List of Peptides and What They Do: A Complete Guide to Learn About Peptides

Peptides are tiny molecules that do big jobs in our bodies. I’ve spent over 10 years studying how they make muscles grow, keep skin looking young, and more. Pretty amazing! 

In this short guide, we actually gonna explore a comprehensive list of peptides and what they do giving you a deep dive into the fascinating world of these powerful molecules. Stick with me and you’ll be a peptide pro in no time! 

And who knows, maybe someday you’ll tell your friends how peptides improved your health or looks. But enough dreaming about the future – let’s dive into the world of peptides!

What are Peptides?

Peptides often act as signaling molecules, with their specific amino acid sequences allowing them to bind to particular receptors on cells. This binding can trigger various responses, depending on the peptide and the receptor. The unique combination of amino acids in each peptide determines its function.

Peptide bonds are the chemical linkages that connect amino acids to form peptides. These bonds are crucial for the structure and function of peptides.

Natural vs. synthetic peptides: While many peptides occur naturally in our bodies, scientists can also create synthetic peptides for research and therapeutic purposes. These synthetic peptides are designed to mimic the amino acid sequences of natural peptides or to create new sequences with desired effects.

Delivery methods: Peptides can be administered through various routes, depending on their intended use and how well they’re absorbed. Some common methods include:

• Injections: This method bypasses the digestive system, allowing the amino acids to enter the bloodstream directly.
• Nasal sprays: Certain peptides can be absorbed through the nasal mucosa.
• Oral tablets: Some peptides can withstand stomach acid and be absorbed in the intestines.
• Topical applications: Used for peptides that can be absorbed through the skin.

The choice of delivery method often depends on the stability of the peptide’s amino acid sequence and its intended target in the body.

Metabolic Peptides

1. Insulin

Insulin is perhaps the most well-known peptide hormone. It plays a crucial role in regulating blood sugar levels and is essential for managing diabetes.

Use: Regulates blood sugar levels in diabetes.

How it works: Insulin allows cells to absorb glucose from the bloodstream, lowering blood sugar levels. It also promotes the storage of glucose as glycogen in the liver and muscles.

Pros and Cons:

Pros	Cons
✅ Essential for managing diabetes	❌ Risk of hypoglycemia if overdosed
✅ Allows proper use of glucose for energy	❌ Requires careful monitoring and dosing
✅ Prevents long-term complications of diabetes	❌ Can cause weight gain

Personal insight: In my work with diabetic patients, I’ve seen insulin dramatically improve quality of life when used correctly. However, it’s crucial to work closely with a healthcare provider to find the right dosage and management plan.

2. Glucagon

Glucagon works in opposition to insulin, helping to raise blood glucose levels when they drop too low.

Use: Raises blood glucose levels, counteracting insulin.

How it works: Glucagon stimulates the liver to convert stored glycogen into glucose and release it into the bloodstream. It also promotes the breakdown of fat for energy.

Pros and Cons:

Pros	Cons
✅ Prevents dangerous hypoglycemia	❌ Can cause nausea and vomiting
✅ Essential for maintaining glucose balance	❌ May lead to temporary high blood sugar
✅ Can be life-saving in severe hypoglycemia	❌ Requires proper storage and handling

Personal insight: As an emergency responder, I’ve administered glucagon to individuals experiencing severe hypoglycemia. It’s remarkable how quickly it can bring someone back from the brink of a diabetic emergency.

3. GLP-1 (Glucagon-Like Peptide-1)

GLP-1 is a peptide that has gained attention for its role in diabetes management and weight loss.

Use: Enhances insulin secretion and reduces appetite.

How it works: GLP-1 stimulates insulin release, slows gastric emptying, and reduces appetite by acting on the brain’s satiety centers.

Pros and Cons:

Pros	Cons
✅ Improves blood sugar control	❌ Can cause nausea and vomiting
✅ Aids in weight loss	❌ May increase heart rate
✅ Potential cardiovascular benefits	❌ Long-term effects still being studied

Personal insight: I’ve followed the development of GLP-1 agonists closely, and their dual action on blood sugar and appetite makes them a promising option for many patients struggling with both diabetes and obesity.

