PepRank

Avoid

Peptides with a real risk of harm under the strict safety bar, however well people rate them, each with the reason. They stay listed so you can look them up, and rank behind every other entry.

38 peptides

Safety barPositivePer month

#PeptidePositivePer monthCategoryAbout
1GHRP-6Avoid59% positive€13–81/moHormones & libidoGH/IGF-1 axis elevation plus cortisol rise and reduced insulin sensitivity (FDA), with only single-dose human safety data.
2SurvodutideAvoid56% positive€36–140/moMetabolic & weightUnapproved drug bought as grey-market vials, usually stacked on tirzepatide: the GLP-1 class's pancreatitis, gallbladder and dehydration-kidney routes, a glucagon-driven heart-rate rise whose cardiovascular safety trial is still running, and GI effects harsh enough that about one in five phase 3 participants stopped.
3MazdutideAvoid55% positive€36–140/moMetabolic & weightCarries the GLP-1 class's serious-harm routes on its own label (pancreatitis, gallbladder disease, acute kidney injury, boxed warning for thyroid C-cell tumours in rodents) plus a glucagon-driven heart-rate rise; outside China it is bought as unregulated research vials and mostly stacked on tirzepatide, a combination no trial has tested.
4Polaprezinc (zinc L-carnosine)Avoid54% positive€32/moGutJapanese ulcer drug sold as a supplement; the go-to oral 'stomach lining' option for gastritis.
5PE-22-28Avoid54% positive€36–140/moMood & anxietyNo human data, and it blocks a channel whose loss makes animals more prone to seizures and ischaemic injury.
6Mechano growth factor (MGF / PEG-MGF)Avoid53% positive€27–110/moRecovery, joints & healingAn unapproved growth-factor fragment with no human dosing data at all. The peptide drove prostate-cancer cell growth and metastasis in mice by a route that bypasses the IGF-1 receptor, and the pegylated form people buy has never been characterised.
7LL-37Avoid53% positive€45–110/moImmunePro-inflammatory/autoimmune and context-dependent pro-tumour activity, plus FDA-noted reproductive effects.
8KisspeptinAvoid52% positive€4.1–12/moHormones & libidoDirectly manipulates the HPG axis; continuous or long-acting exposure suppresses it.
9SS-31Avoid52% positive€71–350/moMitochondria & longevityMitochondrial cardiolipin binder; FDA-approved for Barth syndrome, popular for energy and endurance.
10Melanotan IIAvoid51% positive€27–54/moSkin & hairDocumented serious harms (melanoma reports, PRES, priapism) from non-selective melanocortin activation.
11TB-500 / Thymosin beta-4Avoid50% positive€15–73/moRecovery, joints & healingTβ4 has a well-documented pro-angiogenic and pro-metastatic role in cancer biology, and the fragment actually sold has no human safety data.
12DihexaAvoid50% positive€13–53/moNeuroprotection & repairActivates the oncogenic HGF/c-Met pathway, has no human safety data, and its foundational studies are under expressions of concern.
13GHK-Cu (injectable)Avoid50% positive€20–40/moSkin & hairBorderline: theoretical growth-factor/angiogenic signalling at supraphysiological systemic doses with no human injectable safety data. Topical GHK-Cu gives much of the skin benefit without this.
14IGF-1 DESAvoid49% positive€22–180/moHormones & libidoAn IGF-1 receptor agonist about ten times as potent as IGF-1 in cells and the most hypoglycaemic of the IGF-1 variants in primates, with no human data, the same tumour-promotion concern as LR3, and grey-market vials that are rarely tested.
15GLP-1 agonists (semaglutide, tirzepatide, retatrutide)Avoid49% positive€27–1210/moMetabolic & weightPotent drugs with real serious-harm paths (pancreatitis, gallbladder, GI, heart rate, NAION). Worth it for obesity/diabetes under a doctor, but outside a 'clean general-health peptide' list.
16MK-677Avoid48% positive€18–54/moHormones & libidoGH/IGF-1 elevation, insulin resistance and a CHF safety signal in an RCT.
17EpitalonAvoid48% positive€41–82/moMitochondria & longevityIts claimed mechanism, telomerase activation, is a theoretical oncogenic path, and the data come from a single group.
18BPC-157Avoid46% positive€20–41/moRecovery, joints & healingPro-angiogenic mechanism with a plausible path to tumour growth and retinal neovascularisation, plus essentially no human safety data. HHS enforcement discretion (29 Oct 2026) is not a safety finding.
19SermorelinAvoid46% positive€38–94/moHormones & libidoGH/IGF-1 axis elevation, though the mildest of the class.
20HexarelinAvoid45% positive€27–110/moHormones & libidoGH/IGF-1 axis elevation, acute cortisol and prolactin release, and GH-independent actions on heart and coronary vessels via CD36.
