BioLab Metabolic Boost (SLU-PP-332) 500 mcg, 60 caps

BioLab Metabolic Boost (SLU-PP-332) 500 mcg, 60 caps is a BioLab listing of SLU-PP-332, labelled at 500 mcg (0.5 mg) per capsule, 60 capsules per pack. It is supplied through the Muscle Market range for laboratory research only, is not for human consumption, and is sold to adults aged 18 and over. Below: what the published research on SLU-PP-332 reports, what the label documents, how batch certificates are handled for BioLab products, and how the compound differs from 5-Amino-1MQ.

About SLU-PP-332

SLU-PP-332, also written SLU PP 332, is a synthetic pan-agonist of the oestrogen-related receptors ERR alpha, beta and gamma. These are orphan nuclear receptors, unrelated to the oestrogen receptor despite the name, that regulate mitochondrial biogenesis and oxidative metabolism in muscle and heart. The compound was developed by Burris, Walker and colleagues at Saint Louis University and first published in 2023.

In the 2023 ACS Chemical Biology paper, mice given SLU-PP-332 showed a pattern of gene expression in muscle resembling the acute response to aerobic exercise and showed more oxidative type IIa muscle fibres and greater exercise endurance; the authors reported that ERR alpha activation was critical for the endurance effect (Billon et al., 2023). A 2024 follow-up in diet-induced obese mice and in ob/ob mice reported increased energy expenditure and fatty acid oxidation, less fat mass accumulation and improved insulin sensitivity (Billon et al., 2024). The authors of both papers include stockholders in a company focused on ERR-based therapeutics. There is no human data of any kind, no human pharmacokinetic study, and no safety study in people. Nothing above is a claim about this product.

In structural terms SLU-PP-332 is a compact aromatic molecule rather than a peptide or a steroid. PubChem records it as CID 5338394, CAS 303760-60-3, with the formula C18H14N2O2 and a molecular weight of 290.3 g/mol; its IUPAC name is 4-hydroxy-N-[(E)-naphthalen-2-ylmethylideneamino]benzamide. These are the identifiers any analytical report on this product should agree with.

This listing

• Brand: BioLab
• Compound: SLU-PP-332
• Form: Capsules
• Pack size: 60 capsules
• Strength: 500 mcg (0.5 mg) per capsule, as printed on the BioLab label
• Total in pack: 30 mg (500 mcg x 60 capsules)
• Batch certificate of analysis: shown where BioLab supplies one for the batch we hold

This is the highest per-capsule figure BioLab lists for SLU-PP-332. The same 60-capsule format is also sold at 100 mcg (6 mg per pack) and 200 mcg (12 mg per pack), so this pack holds five times the labelled content of the smallest one. Thoroughbred Labs SLU-PP-332 is a separate 60-capsule listing whose label states 250 mcg per capsule, 15 mg per pack, half the per-capsule figure of this tub. When comparing listings, divide cost by total milligrams, as set out in our price per milligram guide.

SLU-PP-332 in the UK: buying, legal status and what to check

Search terms like "SLU PP 332 UK buy", "SLU PP 332 UK sale" and "SLU PP 332 UK source" suggest many people assume the compound is an ordinary retail product. It is not, and the legal framework explains why.

Where the law stands

No regulator anywhere has licensed SLU-PP-332. In the UK it is not a licensed medicine, it has never been assessed by the MHRA, and it is not an authorised food supplement or novel food, so it cannot lawfully be marketed as something to swallow. It is not a controlled drug either. The route left open is supply for laboratory research to adults, and that is the only basis on which this listing exists: 18+ only, and not for human consumption. A marketplace page describing it as a supplement, or a "compounding" service offering it as a treatment, is presenting it as something no authority has approved. In sport, SLU-PP-332 is prohibited at all times: as a substance with no current approval for human therapeutic use it is caught by section S0 (non-approved substances) of the WADA Prohibited List, whether or not the list names it.

