PE-22-28 Peptide: Benefits, side effects, dosage details, and how it works

Anyone who has felt stressed, angry, or blue understands that mood and cognition are connected. Their interrelationship is why we can generally concentrate better when we’re feeling optimistic, and our decision-making suffers when we’re down in the dumps.1 2

It’s also why an experimental peptide like PE-22-28 could be a streamlined solution for what ails your mental health and cognitive function. We’ve examined the extant research on its mechanism and effects to help you determine whether it really has the potential to bolster your brain and sense of well-being.

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions about staying healthy and living healthier lifestyles.

At this point, we’ve put more than 1,000 hours of research and writing into peptides. Our work has taken us through several peptide therapies with neurocognitive and mood-stabilizing effects, giving us multiple points of reference on where PE-22-28 stands in this space. Our peptide-related work has also involved discussions with clinicians who prescribe peptides and people who use them, imbuing our guides with multifaceted perspectives that can better guide readers’ health decisions.

Additionally, like all health-related content on this website, this guide was thoroughly vetted by one or more members of our Medical Review Board for accuracy and will continue to be monitored for updates by our editorial team.

PE-22-28 is an analog fragment of another peptide, spadin, that occurs naturally in the human body. Both spadin and PE-22-28 selectively antagonize a two-pore domain potassium (K2P) channel called TREK-1.

K2P channels are a kind of protein that regulates neurotransmitter release in the brain and the ability of neurons to respond to stimuli.3 In these roles, they take part in numerous biological functions — hormone secretion,4 pain processing, eye pressure regulation,5 etc. — but when overexpressed, they can also contribute to several pathologies. TREK-1, in particular, is implicated in depression, which is associated with weakened neuronal excitability.6 7

TREK-1’s influence on depression and related disorders is what PE-22-28 and spadin act on. By selectively antagonizing this K2P channel, PE-22-28 blocks an inhibitory mechanism that contributes to the mood problem.

Where PE-22-28 diverges from spadin is in its stability and efficacy. Studies have shown, for example, that PE-22-28’s duration of action is more than three times longer than that of spadin, its antidepressant effects lasting nearly a whole day as opposed to just seven hours.8

At this time, studies on PE-22-28 are woefully limited to cellular or animal models, which don’t always neatly translate to efficacy in humans, and even these studies are relatively few in number.

But the little research that’s available to us suggests that PE-22-28 is primarily an antidepressant, and since mood and cognition are interrelated, any impact on the former may also influence the latter.

So far, some of the strongest evidence for PE-22-28’s antidepressant and procognitive effects is described in a 2017 study that analyzed human cell lines in vitro and assessed mouse behavior after the administration of spadin, PE-22-28, or one of several PE-22-28 analogs. The key findings were as follows:8

• PE-22-28 was the “most efficient” TREK-1 blocker. Its inhibition rate of 55.46% was higher than that of any other tested peptide.
• PE-22-28 and its analogs increased neurogenesis and synaptogenesis. Respectively, these processes refer to the creation of neurons and synapses.

In other words, PE-22-28 performed the best in terms of antagonizing a K2P channel closely correlated with mood, and in rodents, it successfully increased the number of units in the brain responsible for processing and transmitting information.

Separate research, not directly related to PE-22-28, has also examined the working relationship between mood and cognition. In a 2002 review, for example, Davidson et al. found via neuroimaging that mood and cognitive processing both influence activity in common brain regions, and multiple medical bodies have noted that depression can deteriorate a person’s ability to concentrate.9 10 11

So, in theory, PE-22-28’s purported antidepressant action may confer attendant (if mild) effects on memory, attention, executive function, and related areas of cognitive health, as has been observed in some mood studies with selective serotonin reuptake inhibitors (SSRIs).12

Just as efficacy studies on PE-22-28 are severely lacking, safety evaluations are practically nonexistent. The closest thing we have to research conclusions on the drug’s tolerability are more or less passing statements, and not about PE-22-28 specifically:

• “The absence of adverse effects differentiates spadin-analogs [sic] from other antidepressant drugs.”8
• “At the cardiovascular level, long-term treatment by spadin has no effect on systolic blood pressure and heart pulses.”13

Though both assessments are broadly positive, neither one is exactly an endorsement of PE-22-28’s safety.

