What peptides is Josh Duhamel using? His own words
In April 2026, at 53, Josh Duhamel gave Yahoo Life the most specific peptide inventory any working actor has put on the record: "With my company, Gatlan, I've really learned a lot about some cheat codes in this business. There's a lot of things you can do to optimize … whether it's NAD or Tesamorelin or the Wolverine stack, the BPC-157, TB-500 — all that stuff has really helped me stay strong, stay fit, stay youthful, all those things." Gatlan is his own wellness company, so the endorsement carries a commercial stake, and he says so himself.
He has gone further on camera. In a social video for the TSC podcast he described his stack as BPC-157, TB-500, KPV and GHK-Cu, combined in one daily injection, for joints and recovery; a blend of that composition circulates online under names like KLOW. In January 2026 he covered BPC-157, TRT and injury recovery on The Genius Life podcast with Max Lugavere, and an ELLE roundup caught him at his most succinct: "I do this thing called the 'Wolverine stack.' It's so good."
What he has not said matters as much. He has named no dose, no supplier and no prescriber. NAD is not a peptide. He has not named ipamorelin or any other growth hormone secretagogue clinics pair with tesamorelin. And every benefit he lists is his own assessment of his own body, offered by a man who also sells wellness products. That is not a criticism; it is how a testimonial should be read.
What peptides does Frank Grillo use? BPC-157, CJC and testosterone
Frank Grillo has been blunter for longer. Talking to TheWrap in December 2024, he said: "Now, I stack peptides. I do BPC-157. It took away the pain in my shoulders and my knee. I take CJC for recovery as well, and my skin and stuff." On testosterone: "Through my doctor, I did TRT for a while, and I found it to be amazing." And on the industry habit of pretending otherwise: "I think guys are crazy to say that they're natural when they're not. It's ridiculous to think you're getting that from eating chicken and broccoli."
A year later, at 60, he discussed testosterone and BPC-157 in his training on the Men's Health Strong Talk podcast, and an ELLE roundup caught a useful hedge: "I take some peptides, BP-157, I think it's helping me recover." The shoulder and knee relief is his experience, reported by him; the "I think" sits closer to what the evidence can support.
What he has not specified matters. CJC is a name shared by two molecules, one with an albumin-binding tail that stays active for about a week and one without it that clears in roughly half an hour, and he has not said which. He has not named TB-500, KPV, GHK-Cu or ipamorelin, even though the market almost always sells CJC-1295 paired with ipamorelin, and a reader should not fill that gap for him. No dose, no source.
Where did the name Wolverine stack come from?
The label predates both actors. On The Joe Rogan Experience in December 2020, Rogan told Andrew Schulz that an elbow tendonitis he could not shift was gone within two weeks of starting BPC-157, and that "athletes swear by" it. Schulz's reply, "Wolverine shit", is as close as anyone will get to a citation for the phrase. By 2026 it was a product category, with TB-500 folded in on the theory that two healing peptides beat one.
Notice what the name accomplishes. It attaches a comic-book image of instant, complete tissue regeneration to two compounds never shown to regenerate anything in a human being. That is marketing doing the work the trial data cannot. Once the famous name comes off the vial, and the Marvel reference with it, what remains is a fifteen-residue peptide with a large rodent literature and a protein fragment with no musculoskeletal trial at all.
Anyone who has spent time around trainers' rooms and Beverly Hills longevity clinics knows how the phrase travels: trainer to clinic menu to junket to search bar. Nobody in that chain opens the literature, because the name has already answered the question the literature would raise.
BPC-157: the rodent evidence and the human gap, as of September 2026
BPC-157 is a synthetic fifteen-amino-acid peptide described as a fragment of a gastric protein. Its animal literature is large: well over a hundred rodent studies across tendon, muscle, ligament, bone, nerve and gut, with treated animals doing better almost every time. Nearly all of it comes from one Zagreb-based group and its collaborators, mostly without the blinding and pre-registration that would let an outsider weigh it. An agent that works in every tissue in every paper is either a universal repair signal or a programme not publishing its nulls.