Questions worth putting to any UK seller

1. Whose product is it? A named brand can be held to its label. Here the brand is BioLab, which describes itself as the distributor of its research preparations.
2. What is the stated content, in which unit? Micrograms and milligrams differ by a factor of a thousand. This pack states 500 mcg per capsule and 60 capsules, 30 mg in total.
3. Is there a certificate for the batch actually in stock? For BioLab we show one only where BioLab has supplied it for the batch we hold, and say so where it has not.
4. Is the seller identifiable? FreeMuscle is registered in Andorra, has its UK operations and dispatch in Scunthorpe, sells only to adults, and accepts returns of unopened items within 30 days.
5. How does it travel? Every UK order ships free by tracked delivery in plain packaging; orders placed before 2pm Monday to Friday are processed the same working day, and EU delivery takes 3-7 working days.
6. Does the listing tell you how to use it? A research listing should not, and this one does not.

Reviews that describe personal outcomes cannot confirm what a capsule contained, so we do not publish them. Terms are on our shipping and guarantee pages, and the UK supplier checklist applies the same tests to any shop.

Capsules compared with other forms

SLU-PP-332 is offered as capsules, as liquids and as vials marketed for injection, which is why "SLU-PP-332 capsules" and "SLU-PP-332 injectable" are both frequent searches. The literature answers part of that question directly. None of the published animal studies tested a capsule. In a 2026 paper introducing a successor molecule, SLU-PP-915, the same research group stated that SLU-PP-332 improves aerobic performance in mice but lacks oral bioavailability, and presented oral activity as the reason for developing the new compound (Billon et al., 2026). The authors disclose that one of them is an inventor on the university's rights and holds shares in companies developing ERR agonists. No study has measured SLU-PP-332 exposure after oral intake in any species, so this page makes no claim about what a capsule does.

Because SLU-PP-332 is a small molecule, the usual explanation for poor oral uptake of peptides, digestion by stomach and gut enzymes, does not describe its problem; the abstract does not give a cause. Our article do oral peptides work covers the separate peptide case.

The practical differences between forms are about measurement and stability. A capsule fixes the amount at the filling stage: at 500 mcg the active is still well under a milligram per capsule, so its accuracy depends on how evenly the powder blend was mixed before filling. A liquid moves that uncertainty to the solvent and the measuring device, and keeps the acylhydrazone link in contact with water for its whole shelf life. Only a batch content assay can show whether either format matches its label.

SLU-PP-332 compared with 5-Amino-1MQ

5-Amino-1MQ is often discussed alongside SLU-PP-332, and our research guide covers the two together, because both are small molecules studied in obese mice and both are sold under metabolic headings. Their mechanisms are unrelated. SLU-PP-332 switches on transcription factors, the ERR receptors, that drive genes for mitochondrial energy production. 5-Amino-1MQ (5-amino-1-methylquinolinium) works on an enzyme instead: it inhibits nicotinamide N-methyltransferase (NNMT), which methylates nicotinamide and in doing so draws on the cell's pools of NAD+ and the methyl donor SAM.

The key 5-Amino-1MQ paper came from the University of Texas Medical Branch. Methylquinolinium inhibitors of NNMT, the chemical series to which 5-Amino-1MQ belongs, were selective against related methyltransferases, lowered the NNMT product 1-methylnicotinamide, raised intracellular NAD+ and SAM, and suppressed fat formation in cultured fat cells. In diet-induced obese mice, a potent inhibitor from the series given systemically reduced body weight, white fat mass and plasma cholesterol without a change in food intake, and the authors saw no observable adverse effects (Neelakantan et al., 2018). That was a short study in mice, not a toxicology programme, and no human trial has been published for either compound.

Feature	SLU-PP-332	5-Amino-1MQ
Target type	Nuclear receptors (ERR alpha, beta, gamma)	Enzyme (NNMT)
Action	Agonist	Inhibitor
PubChem CID and formula	5338394, C18H14N2O2 (neutral)	950107, C10H11N2+ (a cation)
Molecular weight	290.3 g/mol	159.2 g/mol
Evidence base	Mouse and cell studies from 2023 onwards	Cell and mouse studies from 2018 onwards
Licensed anywhere	No	No
WADA position	Prohibited at all times (at least under S0, non-approved substances)	Prohibited at all times (at least under S0, non-approved substances)

Being charged, 5-Amino-1MQ behaves differently in analysis and in solution from the neutral SLU-PP-332, which is one reason their certificates are not interchangeable. The comparison is chemical and regulatory only. It says nothing about using either compound, singly or alongside any other.