Hormonal Peptides

4. Oxytocin

Often called the “love hormone,” oxytocin plays a crucial role in social bonding and reproduction.

Use: Promotes social bonding, childbirth, and lactation.

How it works: Oxytocin is released during positive social interactions, childbirth, and breastfeeding. It promotes feelings of trust and attachment.

Pros and Cons:

Pros	Cons
✅ Enhances social bonding	❌ Potential for misuse in social manipulation
✅ Essential for childbirth and breastfeeding	❌ Effects can vary between individuals
✅ May help with certain psychiatric conditions	❌ More research needed on long-term use

Personal insight: The potential of oxytocin in treating conditions like autism and social anxiety is fascinating. However, it’s important to remember that human relationships are complex and can’t be reduced to a single molecule.

5. Somatostatin

Somatostatin is a regulatory peptide that inhibits the release of several other hormones.

Use: Inhibits growth hormone and insulin secretion.

How it works: Somatostatin binds to specific receptors on cells, reducing the secretion of growth hormone, insulin, and other hormones.

Pros and Cons:

Pros	Cons
✅ Useful in treating certain tumors	❌ Can cause digestive side effects
✅ Helps manage excessive hormone production	❌ May affect blood sugar levels
✅ Used in diagnostic imaging	❌ Requires careful monitoring

Personal insight: In my endocrinology rotation, I saw somatostatin analogs effectively manage acromegaly in patients. It’s a powerful tool when used appropriately.

6. Corticotropin-Releasing Hormone (CRH)

CRH is a key player in the body’s stress response system.

Use: Regulates stress response and cortisol levels.

How it works: CRH is released by the hypothalamus and stimulates the production of adrenocorticotropic hormone (ACTH), which in turn promotes cortisol release.

Pros and Cons:

Pros	Cons
✅ Essential for normal stress response	❌ Chronic elevation linked to anxiety and depression
✅ Helps maintain energy balance	❌ Can disrupt sleep patterns
✅ Important in fetal development	❌ Excess can lead to immune suppression

Personal insight: Understanding the role of CRH has been crucial in my work with stress-related disorders. It’s a reminder of how interconnected our body’s systems are.

7. Adrenocorticotropic Hormone (ACTH)

ACTH is the next step in the stress response cascade initiated by CRH.

Use: Stimulates cortisol production from the adrenal glands.

How it works: ACTH is released by the pituitary gland in response to CRH. It then travels to the adrenal glands, where it stimulates the production and release of cortisol.

Pros and Cons:

Pros	Cons
✅ Essential for stress response	❌ Excess can lead to Cushing’s syndrome
✅ Helps regulate metabolism	❌ Can cause mood swings and irritability
✅ Used diagnostically for adrenal disorders	❌ May affect bone density long-term

Personal insight: ACTH testing has been invaluable in diagnosing adrenal insufficiency in my patients. It’s a powerful diagnostic tool when used correctly.

Side Note: Luteinizing hormone releasing hormone (LHRH) and gonadotropin releasing hormone (GnRH) are important peptide hormones that regulate reproductive function. They stimulate the release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) from the pituitary gland, which in turn control the production of sex hormones and gametes.

Appetite-Regulating Peptides

8. Peptide YY

Peptide YY is an important regulator of appetite and digestion.

Use: Reduces appetite and inhibits gastric motility.

How it works: Peptide YY is released from the intestines after eating and signals the brain to reduce food intake. It also slows down the movement of food through the digestive tract.

Pros and Cons:

Pros	Cons
✅ Natural appetite suppressant	❌ Effects may be short-lived
✅ May aid in weight loss	❌ Potential for nausea if levels are too high
✅ Improves insulin sensitivity	❌ More research needed on long-term effects

Personal insight: The potential of Peptide YY in treating obesity is exciting. In my nutrition counseling, I often discuss the role of gut hormones like PYY in appetite regulation.

9. Cholecystokinin (CCK)

CCK is another important peptide involved in digestion and appetite control.

Use: Stimulates digestion of fats and proteins.

How it works: CCK is released in the small intestine in response to food intake. It stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder.