The human record can be stated in full. There is no published randomised, placebo-controlled trial of BPC-157 in humans for any indication, including the joint pain Grillo attributes it to. An oral formulation coded PL 14736 entered early clinical testing for inflammatory bowel disease about two decades ago; tolerability was called acceptable and no efficacy results were ever published. The rest is a handful of small uncontrolled pilots from one US group, the latest a 2025 intravenous safety pilot in a couple of healthy adults.
The regulatory arc is where 2026 changed things. In September 2023 the FDA placed BPC-157 among nineteen substances in Category 2 of its 503A bulk-substances review, barring compounding pharmacies from preparing it. On 15 April 2026, after Robert F. Kennedy Jr had promised on Rogan's show to restore access, the agency moved twelve peptides out of Category 2, not into Category 1 but into a limbo pending advisory meetings. On 23 and 24 July 2026 the Pharmacy Compounding Advisory Committee voted 8 to 6, with one abstention, for BPC-157 in ulcerative colitis.
Three things about that vote matter. It was for ulcerative colitis, not tendons or joints. It was non-binding; Category 1 placement requires notice-and-comment rulemaking that realistically runs into 2027. And the FDA's own scientists told the committee they lacked the evidence to assess safety and effectiveness, their core concern being the absence of accepted chemical definitions, so that the identity of anything sold as BPC-157 remains unclear. An 8 to 6 vote on a compound with no controlled human data is a judgement about demand, not evidence.
TB-500 is not the thymosin beta-4 that ran the trials
Thymosin beta-4 is a 43-amino-acid protein that sequesters actin monomers inside cells and, released into wound fluid, promotes cell migration and new vessel growth. A company-sponsored ophthalmic programme, RGN-259, took the full-length protein through randomised, vehicle-controlled dry eye trials, with inconsistent results and no approval anywhere. An intravenous formulation went through a phase 1 safety study in healthy volunteers, showing short-term tolerability and a half-life on the order of hours; the heart-attack trial it was meant to enable never returned a result.
TB-500 is not that molecule. It is a trade name for a synthetic fragment, usually the short actin-binding motif from the middle of the protein, under a thousand daltons against the parent's five thousand, and some material sold under the name appears to be the full protein while some is the fragment. No randomised controlled trial has tested injected TB-500 for tendon, ligament or muscle injury in humans. Every claim made for it is borrowed from eye drops of a different molecule and from rodent transection models.
Two further facts belong here. Thymosin beta-4 is overexpressed in several tumour types, including colorectal carcinoma and melanoma, where higher expression tracks with invasive behaviour; a migration-promoting, pro-angiogenic protein is exactly the kind of agent regulators want carcinogenicity data on before chronic dosing. And the anti-doping regulator has already drawn the fragment distinction: the WADA list names thymosin beta-4 and its derivatives, gives TB-500 as the example, and bans them at all times. In 2016 the Court of Arbitration for Sport sanctioned 34 Essendon Football Club players over thymosin beta-4.
TB-500 travelled the same regulatory road as BPC-157: Category 2 in September 2023, then an 8 to 6 advisory vote with one abstention in July 2026, in its case for wound healing. Same caveats: non-binding, indication-specific, and made over the FDA scientists' stated inability to define what the substance chemically is.
KPV and GHK-Cu: the two add-ons in the four-peptide syringe
KPV is the smallest active piece of alpha-melanocyte-stimulating hormone, the three C-terminal residues lysine, proline and valine. It keeps the parent's anti-inflammatory activity and drops the pigmentation effect, by blocking NF-kappa-B signalling inside cells. The interesting data are in mouse colitis models, where KPV taken up through the intestinal peptide transporter reduced inflammation. That is a gut story: there is no human trial of KPV for anything, and nothing connecting an injected tripeptide to a joint. It sat on the 2023 Category 2 list and drew an 8 to 6 vote with one abstention in July 2026 for wound healing and inflammatory indications.
GHK-Cu is the outlier in the syringe, because it has controlled human data: vehicle-controlled cosmetic studies on photoaged skin and a controlled trial in diabetic foot ulcers, all topical. Injected GHK-Cu has no controlled human trial for any indication. Roughly a sixth of the complex by mass is copper, and injection bypasses intestinal absorption, where the body regulates copper. The Hollywood Reporter and NPR both reported in 2026 on physicians warning of copper toxicity, immune reactions, and grey-market vials found to contain arsenic and lead.
