Product guide · Restricted substance
Core Labs Bulk Rx 90 caps
Prohormone product from Core Labs, 90 capsules. This guide sets out what the manufacturer states about the composition of Core Labs Bulk Rx 90 caps, what independent research says about its main ingredients, and the safety and regulatory points that apply. It contains substances that are not authorised as food or medicine in the EU. This guide is educational: it does not recommend use and gives no directions for use.
Back to the product- Named ingredients
- 3
- Amounts stated
- None
- Status
- Restricted substance
- Evidence summaries
- 3
Overview
Manufacturer informationIngredients & composition
Manufacturer information| Ingredient | Amount |
|---|---|
| 2,17α-Dimethyl-17β-hydroxy-5α-androst-1-en-3-one (methylstenbolone) | Not stated |
| (25R)-5α-Spirostane-2α,3β,5α-triol-6-OH, stated as combined with an undecanoate ester | Not stated |
| Vitamin E | Not stated |
The manufacturer does not state the amount of any ingredient. Without amounts, the research summarised in this guide cannot be related to this product's dose.
Scientific background
Independent researchProhormones and designer anabolic steroids
Prohormones and "designer steroids" are synthetic anabolic-androgenic steroids, or precursors converted to them in the body, sold in supplement-style products. Examples include methasterone ("Superdrol"), methylepitiostanol ("Epistane") and trendione ("Trenavar").
Plant "anabolic" sterols (laxogenin, ecdysterone)
Laxogenin (5α-hydroxy-laxogenin) and ecdysteroids such as ecdysterone (20-hydroxyecdysone, from Ajuga turkestanica or Cyanotis) are plant sterols marketed as natural anabolic agents.
Vitamin E (α-tocopherol)
Vitamin E is a fat-soluble antioxidant. EFSA set adequate intakes of 13 mg a day for men and 11 mg a day for women, as α-tocopherol1. Vitamin E TPGS is a water-soluble form used as an ingredient and absorption enhancer.
Research evidence
Independent researchProhormones and designer anabolic steroids
No controlled trials support the safety of these products. Their muscle-building effect derives from anabolic-androgenic steroid activity, the same mechanism as controlled steroid drugs.
Plant "anabolic" sterols (laxogenin, ecdysterone)
In a 12-week randomised double-blind training study, a commercial ecdysterone product gave no additional benefit over training alone, and its actual content differed markedly from the label2. In castrated rats, 5α-hydroxy-laxogenin showed neither androgenic nor anabolic effects3.
Vitamin E (α-tocopherol)
The EU authorises the claim that vitamin E contributes to the protection of cells from oxidative stress4. Benefits of high-dose supplements beyond meeting needs are not established.
Evidence limitations
Independent researchThis product does not state all ingredient amounts, so the doses used in research cannot be compared with what one serving provides.
The studies summarised in this guide examined single ingredients. No published study has tested this product or this combination of ingredients.
Prohormones and designer anabolic steroids
Products are often mislabelled or adulterated, so the actual steroid and dose are uncertain56.
Plant "anabolic" sterols (laxogenin, ecdysterone)
Label accuracy is poor and human trials are few2.
Vitamin E (α-tocopherol)
Most people in the EU meet their needs from food1.
Safety & potential risks
Independent researchProhormones and designer anabolic steroids
Case reports describe drug-induced liver injury, including cholestasis, from prohormone and bodybuilding supplements containing anabolic-androgenic steroids567. Anabolic steroids also suppress natural testosterone production and adversely affect blood lipids and the heart.
Plant "anabolic" sterols (laxogenin, ecdysterone)
Human safety data are limited.
Vitamin E (α-tocopherol)
The EU Scientific Committee on Food set a tolerable upper intake level of 300 mg a day for adults8. High doses may increase bleeding risk in people taking anticoagulants.
Regulatory status
Contains synthetic anabolic-androgenic steroid compounds (methylstenbolone). These are not authorised as food (including food supplements) or as medicinal products in the EU and are on the WADA Prohibited List. No dosing information for human use is provided.
Prohormones and designer anabolic steroids
Anabolic-androgenic steroids are medicinal substances and are not permitted in food or food supplements in the EU910. Anabolic agents are prohibited at all times by the World Anti-Doping Agency11.
Scientific references
- EFSA NDA Panel. Scientific Opinion on Dietary Reference Values for vitamin E as α-tocopherol. EFSA Journal. 2015;13:4149. DOI 10.2903/j.efsa.2015.4149
- Dissemond J, Havers T, Held S, et al. How reliable is the labeling of a commercial phytosteroid product? A 12-week randomized double-blind training study. J Int Soc Sports Nutr. 2025;22:2540408. PubMed 40781783
- Derwand D, Zierau O, Wolf CA, et al. Effects of the dietary supplement 5α-hydroxy-laxogenin in the orchiectomized rat model. Drug Test Anal. 2025;17:1743-1749. PubMed 40038867
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. Official Journal of the European Union. Source
- Magee CD, Witte S, Kwok RM, Deuster PA. Mission compromised? Drug-induced liver injury from prohormone supplements containing anabolic-androgenic steroids in two deployed U.S. service members. Mil Med. 2016;181:e1169-e1171. PubMed 27612377
- Matusak M, Aljabban J, Wirtz M, et al. Cholestasis linked to bodybuilding supplements: exploring the risks of contamination. Case Reports Hepatol. 2024;2024:5112461. PubMed 38826497
- Nash E, Nicoll A, Batt N, et al. Drug-induced liver injury from selective androgen receptor modulators, anabolic-androgenic steroids and bodybuilding supplements in Australia. Aliment Pharmacol Ther. 2024;59:953-961. PubMed 38372012
- Scientific Committee on Food / EFSA. Tolerable Upper Intake Levels for Vitamins and Minerals. European Food Safety Authority; 2006. Source
- Directive 2001/83/EC on the Community code relating to medicinal products for human use. Official Journal of the European Union. Source
- Regulation (EU) 2015/2283 on novel foods. Official Journal of the European Union. Source
- World Anti-Doping Agency. The Prohibited List (current edition). Source
- Directive 2002/46/EC on the approximation of the laws of the Member States relating to food supplements. Official Journal of the European Union. Source
Sources checked against PubMed, Crossref or the official publisher on 2026-11-04. Manufacturer information is taken from the product's own data and has not been independently tested.
The product
Core Labs Bulk Rx 90 caps
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