Peptide Expert: What Do Peptides Actually Do? (EXPLAINED) - Dr Alex Tatem
A long interview with a urologist who explains what peptides are, which ones he finds interesting, how the FDA and compounding pharmacies fit in, and why he warns against gray-market products.
With Dr. Alex Tatem, Stephen
Key moments
Tap a moment to play the video from there.
- 3:35What a peptide actually isTatem describes peptides as fragments of proteins built from amino acids that target specific receptors. He contrasts them with small-molecule drugs that act more broadly.
- 5:34Keys, locks, and BPC-157Using BPC-157 as his example, Tatem cites preclinical work on tendon injury and says he has not seen a harm threshold established. He adds that human data is still needed.
- 8:54Patents, compounding, and the 2023 banTatem traces the rise of interest to a patent ruling, new compounding rules, and the 2023 move of 19 peptides to a banned category. He says the official reason was insufficient safety data.
- 24:48The FDA's seven-peptide announcementTatem says the FDA announced that day it will consider moving seven peptides back to the compoundable category in July. He names BPC-157, TB-500, KPV, MOTS-c, DSIP, epithalon and C-max.
- 26:25Gray market and research-use-only vialsTatem explains how the gray market filled the gap after the ban and why he advises against it. He also explains why most peptides have to be injected.
- 29:58Compounded versus branded tirzepatideHe compares a branded tirzepatide pen with a compounded vial that allows smaller, more frequent doses. He says regulatory pressure on compounders reflects drugmaker interests.
- 43:23Keeping muscle on GLP-1 drugsTatem raises muscle loss during rapid weight loss and says myostatin-inhibiting antibodies are coming. He names bimagrumab, and also roledumab and trevogrumab as given in the captions.
- 52:29Trade-offs and a tour of the tableTatem lists the trade-offs of peptides, then covers tesamorelin, melanotan II, PT-141 and retatrutide. He says retatrutide has been used from research-use-only sources before approval.
- 1:01:58What happens after stopping GLP-1sTatem says people regain weight when they stop, though often not all of it if they change their lifestyle. He also mentions data on staying on a much lower dose.
- 1:07:53GHK-Cu for skinAsked about a super peptide for skin, Tatem points to GHK-Cu. He says topical versions are regulated differently from injectables and can be bought today.
What the video says
This is an interview from The Diary of a CEO in which the host questions Dr. Alex Tatem, a urologist who describes his work as men's health, about peptides. Peptides are the main subject for roughly the first 70 minutes. The last stretch covers Tatem's surgical training and burnout, the Enhanced Games, and erectile dysfunction implants.
Tatem defines peptides as short chains of amino acids that act like keys for specific receptors. He contrasts them with small-molecule drugs, which he compares to a hammer with broad effects. He says interest has surged for several reasons: a 2013 patent ruling that removed the commercial incentive to develop natural compounds, tighter compounding rules after a contamination scandal, the 2023 FDA decision that moved 19 popular peptides into a banned category, and viral social media. He says he prescribed several of them before the ban and saw no adverse events. He suggests, while saying he cannot prove it, that pharmaceutical interests may have influenced the ban. He says that on the day of recording, April 15, the FDA announced it would consider returning seven peptides to the compoundable list in July.
He then goes through the vials on the table, including BPC-157, TB-500, GHK-Cu, tesamorelin, melanotan II, CJC-1295 with ipamorelin, growth hormone, epithalon, and sleep and cognition peptides. He is openly skeptical about epithalon as a longevity compound. He stresses that most peptides must be injected, that research-use-only products carry no quality control, and that people should talk to a doctor instead of ordering online. A large share of the conversation is about GLP-1 drugs: compounded tirzepatide and split dosing, muscle loss during rapid weight loss, upcoming myostatin inhibitors, weight regain after stopping, and retatrutide.
Tatem is an advocate for legal access, and the host largely agrees with him. The claims about benefits and safety are his own and are not backed by studies shown on screen.
On each compound
BPC-1576:57
Tatem calls BPC-157 a synthetic version of a gut peptide and cites preclinical tendon work, which he says does not translate one to one to humans. He says he would have wanted it, with TB-500, for his own shoulder injuries.
See how your DNA reads BPC-157TB-50025:23
Tatem describes TB-500 as the 'brother' of BPC-157 that improves blood flow to an injured area. He says it is one of the seven peptides the FDA will consider in July.
See how your DNA reads TB-500MOTS-c25:54
Tatem says some people call MOTS-c 'exercise in a vial'. He says it is described as raising VO2 max and energy availability, and that it is on the FDA's July list.
