Peptides: promising, poorly tested and often gray-market

The Short Version

Peptides are real, active drugs. They are not harmless wellness products, and the evidence behind most of them is still thin. Dr. Craig Koniver, a physician who has used peptides in his clinic for about eight years, reports thousands of patients helped by compounds like BPC-157, growth hormone secretagogues and pinealon, and says openly that his case rests mostly on clinical observation, not published trials [1]. In his solo review, Andrew Huberman is enthusiastic about the potential, but he stresses that most of the data come from animals, that BPC-157 may feed tumors, and that gray- and black-market products can carry toxins like LPS [2]. His growth hormone episode adds that injecting growth hormone or its secretagogues can shut down the body's own signals, switch on long-lived gene programs and help tumors grow [3]. Put together, the three episodes show why anyone trying peptides needs a board-certified physician, pharmacy-grade sources, the lowest effective dose and regular monitoring. The field is growing fast, and regulation is loose and keeps changing [1][2][3].

Table of contents

What They Said

Dr. Craig Koniver: the clinician's case for peptides

Koniver is a board-certified physician trained at Brown University and Thomas Jefferson University. He practices what he calls "performance medicine" [1]. His definition is plain: peptides are just chains of amino acids, with 40 amino acids or fewer counting as a peptide and 41 or more as a protein [1]. By the last count he read, the body makes around 300,000 peptides, while clinicians have used perhaps 150 of them as treatments. After about eight years of using them, he still thinks the field is early [1].

Where peptides fit. Huberman opens the conversation by placing peptides on a ladder. They "sit somewhere between doing nothing, except diet and exercise, supplements," and the prescription hormone therapies that "can shut down one's natural production of those hormone pathways" [1]. Their appeal, in his words, is that "they don't tend to operate in that negative feedback cycle by shutting down one's own endogenous production" [1]. In the same breath he adds a caveat: "Now that doesn't mean that they aren't without some safety concerns," and he flags "the critical issue of sourcing clean peptides and working with a board certified physician if one is going to pursue peptide use" [1].

Koniver's own philosophy fits that framing. On testosterone and growth hormone he says, "I don't ever want to manipulate hormones," meaning he doesn't want to give people more than they would get in nature [1]. He dislikes testosterone pellets because they expose people "to a concentration of hormones we would never ever see in nature" [1]. For peptides, his goal is to "just stick within kind of the highways of the lane, swim lanes for how they should operate and then take advantage of that" [1].

BPC-157 and its replacement. BPC-157 has been Koniver's most-used peptide. He gave it to almost every patient for its anti-inflammatory effects [1]. He reports thousands of patients becoming less stiff and sore, with improvements in knees and shoulders, and help with recovery after viral illness [1]. His clinic started at 500 micrograms a day and went as high as 5,000, usually five days on and two days off [1]. He found injections under the skin worked better than oral forms, even for gut conditions, and that an injection anywhere seemed to act throughout the body. He says it shines for tendons and ligaments, can be injected directly into tendons mixed with PRP or PRF, and that IV doses served as a quick "spark" [1]. He reports no notable side effects with BPC-157 or its successor [1].

Huberman framed the evidence bluntly in that same conversation. He described BPC-157 as having "a lot of animal data. Very few, if any clinical studies on humans, but a lot of people now taking BPC in various forms" [1]. In October 2023 the FDA put BPC-157 and many other peptides on a list that bars compounding pharmacies from making them [1]. Koniver's alternative is pentadeca arginate (PDA). It differs from BPC-157 by one amino acid and, in his early experience, gives very similar results, at a starting dose of 250 to 500 micrograms a day, Monday to Friday, which he calls conservative [1].

Growth hormone secretagogues and their "flavors. These peptides push the body to release its own growth hormone instead of supplying it. Ipamorelin prompts the pituitary to release growth hormone, which drives the liver to make IGF-1, an anabolic, healing hormone that falls with age [1]. Koniver says each peptide has a flavor" [1]:

• Ipamorelin is the cleanest and most specific: a leaner body, better sleep, few side effects.
• GHRP-6 is more potent, but it also releases prolactin and ACTH (which drives cortisol) and spikes appetite, so it's a tool for gaining mass.
• MK-677 works in a similar way but is taken by mouth. He took it at bedtime once and woke an hour later ravenously hungry, though it can help older adults who struggle to build muscle.
• Tesamorelin (2 milligrams per dose) is FDA-approved for visceral fat in HIV-related lipodystrophy and, in his experience, works better in women.
• Sermorelin has a broad dose range of 200 to 3,000 micrograms.
• Hexarelin (100 micrograms) is his morning "energy endurance" option, with no effect on appetite.

