Being an educator in the health and fitness industry, I have, of course, heard my students talking about peptides in class. Some of you no doubt have seen a lot about peptides popping up on your social media feeds, while others may know little or nothing about them.
But I think one common thing that irks me about people talking about peptides is that they often make sweeping statements about peptides without differentiating between types and their varying health risks.
Let’s start one step earlier, by explaining what a protein is.
When you eat protein, whether it is from oats, beans or chicken, your body breaks it down into amino acids. Your body uses 20 amino acids in different combinations to make the proteins it needs to function.
Imagine amino acids are like Lego bricks. If you arrange the bricks one way, you might build a rocket ship. Use those same 20 types of bricks in another combination, and you could make a race car.
In a similar way, your body arranges amino acids to make the proteins you need for many different functions, such as healthy skin, bigger muscles, or to digest food.
A peptide is a short chain of amino acids. It is similar to a protein, but is mostly used more for signalling roles in the body.
So peptides are usually about 2–50 amino acids, while proteins are usually 100–500+ amino acids. Some are over 1000.
But just because they are shorter does not mean peptides are not complex. Let’s pretend we have amino acids, and we are making a peptide 20 amino acids long. That’s still .05 × 10²⁶ combinations (That’s a 1 followed by 26 zeros).
The reason why this is important to understand is that treating all peptides the same would be a bit like treating all foods the same- some are more natural, some more artificial, some beneficial and some actively harmful.
People often don’t take peptides on their own. Many will use or order what are called ‘stacks’, which means combining multiple different peptides together at once. The idea would be that different peptides target different things, such as weight loss, skin health, muscle hypertrophy or recovery, and theoretically, you should be able to customise a ‘stack’ to suit your own goals.
These stacks can be taken orally or by injection, and are often consumed in cycles.
The issue with taking these stacks is that many peptides are not well-researched, and combining them can increase the risks of side effects or unexpected health complications.
GLP-1 is a peptide that is extremely well researched and has been something of a game changer for certain people struggling with overeating, weight loss, and the health complications that come along with obesity. Ozempic is one such brand of GLP-1 medication, and for most people, it has very few side effects. The medication imitates a signalling hormone in your gut that tells the brain you are satiated, or “full”. On its own, GLP-1s don’t really “cause” weight loss, but they can be a powerful tool to help avoid cravings and help people to change their eating habits.
There is a whole suite of peptides used for muscle growth, recovery and repair. These vary greatly in the amount of research and effectiveness. Growth hormone (GH)- related peptides, such as Ipamorelin, are often hailed as ‘healthier’ ways to increase GH levels due to fewer side effects than traditional steroids. More “old school” forms of steroids usually involve directly injecting various forms of Growth Hormone, while peptide variations cause the body to increase the amount of growth hormone it produces. There are, of course, many variations and mechanisms, but, in general, peptides tend to trigger the body’s own chemical responses rather than directly increasing GH levels.
That this is healthier is not proven, and while there is a lot of marketing and influencers claiming this, the evidence is limited. It’s also worth noting that even if it is ‘healthier’, the side effects of artificially altering hormone levels outside of normal ranges can be quite severe.
Peptide side effects that overlap (or can be the same as) anabolic steroid use include hormonal disruption, increased risk of heart strain, liver stress and mood changes. Side effects more specific to anabolic steroid use include testosterone suppression, infertility, gynecomastia (breast tissue growth in men), severe acne, oily skin and hair loss.
Skin-related peptides vary in how extensively they have been tested, how they are taken, and the risks they carry. Some peptides are designed to increase collagen production in your skin, while others target pigmentation or tanning. Tanning-related peptides tend to carry a greater risk, as they can increase mole development and freckling and may increase skin cancer risk.
Overall, some skin-related peptides show promise, some have very little research, and some are pretty concerning; however, there is an overall lack of research and long-term health-related data.
While all of the above might make me come across as anti- peptide, I want to be clear that I simply don’t like peptides being ‘sold’ or discussed as a collective miracle drug. Instead each one should be assessed on a case by case basis, paying special consideration to the research, risks, who is manufacturing it and who is selling it.
For example, GLP-1 peptides are well researched, manufactured by reputable drug companies, and have side effects, if any, that tend to be quite mild. In addition, the risks of GLP-1 peptides tend to be far milder than those of obesity and chronic disease caused by excessive weight and poor eating habits (Wilding et al., 2021; World Health Organisation, 2023). If used alongside exercise and good dietary habits, they can be a powerful intervention for many people (Davies et al., 2021).
For me personally, the risks of injecting non-regulated and poorly tested drugs is just not worth the claimed benefits of many social media influencers.
There are such widely varying claims regarding fat loss, muscle gain, sleep quality, muscle recovery, and skin health. I’m not denying that some do show promise, most simply aren’t very well tested in humans, especially in the long term. Many are sold online and without proper regulation, which can mean that purity, actual dosage or even the substance itself can be unreliable.
Add to that the risk of hormonal disruption, which may affect testosterone levels, fertility, mood, and metabolism. Some peptides may increase the risk of organ damage, particularly the liver, kidneys, or heart. Others can impact blood sugar regulation or increase the risk of abnormal tissue growth. (U.S. Food and Drug Administration, 2023).
For me, most of the time, the risks are just not worth it. If the goal was improved weight loss, muscle mass and recovery, the first things I would be looking at would be sleep quality, diet and training consistency. Maybe for you, you’ve tried all these things, and the risks of some peptides seem worth it. I just recommend you approach each on a case by case basis.
While I personally won’t use unregulated peptides, I also believe in ‘each to their own’, and that people should be careful not to sit on their high horse. CrossFit carries its own health risks, as does running an ultramarathon or dehydrating yourself before a bodybuilding competition. There are many things we do in the fitness industry that are not strictly ‘healthy’, but whose outcomes might still be considered worth the inherent risks.
Just keep in mind that not all peptides are the same, and so not all the risks and outcomes will be the same.
Davies, M., Færch, L., Jeppesen, O. K., Pakseresht, A., Pedersen, S. D., Perreault, L., Rosenstock, J., Shimomura, I., Viljoen, A., Wadden, T. A., & Lingvay, I. (2021). Semaglutide 2.4 mg once a week in adults with overweight or obesity (STEP 1): A randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet, 397(10278), 971–984. https://doi.org/10.1016/S0140-6736(21)00213-0
Wilding, J. P. H., Batterham, R. L., Calanna, S., Davies, M., Van Gaal, L. F., Lingvay, I., McGowan, B. M., Rosenstock, J., Tran, M. T. D., Wadden, T. A., Wharton, S., Yokote, K., Zeuthen, N., & Kushner, R. F. (2021). Once-weekly semaglutide in adults with overweight or obesity. The New England Journal of Medicine, 384(11), 989–1002. https://doi.org/10.1056/NEJMoa2032183
World Health Organization. (2023). Obesity and overweight. https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
U.S. Food and Drug Administration. (2023). FDA warns about safety risks of unapproved drugs marketed as peptides. https://www.fda.gov