21LinaclotideAvoid45% positive€450/moGutThe label warns of severe diarrhoea (2% in trials), and post-marketing reports describe dehydration with fainting, low blood pressure and low potassium or sodium that needed IV fluids or hospital, plus rare anaphylaxis and angioedema. The harm is obvious at once and stops when the drug does, so under a doctor it is a reasonable IBS-C treatment, but it is a real route to serious harm and does not belong on a clean wellness list.
22PlecanatideAvoid45% positive€540–650/moGutThe label warns of severe diarrhoea (0.6-1% in trials, most within the first days) with instructions to stop and rehydrate, and Reddit users describe days of watery diarrhoea leaving them badly dehydrated. Its sibling linaclotide has post-marketing hospitalisations for the same harm. It is obvious and stops when the drug does, so under a doctor it is a reasonable constipation treatment, but it is a real route to serious harm and does not belong on a clean wellness list.
23Follistatin-344Avoid44% positive€180–450/moHormones & libidoBlocks myostatin and activin signalling (FSH axis, angiogenesis, glucose) with no human safety data for the injected protein; vials often hold other drugs.
24FGLAvoid43% positive—Neuroprotection & repairAgonist of the mitogenic FGF receptor, with only phase-1 data and no users to learn from.
25HumaninAvoid43% positive—Neuroprotection & repairIts anti-apoptotic action helps glioma cells survive chemotherapy in animal studies, and there is no human data.
26Corticotropin (repository ACTH gel)Avoid43% positive—Neuroprotection & repairDrives the adrenals to flood the body with cortisol, so it carries the corticosteroid label warnings (infection, Cushing's syndrome, adrenal insufficiency on withdrawal, GI perforation, psychosis, high blood pressure and glucose, bone loss) plus anaphylaxis. A prescription relapse treatment under a neurologist, not something to take outside one.
27TesamorelinAvoid43% positive€240–480/moMetabolic & weightGH/IGF-1 axis elevation (neoplasm and glucose warnings on label) plus anaphylaxis reports.
28IpamorelinAvoid42% positive€11–100/moHormones & libidoGH/IGF-1 axis elevation plus repeated anaphylaxis reports, including a coroner-attributed death.
29PTD-DBMAvoid42% positive€36–90/moSkin & hairIt works by switching on Wnt/beta-catenin signalling in skin, and sustained beta-catenin activation causes hair-follicle tumours in mice and pilomatricoma in humans. It has no human safety data, and users pair it with valproic acid, a teratogen.
30MOTS-cAvoid42% positive€22–88/moMetabolic & weightBorderline: recurring reports of allergic sensitisation and anaphylaxis-like events, plus no human data on the native peptide at the doses used.
31IGF-1 LR3Avoid40% positive€36–140/moHormones & libidoA potent, long-acting IGF-1 receptor agonist with no human data at all: it accelerated tumour growth in mice, the same receptor causes hypoglycaemic seizures and carries a malignancy warning on the approved IGF-1 drug, and every vial is grey-market.
32CerebrolysinAvoid40% positive€140–540/moNeuroprotection & repairCochrane found more non-fatal serious adverse events than placebo; animal-derived injectable with allergy/immune reaction risk.
33GHRP-2Avoid39% positive€18–45/moHormones & libidoGH/IGF-1 axis elevation with cortisol and prolactin spikes; FDA notes raised insulin needs and deaths in critically ill subjects.
34PT-141Avoid39% positive€24–170/moHormones & libidoCardiovascular effects (BP spikes; contraindicated in CVD) and melanocortin pigmentation effects.
35CJC-1295Avoid38% positive€14–27/moHormones & libidoGH/IGF-1 axis elevation plus FDA-noted tachycardia/vasodilatory reactions and anaphylaxis.
36Glatiramer acetateAvoid37% positive—Neuroprotection & repairPrescription immunomodulator for relapsing MS with an FDA boxed warning for anaphylaxis (82 cases, 6 deaths reported to 2024, some years into treatment), plus label warnings for liver injury and skin necrosis. Worth it for MS under a neurologist; not a self-directed peptide.
37CagrilintideAvoid36% positive€27–110/moMetabolic & weightUnapproved drug bought as grey-market vials and usually stacked on retatrutide or tirzepatide outside any trial: gallbladder disease and fast lean-mass loss, severe hypoglycaemia if combined with insulin (amylin class), days of not eating from dosing errors with home-reconstituted vials, and a pH-sensitive peptide sold in plain powder.
38Orexin-A (intranasal)Avoid1/10 researcher estimate—Focus & memoryEssentially untested, with sympathetic activation and no reliable product.