He sees growth hormone as a resiliency hormone for people who recover slowly from workouts, sprains or cuts. His favorite stack put BPC-157, ipamorelin and tesamorelin in one bedtime shot [1]. He argues that BPC-157 appears to upregulate growth hormone receptors, so it pairs well with growth-hormone-releasing peptides and allows lower doses of them [1].

He is precise about dose. He says the dosage of ipamorelin "and most of these growth hormone released in peptide should be 100 micrograms" [1]. He has heard of anaphylaxis in people who pushed to 200 to 400 micrograms chasing the warm flushing sensation [1]. He recommends injecting at bedtime, with no food for at least 45 minutes beforehand, and being asleep by around 10 p.m., because the largest growth hormone pulse is thought to come between about 10 p.m. and 2 a.m. [1]. He takes breaks even from supplements, because "Anything you expose yourself to continually, doesn't work as well" [1].

Sleep: pinealon. Huberman described injecting pinealon with glycine. Nothing before had increased his REM sleep, and this roughly doubled it according to his sleep tracker, and it seemed to help even on nights he skipped it [1]. Koniver says this matches what his patients see and that he has never seen a negative side effect from pinealon [1]. Again, the evidence here is one person's tracker plus one physician's clinical impressions.

GLP-1s off label. Koniver notes that most medicines in America are prescribed off label, which Huberman finds astonishing to hear said so plainly [1]. His clinic microdoses compounded tirzepatide and semaglutide and raises the dose slowly. In his experience, people losing two pounds a week or less don't lose muscle, especially if they eat enough protein and do resistance training [1]. He has seen inflammation markers fall. But he admits he can't say whether that is a direct effect of the drug or the result of losing fat [1].

Sourcing and the gray market. Here Koniver's view and Huberman's meet. Koniver says, "having a physician who's knowledgeable to me is super helpful," because people "don't know where to get the right information" and are getting it from websites and from people saying "just try this peptide" [1]. He has seen people "who've had anaphylactic reactions to research type peptides, which are not for human consumption" [1]. Huberman describes a "dark, dark gray market" of companies whose labels say "not for human or animal consumption, research purposes only" [1]. Such products may contain lipopolysaccharide (LPS), an inflammatory toxin whose effects Huberman understands may build up over time [1]. Koniver contrasts this with compounding pharmacies. They are regulated by the FDA and state pharmacy boards, inspected regularly, and must have sterile products tested by outside labs for purity and endotoxins [1].

Misuse of hormones. Koniver tells of a 25-year-old who had used testosterone and growth hormone since his late teens and felt like "Superman." When he wanted children he found he had zero sperm and needed drugs like clomiphene and HCG to rebuild his system [1]. Huberman adds that most men from their teens to their early 40s don't need synthetic testosterone if they sleep, eat and train well [1].

The FDA and the regulatory picture. Koniver thinks the FDA's removal of many peptides is "probably both: good intentions to regulate a wild, wild west," plus overreach, alongside drug companies that may see a path to turning popular peptides into expensive branded drugs [1]. The landscape is moving fast. Just before the episode came out, Huberman learned that three peptides discussed as restricted, CJC-1295, ipamorelin and a thymosin peptide, "are now reallowed for prescription in the United States" [1]. Other peptides Koniver values, such as thymosin alpha-1 and epitalon, have been removed [1].

Andrew Huberman's review: potent, pleiotropic and mostly tested in animals

In his solo episode, Huberman sets aside GLP-1 drugs and maps the rest of the field in four categories: tissue repair, growth hormone, longevity, and vitality and libido [2]. His tone is educational and notably cautious. He is openly excited about the potential, but he keeps coming back to the evidence gap, side effects and sourcing [2].

The central idea: peptides do many things at once. Huberman says the most important concept is that peptides have pleiotropic effects. When a peptide binds its receptor it sets off a "bucket brigade" of downstream processes: growth in one pathway, cell migration in another, blood vessel growth in a third [2]. A peptide rarely does one thing. It may do anywhere from four to a thousand things, so anyone taking it for one purpose, such as healing an injury or raising growth hormone, will switch on other pathways too [2]. That shapes the effects, the side effects, the dose, how long to take it and whether to cycle on and off [2].

