What peptides are
Peptides are short chains of amino acids - the same building blocks that make up proteins, just linked in smaller sequences of typically 2 to 50 amino acids. The human body produces thousands of peptides naturally, where they function as signalling molecules: instructing cells to produce growth hormone, modulating immune responses, regulating appetite, triggering tissue repair, and coordinating dozens of other biological processes.
Therapeutic peptides work by mimicking or modulating these natural signalling pathways. Because they are structurally close to naturally occurring molecules, many have a favorable tolerability profile compared to small-molecule drugs. They are also highly targeted - a peptide designed to activate a specific receptor tends to interact with that receptor and not much else.
Most therapeutic peptides are administered by subcutaneous injection, though oral and intranasal forms exist for some compounds. The injection method allows the peptide to enter circulation without being broken down in the digestive tract.
The FDA regulatory landscape: approved, compounded, and restricted
Understanding US peptide therapy means understanding three distinct regulatory categories:
FDA-approved medicines are the clearest category. These have passed clinical trials, been reviewed for safety and efficacy, and are manufactured to strict standards. The most prominent approved peptides in clinical use right now are GLP-1 drugs:
- Semaglutide - approved as Ozempic (type 2 diabetes), Wegovy (weight management), and Rybelsus (oral, type 2 diabetes)
- Tirzepatide - approved as Mounjaro (type 2 diabetes) and Zepbound (weight management)
- Liraglutide - approved as Victoza (type 2 diabetes) and Saxenda (weight management)
- Tesamorelin - approved as Egrifta for HIV-associated lipodystrophy; also used off-label for growth hormone optimization
These can be legally prescribed by any licensed US physician for approved indications, and off-label for other indications at their clinical discretion.
Compounded peptides occupy a grayer space. When FDA-designated drug shortages exist, licensed compounding pharmacies can legally produce versions of drugs like semaglutide and tirzepatide. However, the FDA's 2024 bulk substance list made many other peptides harder to access through compounding. Peptides like BPC-157 were placed on the Category II list (meaning they cannot be compounded under current rules) or Category III (reserved for further FDA review). This has restricted - though not eliminated - access to some commonly sought peptides.
Research chemicals are not a medical option. Products labeled "for research use only" are not approved for human administration and purchasing them outside a clinical setting bypasses every safety safeguard that exists. See more in our guide to what peptides are legal in the US in 2026.
Treatment categories: what physician-supervised programs actually offer
Physician-supervised peptide programs in the US typically fall into four broad treatment goals:
Weight loss and metabolic health - driven almost entirely by GLP-1 receptor agonists. Semaglutide and tirzepatide are the primary options, available as branded drugs or compounded versions. These are the most clinically validated peptides in widespread use and the easiest to access through telehealth. See telehealth peptide clinics in the US for how these programs work remotely.
Growth hormone optimization - using growth hormone-releasing peptides and analogues to stimulate the pituitary gland's own GH production rather than injecting synthetic HGH directly. Tesamorelin (Egrifta) is the only FDA-approved option in this category. Sermorelin and CJC-1295 are compounded peptides that were more accessible before the 2024 bulk substance list changes; their availability now depends on individual pharmacy and physician arrangements.
Tissue repair and recovery - historically the domain of peptides like BPC-157 and TB-500, both of which have significant preclinical evidence but no human clinical trials. Both were placed on restricted FDA bulk substance lists in 2024, making compounding more complex. Access has not disappeared entirely but requires a physician who works with pharmacies navigating current rules.
Sexual health - PT-141 (bremelanotide) is the relevant peptide here and is unique in having FDA approval as Vyleesi for hypoactive sexual desire disorder in premenopausal women. It can be used off-label by physicians for other patients.
How physician-supervised programs work
A legitimate US peptide program follows a structured clinical process, not a checkout flow. It typically involves:
- 1Medical intake - health history, current medications, allergies, treatment goals
- 2Baseline lab work - ordered by the clinic or submitted from your own physician; relevant panels depend on treatment goal (metabolic markers for GLP-1s, hormone panels for growth hormone peptides)
- 3Physician consultation - a real video or phone call with a licensed prescriber who reviews your intake and labs, not an automated approval
- 4Prescription decision - which may be to prescribe, to decline, or to request additional information
- 5Dispensing through a licensed US pharmacy - not an overseas supplier
- 6Follow-up monitoring - scheduled check-ins, repeat labs, and accessible communication if something changes
The consultation and monitoring structure is what distinguishes physician-supervised therapy from everything else. It is not a bureaucratic formality - it is the mechanism by which dosing is calibrated to you specifically and side effects are caught early.
How to find a clinic
The number of clinics advertising peptide therapy in the US has grown significantly. Quality varies. Key things to verify before committing to any program:
- The prescribing physician is named and credentialed (look them up on state medical board databases)
- Lab work is required before prescribing - not optional
- The compounding pharmacy is a licensed US facility (503A or 503B accredited)
- Follow-up appointments are scheduled, not ad hoc
- The clinic can explain the FDA status of any peptide it prescribes
For practical guidance on evaluating clinics, see how to find a physician-supervised peptide clinic in the US. For cost expectations, see the cost of peptide therapy in the US.
Browse the US directory to compare physician-supervised clinics by state, treatment focus, and consultation type.
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*This article is for educational purposes only. Consult a licensed physician before starting any peptide therapy program.*