Sequence

The peptide's chain of amino acids from its start (the N-terminus) to its end, one bead and one letter for each: A alanine, C cysteine, D aspartic acid, E glutamic acid, F phenylalanine, G glycine, H histidine, I isoleucine, K lysine, L leucine, M methionine, N asparagine, P proline, Q glutamine, R arginine, S serine, T threonine, V valine, W tryptophan, Y tyrosine. A modification such as an N-acetyl cap or a C-terminal amide changes how long it lasts in the body. Length tells related peptides apart, from a two-residue dipeptide like carnosine to a 43-residue protein like thymosin beta-4, and predicts neither effect nor safety.

Report grades

Every first-hand Reddit or X report is graded on its own, from glowing through positive, mixed, nothing and negative to bad reaction, and the bar shows how those grades split. Posts that look vendor-adjacent stay on the peptide's page but are left out of the counts.

GlowingPositiveMixedNothingNegativeBad reaction

% positive

The share of a peptide's graded Reddit and X reports that are glowing or positive, vendor-adjacent posts left out. A peptide with few reports is pulled toward the average of all reports, as if it had eight average ones besides its own, so two glowing posts cannot top the list. Peptides rank by this figure, those with no graded report yet after those with one, and Avoid ones after every other entry.

Researcher estimate

No first-hand report of this peptide has been graded yet, so the figure is the researchers' own rating out of 10 from what they read about it. It ranks after every peptide with graded reports until its own arrive.

Safety tier

Each peptide is tiered Clean, Caution or Avoid from its five risk axes under the chosen safety bar. An Avoid peptide carries a real risk of harm, a plausible route to serious harm rather than mere unpleasantness, so it stays listed with the reason but ranks behind every other entry, however good its reviews.

Safety bar

The safety bar sets how much risk it takes to rate a peptide Avoid. Strict: out on any serious mechanism with little human data, or any documented serious harm. Balanced: out on documented serious harm (unless it is obvious, reversible and from a regulated product), or a serious mechanism whose harm would be silent with no human data at all. Evidence only: out only on documented serious harm in humans that is lasting, delayed or from grey-market product.

Seen harm

Documented serious adverse events in humans, from 0 for none despite real exposure to 3 for deaths or several well-documented serious harms. Serious means a hospital or emergency visit or harm lasting weeks, so a headache or a bad night does not count.

Mechanism

A plausible biological route to serious harm at the doses people use, such as growth-factor signalling, hormone-axis suppression, heart or blood-pressure effects or immune activation. It runs from 0 when none is known to 3 when a dangerous pathway has been shown in living animals.

Data gap

How little human safety data exists for the molecule actually sold, from 0 for an approved drug with large trials and years of use to 3 for no human safety data at all. A modified analogue does not inherit its parent's trials.

Silent harm

Whether the feared harm would show quickly or stay hidden, from 0 when it is obvious and goes on stopping to 3 when it is silent and delayed, like tumour promotion or slow organ damage. User reports cannot reveal a harm that takes years to appear, so a high score here limits what good reviews can tell you.

Product

The risk of what people actually buy, from 0 for a regulated pharmacy or supplement product taken by mouth or on the skin to 3 for a grey-market injectable. In one dataset of 6,441 grey-market samples, 42–71% failed basic quality criteria and 15% carried endotoxin; taken by mouth or in the nose, a pack avoids the injection risks.

Evidence

The strongest kind of study behind the peptide's effects, from an approved drug through human controlled trials and small human studies to animal work or nothing of its own. Animal results often fail to carry over to people.

Access

How people get it: as an approved drug, a compounded prescription, an over-the-counter supplement or from the grey market, where nobody checks the vial. The channel decides both the legal position and the risk of a bad batch.

Price per month

Thirty days of the typical dose, from its low end to its high end, priced at the listing a careful buyer would choose: in stock, from a shop scoring 4 of 5 on trust (third-party tested where no score is set), failing that 3, a pure pack before a blend, a European shop first, then the cheapest per mg. The range is the dose's, not the shops'. A per-dose amount counts once a day unless the dose says otherwise. Prices are in euros at ECB rates of 2026-10-29, before shipping; the shop table keeps each listing's price per mg, per gram for bulk supplements. Where no listing can be priced the researchers' own estimate stands in, and says so.

Dose users report

The middle half of the daily doses stated in at least five first-hand reports, vendor posts left out. Where its middle sits more than twice above or below the declared dose, the month is priced at it as well, since what people take is what they pay for.

Shop trust

Each shop's trust on a 1–5 scale, read from its testing and its reputation: 1 for serious red flags (fabricated COAs, scam reports, impersonation, a closed shop), 2 for no public testing, a new shop or active complaints such as seized parcels, 3 for its own COAs or a short track record, 4 for verified third-party testing or a strong reputation, and 5 for third-party batch reports that name the shop, with years of good independent reputation. A shop without a score counts third-party batch testing as 4, its own COAs as 3 and no public tests as 2.

Best value

Within a category or a goal, a peptide that no other beats on both counts: none is rated more positively for the same or a lower monthly price, and none costs less for the same or a higher rating. The chart joins these into the best-value line; the cheapest of them and the best-rated of them both make it, so the line spans the trade-off from cheap to best. Avoid entries never count, and a peptide needs both a % positive and a price to be compared.

Testing

Whether the shop publishes lab results: third-party tested means an independent lab checks each batch, own COA means the shop's own certificate of analysis, and no public tests means neither. A certificate shows purity, not safety.

Added peptide

Some packs sold under one peptide's name hold a second one, such as 5 mg GHK-Cu in a nasal kit, stated only in the description. Sprayed in the nose or injected it reaches the blood like an injection, so it carries the risk of that route and is tiered as the injectable form, whatever its tier on the skin. A pack whose page gives no contents list may hold more than its name.