Beyond a highly uneventful Calcium-D-Glucarate page (there's really nothing remarkable about this "detoxifying agent"), the relevant pages this time around are all based upon sports performance or body composition.
The major update this week is baking soda, more formally known as sodium bicarbonate. In a very general sense, it is comparable to beta-alanine in regards to both mechanisms and overall effect size, but outperforms it on a few parameters:
On price and availability; baking soda is available everywhere
Can reduce the acidity in the blood, whereas beta-alanine only reduces intramuscular acidity
However, baking soda is worse than beta-alanine on a few parameters as well:
Simply ingesting baking soda without much thought would result in a very high dietary sodium load (above 5 g). Although this can be attenuated greatly by taking the lowest effective dose and cutting some of the baking soda with potassium bicarbonate, there will always be a sodium load that needs to be factored into the diet and will contraindicate baking soda supplementation for those with salt-sensitive hypertension
There are well-known intestinal side effects if too much baking soda is taken rapidly. Although there does appear to be a dosing protocol to greatly minimize side effects, this is somewhat inconvenient and requires good timing and adherence to the protocol
In general, there are many more precautions that need to be taken (from both a health and an intestinal perspective) when using bicarbonate supplementation than with beta-alanine
Finally, the limited studies into bicarbonate and beta-alanine as a combination do not find clear additive benefits. If one is already taking beta-alanine, there is likely no need to add in bicarbonate.
Overall, sodium bicarbonate does appear to work, and can potentially be a cheap and widely available ergogenic supplement; yet it requires caution in approaching supplementation.
Beyond bicarbonate, we tackle the branched chain amino acids, and establish an individual page for all three of them: leucine, isoleucine, and valine. Most information is interspersed within the pages (we attempted to collect it all on the BCAA page, and then opted for a cleaner read on the individual amino acid pages).
Leucine seems to be the standard muscle-building agent, and consuming leucine (either via food, BCAAs, or individual leucine supplementation) does promote muscle protein synthesis; this appears to be more significant in persons with lower dietary protein intake.
Isoleucine seems to be a hypoglycemic agent. It is not as effective as leucine at stimulating muscle protein synthesis, but causes dose-dependent increases in glucose uptake in skeletal muscle. The conversion of glucose to energy is enhanced, but glycogen synthesis is not; thus isoleucine may make a nice pre-workout when taken with carbohydrates. It works via a relatively novel mechanism (shared by leucine, but not by many other supplements) and might work nicely with other hypoglycemic agents such as AMPK activators (like berberine) or muscle contraction itself.
Valine, due to being quite understudied, is actually very unremarkable and does not appear to have any known unique properties.
Finally, the metabolite of leucine known as HMB (beta-hydroxy-methyl-butyrate) has been updated. HMB is less effective than leucine at promoting muscle protein synthesis, yet much more potent at inhibiting muscle protein breakdown (on a gram-per-gram basis). However, the human studies using HMB are all structured to measure the muscle-protein-synthesis effects of HMB, and due to this they are quite lackluster in their results. Preliminary evidence in clinical settings (not in athletes) does suggest a relevant anti-catabolic effect, but although it should work, this is not yet demonstrated in the population most likely to supplement HMB.
HMB is technically a potent anti-catabolic but requires further testing in athletes to confirm.