Sourcing: three routes. Peptides come by prescription from a board-certified physician (via drug companies or compounding pharmacies), from the gray market online with questionable safety and efficacy, or from the black market, where products are often contaminated or not what the label claims [2]. The contaminant he singles out is LPS. It can build up during manufacturing and triggers an immune response. A tiny amount may not cause much trouble, but repeated exposure can become a problem over time [2]. Gray- and black-market products may contain the right compound but often haven't had the LPS removed [2]. His stance: "I implore you to do so with a board certified physician," with peptides from a reliable source [2].

BPC-157: strong animal data, almost no human data. Huberman explains why a gut peptide might help healing. The gut lining constantly replaces its cells, which is essentially the same process as wound repair [2]. In animals, BPC-157 promotes angiogenesis (new blood vessels) at injury sites, partly through the endothelial nitric oxide pathway, and draws fibroblasts in to build a scaffold for repair [2]. Rat studies on sciatic nerve and Achilles tendon injuries, including complete transections, show impressive results [2]. How it travels to the injury isn't understood [2].

Then comes the gap. Rigorous animal research goes back to about 1993, but Huberman knows of only one human study, which he calls poorly performed and not a clinical trial, even though hundreds of thousands or perhaps millions of people now take BPC-157 [2]. So placebo effects can't be ruled out [2]. In animals the LD50 is very high, about two grams per kilogram of body weight, and he stresses that this does not mean anyone should take high doses [2]. The prescribed doses he describes are 300 to 500 micrograms under the skin two or three times a week for about eight weeks, then eight to ten weeks off. He thinks taking it daily and indefinitely is a bad idea [2].

The tumor question. Huberman says this warning is rarely discussed. BPC-157 slightly raises growth hormone receptors, and it raises VEGF (vascular endothelial growth factor) to drive blood vessel growth [2]. Tumors thrive on more blood flow and growth factors. The common cancer drug Avastin works by blocking VEGF, the exact opposite effect [2]. His conclusion: "BPC 157 is a potential tumor growth risk" [2]. Anyone with a known cancer or worries about tumors should be very cautious, as should people with eye diseases involving vascular overgrowth [2]. For those who go ahead, he suggests the minimum effective dose, not taking it every day or continuously, and watching health markers for any sign of tumor growth. Faster recovery for training or sport, he says, is not worth growing or speeding up a cancer [2].

TB-500. Thymosin beta-4 and its shorter synthetic version, TB-500, come from the thymus, a gland children have that fades with age [2]. The link between the thymus and children's fast healing is correlational, the evidence is mostly from mice and rats, and people's reports of faster healing have no control comparison [2].

Growth hormone secretagogues, type one and type two. Growth hormone output falls about 15% per decade after 30 [2]. Synthetic growth hormone grows tissues indiscriminately, including any existing tumor, and triggers negative feedback that shuts down the body's own production. That's why secretagogues were developed [2]. Huberman sorts them into his own categories:

• Type one (sermorelin, tesamorelin, CJC-1295) are the best tested in humans, and some are FDA-approved [2]. He describes sermorelin doses of 200 to 400 micrograms before sleep, three to five times a week, because continuous daily use can cause some desensitization [2]. CJC-1295 lasts several days, but there was a death from cardiovascular dysfunction in one of its clinical trials, and it can cause fluid retention. He doesn't see why anyone would choose it until those safety issues are resolved [2].
• Type two (ipamorelin, hexarelin, GHRPs, MK-677) work by mimicking or stimulating ghrelin, the hunger peptide, which can also raise anxiety [2]. Ipamorelin tends to deepen sleep, though it's unknown whether that costs REM sleep [2]. Hexarelin gives the largest pulses, two to three times bigger than the others, but can sharply raise prolactin. Worse, it can desensitize growth hormone releasing hormone receptors, which could shut down the system's response to anything, including the body's own signals [2]. GHRP-3 can more than double circulating cortisol, and MK-677 has similar cortisol and prolactin issues [2].

The major risk across all of them is more tumor and cancer growth. Combining a growth hormone peptide with BPC-157 could increase both the size and the blood supply of a tumor [2]. If you're under 30, he doesn't see why you would raise growth hormone without a clinical need. If you're older, he says to rule out tumors, use the minimum effective dose and choose the mildest compounds [2].