In an inflamed knee, then, the injection delivers one compound with rodent tendon data and no human trial, one fragment of a protein whose only human trials were in the eye, one gut tripeptide tested only in mice, and one skin peptide whose human evidence is entirely topical. None is approved. That is the Wolverine stack without the adjective.
Tesamorelin and CJC-1295: one approved drug, and one that never finished
Tesamorelin is the exception on Duhamel's list. It is a GHRH analogue that stimulates the pituitary's own output, and it holds a full FDA approval, granted in 2010, for one indication: reducing excess visceral abdominal fat in adults with HIV-associated lipodystrophy. Two 26-week randomised trials cut visceral fat by roughly a tenth to a sixth against placebo; the fat returned once treatment stopped. The label calls for IGF-1 and glucose monitoring. Nothing in that file concerns healthy middle-aged men, strength, fitness or youthfulness.
Off-label for a 53-year-old actor has a specific legal meaning. A US-licensed prescriber may lawfully prescribe an approved drug for an unapproved use; the manufacturer may not promote that use, insurers will not pay, and the label's warnings still apply even though its evidence does not. A compounded GHRH analogue sold under the name is a different regulatory situation, and grey-market powder a third. Tesamorelin is also on the WADA list.
Grillo's CJC sits at the other end. CJC-1295 with the drug affinity complex binds albumin and holds growth hormone release elevated for days; its human data are small phase 1 pharmacokinetic studies from 2006 and no efficacy trial for any outcome. The version without the complex behaves like sermorelin, and vendors rarely say which they mean. The FDA placed CJC-1295 and ipamorelin in Category 2 in the same 2023 action; neither was among the seven substances voted on in July 2026. Ipamorelin, the ghrelin-receptor agonist clinics pair with CJC, is a compound neither actor has named.
What happens when four unapproved peptides share one syringe?
No trial has tested any of these combinations: not BPC-157 with TB-500, the pairing the name refers to; not the four-peptide blend; not tesamorelin alongside any of them. Stacking assumes additivity, and additivity is an assumption pharmacology violates routinely. Two agents on overlapping angiogenic pathways may add, cancel or amplify, and nobody has looked.
Mixing multiplies the unknowns rather than diluting them. Each research-grade vial carries its own identity, net peptide content, sterility and endotoxin questions. Draw four into one syringe and a local reaction, a fever or a rash can no longer be attributed to anything. Immunogenicity is the specific worry: short unmodified peptides can raise anti-drug antibodies, and co-injecting several, one a copper complex, in an uncharacterised buffer is a condition no immunology study has examined. Nobody has published data on whether the four even remain intact together in solution.
A Scientific American podcast episode in May 2026 put it plainly: stacking is where the unknowns compound, and much of the supply is research-only product from overseas synthesis houses. Duhamel's daily syringe is the cleanest real-world illustration of that sentence anyone has volunteered.
Why the action-movie economy produces this, and what to take from it
None of this is mysterious to anyone who has watched a physical role get cast. A man in his fifties is offered a shirtless scene and a fight sequence with a prep window measured in weeks, not the months natural adaptation takes. The trainer's job is to deliver a body by a date; recovery, not effort, is the bottleneck, and anything that promises to shorten it will find its way into the room.
Testosterone normalised the conversation first. Grillo's "through my doctor" is the standard phrasing and it is accurate: TRT is an approved drug with a diagnosis attached and decades of controlled data behind it, and the Wolverine stack has neither. The fake-natty quote locates the real harm: the audience that copies an actor's physique cannot copy his physician, his blood panel or his ability to stop working for a month if something goes wrong. What it can copy is the shopping list, the part with the least evidence behind it.
So take the statements at face value. Two actors named specific compounds and attributed specific outcomes to them, and one also sells wellness products. A testimonial is a reason to run a trial, not a substitute for one, and for BPC-157, TB-500, KPV and injected GHK-Cu the trial has never been run. Three of the four hold non-binding advisory votes for indications unrelated to joints; tesamorelin is approved for a condition almost no reader has; CJC-1295 and ipamorelin remain where the 2023 review left them.
Notice who is missing from every one of these quotes: the person who measured anything. Grillo's shoulder feels better and Duhamel feels youthful, and both may be accurate reports. What separates that from evidence is a control group, and a control group is the one thing money and a famous name cannot buy in a clinic.