Choosing dietary supplements should be based on quality criteria, manufacturing technology, and alignment with scientific evidence. In practice this means moving away from marketing slogans and focusing on the aspects that actually determine the effectiveness and safety of supplementation. Below is an overview of the key rules that allow you to assess the real value of a given supplement.
1. Standardized supplements - why does it matter?
Standardization is the process by which a plant extract or a blend of synthetic substances is prepared so that it contains a defined amount of a specific active compound (or group of compounds). This means that every batch of the product delivers a repeatable dose of a biologically active substance, and as a result it can produce effects similar to those observed in clinical studies.
Without standardization, the content of active ingredients can vary significantly between batches. The biological effect is unpredictable - the supplement may contain only trace amounts of active substances, which translates into a lack of therapeutic effect, and the product loses its scientific value and can be compared to a placebo for a given health indication.
In practice, then, if a manufacturer does not state the percentage content of the active substance, its effectiveness is hard to assess. Examples of standardization look as follows:
- Turmeric (Curcuma longa) - extract standardized to 95% curcumin content.
- Indian frankincense (Boswellia serrata) - extract standardized to 65% boswellic acids.
- Rhodiola (Rhodiola rosea) - extract standardized to 5% rosavins and 3% salidroside.
- Bovine colostrum - standardized to >60% IgG (immunoglobulin G) content.
- Sulforaphane - broccoli sprout extract standardized to 4 mg of sulforaphane.
2. Proper doses and the advantage of single-ingredient products
The mere presence of an active ingredient at a given standardization is not enough. What matters is the therapeutic dose, consistent with clinical trials. Many supplements contain ingredients in amounts below the threshold of biological effectiveness. This often results from attempts to „pack” many substances into a single capsule for purely marketing reasons. Even if a supplement blend that acts as a „silver bullet” for a given condition could be found, it cannot physically be packed into a single capsule.
For magnesium, for example, the effective supplemental dose is usually 300-400 mg of magnesium ions per day. Multi-mineral or multivitamin products often contain only 50-100 mg, which does not even reach a sub-clinical dose.
It is also worth remembering that the mass of the whole salt - for example magnesium citrate or a chelate such as magnesium glycinate - is much higher than the mass of magnesium ions inside it, so in three average large capsules you can obtain about 480-530 mg of magnesium ions (depending on the chemical form).
The same applies to Omega-3 oils - the cardioprotective effect is observed at an intake of about 1-2 g of EPA+DHA per day, not 200-500 mg in a single serving. The same is true for herbal extracts - for example, with red sage (Salvia miltiorrhiza) supplementation, a blood-pressure lowering effect is observed at doses of 20-40 mg of tanshinone IIA, one of the main active compounds of the plant. With a 2% standardization assumption, this corresponds to 1000-2000 mg of red sage extract per day.
It is therefore better to use single, well-chosen ingredients in effective doses than multi-ingredient mixtures of unknown effectiveness. This approach is consistent with pharmacology, where what counts is a precise dose and a clearly defined mechanism of action.
3. The right form of supplement - bioavailability matters
The form in which an ingredient occurs directly influences its absorption and biological effectiveness.
We already know that standardized extracts have a significant advantage over powders made from roots, leaves, or other plant parts without a defined amount of the main active substances. It is also worth remembering that the preparation method, e.g. DER 10:1, does not say much either and is not a true marker of product quality.
In the case of minerals or specific compounds, the chemical form is what matters most, because different groups of substances are absorbed differently. Magnesium and zinc are good examples. Citrate or diglycinate forms of these elements are characterized by high bioavailability and good dissociation in the human body, in contrast to oxide (often present in cheaper supplements) or zinc picolinate, which is absorbed efficiently but is harder for cells to use.
It is similar when choosing products containing B-group vitamins. Their synthetic forms do not produce the same therapeutic effects as natural equivalents (active forms) - starting from the degree of absorption from the gastrointestinal tract, through effectiveness, to metabolism. The key difference is that active forms bypass the unnatural step of metabolic conversion, often work at lower doses than synthetic forms, and there are no additional problems with their elimination from the body when they are not properly metabolized.
For example, the best-known counterpart of folate is folic acid - a substance that does not occur in nature. With certain exceptions (well-described in the scientific literature), 5-MTHF (the active form of folate) is usually a better choice. The same applies to the other B-group vitamins, including vitamin B6 (pyridoxine), where its hydrochloride is not as effective as the active coenzyme form - P-5-P (pyridoxal 5-phosphate).
4. No fillers or unnecessary additives
A high-quality supplement should contain a minimal or zero amount of so-called „excipients”. In practice, however, many products contain artificial dyes, titanium dioxide, magnesium stearate (in large amounts), silica, microcrystalline cellulose, sweeteners, and flavorings. These are technological substances added to increase capsule volume, improve manufacturing properties, and stabilize the product.
In most cases they are considered safe when consumed in small amounts, although high-quality scientific evidence (especially for titanium dioxide) of their long-term, harmless impact on health is lacking. They may also affect the bioavailability of active ingredients on their own, and in sensitive individuals they can cause gastrointestinal complaints.
Exceptions that stabilize the raw material in a supplement include certain types of natural fiber such as inulin - although these too (despite trace amounts) may be a contraindication for people with intestinal problems such as IBS. A good supplement should have the simplest possible composition - the shorter the list of excipients, the better. If there are none and the manufacturing technology can protect the product from moisture and microorganisms in another way, that is excellent.
5. The problem of price and availability
The final obstacle to effective supplementation is often the price of the product and the daily dose recommended by the manufacturer. A flagship example is sulforaphane. In most human studies, the effective doses of this ingredient (for popular indications) ranged from 10-40 mg of pure sulforaphane per day. Easily available supplements typically deliver only 200-400 mcg. That is often 50-100 times less. This is why combining high-quality scientific evidence with the commercial side is so important.
Summary - practical selection rules
When choosing a supplement, it is worth following the iron-clad scientific criteria below, rather than the manufacturer's marketing claims or the look of the packaging. To get the best results, a product should show characteristics such as:
- Standardization to a defined content of the active ingredient
- A clinically justified dose
- An appropriate chemical form and manufacturing technology
- A simple composition, with no unnecessary additives
- Single ingredients instead of mixtures