Are peptides safe?

Written by:

Alexandra Smith,
22 Jul 2026 • 11 min read

Reviewed and fact-checked:

Ayesha Bashir, Prescribing Pharmacist, 03 Jul 2026

Peptides have been making headlines lately, but with so much noise out there, it can be hard to know what's really true. If you've been hearing about peptides and wondering whether they're safe, effective, or even legal, you're not alone.

Here, we'll cut through the confusion and give you the facts you need to make informed decisions about your health.

Key points

Not all peptides are the same. Approved medicines like Mounjaro and Wegovy have years of rigorous testing behind them. Unregulated peptides don't.
Unregulated peptides come with risks. Without proper manufacturing standards, there's no guarantee of what's actually in them. They can be contaminated, incorrectly dosed, or simply not what they claim to be.
The safest route is always a regulated one. Going through an official provider with qualified clinicians is the only way to know you're getting something safe and right for you.

What are peptides?

Peptides are short chains of amino acids, the building blocks of proteins. Your body naturally produces many different peptides, which play important roles in:

regulating hormones
acting as neurotransmitters
signalling molecules

These help to control key processes, like:

blood sugar
mood
reproduction
tissue repair
inflammation
appetite

For example, insulin is a peptide hormone that helps to regulate blood sugar levels, while oxytocin acts as a signalling molecule involved in social bonding, reproduction, and childbirth.

Collagen is another protein found in the skin, bones, and muscles that can be broken down into smaller collagen peptides, which are often used in wellness supplements to support skin, joint, and connective tissue health.

Scientists can also create synthetic peptides in the lab for use in medicines. Well-known examples include insulin, which is used to treat diabetes, and GLP-1 receptor agonists like semaglutide, the active ingredient in Ozempic and Wegovy.

These medications mimic the effects of naturally occurring peptides to help regulate blood sugar levels in people with diabetes and support weight loss by reducing appetite.

What are peptides used for?

Because peptides act as signalling molecules in the body, they have a wide range of roles, from prescription medicines to skincare products and dietary supplements.

Medical and prescription drugs

Some of the most important medicines in modern healthcare are peptide-based, like:

Semaglutide (Ozempic, Wegovy), which regulates blood sugar and reduces appetite, supporting weight loss in people with obesity or to manage type 2 diabetes.
Tirzepatide (Mounjaro), which works on two hormone pathways (GLP-1 and GIP) involved in insulin release and appetite regulation.
Retatrutide, which is currently in clinical trials and is not yet approved, works across three hormone pathways: GLP-1, GIP, and glucagon (which increases the amount of energy the body burns at rest).

Skincare and cosmetics

Anti-ageing: Peptides like Matrixyl are marketed to support collagen production, helping to reduce the appearance of fine lines and wrinkles.
Skin repair: Copper peptides are used in some skincare and hair products and are studied for their potential role in supporting skin texture and repair.

Fitness, performance, and recovery

This is where peptide use becomes more complex. Many peptides marketed in fitness communities aren't approved medicines.

Some peptides are promoted for muscle growth, fat loss, recovery, and joint or tendon support.
Common examples include CJC-1295, Ipamorelin, AOD-9604, BPC-157, TB-500, and PT-141.
Many are prohibited in competitive sport.

Dietary supplements

Some peptides are available as over-the-counter supplements, most commonly collagen-based products.

Collagen peptides are broken-down forms of collagen protein, commonly used to support skin, hair, nails, and joint health.

What are people using unregulated peptides for?

It's important to distinguish between approved medicines and unregulated peptides sold online or in wellness communities. While prescription peptides have gone through rigorous testing, unregulated peptides often have limited safety and effectiveness data.

People are currently using unregulated peptides for:

weight loss and fat burning (like CJC-1295, Ipamorelin, and AOD-9604)
muscle building and performance (like BPC-157 and TB-500)
anti-ageing and skin rejuvenation
libido or sexual function (like PT-141)
sleep
injury recovery

Why are more people using peptides?

Over the last few years, peptides have become a hot topic online. Fitness influencers, biohackers, and high-profile podcasters like Joe Rogan have spoken openly about using peptides like BPC-157 and TB-500 for things like injury recovery, anti-ageing, and performance.

This kind of high-visibility endorsement, combined with the before-and-after results that flood platforms like TikTok and Instagram, has made peptides feel like an accessible shortcut to better health for many people.

The success of GLP-1 medications like Mounjaro and Wegovy has also played a role. As these drugs became widely talked about for weight loss, interest in peptides more broadly has spiked.

People who can't access or afford regulated medications have started looking for alternatives online, and the unregulated peptide market has been quick to fill that gap.

Are peptides regulated in Ireland?

It depends on the peptide. Some peptide-based medications are fully regulated and approved for use in Ireland by the Health Products Regulatory Authority (HPRA). These include:

Semaglutide (Ozempic, Wegovy): Approved for type 2 diabetes and weight management.
Liraglutide (Victoza, Saxenda): Approved for diabetes and obesity.
Insulin: Approved for diabetes management.
Tirzepatide (Mounjaro): Approved for type 2 diabetes and weight loss.