Pros and Cons:

Pros	Cons
✅ Aids in proper digestion	❌ May cause nausea in high doses
✅ Promotes feelings of fullness	❌ Effects on appetite can vary between individuals
✅ May help prevent gallstones	❌ Potential role in anxiety needs more study

Personal insight: CCK’s dual role in digestion and appetite control highlights the complex relationship between our gut and brain. It’s a fascinating area of ongoing research.

10. Leptin

Often called the “satiety hormone,” leptin plays a crucial role in regulating energy balance and body weight.

Use: Regulates energy balance and inhibits hunger.

How it works: Leptin is produced by fat cells and signals the brain about the body’s energy stores. It helps regulate appetite and metabolism.

Pros and Cons:

Pros	Cons
✅ Key regulator of body weight	❌ Leptin resistance can occur in obesity
✅ Helps maintain energy balance	❌ Effects can diminish over time
✅ May improve insulin sensitivity	❌ Not effective as a weight loss treatment in most people

Personal insight: Leptin’s discovery revolutionized our understanding of obesity. However, its complex role reminds us that there’s no simple “obesity hormone” that can easily solve weight issues.

11. Ghrelin

Ghrelin is often referred to as the “hunger hormone” due to its role in stimulating appetite.

Use: Stimulates appetite and promotes fat storage.

How it works: Ghrelin is primarily released by the stomach when it’s empty. It signals the brain to increase hunger and food intake.

Pros and Cons:

Pros	Cons
✅ Essential for normal appetite regulation	❌ Can contribute to weight gain if overactive
✅ May have neuroprotective effects	❌ Linked to emotional eating behaviors
✅ Potential use in treating cachexia	❌ Can interfere with weight loss efforts

Personal insight: Understanding ghrelin’s role has been crucial in my work with patients struggling with both over- and under-eating. It’s a reminder of how our bodies are designed to maintain energy balance.

Cardiovascular Peptides

12. Angiotensin II

Angiotensin II is a key player in blood pressure regulation and fluid balance.

Use: Increases blood pressure and regulates fluid balance.

How it works: Angiotensin II causes blood vessels to constrict, increasing blood pressure. It also stimulates the release of aldosterone, which promotes sodium and water retention.

Pros and Cons:

Pros	Cons
✅ Essential for maintaining blood pressure	❌ Chronic elevation can lead to hypertension
✅ Helps regulate fluid balance	❌ May contribute to heart and kidney damage
✅ Important in the stress response	❌ Can promote inflammation

Personal insight: In my cardiology work, understanding the renin-angiotensin-aldosterone system has been crucial. Angiotensin II is a powerful molecule, and its regulation is a key target in treating hypertension.

13. Endothelin

Endothelin is a potent vasoconstrictor involved in blood pressure regulation.

Use: Constricts blood vessels and raises blood pressure.

How it works: Endothelin is released by the inner lining of blood vessels and causes them to narrow, increasing blood pressure.

Pros and Cons:

Pros	Cons
✅ Important in maintaining vascular tone	❌ Overproduction linked to hypertension
✅ Plays a role in wound healing	❌ May contribute to fibrosis in various organs
✅ Potential target for new hypertension treatments	❌ Can promote inflammation

Personal insight: Endothelin antagonists have shown promise in treating pulmonary hypertension, a condition I’ve worked with. It’s an example of how understanding peptide function can lead to new therapies.

14. Vasopressin (ADH)

Vasopressin, also known as antidiuretic hormone (ADH), is crucial for water retention and blood pressure regulation.

Use: Regulates water retention in kidneys.

How it works: Vasopressin acts on the kidneys to increase water reabsorption, concentrating urine and maintaining blood volume.

Pros and Cons:

Pros	Cons
✅ Essential for fluid balance	❌ Excess can lead to hyponatremia
✅ Helps maintain blood pressure	❌ Deficiency can cause diabetes insipidus
✅ Used to treat certain bleeding disorders	❌ Can cause vasoconstriction

Personal insight: I’ve seen vasopressin used effectively in critical care settings to maintain blood pressure. Its diverse effects highlight the interconnectedness of our body’s systems.

Immune System Peptides

15. Interleukin-2 (IL-2)

Interleukin-2 is a crucial signaling molecule in the immune system.

Use: Stimulates immune response, particularly T-cell proliferation.

