Peptides Are Everywhere — Here’s What You Should Know

By Robert Duhaney, MD, FACP

The excitement — and the reasons for caution

If you’ve been on social media lately, you’ve probably seen peptides promoted for everything from fat loss and muscle gain to injury recovery, brain health, skin rejuvenation, and anti-aging/longevity promotion. Some of that buzz is deserved—peptides are a real and important part of modern medicine. But the current marketplace is also full of overpromises, underpowered evidence, and sometimes unsafe or unregulated products.

What are peptides?

Peptides are short chains of amino acids (think: small proteins). Your body naturally makes many peptides that act as hormones, signaling molecules, and immune messengers. In medicine, peptide-based drugs can be powerful because they can “speak the body’s language” with high specificity.

Examples of peptide medications with strong evidence and FDA oversight include:

• GLP-1 medications used for diabetes and weight management (e.g., semaglutide, tirzepatide)

• Insulin

• Certain reproductive hormones and other endocrine therapies

  
  

Where the excitement is justified

There’s real scientific potential in peptide biology. In tightly regulated, well-studied settings, peptide drugs can improve health outcomes—sometimes dramatically. This is why pharmaceutical companies are investing heavily in peptide-related therapeutics.

Where caution is warranted (and why)

The biggest problem is that “peptides” has become an umbrella term. It now includes:

1. FDA-approved peptide medications (high-quality evidence + known manufacturing standards)

2. Compounded peptide products (variable oversight, quality concerns, legal/regulatory limitations)

3. Unapproved “research peptides” sold online (often not evaluated for safety/efficacy; risk of contamination, dosing errors, and unknowns)

The FDA has specifically highlighted safety risks with certain compounded peptides, including concerns about immunogenicity, impurities, and serious adverse events described in case reports for some products. Separately, major reporting has documented a growing trend of people injecting unproven, unapproved peptides marketed for wellness or performance, with physicians warning about lack of evidence and safety concerns.

What does the evidence actually support?

Right now, the strongest evidence in everyday clinical practice is for approved peptide medications (like GLP-1 therapies for obesity/diabetes) used for clear medical indications.

For many popular “wellness peptides” marketed online (often labeled “for research use only”), the evidence is frequently:

• animal or lab data

• small human studies

• anecdotes

• non-standardized formulations

That doesn’t mean every peptide outside big pharma is useless—but it does mean confidence should be low until we have better trials and long-term safety data.

The unknowns patients should understand

Even when a peptide has a plausible mechanism, we often don’t know:

• the true dose-response in humans

• long-term risks (immune reactions, endocrine disruption, cardiovascular effects)

• drug–drug interactions

• safety in pregnancy/postpartum

• quality and purity across suppliers

  
  

A practical way to think about peptides

If you’re considering peptide therapy, here’s a helpful framework:

Green zone (generally safest):

• FDA-approved peptide medications, prescribed for an evidence-based indication, with appropriate monitoring.

Yellow zone (proceed carefully):

• Compounded peptides only when there’s a legitimate clinical rationale, the source is reputable, and you understand that oversight and quality may vary. The FDA has flagged specific compounded substances as higher risk. We do this currently for GLP1s like semaglutide and tirzepatide at trusted compounding locations.

Red zone (avoid):

• Online “research peptides,” unknown sourcing, self-mixing/reconstitution, influencer-driven protocols, or “stacks” without medical supervision—where risk rises and reliable benefit is uncertain.

Common Peptides Used for Wellness That You Are Hearing About (and What to Know Before Consideing Them)

A lot of the peptide buzz online centers around a handful of products that are widely promoted for recovery, performance, and anti-aging. As discussed above, the challenge is that many of these are not FDA-approved for these uses, and the human evidence is often limited compared to the strength of the marketing.

Below are three of the most commonly discussed peptides - sometimes "stacked" together in the same vial:

BPC-157

What it is: BPC-157 is a synthetic peptide derived from a protein found in gastric juice. It’s often promoted in the wellness and sports world.

Purported uses (what people claim it helps with):

• tendon and ligament healing

• muscle injury recovery

• joint pain and inflammation

• gut healing (IBS-like symptoms, gastritis, “leaky gut”)

  
  

What we actually know: Most of the enthusiasm comes from animal studies and early experimental data, not large, high-quality human clinical trials. That means we don’t yet have clear answers about:

• safe dosing

• long-term risks

• interactions with other medications

• purity/quality across sources

Cautions:

• Unregulated sourcing and contamination risk (especially online “research” versions)

• Uncertain long-term safety

• Potential for inconsistent dosing and unexpected side effects

GHK-Cu (Copper Peptide)

What it is: GHK-Cu is a naturally occurring copper-binding peptide found in human plasma, saliva, and urine. It’s commonly used in skincare products and is sometimes discussed in injectable form online.

Purported uses:

• skin rejuvenation and improved elasticity

• hair growth support

• wound healing

• anti-inflammatory effects

  
  

What we actually know: There is some supportive data for topical copper peptides in skin applications, but the leap to systemic use (including injections) is a much bigger step with less established safety data.

Cautions:

• Skin irritation or sensitivity (especially with topical use)

• Limited high-quality human evidence for injectable/systemic use

• Product quality varies widely depending on source

  
  

TB-500 (Thymosin Beta-4 Fragment)

What it is: TB-500 is often marketed as a performance and recovery peptide, related to thymosin beta-4, which plays a role in tissue repair and cell migration.

Purported uses:

• faster injury recovery

• muscle healing

• improved flexibility/mobility

• reduced inflammation

What we actually know: Human evidence is limited, and much of what circulates online is based on theoretical mechanisms, animal data, or anecdotal reports.

Cautions:

• Not FDA-approved for these wellness indications

• Unknown long-term effects

• Risk of contamination and dosing variability

• If a compound influences tissue growth/repair pathways, clinicians are appropriately cautious until safety is clearer

  
  

A note on safety and prescribing at One Medical

For me and our Austin based team at One Medical, our priority is helping patients pursue better health in a way that is evidence-based and safe. For that reason, we do not routinely prescribe unregulated wellness peptides (including products like BPC-157, GHK-Cu, TB-500, and similar compounds), even through trusted compounding pharmacies (such as Victory Medical Pharmacy or East Austin Medicine Shop), until there is more clarity around consistent manufacturing standards, dosing, and long-term safety data.

If you’re curious about peptides, we’re always happy to talk through:

• what you’re hoping to treat or improve

• which options have strong evidence

• safer alternatives that may accomplish the same goal

• and how to avoid products that carry unnecessary risk

  
  

Bottom line

Peptides are not a fad—they’re a foundational part of modern therapeutics. But the current hype cycle has blurred the line between regulated medicine and unregulated experimentation. If you’re interested, the safest path is a thoughtful medical conversation that weighs your goals, your risks, and the quality of evidence with your primary care team.

As a reminder, the views and opinions expressed on this blog are my own and do not constitute an endorsement or official position of Amazon One Medical. This content is provided for informational and educational purposes only and is not intended as medical advice, diagnosis, or treatment. As always, please consult your personal clinician for individualized care.