These medications are prescription-only, meaning you need a clinician to assess whether they're appropriate for you before you can access them.

Retatrutide is not yet approved for use in Ireland, but it's currently in late-stage clinical trials and is expected to go through the regulatory process in the coming years.

Because of this, some people are already trying to get hold of unlicensed versions online, perhaps due to the impressive trial data. But buying unlicensed retatrutide carries the same risks as any other unregulated peptide.

There’s no way to verify what’s in it, how it’s made, or whether the dose is anywhere near accurate. Ultimately, there’s a reason why it isn’t available yet, and shortcuts to getting it now should always be seen as a red flag.

Many other peptides that are popular online, like BPC-157, TB-500, Ipamorelin, and CJC-1295, are also not approved for human use in Ireland. They're not licensed medications and aren't legal to sell for human consumption, though they're often marketed as ‘research chemicals’ to get around this.

How are people getting peptides if they’re not regulated?

“Despite not being licensed for human use, unregulated peptides are surprisingly easy to get hold of. Most people are buying them online, often from overseas websites that ship directly to Ireland.

“These sites typically label their products as being ‘for research purposes only’, which is a legal grey area that many use to avoid regulation.

“Some people also source them through gym communities, personal trainers, or word of mouth. The products arrive in vials or powders with minimal labelling, and users often have to research dosing themselves through forums or social media.

“The problem is that there's no way of knowing what's actually in these products. Without regulation, there's no quality control, and what you order isn't always what you get.”

Ayesha Bashir, weight loss expert at myBMI

Is it safe to take unregulated peptides?

Taking unregulated peptides carries risks that you should be aware of.

Contamination and purity issues: Without regulated manufacturing standards, unregulated peptides can be contaminated with bacteria, heavy metals, or other harmful substances. Studies have found that many products sold online don't contain what they claim to.
Unknown dosing: Regulated medications come with carefully established dosing guidelines. Unregulated peptides don't, which means it's easy to take too much, too little, or the wrong thing entirely.
No medical oversight: There's no clinician monitoring your health, no way to flag side effects, and no accountability if the product harms you.
Interactions with other medications: Peptides can interact with existing conditions or medications in ways that aren't always obvious. Without a proper medical assessment, you could be putting yourself at risk without knowing it.

Do peptides actually work?

Yes, but the evidence depends entirely on the specific peptide.

Regulated peptide-based medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) have been tested in large clinical trial programmes involving thousands of participants. These studies are published in peer-reviewed journals and consistently show clinically meaningful effects on weight loss and blood sugar control.

Retatrutide is still in clinical development, but trial data has already shown some of the highest average weight loss results ever reported in obesity trials. In the TRIUMPH-1 study, retatrutide resulted in an average 30% weight loss after 104 weeks.

With results that impressive, it’s understandable why people don’t want to wait. But remember that trial results like these come from tightly-controlled medical environments, with verified doses and close clinical oversight.

Unlicensed retatrutide that’s bought online can’t replicate that. You don’t know what you’re getting, and without proper oversight, you won’t know if something’s wrong, either.

Other compounds promoted online have limited human clinical evidence, with most of the data coming from animal studies, early-stage research, or anecdotal reports.

So, when dramatic claims appear on social media, ask yourself this: what level of evidence supports this, and has it actually been tested in proper human trials?

How myBMI can help

At myBMI, we only provide approved, regulated medications that have been rigorously tested for safety and effectiveness. All of our treatments are prescribed by qualified clinicians who take the time to understand your health, your goals, and whether a particular treatment is right for you.

That means you get the real thing, with proper dosing guidance, medical oversight, and ongoing support to make sure your treatment is working. You don't have to rely on unverified online sources or put your health at risk. We're here to help you get the results you want, safely and with confidence.

Learn more about Mounjaro Learn more about Wegovy

Frequently asked questions about peptides

Is retatrutide a peptide?

Yes, retatrutide is a peptide. It's a triple hormone receptor agonist that targets GIP, GLP-1, and glucagon receptors simultaneously, which means it works through three separate pathways to support weight loss.

Retatrutide isn't yet approved for use in Ireland, but it's currently in late-stage clinical trials and is expected to become available in the coming years, pending regulatory approval.

Are peptides legal in Ireland?

Regulated peptide-based medications, like Mounjaro and Wegovy, are completely legal in Ireland when prescribed by a registered clinician. Unregulated peptides that aren't licensed for human use occupy a legal grey area.

Are peptides a form of steroids?

No, peptides and steroids are not the same thing. Steroids are derived from cholesterol and work by affecting hormone receptors throughout the body.

Peptides are short chains of amino acids that act as hormones or signalling molecules. Some help regulate hormone production, while others mimic naturally occurring peptides in the body.

Although both can affect how the body functions, they are chemically and biologically very different.