Longevity and libido. Animal studies of epitalon show tumor suppression, telomere lengthening and partial offsetting of aging, but Huberman calls using it to extend human life "a leap," since no clinical trials show it extends life [2]. PT-141 (Vyleesi) is FDA-approved for low sexual desire in premenopausal women and is prescribed off label to men. Its side effects include nausea, skin flushing and raised blood pressure, and people with melanoma should be very cautious with any peptide that stimulates melanocytes [2]. He calls kisspeptin for libido a wild card because it was discovered fairly recently [2].

His bottom line. Because peptides are talked about differently from testosterone or estrogen therapy, many people wrongly assume they are safe, harmless or free of side effects. In fact they are very potent compounds with many effects, and we are early in understanding them [2]. His guardrails are a good board-certified physician, clean sourcing, regular blood work and monitoring for tumor growth. "I'm not here to tell you what to do or what not to do," he says, but he wants listeners informed [2].

Huberman's growth hormone episode: injections carry their own risks

In his Essentials episode on thyroid and growth hormone, Huberman spends most of his time on behavioral tools and ends with a cautious look at peptides [3]. Between ages 30 and 40, nightly growth hormone release drops two- to three-fold. That has made growth hormone replacement therapy "tremendously popular in the last 20 years, which is not to say it doesn't carry its problems" [3].

The main problem with injecting growth hormone is that "growth hormone, if it's in levels that are too high, will cause growth of all tissues," including "the heart and the lungs and the liver and the spleen" [3]. He is careful not to forbid it: "Not saying people shouldn't do this if the doctor has approved it or it's in keeping with their particular life goals" [3].

On sermorelin, he is direct: "Sermoralin is prescription. Do they work? Yes. Do they shut down your natural production of growth hormone releasing hormone? Well, the answer is yes" [3]. He contrasts the short spikes from exercise, arginine or sauna with injections: "when one is injecting over and over a constant level, you can put into action gene expression programs that can be long lived" [3]. And on cancer: "tumors will grow when they see growth hormone even if that tumor is unhealthy for you" [3]. He sums up his position: "So again, not promoting their use, but they're definitely out there" [3].

What sets this episode apart is the alternative it offers. Hard exercise of up to about 60 minutes, with a real warm-up and a prompt cool-down, raised growth hormone 300 to 500 percent, with similar increases the following night [3]. Arginine raised it 400 to 600 percent, but above 9 grams the effect is blunted, because "this is definitely a case of more is not better" [3]. Repeated sauna sessions raised it up to 16-fold, with the warning to "proceed with extreme caution" [3]. Not eating within two hours of bed protects the nightly pulse [3]. Huberman thinks behaviors alone might offset the age-related decline, and his standing advice is to "talk to a doctor before you do anything, including remove any treatments" [3].

Where They Agree, and Where They Don't

Where they agree

• See a physician and use clean sources. This is the one point all three episodes share. Koniver finds a knowledgeable physician "super helpful" and describes anaphylaxis from research-grade products [1]. Huberman says, "I implore you to do so with a board certified physician" [2], and to talk to a doctor before starting or stopping anything [3]. Both men distrust "research purposes only" products and the LPS they may carry, and both trust compounding pharmacies more [1][2].
• The human evidence is thin. Huberman says it outright about BPC-157, both in the Koniver interview [1] and in his review, where he knows of only one poor human study [2]. The summary of the Koniver episode notes that it rests mostly on his clinical observation, not published trials, and that both men say so openly [1].
• Each peptide has its own profile. Koniver's "flavors" and Huberman's "type one" and "type two" describe the same thing: GHRP-6 and MK-677 raise appetite, prolactin and cortisol, while ipamorelin is cleaner [1][2].
• Timing around sleep and food. Both recommend injecting growth hormone peptides near bedtime on an empty stomach, because food and blood sugar blunt the pulse [1][2][3].
• Take breaks. Koniver uses five days on, two off, and breaks even from supplements [1]. Huberman cycles BPC-157 off for eight to ten weeks and warns of desensitization with continuous sermorelin [2].
• Individual responses vary. Huberman's sermorelin experience comes up in two episodes: it gave him deep early-night sleep but wiped out his REM sleep and, as he told Koniver, consistently raised his PSA [1][2].

