MK-677 & BPC-157 Capsule Bundle

The Yakka Strength MK-677 and BPC-157 capsule bundle pairs ibutamoren (MK-677), an orally active growth hormone secretagogue, with BPC-157, a synthetic gastric pentadecapeptide, from the same manufacturer in one listing within our Muscle Market range. Yakka Strength lists the pack as 60 capsules and does not state a content per capsule, so we quote none. Supplied to adults for laboratory research only and not for human consumption.

A bundle is a listing convenience only: it lets separately packaged products from one manufacturer be ordered in a single purchase. Nothing on this page claims that they act together or should be studied together, and Free Muscle publishes no stack or cycle guidance for any product.

About the compounds in this bundle

MK-677 (Ibutamoren)

Ibutamoren (MK-677, L-163,191, nutrobal) is not a SARM but an orally active ghrelin receptor (GHS-R1a) agonist, a growth hormone secretagogue. In a placebo-controlled trial in 65 healthy adults aged 60 to 81, growth hormone and IGF-1 rose over one year; fat-free mass rose by about 1.1 kg while it fell by about 0.5 kg on placebo, with no change in strength or function. Reported adverse findings included increased appetite, mild leg oedema, higher fasting glucose, reduced insulin sensitivity and raised cortisol. Never approved. WADA class S2. Compare brands on the MK-677 (Ibutamoren) collection page.

BPC-157

BPC-157 is a synthetic fifteen-amino-acid peptide based on a sequence from a human gastric protein. Almost all published work is rodent and cell research, largely from one Croatian group, covering animal models of gut, tendon, muscle and vascular injury. No controlled human trial has been published, and oral absorption of any peptide is unproven. WADA lists it under S0 (non-approved substances). Compare brands on the BPC-157 collection page.

The first formal pharmacokinetic study of BPC-157, published in 2022 by a group in Xi'an, gave the peptide to rats and beagle dogs by intravenous and intramuscular injection. The unchanged peptide had an elimination half-life under 30 minutes, bioavailability after intramuscular injection was roughly 14-19% in rats and 45-51% in dogs, and radiolabelled material was quickly broken into small fragments and single amino acids, excreted mainly in urine and bile. The study included no oral arm, so it says nothing directly about capsules; it does show how short-lived the intact molecule was even when injected.

Chemical identifiers

Figures are from PubChem; an identity result on a certificate should match them. BPC-157 here is in capsule form. Our article Do oral peptides actually work? covers why oral absorption of peptides remains unproven.

This listing

• Brand: Yakka Strength (third-party brand, Muscle Market)
• Compounds: ibutamoren (MK-677) and BPC-157
• Form and pack size: 60 capsules, as listed by the manufacturer
• Content per capsule: not stated by the manufacturer
• COA: only where Yakka Strength supplies one for the batch held
• Buyers: adults aged 18 and over, for laboratory research only

Because no milligram figure is given for either compound, the total content of the pack cannot be worked out, and the bundle cannot be compared with single packs on cost per milligram. Our guide to price per milligram explains the method for listings that do state strength. Yakka Strength also sells MK-677 and BPC-157 capsules as separate listings.

MK-677 and BPC-157 in the UK: buying, legal status and what to check

Searches such as "MK677 UK buy", "MK 677 UK legal" and "BPC 157 capsules UK" ask whether a purchase is lawful and how to tell a documented seller from an undocumented one.

Legal status, compound by compound

MK-677. Ibutamoren has never been authorised as a medicine in the UK or anywhere else, and it is not listed under the Misuse of Drugs Act. Our MK-677 legal status page sets out the position in more detail.

BPC-157. The peptide has no marketing authorisation in any country and is not a controlled drug in the UK. It is not an authorised food supplement, so capsule packaging does not make it a food product.

None of the compounds on this page is a licensed medicine in the United Kingdom, none has been assessed by the MHRA and none is an authorised food supplement. Free Muscle supplies them to adults aged 18 and over for laboratory research only. They are not for human consumption. MK-677 falls under WADA class S2 and BPC-157 under S0. Our SARMs research guide has more background.