Reading the certificate of analysis for this product

BioLab is a third-party brand in the Muscle Market range, so the testing position differs from our own label. Every Free Muscle-brand batch is assayed by Janoshik Analytical, an independent laboratory, with the certificate sent on request by email. For BioLab products we show a certificate of analysis only where BioLab supplies one for the specific batch we hold. A generic PDF with no batch number is not a batch certificate, and we do not present one as such. Email us with the product name and we will send what we hold, or say plainly that there is none.

No BioLab certificate is attached to this 500 mcg listing yet. When one is supplied for this pack, read it against the following:

• Identity method. HPLC compares a retention time with a reference standard, which is only as good as that standard; for a compound this new, reference material is scarce. LC-MS adds a measured mass, and for SLU-PP-332 the protonated molecule should appear near m/z 291.1.
• Purity percentage. The proportion of the detected signal attributable to SLU-PP-332. A capsule mostly made of filler can still show high purity, because purity describes the active fraction, not its amount.
• Content per capsule. The result that tests the 500 mcg on the label.
• Batch number. Compare it with the code on the bottle; any difference, even one digit, means the report covers other stock.
• Date and laboratory. A named laboratory and test date place the result in time; a certificate years older than the pack describes earlier stock.

What a gap means is fairly literal. With no content figure, the 500 mcg claim rests on BioLab's label alone. With no batch number, the report cannot be linked to this stock. With no certificate at all, this listing makes no analytical claim beyond what BioLab prints. See our lab tests page, the guide on how to read a certificate of analysis, or contact us about a specific batch.

Detection, sport and testing

Under the WADA Code, SLU-PP-332 is caught by section S0, which covers any pharmacological substance without current approval for human therapeutic use, so it is prohibited in and out of competition whether or not the list names it. Anti-doping laboratories have already published in vitro work on its metabolism: the UCLA Olympic Analytical Laboratory incubated SLU-PP-332 with pooled human liver S9 fractions and, using high-resolution LC-MS, identified 22 metabolites, including hydroxylated, glucuronidated and sulfated forms, several of them proposed as targets for doping control (Avliyakulov et al., 2026). The authors note that further work is needed to confirm the structures.

What has not been published is an excretion study in people, so there is no validated detection window in urine or blood. Any number of days quoted online is unsupported. The accurate position is that the compound is detectable in principle and the window has not been established. Competitors in tested sport, including events run under UK Anti-Doping rules, should treat it as prohibited and check the current list, which changes every January.

Storage, stability and handling

BioLab has published no stability study for these capsules, so the sensible approach follows from the chemistry. The weak point of SLU-PP-332 is the acylhydrazone bridge between its two ring systems. Moisture, particularly with any acidity, can split that bond back into its starting fragments, and light can convert the E arrangement of the carbon-nitrogen double bond into the Z form, a different shape. Warmth accelerates both.

In practice that means leaving the capsules in the original BioLab container with the lid closed and any desiccant in place, stored at or below room temperature in a dark cupboard rather than on a windowsill or near a radiator, kettle or shower. Keep the original label, since the batch number is the only link between the pack and any certificate. Capsules that have stuck together, softened or discoloured should be set aside and disposed of according to local rules rather than examined further. Keep the pack out of reach of children and apart from food, and handle it with the ordinary laboratory precautions of gloves, clear labelling and a clean work surface.

