Homotaurine

Homotaurine, also known as tramiprosate or 3-APS (3-amino-1-propanesulfonic acid) is a naturally occurring compound found in seaweed, closely related to the amino acid taurine (or 2-aminoethanesulfonic acid in chemical nomenclature), which is present in abundance in mammalian tissue as well as in algae. While taurine itself is estimated to make up to 0.1% of total human body weight, it is believed to be extensively synthesized in the liver, and is only considered a conditionally essential amino acid (one that might require auxillary supplementation in times of prolonged stress, illness, intense resistance training, etc.).

Recently, however, multiple studies have reported a finding of greater significance when it comes to its implications: taurine abundance has been found to decline with aging, a trend observed consistently across multiple species (i.e., serum taurine concentrations in elderly humans decreased by more than 80% relative to its levels in young individuals, with lower taurine levels being linked to greater incidence of age-related medical conditions). Furthermore, taurine deficiency has been implicated in several neurological conditions, such as Alzheimer’s, Parkinson’s, certain types of epilepsy, and in the damage of retinal neurons. Studies in evolutionarily divergent species showed that stabilizing taurine levels achieved by supplementation contributed to increased life expectancy and / or healthy lifespan, possibly due to multiple mechanisms that amount to enhanced DNA protection and reduced inflammation.

While there have been identifed metabolic pathways via which taurine is synthesized within the hippocampus and cerebellum, the exgenous molecule appears to be unable to cross the blood-brain barrier, which severely limits the effects of taurine supplemenation on the central nervous system.

Homotaurine, on the other hand does not share that disadvantage, in fact, in vitro studies found it superior to memantine in terms of blood brain barrier permeability, which confirmed its suspected potential as a CNS-targeted agent.

While homotaurine failed to reach the III phase study target as a candidate drug for Alzheimer’s, a post-hoc hanalysis revealed that it was able to exert some significant and positive effects such as a reduction in hippocampal volume loss, lower decline in memory function as well as a reduction in overall cognitive decline. These results support the potential role of homotaurine in prevention of Alzheimer’s.

Homotaurine is thought to bind to soluble amyloid-beta peptides, preventing their aggregation into toxic oligomers and plaques, and reduce neuroinflammation and oxidative stress, both of which are implicated in neurodegenerative diseases. It is also believed to be neuroprotective against glutamate excitotixicity.

In a 2021 study, its anti-inflammatory action limited the spreading of T cell autoreactivity, inhibiting the disease progress in multiple scleroris (MS) model in mice. Homotaurine is also being studied as a possible treatment of cerebral amyloid angiopathy.

Animals studies suggest that homotaurine might be as effective as acaprosate, a closely related compound and drug used for alcohol cravings reduction in recovering addicts – it was able to reduce ethanol intake and preference in a dose-dependent manner. It delayed or suppressed ethanol-stimulated increases in nucleus accumbens dopamine release, suggesting that it may reduce alohol intake by interfering with its ability to produce rewarding effects.

It has also been shown to act as a GABA-A receptor agonist, which could contribute in its potential anxiolytic and neuroprotective effects.

According to a recent study, it also appears to improve cholinergic transmission.

In patients with glaucoma, treatment with a supplement which includes homotaurine, carnosine, forskolin, vitamins B1, B2, and B6, folic acid, and magnesium has been shown to be able to delay the disease progression and improve visual function after two and six months of daily intake.

Benefits of taking homotaurine

• delayed cognitive aging;
• neuroprotective effects;
• reduced alcohol cravings;
• improved episodic memory;
• might help prevent neurodegenerative diseases;
• potential aid in the treatment of glaucoma.

Side effects

• diarrhea;
• nausea;
• vomiting;
• dizziness;
• headaches.

Dosage

In existing human trials, its paricipants ingested homotaurine orally in two 50 – 150 mg doses per day (in the morning and in the evening, to be taken with meals). Homotaurine is believed to be safe and generally well tolerated within the above dose range.