Buy Advanced SARMs Stack UK | 4-Compound Protocol

What Is the Advanced Muscle Stack?

The Advanced Muscle Stack is a four-compound protocol combining LGD-4033 Ligandrol, Ostarine MK-2866, RAD-140 Testolone, and MK-677 Ibutamoren. This is the most comprehensive stack in our range before the specialised Bulk Mass Stack, combining three androgen receptor agonists with growth hormone secretagogue support across two independent growth pathways.

If you’re looking to buy an advanced SARMs stack in the UK, sarms.co.uk supplies all four 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 4-compound SARM stack UK, advanced SARMs cycle, or the most comprehensive multi-SARM research protocol available, this stack provides four separately dosed compounds for maximum research flexibility.

This stack is designed for experienced researchers who have already run individual compounds and simpler stacks, understand their response to SARMs, and are looking for a multi-pathway approach combining three AR agonists with GH secretagogue support.

Important: Stacking three AR agonists significantly increases the likelihood of HPTA suppression. This stack is not recommended for researchers without prior experience managing hormonal recovery protocols.

What’s in the Advanced Muscle Stack?

Compound	Dose	Capsules	Classification	Human Trials
LGD-4033 Ligandrol	10 mg per capsule	90	Non-steroidal SARM	Phase I + Phase II (VK5211)
Ostarine MK-2866	10 mg per capsule	90	Non-steroidal SARM	Phase II + Phase III (Enobosarm)
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 (incl. Nass et al., 2008 – 2-year)

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

Why These Four Compounds?

LGD-4033 Ligandrol: Anabolic Workhorse

Phase I human clinical trial data (Basaria et al., 2013) demonstrated statistically significant lean mass gains at 1 mg/day over 21 days. LGD-4033 provides the reliable, consistent anabolic base with a well-characterised pharmacokinetic profile.

Full compound details: LGD-4033 Ligandrol product page

Ostarine MK-2866: Clinical Breadth

The most clinically studied SARM with Phase II and III human trial data (GTx/Enobosarm). Excels at lean mass preservation, particularly in caloric deficit. Adds breadth to the AR agonist coverage with a different binding profile than LGD-4033 or RAD-140.

Full compound details: Ostarine MK-2866 product page

RAD-140 Testolone: Peak AR Potency

The most potent non-steroidal SARM in this stack. Developed by Radius Health with a Phase I human clinical trial. ~90:1 anabolic-to-androgenic selectivity ratio. Adds the top-tier anabolic stimulus that LGD-4033 and Ostarine alone cannot match.

Full compound details: RAD-140 Testolone product page

MK-677 Ibutamoren: Independent GH Support

Not a SARM. An oral growth hormone secretagogue with a 2-year human trial (Nass et al., 2008). Increases GH and IGF-1 through ghrelin receptor activation. Provides recovery, sleep quality, and body composition support through a mechanism completely independent of the three AR agonists. Does not contribute to HPTA suppression.

Full compound details: MK-677 Ibutamoren product page

How the Advanced Stack Works: Three AR Agonists Plus GH

Pathway 1: Multi-Compound AR Agonism

Three SARMs with different binding affinities and pharmacokinetic profiles create a layered approach to androgen receptor activation:

Ostarine (MK-2866): Moderate binding affinity, ~24-hour half-life. Provides baseline AR coverage and excels at lean mass preservation in caloric deficit
LGD-4033: Stronger binding affinity (~10x Ostarine), ~24-36 hour half-life. Adds substantial anabolic drive for lean mass accrual
RAD-140: Highest binding affinity of the three, ~60-hour half-life. Provides the peak anabolic stimulus with the strongest receptor occupancy

The theoretical advantage of three compounds with different binding kinetics is more complete receptor coverage across the dosing interval and potentially different downstream gene expression profiles. However, this also means cumulative HPTA suppression from three AR agonists.

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

MK-677 operates through ghrelin receptor activation, elevating GH and IGF-1 levels independently of the androgen pathway. This provides complementary growth and recovery support that does not compete with the three SARMs for receptor binding and does not add to the suppressive load.

Advanced Stack vs Other Stacks: How It Compares

Feature	Beginner	Intermediate	Advanced	Bulk Mass
Compounds	2	3	4	4-in-1
AR agonists	2 moderate	1 moderate + 1 potent	2 moderate + 1 potent	2 potent + 1 steroidal
GH pathway	No	Yes	Yes	Yes
Dose flexibility	Full	Full	Full	None (fixed ratio)
HPTA suppression	Moderate	Higher	Highest	Highest
YK-11 included	No	No	No	Yes
Best for	First cycle	Second cycle	Experienced, comprehensive	Experienced, maximum raw potency

Advanced Stack vs Bulk Mass Stack: Key Distinction

The Advanced Stack provides full dose flexibility (four separate bottles) and uses three clinically studied AR agonists. The Bulk Mass Stack replaces Ostarine with YK-11 (which has only in vitro data) and delivers all compounds in a single fixed-dose capsule. Choose the Advanced Stack for maximum flexibility and evidence quality. Choose the Bulk Mass Stack for maximum raw potency in a simplified format.

Who Is the Advanced Muscle Stack For?