Glossary

• Oestrogen-related receptor (ERR): named for sequence similarity to the oestrogen receptor, the ERR alpha, beta and gamma proteins do not respond to oestrogen and govern energy-producing genes.
• Agonist: a molecule that activates a receptor; SLU-PP-332 activates all three ERRs.
• Nuclear receptor: a protein inside the cell that binds a molecule and then switches sets of genes on or off.
• Oxidative metabolism: energy production that uses oxygen, carried out in mitochondria.
• Oral bioavailability: how much of a compound taken in by mouth survives absorption and first passage through the liver to circulate intact, expressed as a percentage.
• NNMT: nicotinamide N-methyltransferase, the enzyme inhibited by 5-Amino-1MQ.
• NAD+: a coenzyme central to cellular energy reactions.
• Acylhydrazone: a C(=O)-NH-N=C bridge; in SLU-PP-332 it joins the naphthalene and hydroxybenzoyl parts and is the likeliest site of breakdown.
• Label claim: the amount per capsule printed on the BioLab label, here 500 mcg.
• m/z: mass-to-charge ratio, the value a mass spectrometer reports for an ion.

About BioLab Metabolic Boost 500 mcg

This is the top strength in BioLab's Metabolic Boost line, the brand's trade name for its SLU-PP-332 capsules; the name belongs to the product and says nothing about effects. With 500 mcg per capsule and 60 capsules, the tub is labelled at 30 mg in total, five times the 100 mcg tub and two and a half times the 200 mcg tub. On the front, a 500 MCG/CAPS arrow tag, a 60 CAPS tag and a yellow 500 mcg starburst mark the strength, while the purple-blue tub, orange trim, tiger head and BIOLAB band match the lower strengths.

BioLab keeps its research compounds in a category separate from its supplements, marks them as not for consumption and says it acts only as their distributor, leaving the maker unnamed.

Comparing the three BioLab strengths

Listing	Per capsule	Capsules	Total per tub	BioLab report on our listing
Metabolic Boost 100 mcg	100 mcg	60	6 mg	Yes, October 2024
Metabolic Boost 200 mcg	200 mcg	60	12 mg	None at present
Metabolic Boost 500 mcg (this listing)	500 mcg	60	30 mg	None at present

Documents for this strength

BioLab says it posts the current report for each product in the gallery and Tests tab of its own shop and supplies it on request. None is shown here for the 500 mcg tub, and the 2024 report on the 100 mcg listing does not cover this fill. A report that could confirm this label would state content per capsule against 500 mcg, with a date and a lot number; mention the lot on your tub when asking what documents are held. The other brand we stock, Thoroughbred Labs, prints 250 mcg per capsule on a 60-capsule tub (15 mg in total); the SLU-PP-332 collection sets the brands against each other, with the full ranges on the BioLab and Thoroughbred Labs pages.

The compound itself is a preclinical research molecule: a pan-ERR agonist from Saint Louis University with no human data, no UK licence and a WADA prohibition that applies at all times.

Related

• All brands of SLU-PP-332 we stock, compared
• All BioLab products
• 5-Amino-1MQ and Cardarine (GW-501516)
• SLU-PP-332 and 5-Amino-1MQ research guide
• Research guide to SARMs and related compounds
• Batch testing and certificates of analysis
• Delivery and returns

Research compounds sold by Free Muscle are supplied for laboratory research use only and are not for human consumption. They are not authorised as medicines by the MHRA, EMA or FDA, are not food supplements, and are sold only to adults aged 18 or over. Nothing on this page is medical or dosing advice. Summaries of published research describe study findings and are not claims about any product.

References

• Billon C, et al. Synthetic ERRalpha/beta/gamma Agonist Induces an ERRalpha-Dependent Acute Aerobic Exercise Response and Enhances Exercise Capacity. ACS Chem Biol. 2023;18(4):756-771. PMID: 36988910.
• Billon C, et al. A Synthetic ERR Agonist Alleviates Metabolic Syndrome. J Pharmacol Exp Ther. 2024;388(2):232-240. PMID: 37739806.
• Billon C, et al. An orally active estrogen receptor-related receptor agonist, SLU-PP-915, enhances aerobic exercise capacity. J Pharmacol Exp Ther. 2026;393(1):103787. PMID: 41421047.
• Avliyakulov NK, et al. Analysis and Identification of In Vitro Metabolites of Exercise Mimetic SLU-PP-332 ERRalpha/beta/gamma Agonist for Doping-Control Purposes. Drug Test Anal. 2026;18(3):439-450. PMID: 41688415.
• Neelakantan H, et al. Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice. Biochem Pharmacol. 2018;147:141-152. PMID: 29155147.