Signs of a well-documented listing

Whatever the compound, the same questions separate a seller who can account for its stock from one who cannot:

1. Is the manufacturer named, and does each container carry a lot or batch number?
2. Is there a certificate of analysis for that lot, from a named laboratory, rather than a generic document reused across batches?
3. Is the strength stated, or does the listing say plainly that it is not?
4. Is sale restricted to adults, with no dosing directions or promised results?
5. Is the seller a traceable UK business with published delivery and returns terms?

How this listing measures up

FreeMuscle LTD is a UK company based in Scunthorpe. Every order goes by free tracked UK delivery in plain packaging, orders placed before 2pm Monday to Friday are processed the same working day, EU delivery takes 3-7 working days, and unopened items may be returned within 30 days (see shipping and our guarantee). The manufacturer is named. Two points depend on Yakka Strength: the label states no content per capsule for either compound, so question three is answered by that disclosure rather than a figure, and a certificate is displayed only where the manufacturer supplies one for the batch we hold. The UK supplier checklist goes through each check in more depth.

Capsules compared with other forms

Both compounds are sold as capsules, tablets and liquids, and BPC-157 also as freeze-dried powder for reconstitution. The molecule is identical in each; what differs is the route research used and how well the material keeps.

Ibutamoren was built as a non-peptide precisely so that it would survive being swallowed. The randomised human trials, including the one-year study summarised above, gave it by mouth, so a capsule matches the route that was studied.

BPC-157 is different. Most rodent studies gave it by injection into the abdominal cavity, with a smaller number adding it to drinking water, and the 2022 pharmacokinetic study used only intravenous and intramuscular routes. No study has measured blood levels in people after an oral dose. A fifteen-residue chain is exactly the kind of substrate that stomach and intestinal enzymes are there to break down. The question of routes is covered at length in BPC-157 capsules vs injection: what the studies used.

On stability, dry formats generally hold up better than solutions, in which hydrolysis and microbial contamination can start. On consistency, a capsule's content is set when powder is blended and filled, so only a content test on individual capsules shows whether fill is even; a liquid depends on full dissolution and accurate measuring. Neither point implies that any format produces an effect.

BPC-157 compared with TB-500

BPC-157 is often listed alongside TB-500, but they are unrelated molecules with separate literatures.

The proposed mechanisms also differ. BPC-157 work has concentrated on gut, tendon and vascular injury models in animals, while thymosin beta-4 binds actin, part of the cell skeleton, and a 2012 review described its study in wound, corneal and cardiac repair models and ongoing or planned clinical trials. Findings for the full protein cannot be assumed to apply to the fragment sold as TB-500, and neither literature can be assumed to transfer to the other peptide. No trial has compared the two. The TB-500 collection lists the brands we hold, and the TB-500 and thymosin beta-4 research guide summarises its studies. For MK-677 the closest relative is ipamorelin, compared in MK-677 vs ipamorelin vs somatropin.

Reading the certificate of analysis for this product

Yakka Strength is a third-party brand sold through Muscle Market. For third-party brands we display a certificate of analysis only where the manufacturer supplies one for the exact batch we hold; if none is shown, none has been supplied and we do not substitute a generic document. Free Muscle-brand products, by contrast, are assayed batch by batch at Janoshik Analytical, with the certificate sent on request by email. Our lab testing page explains what a certificate shows.

A two-compound bundle should come with two results, one per container. When reading either, check these lines in order:

• Sample description. The report should name ibutamoren or BPC-157 and describe the sample as capsules. A report headed only with the bundle name leaves open which material was tested.
• Identity method. HPLC compares the time at which a peak leaves the column with a reference standard. LC-MS adds a mass measurement, which is more specific. For ibutamoren the expected mass corresponds to 528.7 g/mol; for BPC-157, 1419.5 g/mol.
• Purity. The target compound's percentage share of what the instrument detected. It describes cleanliness, not how much is in each capsule.
• Assay or content. A milligram figure per capsule would supply what the Yakka Strength label leaves blank. With BPC-157, see whether it is expressed as net peptide or as total powder weight.
• Batch number, date and laboratory. Set the report's lot code beside the one on the container; a mismatch ends the check there. A dated report from a named laboratory can be followed up.

