Different Forms of Lipoic Acid: What You Need to Know

Lipoic Acid

Lipoic acid, also known as Alpha-Lipoic acid, (ALA, Thioctic acid) is similar in structure and function to a vitamin. ALA has been widely explored as a beneficial nutrient for a variety of bodily functions involving the nervous, cardiovascular, immune and detoxification systems.*

Alpha-Lipoic Acid Occurs In Different Forms

Alpha-Lipoic acid consists of a 50/50 mixture of the R-(natural) and S-(unnatural) enantiomers that are mirror images of each other and is called a ‘racemic’ mixture. It is the most widely available commercial form of alpha lipoic acid.

While it may come as a surprise, the vast majority of Alpha-Lipoic acid products on the market also contain the unnatural S form of Lipoic acid that is not found anywhere in nature and did not even exist until it was chemically synthesized in 1952. There is evidence that the two enantiomers of Alpha-Lipoic acid have different biological activities.

Much of the research over the past 30 years has been done with racemic Alpha-Lipoic acid because the R form was not commercially available. This was due to its instability and tendency to polymerize once isolated from the S form, and due to the challenges of delivering the R form to the body in bio-available dosage forms compared to racemic Alpha-Lipoic acid.

S-Lipoic Acid

S-Lipoic Acid (The S (-) enantiomer) is not found in nature. S-Lipoic acid (SLA) is a by-product from chemical synthesis of racemic Alpha-Lipoic acid and may inhibit the most essential properties of the R form, including interactions with proteins, enzymes and genes.

R-Lipoic Acid

R-Lipoic Acid (the R (+) enantiomer) is the form of lipoic acid that occurs naturally in plants, animals and the human body and is responsible for the specific beneficial effects of Alpha-Lipoic acid. R-lipoic acid (RLA) is the only form that functions as a co-factor for mitochondrial enzymes involved in energy production.

Stability, and Absorption

R-Lipoic acid, despite all its potential health benefits, when separated from the S form, is physically unstable. R-Lipoic acid deteriorates relatively rapidly at slightly above room temperature into a sticky insoluble polymer. Moisture and the heat of friction during encapsulation and the compression of tablets are sufficient to initiate this process. Even a partially polymerized product can pose significant problems in the manufacturing and stability of a dosage form. The polymer reduces the dissolution of tablets or capsules, reduces GI absorption and lowers the bio-availability to less than 10%.

Numerous factors affect absorption. Racemic-ALA has poor solubility and absorption from the GI tract, as 20- 30% reaches the plasma vs. an intravenous dose. R-Lipoic acid is even less soluble and polymerizes on contact with the low pH environment of the stomach. Without special processing, R-Lipoic acid is highly unstable and difficult to absorb.

Get the Benefits You Pay For

The good news is that GeroNova has developed a way to stabilize R-Lipoic acid and make it much more bio-available – this means more of it is absorbed. In fact, a human trial found that people who took Bio-Enhanced® R-Lipoic Acid achieved blood concentrations of Lipoic acid a full 40 times higher than those who took unstabilized RLA.**

Maximum Absorption in nanograms/mL


GeroNova Research has worked on the large-scale manufacturing of R-Lipoic acid since 2002 and has gained considerable experience in producing and processing it into Bio-Enhanced® R-Lipoic Acid – stabilized and highly absorbable products for the nutritional supplement market.

What to Look for in a Lipoic Acid Supplement

GeroNova’s R-lipoic acid supplements:

  • Contain natural R-Lipoic acid, as either Bio-Enhanced® R-Lipoic Acid or as a stabilized Liquid R-Lipoic Acid.
  • Are formulated using a unique stabilization process that ensures maximum stability.
  • Are designed for superior absorption. Pharmacokinetic data has shown that our Bio-Enhanced® R-Lipoic Acid has 40x the absorption rate of unstabilized RLA.

1 Bio-Enhanced® R-Lipoic Acid capsule = 40 Unstabilized R-Lipoic Acid capsules


Learn more about GeroNova’s R-Lipoic Acid supplements or purchase them now.

*This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
**Based on pharmacokinetic data performed using GeroNova’s Na-RALA in solution.