Just like all supplements are not created equal, not all peptides are created equal either. The raw materials from which peptides are produced, the procedures by which they are manufactured, and the processes by which they are purified all affect quality. Much of the dedication to quality comes down to the ethos of the manufacturer. Afterall, some supplements have a good reputation because the people making them insist on using the best ingredients, the best equipment, and the best manufacturing practices. The same is true of peptides, so here is a look at some of the factors that should be considered when purchasing peptides to distinguish premium peptides from run-of-the-mill peptides and inferior peptides. The purer a peptide preparation is, the more certain the outcome of peptide research will be because pure peptides eliminate the possibility of confounding elements like contaminants or binders. Choosing a premium peptide could be the difference between successful research outcomes and complete disaster.
What Is a Premium Peptide?
Defining a premium peptide might seem like a difficult task, but it ultimately comes down to purity. A premium peptide is simply a peptide preparation that contains only the advertised peptide and nothing else. While this definition sounds simple enough, achieving high degrees of purity in the real world is anything but. Achieving 100% purity is an impossibility, but purities well above 99% can be attained with dedication.
For simple benchtop work in a chemistry lab, a moderate protein purity of 80% to 90% is often acceptable. For functional studies, such as X-ray crystallography, high purity levels of 95% to 99% become necessary. For therapeutic proteins used in treatments, animal studies, or clinical trials, the highest standard is always above 99%. The difference in time and resources invested to go from moderate to high to highest is not linear. At each step, the investment often increases by an order of magnitude or more.
Proteins that are not pure enough can lead to several problems including alterations in the 3-D structure of the protein that render it useless or, in very severe cases, dangerous. Obtaining premium peptides is thus critical to ensuring good science with repeatable results and is necessary for safety as well. To get to this point generally means using a multistep purification protocol that adds cost and complexity. Not only are some labs unwilling to undertake this degree of rigor, but some are also simply incapable due to lack of equipment or proper scientific expertise. Choosing a lab that is ISO 9001 certified is one step toward ensuring that it has the people and the equipment to produce a premium peptide product.
The best labs ensure that the best raw ingredients are utilized, but this is just an initial step in producing a premium product. Raw ingredients can be contaminated by residual solvents, byproducts, or side products from production. Sometimes these contaminants can be toxic and though it is impossible to make something 100% pure, impurities can be minimized through proper purification. How this purification is carried out depends on the nature of the peptide being produced, but it is possible to achieve 99% or greater purity with enough time and skill. Getting to this level requires not only taking the necessary steps to achieve purity but ensuring that each of those steps is carried out with the highest degree of fidelity. This means careful buffer preparation, proper adherence to cleanliness, and verification that the final product is as pure as it should be. Developing premium peptides is about diligence and adherence to the highest manufacturing standards from the very beginning to the process right up to the moment the peptide is bottled and shipped to the customer.
Premium Peptides: Raw Ingredients
When it comes to raw ingredients, all peptides are made using amino acid monomers that are strung together into longer chains that we call peptides. These chains are then modified after production, as necessary, to produce a peptide with the correct chemical properties. There isn’t really a lot of room for using inferior amino acids as they are all basically the same. There is, however, plenty of room for inferior ingredients when it comes to modifying the chains after they have been produced.
Perhaps the most egregious way that some manufactures alter peptides is through the addition of bulking agents called fillers or binders. Bulking agents are chemical additives used strictly because they provide a visually satisfying increase in the quantity of the product. They don’t actually increase quantity; they just make it look like there is more product than there actually is. Bulking agents are, at best, inert ingredients that add no overall value to the product. They are simply added to trick the buyer into thinking they are getting more for their money.
In fact, bulking agents don’t simply add volume. Sometimes they interfere with the action of the peptide itself. They do this in several ways including slowing absorption, altering peptide bioavailability, altering half-life, and more. In the research setting, bulking agents can add a confounding factor to experiments and must be added to control groups to ensure the experimental design is valid. This can increase the cost and complexity of research, which can seem anomalous to people who think that purchasing premium peptides is too expensive. What’s worse, is if the use of a bulking agent isn’t explicitly disclosed. It can be difficult to know that it is there without doing expensive analysis via spectrometry, flame atomic absorption, and other methods. In the end, the best practice, and paradoxically the most cost-effective practice, is to purchase a peptide that is as pure as possible. In most cases, this means peptides that are at least 99% pure.