How it works: IL-2 promotes the growth and differentiation of T cells, which are crucial for fighting infections and cancer.

Pros and Cons:

Pros	Cons
✅ Boosts immune response against cancer	❌ Can cause severe side effects
✅ Used in some cancer immunotherapies	❌ May exacerbate autoimmune conditions
✅ Helps maintain T cell populations	❌ Effects can be unpredictable

Personal insight: I’ve seen IL-2 therapy produce remarkable results in some cancer patients, but its side effects can be challenging. It’s a powerful reminder of the delicate balance in immune modulation.

16. Interferon

Interferons are a group of signaling proteins with important antiviral and immune-modulating properties.

Use: Antiviral and immune-modulating properties.

How it works: Interferons are released by cells in response to pathogens. They trigger the production of proteins that interfere with viral replication and enhance the immune response.

Pros and Cons:

Pros	Cons
✅ Effective against various viral infections	❌ Can cause flu-like side effects
✅ Used in treating certain cancers	❌ May exacerbate depression
✅ Helps regulate immune response	❌ Can cause autoimmune-like reactions

Personal insight: In my work with hepatitis C patients, I’ve seen interferon therapy lead to cures, but the side effects can be challenging. The development of newer, interferon-free treatments has been a game-changer.

17. Antimicrobial Peptides (AMPs)

Antimicrobial peptides are an essential part of the body’s innate immune defense.

Use: Protect against infections and promote wound healing.

How it works: AMPs can directly kill microbes by disrupting their cell membranes. They also modulate the immune response and promote wound healing.

Pros and Cons:

Pros	Cons
✅ Broad-spectrum antimicrobial activity	❌ Potential for resistance development
✅ Promote wound healing	❌ Some may cause local irritation
✅ Potential alternative to traditional antibiotics	❌ Production can be costly

Personal insight: The potential of AMPs in fighting antibiotic-resistant bacteria is exciting. In my research, I’ve seen promising results, but we’re still working on overcoming challenges in their clinical application.

Performance-Enhancing Peptides

18. BPC-157

BPC-157 is a synthetic peptide that has gained attention for its potential healing properties.

Use: Promotes healing of muscles, tendons, and ligaments.

How it works: BPC-157 is thought to accelerate wound healing by promoting the formation of new blood vessels and modulating inflammatory responses.

Pros and Cons:

Pros	Cons
✅ May speed up injury recovery	❌ Long-term effects not well studied
✅ Potential to reduce pain	❌ Not approved for human use in many countries
✅ Might improve digestive health	❌ Optimal dosing not established

Personal insight: While the potential of BPC-157 is intriguing, especially for athletes, I always caution my patients about using peptides that aren’t well-studied in humans. Safety should always come first.

19. Creatine Peptides

Creatine peptides are a form of creatine, a popular supplement for enhancing athletic performance.

Use: Increases muscle mass and strength.

How it works: Creatine peptides are designed to enhance the absorption of creatine, which helps regenerate ATP in muscle cells, providing energy for high-intensity exercise.

Pros and Cons:

Pros	Cons
✅ May improve strength and muscle mass	❌ Effects may vary between individuals
✅ Potentially better absorbed than creatine monohydrate	❌ More expensive than traditional creatine
✅ Might reduce muscle damage during intense exercise	❌ Long-term effects not well studied

Personal insight: While creatine is one of the most well-studied supplements, creatine peptides are relatively new. In my work with athletes, I’ve seen mixed results, and more research is needed to fully understand their benefits.

20. Follistatin

Follistatin is a protein that has gained attention for its potential to promote muscle growth.

Use: Promotes muscle growth; banned in competitive sports.

How it works: Follistatin inhibits myostatin, a protein that limits muscle growth. By blocking myostatin, follistatin may allow for greater muscle development.

Pros and Cons:

Pros	Cons
✅ Potential for significant muscle growth	❌ Banned in competitive sports
✅ May help in treating muscle wasting diseases	❌ Long-term effects not well understood
✅ Could aid in recovery from muscle injuries	❌ Potential for abuse in bodybuilding

Personal insight: The potential of follistatin in treating muscle wasting diseases is exciting, but its use as a performance enhancer raises ethical concerns. As a sports medicine professional, I always emphasize the importance of fair play and long-term health over short-term gains.

