Buy Intermediate SARMs Stack UK | 3-Compound

What Is the Intermediate Muscle Stack?

The Intermediate Muscle Stack combines three compounds: LGD-4033 Ligandrol, RAD-140 Testolone, and MK-677 Ibutamoren. This is a three-compound protocol for researchers who have already established their baseline response to individual SARMs and are ready to explore multi-pathway research involving both androgen receptor agonism and growth hormone secretion.

If you’re looking to buy a SARMs stack UK for intermediate-level research, sarms.co.uk supplies all three compounds at 99%+ HPLC-verified purity with full Certificates of Analysis, GMP-certified UK manufacture, and free next-day delivery. Whether you’re searching for a RAD-140 LGD-4033 MK-677 stack, an intermediate SARM cycle UK, or a three-compound research stack, this combination pairs two potent AR agonists with non-androgenic GH pathway support.

This stack steps up from the Beginner Stack in two important ways: it replaces Ostarine with the more potent RAD-140, and it adds MK-677, a growth hormone secretagogue that targets an entirely independent growth pathway without adding androgen receptor load.

What’s in the Intermediate Muscle Stack?

Compound	Dose	Capsules	Classification	Human Trials
LGD-4033 Ligandrol	10 mg per capsule	90	Non-steroidal SARM	Phase I (Basaria et al., 2013) + Phase II (VK5211)
RAD-140 Testolone	10 mg per capsule	90	Non-steroidal SARM	Phase I (Miller et al., 2022)
MK-677 Ibutamoren	10 mg per capsule	90	Growth hormone secretagogue	Multiple (including Nass et al., 2008 – 2-year trial)

90 capsules of each compound. Three separate bottles per stack.

Why These Three Compounds?

LGD-4033 Ligandrol: Lean Mass Foundation

LGD-4033 provides the reliable anabolic base. The Phase I human clinical trial by Basaria et al. (2013) demonstrated statistically significant lean mass gains at just 1 mg/day over 21 days in healthy volunteers. It has a well-characterised pharmacokinetic profile with a ~24-36 hour half-life, established dose-response data from human trials, and serves as the consistent mass-building foundation of this stack.

Full compound details: LGD-4033 Ligandrol product page

RAD-140 Testolone: Potent AR Agonist

RAD-140 is the step up in anabolic potency. Developed by Radius Health with a completed Phase I human clinical trial (Miller et al., 2022), RAD-140 has stronger AR binding affinity than LGD-4033 and a reported anabolic-to-androgenic selectivity ratio of approximately 90:1. Additional preclinical data includes neuroprotective properties demonstrated in cultured neurons and kainate-lesioned rats (Jayaraman et al., 2014).

Full compound details: RAD-140 Testolone product page

MK-677 Ibutamoren: GH Pathway Support

MK-677 is not a SARM. It is an oral growth hormone secretagogue that increases GH and IGF-1 levels by activating the ghrelin receptor. It adds an entirely independent growth pathway to the stack without increasing androgen receptor load or contributing to HPTA suppression. The Nass et al. (2008) two-year human trial provides long-term safety and efficacy data that is exceptional for this class of compound.

MK-677’s role in this stack is complementary support: enhanced recovery, improved sleep quality, sustained GH/IGF-1 elevation, and body composition benefits through a mechanism completely independent of the two AR agonists.

Full compound details: MK-677 Ibutamoren product page

How the Intermediate Stack Works: Two Independent Pathways

The key design principle of the Intermediate Stack is multi-pathway activation. Rather than simply stacking more AR agonists (which increases suppression proportionally), this stack combines androgen receptor stimulation with growth hormone secretion. These two pathways are mechanistically independent.

Pathway 1: Androgen Receptor Agonism (LGD-4033 + RAD-140)

Both LGD-4033 and RAD-140 bind to androgen receptors in skeletal muscle and bone tissue, triggering downstream gene expression that promotes protein synthesis and lean mass accrual. RAD-140’s higher binding affinity means it occupies receptors more aggressively, while LGD-4033 provides broader, consistent AR activation.

Pathway 2: GH/IGF-1 Axis (MK-677)

MK-677 stimulates growth hormone release through ghrelin receptor activation, leading to elevated IGF-1 levels. This pathway promotes recovery, connective tissue repair, sleep architecture improvement, and synergistic body composition effects. Importantly, MK-677 does not interact with androgen receptors and does not contribute to HPTA suppression.