One commonly used filler is mannitol. Mannitol, a sugar alcohol, is an osmotic agent, which means it attracts water. It is safe for human consumption and is used as both a sweetener and in certain medical treatments. However, just because it is safe for human consumption does not mean that mannitol is without side effects. Mannitol is contraindicated in people with severe heart, lung, or kidney diseases. It is also not safe for use by animals in a dehydrated state and can cause electrolyte imbalances following exercise. Common side effects of mannitol consumption or injection include increased urination, bloating, nausea, and changes in vision.
TFA, trifluoroacetic acid, is commonly used as an additive in the mobile phase of high-pressure liquid chromatography (HPLC) separation and can add some bulk. Bulking is just a side effect of TFA addition; however, it isn’t the primary reason for using the acid. As we will see in the next section, TFA is primarily used to adjust the pH in HPLC, a necessary step in purifying many peptides. As it turns out, certain manufacturing processes can contribute to what some might consider to be contaminants or may fail to remove inert or otherwise useless byproducts resulting in a final product that is not nearly as pure as it could be. These processes are often chosen over others for cost or convenience, separating premium peptide preparations from run-of-the-mill preparations. Premium peptides always have TFA removed during the final phase of filtration.
Premium Peptides: Manufacturing Process
The addition of bulking agents is not the only way that peptide purity can be affected by a manufacturing process. Manufacturing of peptides often produces byproducts or inert secondary products that, while not dangerous, are also not useful. Many manufacturers use the cheapest means possible to remove these byproducts or simply do not remove them at all. This, once again, leads to a final preparation that is not as pure as it could be and introduces confounding factors into research design.
TFA was mentioned in the section above. TFA is commonly used in HPLC to adjust the pH (acid levels) of a solution and thus aid in the separation of biological molecules. TFA is not without its drawbacks even when found in exceptionally small quantities. TFA is corrosive and, in high enough concentrations, may cause liver damage. Though the risk is small, there are alternatives to TFA like acetic acid (the acid in vinegar) that are safer and cause fewer problems. They are also just as affordable so there is really no reason to utilize TFA. TFA in 0.1% is considered “trace” levels and considered normal levels according to industry standards.
The other problem with some manufacturing processes is that additional steps are necessary to ensure purity. A perfect example of this is FOXO4-DRI. Like many peptides, FOXO4-DRI comes in two optical isomers referred to as L-form and D-form. In the case of FOXO4-DRI, only the D-form is of use. In fact, contamination by the L-form can make an entire preparation useless. Separation of optical isomers is not a simple process and can really set the bar for premium peptides. The most popular way to address such purification is using chiral HPLC to differentially interact with optical isomers. Of course, doing this means that yield can be reduced substantially, making the whole process significantly more expensive. For some peptides, this step isn’t completely necessary while for others, like FOXO4-DRI, skipping this step can render an entire preparation useless. Thus, even though a buyer is technically getting FOXO4-DRI, it is what is called a racemic mixture. That means it contains more than one optical isomer. Many pharmaceutical companies go out of their way to remove ineffective optical isomers from common medications like ibuprofen, cetirizine, Adderall, omeprazole, and many others. Non-racemic mixtures, called enantiopure preparations or chiral specific preparations, are done to improve safety and therapeutic index. Even if one form of the peptide is simply inert, removing it means that less compound needs to be injected or administered to achieve the same effect. This can greatly simplify research trials, reduce injection site reactions, and more.
Premium Peptides: Overview
Except for the most basic of applications, there is little reason to use peptides that are less than 99% pure. Premium peptides make it easier and safer when designing experiments, but they also decrease costs and time invested in work. Premium peptides can be identified by their lack of fillers/binders, purity levels above 99%, the raw materials used, and the manufacturing practices utilized. Discerning researchers should look to purchase only premium peptides.