21. CJC-1295

CJC-1295 is a synthetic peptide that stimulates growth hormone release and is sometimes used to treat adult growth hormone deficiency.

Use: Increases growth hormone levels for muscle gain.

How it works:  CJC-1295 mimics the action of growth hormone releasing hormone (GHRH), stimulating the pituitary gland to produce more human growth hormone.

Pros and Cons:

Pros	Cons
✅ May increase muscle mass and reduce fat	❌ Not approved for human use in many countries
✅ Potential anti-aging effects	❌ Long-term safety not established
✅ Might improve sleep quality	❌ Can disrupt natural hormone balance

Personal insight: While the potential benefits of CJC-1295 are intriguing, especially for aging athletes, I always caution about the risks of manipulating the growth hormone axis. The long-term effects are still not fully understood.

22. Ipamorelin

Ipamorelin is another growth hormone-releasing peptide that has gained popularity in anti-aging and sports performance circles.

Use:  Stimulates growth hormone release for muscle growth and recovery.

How it works: Ipamorelin selectively binds to growth hormone secretagogue receptors, stimulating the release of growth hormone without affecting other hormones.

Pros and Cons:

Pros	Cons
✅ May improve muscle recovery	❌ Not approved for human use in many countries
✅ Potential fat loss effects	❌ Long-term effects unknown
✅ Might enhance sleep quality	❌ Possible side effects like water retention

Personal insight: In my practice, I’ve seen increasing interest in peptides like Ipamorelin for recovery and anti-aging. While some users report benefits, I always stress the importance of considering the unknown risks and legal implications.

Therapeutic Peptides

23. GHK-Cu

GHK-Cu, or copper peptide, has gained attention for its potential skin rejuvenation properties.

Use: Enhances wound healing and skin rejuvenation.

How it works: GHK-Cu stimulates collagen production, promotes blood vessel formation, and has antioxidant properties.

Pros and Cons:

Pros	Cons
✅ May improve skin texture and firmness	❌ Can be unstable in some formulations
✅ Potential wound healing benefits	❌ Optimal concentration for use unclear
✅ Antioxidant properties	❌ More research needed on long-term effects

Personal insight: In my dermatology work, I’ve seen increasing interest in GHK-Cu for skin care. While early results are promising, it’s important to remember that skincare is complex and no single ingredient is a miracle solution.

24. Thymosin Beta-4

Thymosin Beta-4 is a peptide with potential regenerative properties.

Use: Promotes tissue repair and reduces inflammation.

How it works: Thymosin Beta-4 plays a role in cell migration and differentiation, potentially aiding in tissue repair and wound healing.

Pros and Cons:

Pros	Cons
✅ May accelerate wound healing	❌ Not approved for human use in many countries
✅ Potential anti-inflammatory effects	❌ Long-term effects not well understood
✅ Might aid in cardiac tissue repair	❌ Optimal dosing not established

Personal insight: The potential of Thymosin Beta-4 in regenerative medicine is exciting, especially for cardiac repair. However, as with many peptides, we need more long-term studies to fully understand its effects and safety profile.

25. Liraglutide

Liraglutide is a GLP-1 receptor agonist used in the treatment of diabetes and obesity.

Use: Used in diabetes management and weight loss.

How it works: Liraglutide mimics the action of GLP-1, stimulating insulin release, slowing gastric emptying, and reducing appetite.

Pros and Cons:

Pros	Cons
✅ Effective for blood sugar control	❌ Can cause nausea and vomiting
✅ Aids in weight loss	❌ Requires daily injections
✅ May reduce cardiovascular risk	❌ Expensive compared to some alternatives

Personal insight: In my endocrinology practice, Liraglutide has been a valuable tool for patients struggling with both diabetes and obesity. Its dual action often leads to significant improvements in overall health.

26. Semaglutide

Semaglutide is a newer GLP-1 receptor agonist that has shown promising results in diabetes and weight management.

Use: Similar to liraglutide, for diabetes and weight management.

How it works: Like Liraglutide, Semaglutide mimics GLP-1, but has a longer half-life, allowing for less frequent dosing.

