What a peptide is

A peptide is a short chain of amino acids, the same building blocks that make up proteins. The line between a peptide and a protein is a convention rather than a law of nature; chains of up to about 50 amino acids are usually called peptides.

Your body runs on them. Insulin is a peptide hormone. So is GLP-1, the gut hormone that semaglutide and tirzepatide imitate. So is growth hormone-releasing hormone, whose first 29 amino acids became the drug sermorelin. Most therapeutic peptides work as signals: they bind a receptor and tell a cell to do something it already knows how to do.

Because they are digested like food, most peptides are injected under the skin rather than swallowed. A few are designed to survive the gut, which the oral vs injectable guide covers.

Approved medicines vs research compounds

Every compound on this site falls into one of two groups, and the difference matters more than anything else on a page.

Approved medicines have been through phase 3 trials, carry a prescribing label and are registered with a regulator. In the Philippines, Ozempic and Wegovy (semaglutide) and Mounjaro (tirzepatide) are sold through pharmacies with a prescription. Prescribing belongs with a licensed Philippine physician.

Research compounds such as BPC-157, TB-500 and retatrutide are not registered as medicines here. They are sold for research use only. That phrase is a legal category, not a quality grade. It means the product has not been evaluated by FDA Philippines for safety, efficacy or manufacturing quality, comes with no dosing information, and is not sold for human use.

Lyophilised vials

Research peptides usually arrive as a small glass vial containing a white cake or powder. This is lyophilised, or freeze-dried: the peptide was dissolved, frozen and then dried under vacuum. Removing the water makes the peptide far more stable than it would be in solution, which is why it ships this way.

The number on the label (5 mg, 10 mg) is the amount of peptide in the vial. Before use, the powder is dissolved in a measured amount of liquid. That step is called reconstitution.

Bacteriostatic water

Bacteriostatic water is sterile water with benzyl alcohol added as a preservative. The US label for one widely used product lists 0.9% benzyl alcohol (a 1.1% version also exists), describes it as a multiple-dose container "from which repeated withdrawals may be made", and says it is for drug diluent use only. It also carries a clear warning: not for use in newborns.

Plain sterile water for injection has no preservative. Once punctured, it is meant for single use. That is the practical difference: bacteriostatic water is what makes a multi-dose vial workable.

A few handling points that apply to any vial:

  • Wipe the rubber stopper with an alcohol swab before every puncture.
  • Add the water slowly down the inside wall of the vial, not straight onto the powder.
  • Swirl gently or roll the vial between your palms. Do not shake it hard.
  • Use a new sterile syringe every time.

Reconstitution math

The math is simple, and getting it wrong is the most common beginner mistake. It has three parts.

1. Concentration. Divide the milligrams in the vial by the millilitres of water you add.

10 mg vial + 2 ml water = 5 mg per ml

2. Syringe units. Insulin syringes are marked in units, not millilitres. On a U-100 syringe, 100 units = 1 ml, so 1 unit = 0.01 ml.

5 mg per ml x 0.01 ml = 0.05 mg (50 mcg) per unit

3. Units to draw. Divide the amount you want to measure by the amount per unit.

units = amount in mg / mg per unit

Two traps catch people:

  • mg and mcg. 1 mg = 1,000 mcg. A slip of a decimal place is a tenfold error.
  • U-40 syringes. Some syringes are made for U-40 insulin, where 40 units = 1 ml. Unit markings on the two do not match. Check the packaging says U-100.

Use the reconstitution calculator to check your numbers and the insulin syringe units chart to see what a given volume looks like on the barrel. Adding more water does not change how much peptide is in the vial; it only spreads it across more units, which can make small amounts easier to measure.

Storage in Philippine heat

Heat, light and moisture break peptides down. The rules below are general; where a product has its own label, the label wins.

Powder (lyophilised). More forgiving, but not heat-proof. Keep it in the fridge at 2 to 8°C, in its box, away from light. A day on a cool shelf is not a disaster; a week in a hot room or a car is a different matter.

Mixed (reconstituted). Always in the fridge, never in the freezer. Keep vials in the main compartment rather than the door, where the temperature swings every time it opens. There is no published stability data for most research peptides in solution. As a reference point, US CDC injection-safety guidance says an opened multi-dose vial should be dated and discarded within 28 days unless the manufacturer states another date. Write the mixing date on the vial.

Pens. Approved GLP-1 pens come with their own storage leaflet, including how long they can be kept out of the fridge and at what maximum temperature. Follow it.

Brownouts. A closed fridge holds its cold for a while. US food-safety guidance says a refrigerator keeps food safe for up to 4 hours in an outage if the door stays closed. For longer outages:

  • Keep the door shut and do not check the vials every hour.
  • Have an insulated cooler and ice packs ready. Wrap vials in a cloth or zip bag so they do not touch the ice directly; freezing a mixed peptide can damage it.
  • A cheap fridge thermometer tells you what actually happened while you were out.
  • If you live somewhere with frequent long outages, a small cooler with ice packs is cheaper than replacing a month of product.

Travel and delivery. An insulated bag with an ice pack for any trip. Be home when a delivery arrives and get it into the fridge straight away. Never leave vials or pens in a parked car.

A short summary, not legal advice.

  • Under RA 9711, the FDA Act of 2009, it is a prohibited act to sell, offer for sale or distribute a health product that requires registration but is not registered. The enforcement actions reported in 2026 were against sellers and clinics. In May 2026 the NBI arrested two people in Tondo for selling unregistered tirzepatide through Facebook.
  • Semaglutide and tirzepatide brands registered or sold here (Ozempic, Wegovy, Mounjaro) are prescription medicines from licensed pharmacies.
  • Research peptides are sold for research use only and are not registered as medicines. They are not scheduled dangerous drugs under RA 9165, the drugs law, but that does not make them registered medicines.
  • The Philippine College of Physicians warned in March 2026 against compounded and non-registered semaglutide and tirzepatide, including products sold online.

Each compound page has a Status in the Philippines section with the specifics.

How to read a compound page

Every compound page follows the same layout, so you can compare them quickly.

  • Infobox. Class, sequence, half-life, route, research stage and regulatory status at a glance. Research stage is the most important line: "FDA-approved", "phase 3", "small human pilots" and "animal studies only" are very different levels of evidence.
  • What the research found. Split into human and animal work. When a finding comes from rats, the page says so.
  • Doses used in published research. A table of what a specific study gave to a specific population, with a link. It is a record of the research, not a recommendation, and animal doses do not convert to human doses.
  • Side effects reported in studies. What trials or labels recorded. For compounds with little human data, the honest answer is that we do not know much.
  • Status in the Philippines. Registration, availability and any enforcement news.
  • References. Links to the sources. Open them.
  • Last reviewed. The date the page was last checked.

Some pages also show a box linking to a local supplier. That box is a link to a shop, separate from the article.

Common beginner mistakes

  1. Getting the reconstitution math wrong, usually mg against mcg or a U-40 syringe.
  2. Leaving vials at room temperature in Philippine heat.
  3. Reusing needles.
  4. Injecting the same spot every time instead of rotating sites.
  5. Skipping baseline bloodwork. See the bloodwork guide.
  6. Buying injectables from marketplace listings. See the sourcing guide.

Where to go next