Why Two Pathways Matter

Single-pathway stacking (adding more AR agonists) produces diminishing returns because receptor saturation limits the incremental benefit while cumulative suppression increases linearly. Adding MK-677 provides additional anabolic and recovery support through a pathway that has no receptor competition with the SARMs and no additive suppressive effect.

Intermediate Stack vs Beginner Stack: Key Differences

Feature	Beginner Stack	Intermediate Stack
Compounds	2 (MK-2866 + LGD-4033)	3 (LGD-4033 + RAD-140 + MK-677)
AR agonists	2 moderate	1 moderate + 1 potent
GH pathway	No	Yes (MK-677)
Total AR potency	Moderate	Higher (RAD-140 adds significant potency)
HPTA suppression risk	Moderate	Higher (RAD-140 is more suppressive)
Recovery support	AR-mediated only	AR + GH/IGF-1 mediated
Best for	First cycle, evidence priority	Second cycle, multi-pathway research

Who Is the Intermediate Muscle Stack For?

Researchers who have completed at least one SARM cycle and understand their individual response to AR agonists
Those wanting to add GH pathway support without jumping to a four-compound protocol
Multi-pathway research protocols investigating the combination of AR agonism and GH secretion
Bulking and lean mass research where a stronger anabolic stimulus than the Beginner Stack is desired
Recovery-focused protocols: MK-677’s effects on sleep quality and GH-mediated recovery add a dimension not available in AR-only stacks

Who Should Consider Other Stacks?

First-time researchers: the Beginner Stack is a more appropriate starting point
Those wanting Ostarine in the mix: the Advanced Stack includes all four compounds (LGD + MK-2866 + RAD-140 + MK-677)
Maximum potency protocols: the Bulk Mass Stack adds YK-11 for the most aggressive approach

Dosage and Administration (Research Use Only)

LGD-4033 Ligandrol: 10 mg per capsule, 90 capsules per bottle
RAD-140 Testolone: 10 mg per capsule, 90 capsules per bottle
MK-677 Ibutamoren: 10 mg per capsule, 90 capsules per bottle
Typical research cycle: 8-12 weeks for the SARMs; MK-677 is sometimes run for longer periods (the Nass et al. trial ran for 2 years)
Administration: All three are oral capsules. Can be taken together at the same time of day. Some researchers take MK-677 before bed due to its effects on sleep quality and GH release during sleep

No published research exists on this specific three-compound combination. Individual compound dosing is based on single-agent clinical trial data. Consult the individual product pages for detailed dosing information:

Side Effects and Safety Considerations

HPTA Suppression

Both LGD-4033 and RAD-140 cause dose-dependent HPTA suppression. RAD-140 is generally considered more suppressive than LGD-4033 at comparable doses. The combined use of two potent AR agonists increases the likelihood and severity of testosterone, LH, and FSH suppression. MK-677 does not cause HPTA suppression.

MK-677-Specific Considerations

Increased appetite: MK-677 activates the ghrelin receptor, which can significantly increase appetite. This is desirable in bulking protocols but may be problematic for cutting research
Water retention: GH elevation can cause mild water retention, particularly in the first few weeks. This is GH-mediated, not oestrogenic
Blood glucose: MK-677 can affect insulin sensitivity and fasting blood glucose levels. The Nass et al. 2-year trial reported increases in fasting glucose and HbA1c in some subjects
Numbness/tingling: Some researchers report transient numbness or tingling in extremities, consistent with GH elevation effects

Lipid and Liver Considerations

Both AR agonists may cause mild HDL suppression and liver enzyme elevations. RAD-140’s Phase I trial reported liver enzyme changes at higher doses. Baseline and periodic blood panels are standard practice.

Does the Intermediate Stack Require PCT?

Yes. The combination of LGD-4033 and RAD-140 (two potent AR agonists) makes HPTA suppression likely at research-relevant doses. PCT protocols should be considered standard practice for this stack. MK-677 does not require PCT and can be continued through the post-cycle period if desired, as it does not interact with the androgen axis.

Some researchers continue MK-677 during PCT, reasoning that GH/IGF-1 support helps preserve gains during the recovery period when androgen levels are returning to baseline. This approach has anecdotal support but no published clinical data.

