Disclaimer: None of the information in this article constitutes medical advice. All statements are merely the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to weight loss.
Every year more consumers are looking for supplements to aid in their weight loss goals. Many supplement brands have popped up in recent years suggesting that peptides can promote weight loss.
But are there any clinical studies showing that peptides cause weight loss? And if so, which peptides are proven to work? Is it dangerous to use peptides for weight loss? And did our Product Tester lose weight trying peptides for weight loss?
In this article we'll answer all of these questions and more, as we review clinical studies on oral supplementation with peptides for weight loss, to give our take on whether or not this strategy is likely to be effective.
We'll also discuss the potential for side effects, explain if collagen peptides (one of the most popular peptide supplements) can cause weight loss, and share our Product Tester's honest experience trying peptides for weight loss for a month.
Key takeaways:
- Some peptides may have indirect weight loss effects
- We can't find any clinical studies showing any peptides to directly cause weight loss
- We do not currently recommend peptides for weight loss
Do Peptides Cause Weight Loss?
Peptides are chains of amino acids, which are the building blocks of proteins. Generally proteins contain 50 or more amino acids, while peptides can contain as few as two.
Some peptides have been studied in clinical trials for their effects on weight.
A medical review published in the Frontiers in Nutrition journal found that peptides from milk have an appetite-suppressing effect, and therefore may support weight loss.
MOTS-C is a peptide that was shown in a 2019 clinical trial to decrease fat accumulation. It’s theorized to work by downregulating certain metabolic pathways that become dysfunctional in obese animals and people.
Ipamorelin is another peptide which has been used for weight loss because it’s been shown in research studies to cause human growth hormone (HGH) release.
HGH supplementation is clinically shown to cause body fat loss, so users of ipamorelin figure that by taking the peptide, they may reap the same benefits.
We can't find any clinical trials linking ipramorelin to weight loss.
Overall, we find it unlikely that peptide supplementation will cause weight loss, because we can't locate any clinical studies directly proving such.
While there are some theoretical benefits and indirect relationships between peptide supplementation and weight, we'll wait for more research to emerge before considering a recommendation of this weight loss approach.
We Tested Peptides for Weight Loss:
One of our Product Testers named Amy Lau tested a popular peptide weight loss supplement called InfiniWell IgNIGHT for a month.
Here's her experience:
The product is straightforward to use — no hassle opening, no clumping, and the capsules go down easily. Nothing fancy with the packaging, but functional.
The capsules have a fresh, natural smell — more like a food product than something overly "processed." For me, that felt like a reassuring indicator that the formula leans more natural than synthetic.
Efficacy is where IgNight really stands out.
Within the first few nights, I felt noticeably more relaxed at bedtime, and I slept straight through the night without getting up to use the bathroom — a rare win for me.
Waking up felt smooth and clear, with none of the classic melatonin drawbacks (dry mouth, grogginess, or that “hungover” feeling).
The metabolism support was an unexpected added benefit. I had more consistent daytime energy, and over one month I went from 142 pounds (lbs) to 137 lbs — a 5-lb loss without changing anything else in my routine.
I experienced zero negative effects. No digestive upset, grogginess, vivid dreams, or rebound fatigue.
I’ve tried several sleep aids, especially melatonin-based ones, and they’ve always come with trade-offs. IgNight didn’t. Better sleep quality + better energy the next day is a rare combination for me.
Overall, I would rate this peptide supplement 10/10, and I plan to purchase it again.
Can Peptides be Dangerous?
Most peptides are only cleared for medical research, and don’t have nearly the same safety and toxicology studies that pharmaceutical drugs and many herbal supplements have.
The unknown nature of the long-term risks associated with use of novel peptides for weight loss is concerning in our opinion.
It’s surprising to us that so many health sites online tout the health benefits of peptides for all types of purposes including weight loss, without linking to one single safety study in many cases.
We find it to be illogical and potentially dangerous to use peptides for weight loss given the lack of safety data in human trials.
There are many weight loss supplements as well as lifestyle modifications that are shown to be effective in clinical studies, which we would consider to be much safer options than peptides.
Do Collagen Peptides Cause Weight Loss?
Collagen peptides are one of the most popular dietary supplements, and for good reason.
They're proven in medical studies to have significant benefits for skin, and are one of the most promising dietary supplements for anti-aging in our opinion, especially given their lack of side effects.
Collagen is a type of protein, so it's more of a food product than a dietary supplement.
While we do recommend collagen for skincare and joint health, we don't recommend collagen peptide supplementation for weight loss.
We cannot identify any medical research suggesting that collagen peptides are effective for weight loss.
The vast majority of clinical trials on collagen relate to skin, joints or pain relief, and collagen is caloric, which makes it an illogical peptide supplement for weight loss.
Our Clean Weight Loss Picks
Ceylon cinnamon was described as "an effective anti-obesity agent" in a 2022 meta-analysis. The study authors concluded that effects were greater at doses at or over 3 grams daily.
Illuminate Labs Ceylon Cinnamon Extract is our standardized Ceylon cinnamon supplement which is third-party tested to ensure purity and potency.
Dietary fiber was shown in a medical review published in The Journal of Nutrition to cause 16 pounds of weight loss in 6 months when combined with moderate caloric restriction (750 calories per day below baseline).
MBG Organic Fiber Potency+ is our top fiber pick because it's certified organic, provides 7 g of fiber per serving and costs under $1.85 per serving at the time of updating this article.
Both of the products mentioned in this section are entirely free of additive ingredients that we consider to be unhealthy.