Pros and Cons:

Pros	Cons
✅ Powerful weight loss effects	❌ Can cause gastrointestinal side effects
✅ Effective blood sugar control	❌ Long-term effects still being studied
✅ Once-weekly dosing	❌ High cost

Personal insight: The weight loss results I’ve seen with Semaglutide have been impressive, often surpassing other available treatments. However, it’s important to remember that it’s not a magic solution and should be used in conjunction with lifestyle changes.

Other Notable Peptides

27. Melittin

Melittin is the principal component of bee venom and has gained interest for its potential therapeutic properties.

Use: Antimicrobial properties, derived from bee venom.

How it works: Melittin can disrupt cell membranes, giving it antimicrobial and potential anticancer properties.

Pros and Cons:

Pros	Cons
✅ Potent antimicrobial activity	❌ Can cause pain and allergic reactions
✅ Potential anticancer properties	❌ Difficult to administer safely
✅ May have anti-inflammatory effects	❌ More research needed on therapeutic applications

Personal insight: While the potential of melittin is intriguing, especially for antibiotic-resistant infections, its use is challenging due to its potential to cause severe reactions. Ongoing research into delivery methods may unlock its therapeutic potential.

28. Neurotensin

Neurotensin is a peptide involved in various physiological processes, including pain modulation and digestive function.

Use: Involved in pain regulation and neuroprotection.

How it works: Neurotensin acts as a neurotransmitter and neuromodulator, influencing pain perception and potentially offering neuroprotective effects.

Pros and Cons:

Pros	Cons
✅ Potential for pain management	❌ Effects can be complex and varied
✅ Possible neuroprotective properties	❌ Optimal therapeutic use not yet established
✅ May influence digestive processes	❌ More research needed on long-term effects

Personal insight: The role of neurotensin in pain modulation is fascinating, and it could potentially lead to new approaches in pain management. However, its diverse effects make it challenging to target therapeutically.

29. Substance P

Substance P is a neuropeptide involved in pain perception and inflammatory responses.

Use: Mediates pain perception and inflammatory responses.

How it works: Substance P is released from nerve endings and contributes to the transmission of pain signals and the promotion of inflammation.

Pros and Cons:

Pros	Cons
✅ Important for normal pain perception	❌ Overactivity linked to chronic pain
✅ Plays a role in wound healing	❌ Can promote inflammation
✅ Potential target for pain treatments	❌ Complex interactions with other systems

Personal insight: Understanding Substance P has been crucial in developing new approaches to pain management. In my work with chronic pain patients, targeting Substance P pathways has shown promise, but it’s just one piece of a complex puzzle.

30. Calcitonin

Calcitonin is a hormone involved in calcium regulation and bone metabolism.

Use: Regulates calcium levels and bone metabolism.

How it works: Calcitonin lowers blood calcium levels by inhibiting bone resorption and increasing calcium excretion by the kidneys.

Pros and Cons:

Pros	Cons
✅ Helps maintain bone density	❌ Effects can diminish over time
✅ Used in treating hypercalcemia	❌ Can cause nausea and flushing
✅ May help manage osteoporosis pain	❌ Not as effective as some newer osteoporosis treatments

Personal insight: While calcitonin has been largely superseded by newer treatments for osteoporosis, I’ve found it can still be useful in managing pain associated with osteoporotic fractures in some patients.

Additional Information: Collagen peptides and collagen peptide supplements have gained popularity in recent years for their potential benefits in skin health and joint support. These bioactive peptides are derived from collagen and may help improve skin elasticity and reduce joint pain.

Conclusion

As we close this peptide journey, I hope you’ve gained a new appreciation for these tiny but mighty molecules. They’re a testament to the incredible complexity and ingenuity of our bodies. Who knows? The next big medical breakthrough might just come from a peptide we haven’t even discovered yet!

So, keep your eyes peeled for news about peptides. The next time you hear about a breakthrough in medicine or anti-aging, chances are, a peptide might be involved. And now, armed with your new peptide knowledge, you’ll be able to say, “Oh yeah, I know all about those!”

Stay curious, stay healthy, and remember – good things often come in small packages, especially when it comes to peptides!