Does the combination of glycine and NAC (GlyNAC) help against ageing?
Early studies in older adults show that GlyNAC can simultaneously improve multiple signs of ageing, from muscle strength and walking ability to inflammation and energy metabolism. The results are positive, although they still come from small studies.
GlyNAC is a combination of two amino acids, glycine and N-acetylcysteine, which together stimulate the production of glutathione. Glutathione is a powerful antioxidant that protects cells from damage. As we age, glutathione levels decline, and that decline is associated with greater oxidative stress and poorer cell function. In older adults with excellent physical and mental health, higher glutathione levels have been measured, although it has not been proven that glutathione is the cause of this.
In a placebo-controlled study of 24 older adults, participants received GlyNAC or a placebo for 16 weeks. The GlyNAC group showed improvements on multiple fronts: the glutathione deficit decreased, oxidative stress fell, mitochondrial function (the cell's energy system) improved, inflammation markers declined and insulin resistance also decreased. In addition, walking speed and muscle strength increased, and participants scored better on a 6-minute walk test. The placebo group showed none of these changes.
A smaller open-label pilot study, without a control group, followed 8 older adults for 24 weeks. In that study too, glutathione levels, cognition, muscle strength and body composition all improved. Notably, after stopping GlyNAC for 12 weeks, most of the benefits returned to baseline. This suggests that continuous use is needed to maintain the effect.
GlyNAC was well tolerated in both studies. Over 16 to 24 weeks, none of the participants reported serious side effects. The studies are small, however, and a review article from the same research group that conducted the trials itself emphasises that larger, independent studies are needed for real confirmation. That larger confirmation is not yet available.
The strongest evidence comes from one placebo-controlled study of 24 older adults and one small pilot study of 8 participants. The review articles are partly from the same research group that conducted the trials, which carries a risk of overly favourable interpretation. Larger, independent studies are still lacking. The findings are promising, but the evidence base remains narrow.
Does stem cell therapy work against ageing in humans?
For physical frailty in older adults there is one positive study in people. For all other ageing-related applications it is too early for firm conclusions. Stem cell therapy cannot yet be considered a proven anti-ageing treatment.
What does a NAD supplement do, and does it work in people?
NAD supplements demonstrably raise NAD levels in your blood, but whether you actually benefit from that remains uncertain. If you want to try them, keep your expectations realistic and choose a dose with the best available evidence behind it.
At what age does taking NAD+ supplements make sense?
There is no established age at which NAD+ supplementation becomes worthwhile. Studies focus on middle-aged and older adults, but a measurable functional benefit in humans has not yet been demonstrated.
Does taking resveratrol make sense as an anti-ageing supplement?
Research shows that resveratrol does not activate the mechanism behind the anti-ageing theory in people. There are small indications of benefit for muscle function in people who exercise, though that evidence is thin.
Does quercetin work against ageing and inflammation?
Quercetin shows promising signals in the laboratory and in animals, but in humans there is not yet solid evidence. Taking supplements on the basis of this early-stage research gets too far ahead of the science.
Do GLP-1 medications (such as Ozempic) help you age more healthily?
For people with cardiovascular disease, kidney disease, or fatty liver disease, GLP-1 medications offer proven benefits that are also relevant at older ages. As an anti-ageing intervention in healthy people, their use is not yet supported by evidence.