What a missing field means is straightforward. No identity line: nothing confirms the compound. No content line: the strength remains unknown, as it is on this label. No matching batch number: the report describes other material. Contact us with the batch numbers from your containers and we will tell you what exists for current stock. Our article on how to read a certificate of analysis covers the same lines in more detail.

Detection, sport and testing

Both compounds are prohibited at all times, in and out of competition, under the World Anti-Doping Code, which UK Anti-Doping enforces for British sport. Ibutamoren appears in section S2 among growth hormone secretagogues. BPC-157 is named in section S0, which covers pharmacological substances with no current approval for human therapeutic use. The anti-doping rule of strict liability means an athlete is responsible for any prohibited substance found in a sample, whatever a label said and whatever the intention.

None of the references on this page establishes how long either stays detectable in human urine or blood after exposure, so the accurate statement is: detectable, window not established. The short half-life measured in animals for intact BPC-157 is not a detection window, because testing can target metabolites as well as the parent molecule. Anyone subject to testing should treat exposure to either compound as incompatible with competition.

Storage, stability and handling

No stability study has been published for either compound in capsule form, so the manufacturer's expiry or best-before date, where printed, is the limit to work to. The two molecules have different weak points. BPC-157, as a peptide, is vulnerable to moisture, because water slowly hydrolyses peptide bonds, and to heat, which speeds that reaction. Ibutamoren has no peptide backbone, but is still best kept from damp, heat and direct light, and capsule shells themselves soften in humidity and turn brittle in dry heat.

Keep each container tightly closed in a cool, dry and dark place, with any desiccant sachet left inside. If containers are kept in a fridge, allow them to reach room temperature before opening so that condensation does not form on the contents. Keep each compound in its original labelled container so the lot number stays with it. As laboratory reagents they should be handled with gloves once capsules are opened, kept apart from food and drink, stored out of reach of children and animals, and disposed of as chemical waste rather than in household rubbish or drains.

Glossary

• Ghrelin: a hormone released mainly by the stomach; its receptor is the target of ibutamoren.
• GHS-R1a: the growth hormone secretagogue receptor type 1a, the ghrelin receptor.
• Growth hormone secretagogue: any compound whose action is to trigger growth hormone release from pituitary stores rather than to replace the hormone.
• IGF-1: insulin-like growth factor 1; its blood level is the usual marker researchers use to track growth hormone activity.
• Pentadecapeptide: from the Greek for fifteen; BPC-157 is so called because its chain has fifteen amino acids.
• Half-life: the time taken for the concentration of a substance in blood to fall by half.
• Bioavailability: the fraction of a dose that reaches the circulation unchanged.
• Hydrolysis: breakdown of a chemical bond by water; the main route by which peptides degrade in storage.
• HPLC and LC-MS: laboratory methods that separate a sample; LC-MS also measures molecular mass.
• Assay: a measurement of how much of a compound a sample contains, as distinct from its purity.
• Strict liability: the anti-doping principle that an athlete is responsible for any prohibited substance in a sample.

Related

• MK-677 (Ibutamoren) collection
• BPC-157 collection
• TB-500 collection
• Yakka Strength brand page
• Peptides collection
• Bundles collection
• Research articles: MK-677: what the research says and BPC-157: what research shows

Supplied for laboratory research use only. Not a medicine, not evaluated by the MHRA, EMA or FDA, and not for human consumption. Buyers must be 18 or over. Nothing on this page is medical or dosing advice or a recommendation to use, stack or cycle any compound; research summaries describe findings in study participants or animals, not claims about this product.

References

1. Nass R, et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Ann Intern Med. 2008;149(9):601-11. PMID: 18981485.
2. Sikiric P, et al. Brain-gut Axis and Pentadecapeptide BPC 157: Theoretical and Practical Implications. Curr Neuropharmacol. 2016;14(8):857-865. PMID: 27138887.
3. He L, et al. Pharmacokinetics, distribution, metabolism, and excretion of body-protective compound 157, a potential drug for treating various wounds, in rats and dogs. Front Pharmacol. 2022;13:1026182. PMID: 36588717.
4. Goldstein AL, et al. Thymosin beta4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther. 2012;12(1):37-51. PMID: 22074294.