Analysis of DHEA in the Laboratory

DHEA Laboratory Analysis

Dietary supplements that are critically important to the consumer are manufactured and sold in the general absence of self-regulation or government controls over their quality.
One product is DHEA that plays a role in the body's defense against many age-related and other disorders: e.g., heart disease, cancer, autoimmunity, chronic fatigue syndrome, esteoporosis, rheumatoid arthritis, obesity and possibily AIDS.
DHEA also acts as a neurosteroid, antioxidant and antidepressant.
Its importance as a dietary supplement increases with a person's age after the mid-20's, because at that point the ability to produce DHEA begins to diminish steadily.

Expert medical advice on dosages focuses on DHEA replacement, meaning that the daily recommended amounts should be calculated to bring a patient's blood level of this hormone up to that of a 25-year old. Deficiencies can range from 10 to 50 milligrans, depending on body size and age. Consumers therefore need to know the exact amount of DHEA in a capsule or the concentration in a dropper bottle for whatever brand they use.

Commericial DHEA is a semisynthetic hormone, which means that chemists make it in the laboratory from a precursor substance in a series of chemical reactions. One such precursor is diosgenin from yams; another is cholesterol. Unfortunately, impurities end up in the final DHEA product from the precursor and from the synthesis of side products during these reactions. Nevertheless, it is cheaper to make DHEA from such precursors than to isolate it in pure form from any natural source. The quality of a DHEA product, therefore, depends on how much of the impurities are removed after its synthesis.

The best products should have NO impurities for two main reasons:

DHEA concentrations cannot be calculated accurately in the presence of an unknown amount of impurities.
The precursors and side-products of DHEA synthesis are steroids that affect the health of the consumer in unknown ways.

For this initial study, I compared the quality of six commercial brands of DHEA by two different analytical methods. The six brands, in alphabetical order, are distributed by:
Discovery Experimental and Development, Inc.(DE),
Life Enhancement (LE),
LifeLink (LL),
Only Natural (ON),
Sabinsa (Sa),
and TriMedica (TM).

Three products (DE, Sa,LL) were isolated powders of DHEA, and three products, (LE, ON, TM) were capsules containing DHEA mixed with fillers.

Method One

Each product was first dissolved in 100% methyl alcohol (meOH) at a concentration of 28.8 mg/mL. It was immediately apparent that the three capsule products contained substances that would NOT dissolve in this solvent, while the three isolated powers dissolved completely.

Furthermore, undissolved particles in two of the products, (LE,TM) could be removed by high-speed centriguation, but the third (ON) contained particles so fine that could not be pelleted out of the solution. All solutions were analyzed directly by scanning UV spectroscopy to compare their absorption spectra with that of a standard DHEA sample (Sigma Chemical Co.).

Results from Method One

The results showed that only two products (DE, SA) gave spectra that matched the standard (peaks at 214 and 294 nanometers), without any apparent contaminant. However, the main absorption band at 214 nanometers was slightly lower in the SA sample, indicating a smaller amount of DHEA than expected. The third isolated powder also showed a lower absorption at this absorption band, as well as an additional, non-DHEA, peak at about 235 nanometers. All three capsule products showed lower absorption at 214 nm as well as other, non-DHEA, peaks. One of the non-DHEA peaks in ON and LE may be from Vitamin C; others are unidentifiable but resemble peaks from other steroids. The expected amounts of DHEA in each capsule cannot be calculated accurately from these data, but they are far from pure according to the label on each product. The contents of a capsule from ON weighed 403 mg, of which 50 mg are supposed to be "99%" DHEA and 60 mg are supposed to be vitamin C; each capsule also contains 30 I.U. of vitamin E. A capsule from LE weighed 466 mg, which is labeled to contain 25 mg DHEA, 25 mg vitamin C, and an unkonwn amount of "rice." And a capsule from TM, weighing 381 mg, supposedly contained 5 mg of "99.5%" pure DHEA in a "hpoallergenic rice starch base."

Method Two

A known amount of each sample was dissolved in 1 ml of 70% MeOH for analysis by high-performance liquid chromatography (HPLC). Samples were applied directly to HPLC, with elution in 70% acetonitrile and detection at 214 nm. The amount in each sample was calculated from a calibration curse of know concentrations of a DHEA standard. The final data are expressed as a percentage of what would have been expected if the sample had been 100% pure DHEA. In addition to analyzing the commercial samples, I also examined the mother liquor (i.e. dissolved substances) that was left over from recrystallizing DHEA from the product distributed by LL. The aim of this analysis was to find out how many kinds of impurities are contained in this brand.

Results from Method Two

The only sample whose actual amount, within experiment error (ca 1%), matched what was expected was DE - Discovery Experiment & Development, Inc. Both of the other isolated powders were about 89% of what would have been expected. This result corroborates the previous analysis that showed LL and Sa to have lower amounts of DHEA based just on a visual inspection of their UV absorption spectra. This was more obvious for LL, which had a substantial non-DHEA absorption peak. The small amounts of DHEA in the capsule products led to a relatively high experimental error (more than 10%) for these samples, which precluded any accurate assessment of the purity of their DHEA. HPLC of the LL mother liquor showed at least six major substances and several minor ones of a steroidal nature other than DHEA in this sample.

Commentary

Although the purpose of this study is to provide information for personal evaluation of products by the public, and not to endorse any particular product, I think that the data clearly show the product distributed by DE - Discovery Experiment & Development, Inc. to be cleaner in every respect than any other brand. Sa also looks good based on its UV absorption spectrum, but its lower than expected concentration means that there is a likelihood that this brand contains non-DHEA steroids like those from LL. This possibility should be evaluated by a recrystallization experiment like that conducted on the LL product. A consumer who is concerned about ingesting potentially harmful steroidal impurities should demand cleaner products than SA and LL have to offer. It is more difficult to evaluate the purity of DHEA in LE, ON and TM because their capsules have so little DHEA in the first place. Moreover, two of these brands (ON,TM) illustrate the prevalence of misleading labeling on DHEA products. They claim 99% or 99.5% purity in capsules that are labeled as 50 mg (12.4%, ON) and 25 mg (1.3%,TM) DHEA. These capsules are obviously not pure anything, much less DHEA. So what does the "purity" claim mean? There is no way to tell.

Dr. W. Dennis Clark, Associate Professor of Botany, Arizona State University