Antioxidant

Alpha-lipoic acid (ALA) is a sulfur-containing mitochondrial cofactor, used as a racemic drug for the pain and pins-and-needles of diabetic nerve damage. Meta-analyses of randomized trials support it for diabetic neuropathy symptoms. Its effects on weight and blood sugar are real but small. Supplements come as the racemic mix, as pure R-ALA, or as Na-R-ALA, a sodium salt of R-ALA made to absorb better.

Astaxanthin is the red carotenoid that colors salmon, shrimp and crayfish. Supplements usually contain an extract of the microalga Haematococcus pluvialis. It is sold as a very strong antioxidant, and pooled trials do show a modest fall in the lipid-peroxidation marker malondialdehyde. The effects that matter clinically are small or inconsistent. Meta-analyses find a little more skin moisture and elasticity but no change in wrinkle depth, no reliable effect on blood lipids or blood pressure in the general population, and no gain in endurance performance. Its safety at up to 8 mg a day is well studied.

Coenzyme Q10 (CoQ10) is part of the mitochondrial energy chain and one of the most widely used supplements. Its best evidence is in chronic heart failure. There, the Q-SYMBIO trial found fewer major cardiovascular events and deaths over two years. For statin muscle pain, migraine and blood pressure, the results are mixed or modest.

Elamipretide (SS-31) is a four-amino-acid peptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, a membrane lipid that mitochondria need to form their inner folds (cristae). In September 2025 the US FDA gave it accelerated approval, as Forzinity, to improve muscle strength in Barth syndrome. Its randomized trials have mostly missed their primary endpoints, in Barth syndrome, mitochondrial myopathy, heart attack and macular degeneration. The positive signals come mainly from open-label extensions and secondary measures.

Epitalon is a four-amino-acid peptide, Ala-Glu-Asp-Gly, designed in St Petersburg from the amino acid composition of Epithalamin — a bovine pineal gland extract — and later shown to be present in that extract. It is the peptide behind the claim that you can lengthen your telomeres, and that claim does rest on real experiments: Khavinson's group reported telomerase activation and telomere elongation in human fetal fibroblasts in 2003, and an independent laboratory reproduced dose-dependent telomere lengthening in human cell lines in 2025. What the marketing tends to blur is that the long-term human trials — the ones showing lower mortality in elderly cardiac patients — used Epithalamin, the extract, not the synthetic tetrapeptide, and that almost the entire literature on both comes from one research group.

Indolepropionamide (IPAM) is the amide of indole-3-propionic acid, a small indole related in structure to melatonin. Its inventors made it to get an antioxidant indole into the brain more easily, then reported finding a matching trace compound in rat brain. In their one published study it protected isolated rodent brain mitochondria at 10 nM and more than tripled the lifespan of a rotifer. That 2010 paper and the same authors' abandoned patent application are the whole evidence base: no other laboratory has published an experiment with IPAM, and it has never been tested in a mammalian disease model or in people.

Myricetin is a flavonol found in berries, vegetables, tea and wine. It is studied for glucose regulation, mitochondrial function and neuroprotection, but the evidence for the isolated molecule remains preclinical. Small human trials have used blends containing myricetin; none separates its contribution from the other ingredients.

N-acetylcysteine (NAC) is an acetylated form of the amino acid cysteine. It is the standard antidote for acetaminophen (acetaminophen) overdose, a mucolytic that modestly cuts flare-ups of COPD and chronic bronchitis, and a widely sold supplement. Its psychiatric uses rest on a mixed record: a positive trial in adolescents who used cannabis failed to repeat in adults, and large trials found no benefit for idiopathic pulmonary fibrosis or for protecting the kidneys during angiography. Only about a tenth of an oral dose reaches the blood.

Fish oil supplies the two long-chain marine omega-3 fatty acids EPA and DHA. Its best-established effect is on triglycerides: high-quality evidence puts the reduction at roughly 15%, dose-dependently, and prescription formulations at 4 g a day are licensed drugs for severe hypertriglyceridemia. What it does not do is what most people buy it for. A Cochrane review of 79 trials in 112,059 people found little or no effect of EPA and DHA on all-cause mortality, cardiovascular mortality or cardiovascular events, and the three largest modern supplement trials — VITAL, ASCEND and STRENGTH — were all null.

PQQ (pyrroloquinoline quinone) is a redox cofactor first found in bacteria. Mammals do not make it but take in trace amounts from food. In cells it switches on mitochondrial biogenesis through the PGC-1α pathway. In humans, small 12-week trials of PQQ disodium salt reported better memory and attention scores.

S-acetylglutathione (SAG) is glutathione with an acetyl group attached to its sulfur. It is sold as a supplement on the idea that it survives digestion better than plain glutathione. In the only human pharmacokinetic study, a 3.5 g dose produced no detectable SAG in the blood, and the rise in blood glutathione looked much like the rise after plain glutathione. Every other result comes from cells, animals, or one small open-label trial of a multi-ingredient product. EFSA judged it safe as a food at up to 300 mg a day for adults.

Ubiquinol is the reduced, electron-carrying form of coenzyme-q10, sold as a better-absorbed version. One small study found it raised blood CoQ10 more than ubiquinone. A randomized crossover study in older adults found no significant difference. Its most notable trial is in multiple-system atrophy, where high doses improved a motor score.

Urolithin A is not something plants make. It is what some people's gut bacteria make out of the ellagitannins in pomegranates, walnuts and berries, and only about one person in seven produces enough of it to show up in blood without a supplement. Synthetic urolithin A was identified as the first natural compound to induce mitophagy — the pathway that clears worn-out mitochondria. Four randomized trials have now tested it in people. The two muscle trials both missed their primary endpoint and both reported gains on secondary measures; a 2025 trial found changes in T-cell composition and metabolism; and a trial in trained runners found no performance benefit.