardiovascular and sexual health, as well as treatment of symptoms of inflammatory disease .
Popular peptides used in HGH peptide therapy include synthetic growth hormone secretagogues and synthetic analogs of growth hormone-releasing hormones, both of which augment endogenous HGH levels to varying effects. Here are the top three peptides used in HGH peptide therapy:
This synthetic analog of the human growth-releasing hormone held FDA approval until 2008 as a treatment and diagnostic tool for HGH deficiency in children and adults. Its withdrawal from the market was unrelated to its efficacy or safety [32, 33]. Sermorelin also shows the clinical potential to reduce the visible effects of aging, improve body composition, and aid cardiovascular health [34, 35, 36, 37, 38].
A potent growth hormone secretagogue, ipamorelin is known for its targeted interaction with the pituitary gland . Studies on animal models demonstrate its ability to prevent muscle catabolism from glucocorticoid use, as well as stimulate growth in various tissue types, including muscle, bone, and blood vessels [40, 41, 42]. It is also linked with the repair and synthesis of collagen .
This synthetic nonpeptide is a selective ghrelin agonist and growth hormone secretagogue, valued for its targeted GH release and oral route of administration . Most notably studied as a treatment for HGH deficiency, its further therapeutic potentials include improved sleep, physical composition, and bone formation [45, 46, 47, 48]. MK-677 is also under investigation as a prospective treatment for neurodegenerative disease .
Best Peptides For Weight Loss?
Many peptides exhibit therapeutic potential for weight loss, affected through a range of modalities that include enhanced metabolism, reduced adiposity, and energy regulation. Here are the three most popular peptides for this use:
This synthetic analog of a human growth hormone segment is a GH receptor agonist, eliciting targeted benefits compared to the parent hormone. Documented benefits in clinical studies include the regulation of blood sugar as well as increased thermogenesis to affect weight loss. It may also stimulate cartilage synthesis and displays the potential to treat type 2 diabetes and prediabetes [50, 51].
A synthetic analog of GH-releasing hormone (GHRH), tesamorelin is a 44 amino acid peptide with a demonstrated potency much higher than endogenous GHRH . It is currently FDA-approved to treat HIV-related lipodystrophy, a disorder of adipose tissue that causes excess abdominal fat . It is also shown to enhance metabolic health, boosting insulin resistance and improving cholesterol levels, for potential weight reduction . Further therapeutic potentials include neuroregeneration in peripheral nerve injuries, as well as the prevention of age-related cognitive decline [55, 56].
AICAR is applied to modulate the nucleotide adenosine and the protein AMPK, respectively involved in cardiovascular function and metabolic health. As an AMPK-activator, AICAR balances energy expenditure and decreases adiposity to affect weight loss. It is also noted for its potential to enhance exercise performance, combat signs of aging, and treat metabolic and cardiovascular diseases .
Is Peptide Therapy Legal?
Unless otherwise stated, research peptides are non-prescription and uncontrolled substances, legal for purchase, sale, and handling by qualified individuals for strictly educational purposes. However, the marketing of peptides as medicinal products is illegal in the USA when these substances have not been approved by the US Food and Drug Administration [58, 59, 60].
Unfortunately, a lack of regulation has given rise to an illicit market of low-quality peptides, marked with unsubstantiated claims and potentially dangerous substances. Because most peptides are not authorized medical products in the USA and other countries, their commercial sale is illegal outside of laboratory environments. Unlawful vendors are vulnerable to appropriate sanctions, and buyers of illegally marketed products risk both poor quality and hazardous side effects.
Qualified researchers can legally purchase and handle research peptides for educational purposes. To guarantee the legality and quality of peptide vendors, there are standard signs of legitimacy to be mindful of. [58, 61]:
- The source must state that the marketed peptides are intended strictly for research and handling by qualified buyers.
- There should be no direct claims in marketing material or product literature of the guaranteed benefits of peptide administration.
- Because the industry lacks quality assurance regulations, peptide retailers should display test results verifying peptide purity from third-party lab partners.
The legality of research peptides is likely to shift with ongoing clinical studies and approval from regulatory bodies. Researchers should keep abreast of clinical developments and maintain vigilance to avoid illegal marketers of impure peptides.
Peptide Therapy with a Doctor vs. Buying Online
While a few peptides are available through prescription, virtually all may be purchased online as reference materials for research use only. The primary difference between these two modes is that doctor-prescribed peptides are classed as pharmaceutical drugs, meaning that they have been approved for safety in human subjects and specific therapeutic applications .
While this guarantee of regulation in prescription peptides is certainly a plus, it can limit the selection of peptides available to researchers. This is due in part to the novel status of peptide therapy, as well as the relative lack of commercially-viable production methods of peptide therapeutics .
Fortunately, the downfalls of the under-regulated market can be avoided with the implementation of the following best practices:
- Purchase research peptides strictly from a reputable source, referring to the above-mentioned markers of legitimacy.
- Always consult the latest peer-reviewed scientific literature that is relevant to your studies to learn the standard clinical guidelines for safe and effective application.
- Maintain caution and discontinue the use of peptides if serious side effects ensue.
Following these measures, qualified researchers can safely enjoy the benefits of research peptides from reputable sources.
Peptide Therapy | Verdict
This closes our comprehensive guide on peptide therapy. With an ever-growing number of evidenced benefits, peptides present great potential in pharmaceutical and medical advancements, capturing the interest of leading researchers around the world. Our guide has shared many of these documented benefits, as well as the main features and ongoing developments of the burgeoning area of peptide therapy.
When sourced from a reputable vendor, research peptides are safe for handling and analysis by qualified buyers. Consult our favorite peptide retailer to access top-quality peptides for use in your research into this dynamic and exciting field of therapeutics.