Where they don't

• How much BPC-157, and how often. Koniver used 500 to 5,000 micrograms a day, five days a week, and gave it to almost every patient [1]. Huberman describes 300 to 500 micrograms two or three times a week, cycled off after about eight weeks, and calls daily, indefinite use a bad idea [2]. The gap reflects what each trusts. Koniver trusts years of seeing patients do well with no notable side effects [1]. Huberman looks at the biology, where more VEGF and blood vessel growth could help a tumor as easily as a tendon [2].
• Stacking BPC-157 with growth hormone peptides. For Koniver, the fact that BPC-157 boosts growth hormone receptors is a feature: it lets him lower the doses of the growth hormone peptides, and his favorite stack combines BPC-157 with ipamorelin and tesamorelin [1]. For Huberman, the same combination could increase both the size and the blood supply of a tumor [2]. They see the same mechanism and judge it differently.
• Side effects. Koniver reports no notable side effects from BPC-157, PDA or pinealon [1]. Huberman warns that assuming peptides are free of side effects is a mistake, because every peptide does many things at once [2]. The difference is partly about what each is looking for. A clinician watches for reactions he can see. A tumor that grows slowly over years won't show up in a clinic visit, which is why Huberman asks for ongoing monitoring [2].
• Do peptides spare the body's own production? In the Koniver interview, Huberman says peptides "don't tend to operate in that negative feedback cycle" [1], and Koniver likes them for staying within the body's "swim lanes" [1]. In the growth hormone episode, Huberman says sermorelin does shut down natural growth hormone releasing hormone production [3]. In his review, he warns that hexarelin can desensitize the receptors and that continuous sermorelin can cause desensitization [2]. The best reading is that peptides are gentler than taking hormones directly, not free of feedback, especially with constant dosing.
• Sermorelin's range. Koniver cites a broad range of 200 to 3,000 micrograms [1]. Huberman describes 200 to 400 micrograms, three to five times a week [2].
• The FDA. Koniver sees the peptide removals as partly overreach and partly drug-company interest, and worries about patients losing affordable access [1]. Huberman's review focuses less on policy and more on the dangers of unregulated sources [2]. Both accept that the market has been a "wild, wild west" [1].
• Whether to use them at all. Koniver uses peptides widely and sees them as gateways that help people feel better [1]. In the growth hormone episode, Huberman lists behavioral tools first and describes peptides as "not promoting their use" [3]. In his review he says he isn't there to tell people what to do, but that people under 30 have little reason to raise growth hormone without a clinical need [2].

Why It Works

The sources explain both why peptides can help and why that same power carries risk.

Signaling instead of replacing. Growth hormone secretagogues copy the brain's signals. The hypothalamus releases growth hormone releasing hormone, the pituitary releases growth hormone, and the liver makes IGF-1 [2][3]. Sermorelin is a partial sequence of growth hormone releasing hormone. It prompts the pituitary to release growth hormone instead of supplying the hormone itself [3]. Type two peptides act through ghrelin, and ipamorelin also suppresses somatostatin, the body's brake on growth hormone [2]. That's why they can raise growth hormone with milder effects than injecting the hormone [2].

Why BPC-157 might heal tissue. In animals it drives angiogenesis through the endothelial nitric oxide pathway and draws fibroblasts to the injury [2]. The gut lining's constant turnover is essentially wound repair, which may explain why a gut-derived peptide helps healing [2]. Koniver adds that it seemed to act throughout the body wherever it was injected, and compares this to a study in which tagged intravenous stem cells gathered at a wrist fracture within 24 hours [1].

Why the same mechanisms raise concerns.

• Pleiotropy. One peptide can set off anywhere from four to a thousand effects, so side effects come with the territory [2].
• Blood vessels feed tumors. BPC-157 raises VEGF, and a leading cancer drug works by blocking VEGF [2]. Growth hormone grows all tissues, and "tumors will grow when they see growth hormone" [3].
• Constant dosing differs from natural pulses. Short spikes from exercise, arginine or sauna are transient. Repeated injections at a constant level can start long-lived gene expression programs [3]. They can also shut down growth hormone releasing hormone production [3] or desensitize its receptors [2].
• Off-target hormones. GHRP-6, GHRP-3, hexarelin and MK-677 can raise prolactin and cortisol, which can suppress libido, cause fluid retention and more [1][2].
• Contamination. LPS left in from manufacturing triggers an immune response that may build up over repeated doses [1][2].

Why dose matters. Koniver says ipamorelin's effective ceiling is 100 micrograms, and pushing past it has been linked to anaphylaxis [1]. Huberman stresses the minimum effective dose throughout [2]. The arginine data in [3] show the same principle outside peptides: more is not better.

