Approved vs. Investigational vs. Compounded vs. RUO
Four legal categories that look similar in marketing and are completely different in practice.
Why the category matters more than the molecule
Two vials can contain the same amino acid sequence and sit in entirely different legal and safety universes. The category determines who may lawfully supply it, what quality standards apply, whether anyone is accountable for purity, and whether a clinician can prescribe it at all. Category language is also the most common place consumer marketing becomes misleading — an FDA-registered facility is not an FDA-approved product, and a certificate of analysis is not a regulatory clearance.
The four categories
| Category | What it means in practice |
|---|---|
| FDA-approved | A specific manufacturer's product, at a specific dose and indication, cleared after review of manufacturing, safety, and efficacy data. Comes with FDA-approved labeling. Example: Semaglutide as Wegovy or Ozempic. |
| Investigational | Under active study; may be in clinical trials under an IND. Not approved, not lawfully marketed for treatment. Access is normally through enrollment in a trial or an expanded-access pathway. |
| Compounded | Prepared by a licensed pharmacy (503A) or outsourcing facility (503B) for an identified patient need. Not FDA-approved as a product; the pharmacy is accountable for the preparation. Legitimacy depends on a valid prescription, the ingredient's eligibility for compounding, and the pharmacy's licensure and inspection record. |
| Research Use Only (RUO) | Labeled and sold strictly for laboratory research. Not manufactured to pharmaceutical standards, not intended or lawful for human or veterinary administration, and not subject to the same purity, sterility, or endotoxin requirements. |
Practical differences you can act on
- Accountability: with an approved product a manufacturer answers for defects; with an RUO vial nobody does.
- Purity and sterility: pharmaceutical products have specified impurity, endotoxin, and sterility limits. RUO material does not.
- Labeling: approved products carry validated dosing, contraindications, and warnings. RUO vials carry a research disclaimer.
- Legal exposure: administering RUO material to a person or animal is outside the labeled use and can carry regulatory and liability consequences.
- Insurance and continuity of care: approved and appropriately compounded products can be documented in a medical record; RUO purchases generally cannot.
Language that should raise a flag
- "FDA-registered facility" or "FDA-inspected" used to imply product approval.
- "Pharmaceutical grade" — not a regulatory term and not independently defined.
- "Legal to purchase" — true for research chemicals, and irrelevant to whether administration is lawful or safe.
- Dosing instructions on a product sold as Research Use Only.
- Before-and-after photography attached to an investigational or RUO compound.
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Educational reference only. Not medical advice. Consult a qualified, independently licensed clinician before starting any protocol. Full disclaimer.