Published Research on the Individual Compounds

Basaria S, et al. (2013). “The safety, pharmacokinetics, and effects of LGD-4033 in healthy young men.” J Gerontol A Biol Sci Med Sci, 68(1), 87-95. PMID: 22459616
Miller CP, et al. (2022). “Design, Synthesis, and Preclinical Characterization of RAD140.” ACS Med Chem Lett. PMID: 36368886
Jayaraman A, et al. (2014). “Selective androgen receptor modulator RAD140 is neuroprotective.” Endocrinology, 155(4), 1398-1406. PMID: 24428527
Nass R, et al. (2008). “Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults.” Ann Intern Med, 149(9), 601-611. PMID: 18981485

Why Buy the Intermediate Stack from sarms.co.uk?

99%+ HPLC-Verified Purity

All three compounds are independently tested via High-Performance Liquid Chromatography by accredited third-party laboratories. Full Certificates of Analysis available for every batch.

GMP-Certified UK Manufacture

All products compounded in GMP-certified UK facilities. Not imported from unregulated overseas laboratories.

Separate Bottles for Dose Flexibility

Each compound is supplied in its own bottle, allowing researchers to adjust individual doses independently, start or stop any compound mid-protocol, or run MK-677 for longer than the SARM cycle.

Stack Savings

Purchasing as a stack saves compared to buying the three compounds individually.

Free Next-Day UK Delivery

All orders ship free with next-day UK delivery.

Frequently Asked Questions About the Intermediate Muscle Stack

Is this stack suitable for a first SARM cycle?

No. This stack includes two potent AR agonists and is designed for researchers who have already completed at least one single-compound or beginner stack cycle. The Beginner Stack is the recommended starting point for new researchers.

Why is MK-677 included if it’s not a SARM?

MK-677 adds growth hormone pathway support through an entirely independent mechanism. It does not increase AR load or HPTA suppression while providing complementary benefits (recovery, sleep quality, GH/IGF-1 elevation). This multi-pathway approach is more efficient than simply adding a third AR agonist.

Can I take MK-677 before bed?

Yes. Many researchers time MK-677 before sleep because growth hormone is naturally released in pulses during deep sleep. MK-677’s ghrelin receptor activation complements this natural rhythm. The increased appetite side effect is also less disruptive when taken at bedtime.

Can I run MK-677 longer than the SARMs?

Yes. Since MK-677 does not cause HPTA suppression or interact with androgen receptors, it can be run for extended periods independent of the SARM cycle. The Nass et al. trial ran MK-677 for two years. Some researchers continue MK-677 through PCT and beyond.

What is the difference between this and the Advanced Stack?

The Advanced Stack adds Ostarine MK-2866 as a fourth compound, giving three AR agonists plus MK-677. The Intermediate Stack uses two AR agonists plus MK-677. The Advanced Stack provides broader AR coverage but with greater suppression potential.

How does RAD-140 compare to Ostarine in this context?

RAD-140 has substantially higher AR binding affinity than Ostarine, making it a more potent anabolic agent. The trade-off is potentially greater HPTA suppression. The Intermediate Stack swaps the Beginner Stack’s Ostarine for RAD-140 to increase overall anabolic potency while keeping MK-677 as the third compound for non-AR pathway support.

Will this stack cause water retention?

The SARMs (LGD-4033 and RAD-140) do not aromatise and do not cause oestrogenic water retention. MK-677 may cause mild GH-mediated water retention, particularly in the first 2-4 weeks. This is typically subcutaneous and temporary.

Does the Intermediate Stack require PCT?

Yes. LGD-4033 and RAD-140 combined produce significant HPTA suppression at research-relevant doses. PCT is considered standard practice. MK-677 does not require PCT and can be continued through the post-cycle period.

Can I add Cardarine to this stack?

Yes. Adding Cardarine GW-501516 would introduce PPAR-delta-mediated fat oxidation for recomposition research. Cardarine does not interact with androgen receptors or the GH axis, making it compatible without adding to suppression or interfering with either growth pathway.

Is this stack good for bulking?

Yes. The combination of two potent AR agonists (LGD-4033 + RAD-140) for direct anabolic stimulus with MK-677’s GH elevation and appetite-increasing effects makes this stack well-suited for bulking research protocols. MK-677’s appetite increase is particularly useful for researchers who struggle to maintain caloric surplus.

Disclaimers

This stack is sold strictly for laboratory and research purposes only
These products are not intended for human consumption
Not medicines, supplements, or food products
Not suitable for individuals under 18 years of age
Pregnant or breastfeeding women must not handle these compounds
Researchers should consult qualified professionals and adhere to all applicable regulations
sarms.co.uk does not provide medical advice and makes no claims regarding therapeutic outcomes
The content on this page does not constitute medical advice

Content last reviewed: 17 February 2026

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