Where It Applies, and Where It Doesn't

Where peptides may be reasonable:

• Older adults with a clear need, under medical care. Huberman sees more reason to consider growth hormone support after 30, once tumors have been ruled out [2]. Koniver describes MK-677 as possibly helping older adults who struggle to build muscle [1].
• Slow healing of tendons and ligaments. This is the use where Koniver reports his strongest results with BPC-157 and PDA [1], and where animal data are most impressive [2]. Human proof is still missing [2].
• Uses with FDA approval. Tesamorelin for visceral fat in HIV, sermorelin for short stature and PT-141 for low desire in premenopausal women have a stronger footing than purely experimental uses [2].

Where caution, or avoiding them, makes sense:

• Anyone with cancer, a history of tumors or tumor concerns. Both BPC-157 and growth hormone peptides may feed tumor growth [2][3]. People with melanoma should be very cautious with melanocyte-stimulating peptides [2]. People with eye diseases involving vascular overgrowth should also be careful with BPC-157 [2].
• People under 30 with no clinical need. Huberman doesn't see why they would raise growth hormone [2]. Koniver's story of the 25-year-old left with zero sperm after years of testosterone and growth hormone shows the cost of misuse [1].
• Gray-market "research" products. Both experts warn against them because of LPS and anaphylaxis risks [1][2].
• People who care about REM sleep. Sermorelin cost Huberman his REM sleep, and it's unknown whether ipamorelin's deeper sleep comes at the expense of REM [1][2].
• Longevity claims. Using epitalon to extend human life remains "a leap" [2].
• Anyone who hasn't tried the basics. Sleep, not eating within two hours of bed, hard exercise and heat can raise growth hormone substantially without injections [3].

A moving target. What is legal to prescribe changes quickly. BPC-157 was barred from compounding in October 2023, and CJC-1295, ipamorelin and a thymosin peptide were restricted and then allowed again within the span of one episode's release [1]. Advice tied to a specific compound may go out of date.

What To Do With It

Peptides are prescription-level decisions. Talk to a qualified physician before starting or stopping any of them [2][3].

1. Start with the free tools. Protect deep early-night sleep, stop eating about two hours before bed, and train hard for up to about 60 minutes with a real warm-up and a prompt cool-down. These can raise growth hormone 300 to 500 percent [3].
2. Work only with a board-certified physician who knows peptides. Both experts insist on this [1][2]. Stacking and relative dosing especially need someone experienced, to avoid needless prolactin and cortisol increases [2].
3. Refuse "research purposes only" products. Use compounding pharmacies or drug companies, whose sterile products are tested by outside labs for purity and endotoxins [1][2].
4. Screen for tumors first, and keep monitoring. Huberman advises ruling out tumors before raising growth hormone, getting regular blood work, and watching for signs of tumor growth. Take this especially seriously if you're combining BPC-157 with a growth hormone peptide [2].
5. Use the minimum effective dose and respect the ceilings. For ipamorelin and most growth hormone releasing peptides, Koniver's ceiling is 100 micrograms. Going to 200 to 400 micrograms has been linked to anaphylaxis [1]. Huberman recommends the mildest compounds at the lowest doses that work [2].
6. Cycle. Use five days on, two days off [1], or for BPC-157, about eight weeks on and eight to ten weeks off [2]. Don't take it every day indefinitely [2].
7. Time growth hormone peptides around sleep and food. Inject near bedtime, with no food for at least 45 minutes before [1], or better, one and a half to two hours after eating and nothing for 30 minutes after [2]. Aim to be asleep by around 10 p.m. [1].
8. Track your own response. Huberman's trackers showed sermorelin wiping out his REM sleep, and his blood tests showed a rising PSA. Both were reasons to stop [1][2]. Measure sleep and relevant blood markers before and during use.
9. Be wary of compounds with known red flags. Huberman sees no reason to pick CJC-1295 until the safety question from the trial death is resolved [2]. Hexarelin can desensitize the growth hormone system [2]. GHRP-6 and MK-677 raise appetite, prolactin and cortisol [1][2].
10. Treat benefits as unproven until trials say otherwise. Many reported gains come from one clinician's experience, animal studies or one person's tracker, where placebo effects can't be ruled out [1][2]. Expect the rules to change, and check a compound's current status with your physician [1].

Sources

1. Dr. Craig Koniver: Peptide & Hormone Therapies for Health, Performance & Longevity · Huberman Lab
2. Benefits & Risks of Peptide Therapeutics for Physical & Mental Health · Huberman Lab
3. How to Control Your Metabolism by Thyroid & Growth Hormone · Huberman Lab