See how your DNA reads MOTS-cDSIP42:42
Tatem says DSIP has been shown to help regulate circadian rhythm and is among the peptides he hopes will be approved for compounding. He lists it with sleep and recovery roles.
See how your DNA reads DSIPSelank42:42
Tatem mentions Selank as a compound that can help calm a person about an hour before sleep. He also says it supports deep delta-wave sleep.
See how your DNA reads SelankGHK-Cu39:10
Tatem calls GHK-Cu a copper tripeptide that declines with age and, applied topically, is described as increasing collagen and elastin. He says he would consider it for his own rosacea.
See how your DNA reads GHK-CuIGF-1 LR336:40
Tatem says IGF-1 LR3 is the only peptide that could be construed as a muscle builder, but that it is not the way to gain significant muscle. He says peptides cannot replace training.
See how your DNA reads IGF-1 LR3Tirzepatide29:58
Tatem says tirzepatide is the leading GLP-1 product and the only peptide he currently takes, at a low dose, to slim down. He favors compounded vials for patients who do better on smaller split doses.
See how your DNA reads TirzepatideSemaglutide22:18
Tatem groups semaglutide with tirzepatide as GLP-1 drugs and cites a patient who lost 100 lb on tirzepatide. He says GLP-1 drugs are the best peptides for insulin sensitivity because they slow gastric emptying.
See how your DNA reads SemaglutideRetatrutide54:22
Tatem says retatrutide adds glucagon receptor activation to GLP-1 and GIP, and cites weight loss of 20 to 25% of body weight in trials and anecdotal reports. He says it belongs to Lilly and calls it what he is most excited about.
See how your DNA reads RetatrutideTesamorelin51:51
Tatem describes tesamorelin as a commercially available peptide that raises growth hormone and is 'uniquely good' at reducing visceral fat. He says the effect fades if you stop and change nothing else.
See how your DNA reads TesamorelinMelanotan II52:52
Tatem says melanotan II produces a deep tan with little UV exposure and can cause strong erections. He mentions possible melanoma-related safety concerns.
See how your DNA reads Melanotan IIPT-14153:23
Tatem says PT-141 (bremelanotide) is a derivative of melanotan II that is prescribable now. He says it lacks the tanning effect but has the sexual effects.
See how your DNA reads PT-141CJC-129556:25
Tatem describes CJC-1295 as a growth hormone-releasing hormone derivative, often combined with ipamorelin to boost natural growth hormone release.
See how your DNA reads CJC-1295Ipamorelin56:25
Tatem calls ipamorelin a ghrelin receptor agonist that works with CJC-1295 through a different, synergistic mechanism to raise growth hormone.
See how your DNA reads IpamorelinEpithalon59:29
Tatem says epithalon is meant to enhance telomerase and is touted as a fountain of youth, but he is very skeptical. He says it does show some benefit for brain regions tied to circadian rhythm.
See how your DNA reads Epithalon“peptides are almost like an app on your phone”
“it's kind of like getting gas station sushi”
What this video doesn’t settle
- Tatem says no harm threshold has been found for BPC-157, but the video shows no human trial data and he says himself that more data is needed.
- His claim that pharmaceutical interests drove the 2023 ban is something he says he suspects rather than can prove.
- The FDA's July decision on the seven peptides had not happened when this was recorded, so the video does not say what was decided.
Questions this video answers
What is a peptide according to Dr. Alex Tatem?
Tatem says peptides are fragments of proteins made of amino acids, designed to target particular receptors in a focused way. He compares them to a specific key for a specific lock, in contrast to small-molecule drugs that act more broadly.
What does Tatem say about buying research-use-only peptides?
He says the label is a way of avoiding FDA jurisdiction and that there is no quality control. He lists unknown contents, contamination and unknown dosing as the problems, and advises talking to a doctor instead.
Which peptides does Tatem say the FDA may reconsider in July?
He says the FDA announced it will consider moving seven peptides back to the compoundable category in July. He names BPC-157, TB-500, KPV, MOTS-c, DSIP, epithalon and C-max.
What does Tatem say happens when you stop taking GLP-1 drugs?
He says people regain weight if nothing else changes, though people who make lifestyle changes tend to regain some but not all of it. He also mentions data suggesting a much lower maintenance dose may be an option.
Can peptides build muscle, according to Tatem?
He says peptides cannot independently add significant lean mass and that you still need training and nutrition. He names IGF-1 LR3 as the only one that could be construed that way, and says it is not the way to gain significant muscle.
Video by The Diary Of A CEO on YouTube, embedded as published. The summary is written by PeptidesDNA from the video; every claim in it is the speaker’s. Not affiliated with or endorsed by the creator. Not medical advice.