Perhaps more notably, however, PE-22-28 is one of the few restricted peptides we’ve covered that the United States Food & Drug Administration (FDA) has not flagged as a bulk drug substance that may present significant safety risks.14 Normally, when we discuss a non-GLP-1 peptide therapy, we find that the FDA has published good reasons for having denied the peptide’s approval (e.g., immunogenicity or other serious adverse effects), but that isn’t the case here. That is, the FDA hasn’t explicitly said that PE-22-28 may be unsafe.

At the same time, the absence of a federal warning isn’t the same as evidence of a drug’s safety. The bare fact is that PE-22-28 doesn’t have enough research behind it to say much about its health risks or lack thereof. It’s simply invisible on the FDA’s radar until human trials enter the picture.

Research-grade vs. pharmaceutical-grade PE-22-28

Regardless of PE-22-28’s safety profile, one of the best things that anyone can do to minimize a potential health risk is to use only a pharmaceutical-grade form of the drug.

A pharmaceutical-grade peptide is one that has been deemed suitable for human use. It meets a very high standard of purity — around 99% pure, at least — and is therefore free of the contaminants that could induce an adverse reaction.

On the other hand, a research-grade peptide is not intended for human consumption. It's for laboratory use only, as in cellular studies or animal models, where the risk of adverse events isn’t necessarily a mission-critical concern. Research-grade substances are therefore permitted to contain a much larger proportion of additives, fillers, and contaminants, resulting in purity levels as low as 60%.15 If something like that were to enter your body, it could trigger a potentially life-threatening immune reaction.

It isn’t always clear whether a peptide purveyor deals in research- or pharmaceutical-grade products, but as long as you’re vigilant, you can safeguard yourself against inadvertent risk. At the very least, make sure your peptide source requires a prescription, as PE-22-28 is not an over-the-counter substance, and do your due diligence in verifying your source’s reputability.

With neither common use nor human studies behind it, PE-22-28 can hardly be said to have a standard treatment protocol. But there are several known treatment factors about PE-22-28, and we can lean on our relationships with clinicians to fill in the blanks.

With what we know about PE-22-28, we’d say the most suitable candidate for the peptide is someone who:

• Lives with a mood disorder, such as depression
• Is willing to try an experimental therapy

Also, because it’s commonly administered via intranasal spray, PE-22-28 is a viable option for those who’d rather not deal with needles.

As for who isn’t suited for treatment, it’s likely the usual cohorts. Pregnant or breastfeeding women may be contraindicated, as may be anyone with a history of cancer, given how little is known about PE-22-28’s effects on fetal/child development and tumorigenesis.

But even among the indicated population, PE-22-28 should be regarded with sober expectations. As of this writing, the peptide has yet to withstand the crucible of clinical trials, so it’s unclear whether its effects on rodents can be recreated in humans, or what its safety profile will ultimately look like.

So, whether you’re a candidate or not, you’ll want to speak with your doctor about PE-22-28. If they feel that PE-22-28 can improve your symptoms better than a more common antidepressant, then you can go about obtaining a prescription.

Getting your primary care provider to write a PE-22-28 prescription may be a tough go. With well-tested SSRIs at their disposal, they aren’t likely to consider an unproven, experimental peptide unless all reasonable alternatives have been exhausted.

That means you’ll probably need a licensed provider at a peptide clinic to fill the script instead. To that end, you can either look locally or look online.

For the online route, the ideal source for PE-22-28 would be a licensed telehealth outfit, which can adjust your therapy as needed, not just send you the product and wish you luck.

The legal and regulatory status of therapeutic peptides is always in flux. If and whenever PE-22-28 becomes more widely available to health consumers, we’ll update this guide with the latest research and recommendations.