Experienced researchers who have completed multiple SARM cycles and understand their individual response
Researchers seeking the most comprehensive evidence-backed stack: all four compounds have human clinical trial data
Multi-pathway research protocols investigating the combination of multiple AR agonists with GH secretion
Those who want dose flexibility: four separate bottles allow independent adjustment of each compound
Researchers with PCT experience: three AR agonists make robust post-cycle recovery essential

Dosage and Administration (Research Use Only)

LGD-4033: 10 mg per capsule, 90 capsules
Ostarine MK-2866: 10 mg per capsule, 90 capsules
RAD-140: 10 mg per capsule, 90 capsules
MK-677: 10 mg per capsule, 90 capsules
Typical research cycle: 8-12 weeks for SARMs; MK-677 can be run longer
Administration: All oral capsules. Can be taken together. Some researchers take MK-677 before bed

No published research exists on this specific four-compound combination. Consult individual product pages for detailed dosing based on published clinical data:

LGD-4033 dosing | Ostarine dosing | RAD-140 dosing | MK-677 dosing

Side Effects and Safety Considerations

HPTA Suppression: The Primary Concern

Three AR agonists make HPTA suppression virtually certain at research-relevant doses. The combined androgen receptor load from LGD-4033, Ostarine, and RAD-140 will suppress testosterone, LH, and FSH production to a greater degree than any two-compound combination. This is the most suppressive stack in our range alongside the Bulk Mass Stack.

Lipid and Liver Panels

HDL suppression is expected from three concurrent AR agonists. Liver enzyme monitoring is essential, particularly given RAD-140’s Phase I data showing dose-dependent enzyme elevations. Baseline and mid-cycle blood panels are strongly recommended.

MK-677 Considerations

Increased appetite (ghrelin receptor activation)
Mild GH-mediated water retention (temporary, not oestrogenic)
Potential blood glucose/insulin sensitivity effects
Transient numbness or tingling in extremities

What This Stack Does NOT Cause

No oestrogenic effects (no compound aromatises)
No DHT conversion
No androgenic side effects typical of traditional steroids at comparable incidence

Does the Advanced Stack Require PCT?

Absolutely. Three AR agonists at research-relevant doses will produce significant HPTA suppression. Robust PCT is essential, not optional. Pre-cycle, mid-cycle, and post-cycle blood work is the minimum standard for a four-compound protocol of this complexity.

MK-677 can be continued through PCT. It does not interact with the androgen axis and its GH/IGF-1 support may help preserve gains during the recovery period when testosterone is returning to baseline.

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
Dalton JT, et al. (2011). “The selective androgen receptor modulator GTx-024 improves lean body mass and physical function.” J Cachexia Sarcopenia Muscle, 2(3), 153-161. PMID: 21527404
Miller CP, et al. (2022). “Design, Synthesis, and Preclinical Characterization of RAD140.” ACS Med Chem Lett. PMID: 36368886
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 Advanced Stack from sarms.co.uk?

99%+ HPLC-Verified Purity

All four compounds independently tested by accredited third-party labs. Full COAs available for every batch.

GMP-Certified UK Manufacture

All products compounded in GMP-certified UK facilities. Two-stage quality control with full documentation.

Four Separate Bottles for Maximum Flexibility

Unlike single-capsule combination products, each compound comes in its own bottle. Adjust doses independently, start or stop any compound mid-protocol, run MK-677 longer than the SARMs, or titrate individual compounds up or down based on response.

Stack Savings + Free Next-Day UK Delivery

Purchasing as a stack saves compared to buying four compounds individually. Free next-day shipping on all UK orders.

Frequently Asked Questions About the Advanced Muscle Stack

Is this stack suitable for beginners?

No. This is a four-compound protocol with three AR agonists that will produce significant HPTA suppression. It requires prior experience with individual SARMs, simpler stacks, and PCT protocols. Start with the Beginner Stack if you are new to SARMs research.

Why include both Ostarine and LGD-4033 when RAD-140 is already in the stack?

Each compound has a different binding affinity, pharmacokinetic profile, and clinical evidence base. Ostarine excels at lean mass preservation in deficit, LGD-4033 provides consistent anabolic drive, and RAD-140 adds peak potency. The combination provides layered AR coverage across different binding strengths.

Can I remove one compound from the stack?

Yes. Each compound is supplied separately. You can start with two or three compounds and add the fourth later, or run a partial stack based on your research requirements. Removing one AR agonist reduces suppression while still maintaining a multi-compound protocol.

How does this compare to the Bulk Mass Stack?

The Bulk Mass Stack replaces Ostarine with YK-11 (a steroidal SARM with myostatin-inhibiting properties but only in vitro data) and delivers all four compounds in a single capsule. The Advanced Stack uses three clinically studied SARMs and offers full dose flexibility.

Should I take all four at the same time?

All four are oral capsules that can be taken together. Some researchers split dosing (SARMs in the morning, MK-677 before bed) based on MK-677’s sleep quality and GH release effects.

What PCT do I need for this stack?

Three AR agonists require robust PCT. The specific protocol depends on the degree of suppression (confirmed via blood work). Consult the individual product pages for PCT guidance. Pre-cycle, mid-cycle, and post-cycle blood panels are essential for a four-compound protocol.

How long should I cycle the Advanced Stack?

Most research protocols reference 8-12 weeks for the three SARMs. MK-677 can be run longer. Shorter cycles (6-8 weeks) reduce cumulative suppression. Longer cycles increase the risk of significant HPTA impact and the robustness of PCT required.

Will this stack cause water retention?

The three SARMs do not aromatise and do not cause oestrogenic water retention. MK-677 may cause mild GH-mediated subcutaneous water retention, particularly in the first 2-4 weeks.

Can I add Cardarine or SR-9009 to this stack?

Yes. Both Cardarine GW-501516 (PPAR-delta agonist) and SR-9009 Stenabolic (Rev-Erb agonist) operate through non-androgenic pathways and do not add to HPTA suppression or AR load.

Is this the strongest stack you sell?

In terms of AR coverage breadth, yes. The Bulk Mass Stack may have higher peak potency due to YK-11’s dual SARM/myostatin mechanism but uses only in vitro-studied YK-11 instead of clinically trialled Ostarine.

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

The content on this page does not constitute medical advice

Content last reviewed: 25 February 2026

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